Class 8 Geography

WBBSE Chapter 7 Human Activities And Environmental Degradation Synopsis

The physical and biotic processes of nature have a self-regulatory style of working. Any change or damage caused by them to the environment is naturally restored, compensated, or adjusted. This is called a homeostatic mechanism.

The Industrial Revolution in Europe in the eighteenth century was a giant step in the advancement of human civilization.

Environmental degradation means the overall lowering of environmental qualities because of adverse changes brought about by natural processes and human activities.

The main causes of environmental degradation are soil erosion, deforestation, floods, desertification, and loss of biodiversity.

Read and Learn More WBBSE Solutions For Class 8 Geography

The degradation of any component of the environment caused by natural processes or human activities is called Environmental pollution.

Bhopal Gas Tragedy occurred in December 1984 due to the leakage of Methyl Isocyanate gas from a plant of the Union Carbide Factory.

Consequences of environmental degradation

The Chornobyl disaster occurred in April 1986 in a nuclear reactor plant in Chornobyl.

The Fukushima Daiichi accident occurred in March 2011 in a nuclear power plant in Fukushima Daiichi.

Sustainable development refers to development aimed at the optimum use of natural resources in the present scenario so that development can take place without the environment being hampered and also preserving the reserves of nature and the potential of human society to develop, for future use.

Lack of education and poverty are the two main indirect causes of environmental degradation.

Earth Summit or Rio Summit was another name for the United Nations Conference on Environment and Development. It was held in Rio de Janeiro, Brazil, from 3 June to 14 June 1992. 178 nations and more than 30 thousand people participated in this conference.

Ganga Action Plan (GAP) has been taken up to make the Ganga pollution-free and maintain the ecological balance. This project was officially initiated in Varanasi on January 14, 1986.

G20 or Group of 20 is an international association formed by 20 countries. This group came into being in 1999 and now has a total membership of 20 nations (2017). It was created primarily to develop trade relations among its member nations.

The full form of WHO is the World Health Organisation. Its headquarters is in Geneva Switzerland. As an agency of the United Nations, WHO is responsible for issues on public health around the world. It plays an important role in the eradication of diseases.

The Chipko movement was started in 1973 in the Garhwal region of Uttarakhand to protect trees. The name of the movement came from the Hindi word ‘Chipko meaning ‘to embrace’, as the villagers hugged the trees and prevented the contractors from felling them.

The Green Revolution in India has contributed much to improving crop production and the overall condition of agriculture in the country. But it also exerted some negative impacts such as degradation of soil fertility, change in biodiversity genetic modification of the seeds, etc.

We, the students, can contribute much to keeping our environment clean by reducing waste, planting saplings, organizing seminars and rallies, etc.

WBBSE Chapter 7 Topic A Consequences And Control Of Environmental Degradation Analytical Type Questions

Question 1. How has the evolution of human civilization affected the environment?
Answer:

Evolution Of Human Civilisation Affected The Environment:-

Based on primary means of subsistence, human beings can be said to have evolved through different phases. These are divided as- hunter-gatherer, pastoral, agrarian, and industrial phases.

Hunter-gatherer phase:

In this phase, human beings used to sustain themselves by gathering fruits and hunting animals in the forests. They did not cause any change or damage to the surrounding environment.

Pastoral phase:

With the discovery of fire and awareness of its use, the evolution of civilization took an important turn, which started with the domestication and rearing of animals. Primarily the pastoralists were nomadic.

They reared livestock for milk and meat, but slowly they started exploiting the environment.

Agrarian phase:

Taking up the practice of farming to obtain food was a notable stage in the evolution of mankind. This resulted in the clearing of forests for agricultural lands and settlements.

The increase in population created an increasing demand for farmlands and slowly human beings began to modify the environment.

Control measures for environmental degradation

Industrial phase:

The Industrial Revolution from the 1760s marked the beginning of a rapid change in the environment as well as an increase in population.

Demand for land for agriculture, industry, and townships increased and human beings started the indiscriminate exploitation of natural resources.

Human activities, in the name of development, are damaging the environment. which cannot be repaired again. The effect of this can be felt by everyone at present.

Question 2. Classify different kinds of human activities according to their nature and enlist them below. How do you think, these activities influence the human environment?
Answer:

Different kinds of human activities according to their nature and their influence on the environment are listed below-

 

Question 3. Discuss the reasons for environmental degradation.
Answer:

Reasons For Environmental Degradation:-

Environmental degradation occurs due to the two following reasons

1. Natural events and
2. Human activities.

1. Natural events:

Different natural events are often responsible for the degradation of the environment.

These include

1. Volcanic activities,
2. Floods,
3. Droughts,
4. Earthquakes,
5. Landslides,
6. Tsunamis,
7. Forest fires,
8. Acid rain,
9. Formation of methane gas,
10. Excessive snowfall snowstorms,
11. Flash floods,
12. Cyclones, etc.

These pollute the environment and lead to its degradation. Normal life cycles of human beings, animals, plants, and microbes are disrupted by this.

Human activities:

Some of the primary human activities that cause environmental degradation are-

1. Excessive use of fossil fuels,
2. Population explosion,
3. Unplanned urbanization,
4. Unplanned farming with the help of machinery,
5. Testing of weapons and war equipment,
6. Excessive use of chemical fertilizers and pesticides,
7. Dumping of industrial wastes into lakes, rivers, and seas,
8. Misuse of natural resources,
9. Deforestation,
10. Extraction of excessive mineral resources,
11. Construction of dams on rivers,
12. Indiscriminate use of plastic and other non-biodegradable materials,
13. Establishments of nuclear power plants, etc. Landslide floods, earthquakes, droughts, etc., Are nowadays considered to be greatly related to human activities.

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Human activities causing environmental degradation

Question 4. What are the environmental impacts of technology-dependent activities?
Answer:

Environmental Impacts Of Technology-Dependent Activities:-

Technology has made our lives easier, but it also has several adverse effects on the environment. Some of these effects are as follows

1. The burning of coal and mineral oil for the production of thermal power releases SO2, CO2, and other harmful gases into the atmosphere in large amounts. This is one of the main causes of air pollution.
2. The construction of roads also has the same adverse effect on the atmosphere.
3. The construction of dams and hydel power stations is responsible for the destruction of the ecological balance at the construction site.
4. Smoke and untreated water discharged from factories are responsible for polluting air and water.
5. Pollution occurs from almost all kinds of activities related to infrastructural development.

Question 5. Discuss the effects of environmental degradation.
Answer:

Effects Of Environmental Degradation:-

The different effects of environmental degradation are as follows-

1. Pollution:

One of the main effects of environmental degradation is pollution.

This mainly includes

1. Toxic gases released by vehicles running on fossil fuels (petrol, diesel), nuclear power plants, etc., into the atmosphere and render it toxic. for life on earth. This causes air pollution.
2. Dumping of industrial wastes in waterbodies, oil spills in oceans, etc., thus renders the water unsuitable. This causes water pollution.
3. Use of chemical fertilizers, pesticides, excessive irrigation, etc., which wash away the top layer of the soil and thus render it unfit for plant and crop growth, causing soil pollution.

2. Floods and droughts:

Floods and droughts are the results of climatic degradation. Excessive deforestation is one of the main reasons for drought. On the other hand, deforestation also causes flash floods in hilly areas as there is no vegetation cover to absorb the surface runoff during heavy rainfall.

Besides, soil erosion causes the deposition of too much silt in the river beds, causing them to overflow their banks and flood the surrounding areas.

3. Global warming and climatic change:

Practices such as excessive use of fossil fuels and deforestation are increasing the average temperature of the earth. This in turn, is causing the polar ice caps to melt, causing a significant rise in the sea level.

4. Depletion of natural resources:

As the environment gets degraded over time, various mineral resources, forests, drinking water, fertile soil, etc., are slowly depleting from the surface of the earth.

5. Loss of biodiversity:

Several plant and animal species that have evolved on the surface of the earth over thousands of years have been wiped out in the last few centuries. This steady loss in biodiversity is aggravating the rate of degradation of the environment.

6. Earthquakes:

Terrace farming, deforestation construction of roads in hilly areas, extraction of minerals, unregulated use of groundwater, etc., are all factors that induce earthquakes. Earthquakes occurring in an area degrade the physical and human environment of the area.

7. Diseases:

As the global environment is degrading, human health is getting affected as well. As a result, the rate of occurrence of diseases such as cancer, tuberculosis, malaria, encephalitis, and various lung and heart diseases is rapidly increasing.

8. Chemical Inadequate disaster:

Infrastructure, lack of skilled laborers, upgraded technology not being used, and carelessness on the part of the workers can cause fatal chemical disasters at factories.

9. Inflation and disequilibrium between demand and supply:

Inflation in society is an economic problem. Poor economic decisions, business houses going bankrupt, and imports exceeding the exports of a country all lead to inflation. These also disrupt the equilibrium between demand and supply.

Effects of pollution on the environment

Question 6. Discuss the ways of conserving the environment. Or, How can degradation be controlled?
Answer:

Ways Of Conserving The Environment:-

Environmentalists have suggested several steps to control environmental degradation.

Few of these are

1. Increase in awareness and fighting poverty:

Awareness about the environment needs to be spread so that people understand its importance and hence try to reduce its degradation.

It has been found that environmental degradation is closely related to poverty. Thus, people in economically backward countries need to be made aware through education.

2. Use of eco-friendly forms of energy:

The use of coal, mineral oil, and natural gas should be reduced and instead, alternative and pollution-free eco-friendly forms of energy should be used. Per-capita consumption of energy should be decreased.

Example The increased use of wind energy, solar energy, and other forms of non-conventional sources of energy can prevent further environmental degradation.

3. Recycling of resources:

With the help of technology, resources should be recycled. Recycling and judicious use of resources will prevent the misuse of natural resources. Consumers should be encouraged to buy reusable commodities.

4. Population control:

A balance between the population of a nation and the resources available to it is necessary, or else it is bound to cause degradation of the environment. Thus, regulation of the population in a country is essential.

5. Conservation of biodiversity:

A loss in biodiversity can have adverse effects on the local ecosystem and eventually on the environment. Thus, it is necessary to preserve the natural environment. Man must allow all animals and plants to grow in their natural habitat.

Cleanliness of air, water, soil, and woodlands should be maintained.

6. Planned development:

Urbanization, construction of roads, railways, factories, watershed management, dams on rivers, power plants, etc., should be done in a planned manner, keeping in mind the short and long-term effects they shall have on the environment.

People should be made aware of environmental issues.

7. Implementation of laws:

Special laws regarding the protection of the environment and their strict implementation can reduce and eventually stop environmental degradation at the hands of human beings.

8. Assessing the environmental impact of projects:

The environmental impacts of a project or proposal should be assessed properly before their implementation. Steps should be taken so that a development plan does not affect the environment too adversely.

Environmental degradation solutions for students

Question 7. What is meant by eco-friendly forms of energy? Why are these unconventional forms of energy regarded as eco-friendly forms?
Answer:

Eco-friendly forms of energy:

Eco-friendly forms of energy are those which do not harm the environment when they are generated or used. The discovery of solar-powered pumps, engines, cookers, refrigerators, etc., was aimed at the reduction of the use of fossil fuels.

Even though hydel power plants reuse water for generating electricity, hydel power is not considered eco-friendly. This is because building a hydel power plant causes great damage to the ecosystem.

Unconventional forms of energy as eco-friendly forms of energy:

Unconventional forms of energy include solar energy, wind energy, tidal energy, geothermal energy, biogas, etc. The above-mentioned forms of energy are eco-friendly because of the following reasons

1. The generation of energy from these forms does not use any non-renewable natural resources. Thus, the environment is not damaged.
2. No fossil fuel is used in the production of these power sources. Therefore the fossil fuel reserves are not used up.
3. The generation of unconventional forms of energy does not cause any kind of pollution.
4. Even though the initial establishment cost to generate this energy is high, later the energy can be obtained practically free of
   cost.
5. There is no chance of global warming in the process of generation of electricity from non-conventional sources.

Therefore, unconventional forms of energy are eco-friendly.

Question 8. How can sustainable development be achieved by any nation?
Answer:

Sustainable Development Be Achieved By Any Nation As Follows:-

The agenda of sustainable development was taken up in the 1992 Earth Summit at Rio de Janeiro, Brazil. Steps taken to achieve sustainable development by any nation are as follows-

1. Environment-friendly technology should be used.
2. Local ecosystems should be looked after and preserved.
3. Steps should be taken to control social problems such as poverty, hunger, and illiteracy.
4. Developmental programs should be implemented according to the environment of a particular place.
5. Efforts should be made to establish a balance in society between the natural environment and anthropological activities.
6. Levels of pollution should be controlled. Steps should be taken to control the misuse of natural resources.
7. A vigilant eye should be kept on the maintenance of the balance between population and natural resources in a country.
8. Recycling of materials should be done.

Question 9. What are the effects of war on the environment? 
Answer:

Effects Of War On The Environment:-

A war is not only a conflict between two or more nations involving humans, it also causes damage to air, soil, and water resources. The flora and fauna of the region also incur damage due to war.

The effects of war on the environment are-

1. Loss of life:

Loss of life is the inevitable and immediate consequence of war. It is the greatest damage caused to the environment of a place or region.

2. Air pollution:

The explosion of bombs and firing of missiles during a war cause air pollution. The explosion from nuclear bombs degrades the environment.

Hiroshima and Nagasaki are prominent examples of how war affects the environment. Chemical warfare also causes air pollution, killing human beings and other animals.

3. Soil pollution:

The explosions not only damage the air but also damage the soil. The area of land where the explosion occurs is greatly damaged and becomes unfit for use.

4. Water pollution:

Wars are also responsible for causing water pollution. The Gulf War Oil Spill was one of the largest oil spills in the history of mankind which eventually led to the Gulf War.

Oil Spill damages the aquatic ecosystem and leads to the death of numerous aquatic flora and fauna.

5. Morale damage:

War damages human morale also. It creates a lasting fear in people’s minds.

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 10. How do multipurpose river valley projects affect the environment?
Answer:

Multipurpose River Valley Projects Affect The Environment:-

Multipurpose river valley projects affect the environment in several ways. These are

1. Earthquakes:

The huge amount of water stored by dams exerts pressure on the underlying rock strata and often causes earthquakes.

For example, the earthquake at Koyna, Maharashtra in 1967.

2. Destruction of forests:

To implement a multipurpose project many canals need to be dug up. This damages forest cover in the surrounding areas.

3. Ecosystem disrupted:

Multipurpose river valley projects create an imbalance in the ecosystem of that area, and that consequently affects the catchment area and the whole river basin.

4. Floods:

An excessive amount of silt, carried by rivers, gets deposited in the dams. Thus the depth of the dams is reduced and the surrounding areas are very often inundated.

5. Displacement of people:

Another ill-effect of a multipurpose river valley project is that it displaces the residents of that area, forcing them to leave their homes and shift elsewhere.

Chapter 7 Topic A Consequences And Control Of Environmental Degradation Short Analytical Type Questions

Question 1. What do you understand by nature-based activities?
Answer:

Nature-Based Activities:-

All sorts of human activities which are dependent on products found in nature, involve the gathering of resources from nature.

Example

1. Gathering of wood, flowers, leaves, fruits, etc., from forests,
2. Fishing from rivers and lakes,
3. And hunting of animals from known nature-based activities. forests and
4. Cultivating crops using ancient cultivation techniques.

These resources of nature are mostly non-renewable. If the number of fish in a river is reduced due to overfishing, it cannot be replenished. The same happens in case of loss. of the fertility of the soil.

If the soil loses its natural fertility, the land becomes unsuitable for agriculture and the use of fertilizers to enhance productivity becomes useless.

Question 2. What do you mean by environmental degradation?
Answer:

Environmental Degradation:-

The overall deterioration of the quality of the environment due to human activities is known as environmental degradation. It is, therefore, the complete destruction of the balance in the ecosystem.

In this case, homeostatic mechanism cannot restore the natural balance of the environment.

The main aspects of environmental degradation are

1. Environmental pollution,
2. Deforestation,
3. Expansion of towns and cities,
4. Loss of biodiversity,
5. Loss of fertility in agricultural lands,
6. Construction of dams on rivers,
7. Desertification, etc.

Question 3. How does environmental degradation take place?
Answer:

Environmental Degradation Take Place As Follows:-

Environmental degradation takes place in several ways.

These are as follows

1. Burning fossil fuels emit huge quantities of COCO₂, SOCO_2, and other harmful gases into the atmosphere. This is the main cause of air pollution as well as environmental degradation.
2. Excessive use of chemical fertilizers, pesticides, and irrigation degraded the soil of that area and thus render it unfit for further use.
3. The construction of large dams and hydel power stations are responsible for the destruction of the ecological balance of that area. These thus induce environmental degradation.
4. Unscientific excavation of mineral resources and lifting the of huge amounts of groundwater are the principal causes of environmental degradation.
5. Chemical disaster like Bhopal Gas Tragedy (1984) and nuclear disasters like Chernobyl, Fukushima, etc., are considered as the factors leading to environmental degradation.

Impact of deforestation on environment

Question 4. Differentiate between environmental degradation and environmental pollution.
Answer:

The differences between environmental degradation and environmental pollution are-

 

Question 5. Point out the differences between natural hazards and man-made hazards.
Answer:

The differences between natural hazards and man-made hazards are as follows-

Question 6. How do modern methods of agriculture affect the environment?
Answer:

Modern Methods Of Agriculture Affect The Environment:-

Several modern methods of agriculture, such as use of chemical fertilizers, a high-yielding variety of seeds, excessive irrigation, etc., have been undertaken to increase agricultural production.

However, these have an adverse effect on the environment. Some of these effects are discussed below-

1. Lowering the fertility level of the soil:

Repeated cultivation on a specific area of land, year after year, causes the land to lose its fertility and renders it infertile for a long time in the future.

2. Pollution:

To increase crop production, chemical fertilizers are used for cultivation. These, in turn, cause groundwater pollution. Besides these, the insecticides and pesticides which are used also pollute the soil.

On the other hand excessive use of high yeilding seeds speeds up vital genetic defects.

3. Deforestation:

To increase crop production, large forested areas are being brought under cultivation. This has resulted in rapid deforestation. As a result, many ecosystems have been destroyed.

Question 7. How has urbanization caused the degradation of the environment?
Answer:

Urbanization Caused The Degradation Of The Environment:-

Urbanisation encompasses better lifestyles and better living conditions for the people. However, environmental degradation is an eventual consequence of the process.

The causes of environmental degradation due urbanization are

1. Reduction in the level of watertable:

An increase in population in the towns and cities has naturally increased the need for water. One of the main sources of water used on a daily basis by human beings is groundwater.

The overuse of groundwater is rapidly decreasing the level of underground watertable. This has resulted in arsenic and fluoride pollution.

2. Increased level of pollution:

Urbanisation has resulted in a rapid increase in modes of transport, factories, and other economic activities. This in turn has increased noise and air pollution in the cities.

3. Problem of drainage, sanitation, and housing:

Much of the waste disposed of in urban areas is discharged into waterbodies and into drains. This practice clogs the drainage and sanitation system and aggravates the problem of water logging.

Excessive migration of people to urban areas also causes housing problems. Unplanned urbanization leads to narrow and congested roads. This causes traffic congestion.

4. Disposal of wastes:

Indiscriminate use of plastics and other non-biodegradable materials dumped in nearby areas causes soil pollution. Dumping of garbage contaminates the groundwater and also makes the air stink.

Question 8. How do thermal power plants affect the environment?
Answer:

Thermal Power Plants Affect The Environment:-

Effects of thermal power plants on the environment are

1. Air pollution:

Thermal power plants use coal as their primary source of energy. When coal is used as fuel, it releases huge amounts of carbon dioxide, sulfur dioxide and nitrogen oxide into the atmosphere, which are extremely harmful for living organisms.

2. Increase in atmospheric temperature:

Excessive use of fossil fuels like coal, petroleum increases atmospheric temperature. This results in global warming, which, in turn, affects the earth’s climate.

3. Soil pollution:

Ash from thermal power plants are dumped on the surrounding land and renders it unfit for cultivation.

4. Acid rain:

Sulfur and nitrogen compounds emitted by thermal power plants combine with moisture in the atmosphere and cause acid rain, which has harmful effects on plants, aquatic animals, and infrastructure.

Question 9. How do hydroelectric power plants affect the environment?
Answer:

Hydroelectric Power Plants Affect The Environment:-

The effects of hydroelectric power plants on the environment are as follows

1. Disrupting the flow of rivers:

Dams built on rivers for generating hydroelectricity disrupt the flow of the rivers, and for that reason, catchment areas of the rivers are degraded continuously.

2. Destruction of forests:

When a dam is built on a river for hydroelectric power generation, large areas of surrounding forests are destroyed in order to build reservoirs to store the water.

3. Earthquakes:

The pressure created by the huge quantity of water impounding from the dam can cause earthquakes in the surrounding areas.

4. Loss in biodiversity:

Due to the loss of their habitat, the number of plants and animals in and around the river basin decreases significantly, leading to a loss in biodiversity.

Besides this, many people become homeless as the dam sites are evacuated before construction.

Environmental awareness in schools

Question 10. What are the effects of exploding dynamite during the construction of roads in hilly areas?
Answer:

Effects Of Exploding Dynamite During The Construction Of Roads In Hilly Areas:-

When roads are constructed in hilly regions, dynamites are used for blasting the rocks. The adverse effects of blasting are as follows

1. Noise pollution:

Dynamites explode with a lot of noise. This causes noise pollution.

2. Landslides:

The use of explosives not only causes noise pollution but also induces landslides in hilly areas.

3. Earthquakes:

The explosions can induce earthquakes in the surrounding areas.

4. Air pollution:

Dynamite explosions are responsible for the spreading of rock particles and dust in the air. This causes air pollution.

5. Destruction of the ecosystem:

Repeated explosions have an adverse effect on the flora and fauna of that region. This results in the destruction of the ecosystem of that region. This results in the destruction of the ecosystem of that area.

Question 11. Write a brief note on the Bhopal Gas Tragedy.
Answer:

Bhopal Gas Tragedy:-

On midnight of December 3, 1984, there was a leakage of poisonous MIC (thin Methyl Isocyanate) gas from Bhopal’s Union Carbide factory.

This caused one of the most terrible industrial disasters ever, which had an adverse effect on the environment. It damaged the human lungs and also burnt the cornea, killing many people and rendering others blind or crippled.

This incident came to be known as the Bhopal Gas Tragedy. People of that area are still bearing the brunt.

Effects:

1. About 4000 people and innumerable birds and animals had died.
2. About 200 thousand people were affected in some way or other.
3. Most of the affected people became crippled.
4. Many of the affected people suffered from gene mutations.
5. Pregnant women gave birth to mutated babies.

 

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 12. Write a brief note on the Chornobyl Disaster.
Answer:

Chornobyl Disaster:-

On April 26, 1986, an explosion occurred in a reactor in the nuclear power plant in Chornobyl, Ukraine. This incident came to be known as the Chornobyl disaster.

The operating crew were conducting some tests and had deliberately switched off the reactor’s safety systems. This resulted in the overheating of the uranium fuel rods, which exploded, and highly radioactive fallout spread over a large area of Belarus, Russia, and Ukraine.

 

 

Effects:

1. A few people died and workers of the nuclear power plant were admitted to the hospitals.
2. Thousands of people were evacuated from that area.
3. It affected the environment adversely. The surrounding land became unfit for cultivation.
4. High levels of radioactive elements affected livestock as well. Calves were born physically disabled and the meat and milk obtained from them also showed levels of radiation.
5. Researchers were of the opinion that its effects would continue for the next 100 years.

Question 13. Write a short note on Fukushima Daiichi Nuclear Disaster.
Answer:

Fukushima Daiichi Nuclear Disaster:-

On March 11, 2011, an accident took place in the Fukushima Daiichi nuclear power plant that involved five of its reactors.
This disaster was not directly related to any human activity.

Water from the sea entered the power plant due to a tsunami which had, in turn, occurred as a consequence of an earthquake. This affected five of the reactors in the power plant and the roofs of three reactors were blown off due to a hydrogen explosion.

Effects:

1. Radioactive water from the factory contaminated the seawater.
2. According to Japan’s Nuclear Safety Commission officials, the radiation released during this accident affected both air and water adversely.

Question 14. What do you know about the Minamata Disaster?
Answer:

Minamata Disaster:-

Minamata disease was first discovered in 1956. People of Minamata Bay in Japan were dying or turning disabled after consuming fish from the Bay. This is known as the Minamata Disaster.

The Chisso Corporation’s chemical factory situated in this area manufactured paint and dumped its wastes in the water of Minamata Bay. This waste contained highly toxic methylmercury which was led out in the water of Minamata Bay.

When methylmercury entered the human body through fish consumption caught from the Bay, it became fatal or caused disabilities and disorders.

Effects:

1. As a result of this contamination, 2265 people were victims of the Minamata disease. 1784 of these victims had died.
2. The water of the Minamata Bay became polluted and the ecosystem of the place was destroyed.
3. Importance has been given on controlling the levels of lead while manufacturing paint since then.

Question 15. Discuss the advantages of eco-friendly forms of energy.
Answer:

Advantages Of Eco-Friendly Forms Of Energy:-

The advantages of environment-friendly forms of energy include

1. The production of this form of energy does not cause pollution.
2. The sources for generating this type of energy (the sun, wind, etc.) are inexhaustible.
3. The initial establishment cost is high, but in the long run the production cost is negligible.
4. The generation of electricity through this method can prevent the misuse of energy resources of the earth.

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 16. What is Earth Summit?
Answer:

Earth Summit:-

Earth Summit is an international conference on environment and development which was held in Rio de Janeiro, Brazil in the year of 1992. It is also known as the United Nations Conference on Environment and Development (UNCED) or Rio Summit.

More than thirty thousand people from 178 countries participated in this conference. The famous action plan for the 21st century, Agenda 21, was the product of this Earth Summit.

Some resolutions regarding the environment and development were adopted in this conference.

Question 17. What is sustainable development?
Answer:

Sustainable Development:-

Sustainable development refers to development aimed at the optimum use of natural resources in the present scenario so that development can go unhampered while also preserving the reserves of nature and the potential of human society to develop, for future use.

The objectives of sustainable development are as follows

1. Using the available resources in multiple ways.
2. Judicious use of non- renewable resources.
3. Using technology to optimise the use of available resources.
4. Preventing the misuse of natural resources.

Question 18. How did the idea of sustainable development emerge?
Answer:

Idea Of Sustainable Development Emerge:-

Population explosion, human activities, exploitation of resources for their increasing and uncontrolled demand for comfort has caused degradation of the environment to an alarming extent.

This has hugely depleted the resources and put the very existence of future generations at risk. It is the acknowledgment of this extreme situation that led to the idea of sustainable development being proposed, legislated, and implemented worldwide.

Question 19. What is desertification?
Answer:

Desertification:-

A type of land degradation, where certain areas of land become arid and slowly take the form of a desert, is known as desertification.

Causes:

The causes of desertification are

1. Excessive farming in the desert margins,
2. Indiscriminate felling of trees in the semi-arid regions,
3. Overgrazing by animals,
4. Exploitation of groundwater and
5. Excessive use of chemical fertilizers and pesticides.

Effects:

The effects of desertification are

1. Salinity of the soil increases,
2. Change in climate occurs,
3. Vegetation cover reduces,
4. The growth of cactus-like plants is prominent,
5. Droughts occur frequently.

Question 20. What is Jhum cultivation? What are its impacts on the environment?
Answer:

Jhum cultivation:

Jhum cultivation is one of the ancient practices used for agriculture. It is the process of growing crops on a particular land surface by clearing the existing trees and vegetation cover on it, and burning them thereafter.

After a few years, when the land loses move on to another patch of land and repeat this its fertility, the farmers abandon the land and process. This form of cultivation is also known as shifting agriculture.

Impact of Jhum Cultivation on the Environment:

1. This form of cultivation requires the clearing of forest areas. This affects the environment adversely and also results in the loss of several rare species of flora and fauna.
2. It results in rapid soil erosion.
3. Jhum cultivation creates an imbalance in the existing ecosystems and the burning of trees causes severe air pollution.

Question 21. What is the greenhouse effect?
Answer:

Greenhouse Effect:-

In colder countries, crops are often grown in glass houses to keep them warm.

 

 

These are known as greenhouses. Shortwave radiations from the sun enter through the glass, but the long-wave radiations that are reflected back from the earth are stopped by the glass walls.

As a result, the plants inside the greenhouse remain warm and grow well. French mathematician and physicist Joseph Fourier had compared the earth’s atmosphere to a greenhouse.

The sun’s rays enter the earth as shortwave radiations, but when they are reflected back by the earth as long-wave radiations, different gases, dust particles, water vapour, etc., present in the atmosphere prevent them from leaving.

Instead, these rays are sent back to the earth. This, in turn, increases the temperature of the earth’s surface. This is known as the greenhouse effect and the gases causing it are known as greenhouse gases.

Question 22. What are the consequences of the greenhouse effect?
Answer:

Consequences Of The Greenhouse Effect:-

The consequences of the greenhouse effect are as follows-

1. The average temperature of the earth is gradually rising.
2. The climate is changing.
3. Glaciers are melting at an alarming rate.
4. The sea level is gradually rising.
5. There is a decrease in agricultural production as well as in the supply of drinking water.
6. Loss of biodiversity is seen worldwide.

Question 23. Write a short note on Phailin.
Answer:

Phailin:-

The 260 km/hr cyclone that originated in the Bay of Bengal in 2013 was named Phailin. It is considered to be the second most powerful cyclone that has hit India in recent times.

Phailin first originated as a tropical depression on October 4, 2013, in the Gulf of Thailand. On October 7, it reached the Andaman and Nicobar Islands and on October 12, it wreaked havoc in and around Gopalpur in Odisha.

This cyclone prompted India’s biggest evacuation in 23 years with more than 5 lakh people moving up from the coastline in Odisha and Andhra Pradesh to safer places. Phailin damaged agricultural crops and caused a huge loss of property.

Question 24. Write the differences between environmental hazards and environmental disasters.
Answer:

Differences between environmental hazard and environmental disaster are

 

Question 25. Why do fish at times and other aquatic creatures die in ponds?
Answer:

Fish At Times And Other Aquatic Creatures Die In Ponds:-

When the water in a pond gets polluted, the fish living in it die. Ponds can get polluted due to several reasons

1. Eutrophication:

The process of eutrophication reduces the amount of oxygen present in the water, resulting in the death of fish living in the pond.

2. Dumping of wastes:

Often in towns or villages, nearby ponds are used as a place to dump the garbage. This causes pollution and reduces the depth of the ponds as well, thereby resulting in the death of aquatic life.

3. Water from factories:

Often dirty and toxic water discharged from factories flow directly into nearby ponds, causing an acute level of water pollution. This destroys the eco-system of the pond killing aquatic creatures.

4. Chemical fertilizers and pesticides:

Excessive use of chemical fertilizers and pesticides in agriculture contaminates the nearby waterbodies when the soil mixed with these chemicals enters the waterbodies as a part of surface run-off.

 

Chapter 7 Topic A Consequences And Control Of Environmental Degradation Short Answer Type Questions

Question 1. What do you understand by the nature-based activities of human beings?
Answer:

Nature-Based Activities Of Human Beings:-

Nature-based activities are those in which human beings directly use natural resources as the basis for their economic activities. These are classified as primary economic activities.

Example- hunting, fishing, and primitive agriculture.

Question 2. What are technology-based activities?
Answer:

Technology-Based Activities:-

When the resources obtained from primary economic activities are used to create and develop goods through the use of technology, they are known as technology-based activities.

Example-Generation of electricity from coal.

Question 3. What do you mean by the social activities of human beings?
Answer:

Social Activities Of Human Beings:-

Social activities are those activities that provide human beings with helpful services.

Examples- Banking, insurance, education, healthcare, transport, etc.

Question 4. Name some activities which are considered to be social services.
Answer:

Some activities which are considered as social services are healthcare, teaching, banking, insurance, etc.

Question 5. What is meant by homeostatic mechanism?
Answer:

Homeostatic Mechanism:-

The physical and biotic processes of nature have a self-regulatory style of working. Any change or damage caused by them to the environment is naturally restored, compensated or adjusted. This is called homeostatic mechanism.

Question 6. In the initial stages of civilization, how were human beings totally dependent on nature?
Answer:

In the early years of civilization, human beings were hunters and gatherers, collecting fruits from forests and hunting animals that lived there. Early man lived as a part of nature, without degrading or causing damage to the environment.

Sustainable practices to reduce environmental degradation

Question 7. How did the invention of the wheel increase the pace of evolution?
Answer:

Invention Of The Wheel Increase The Pace Of Evolution:-

With the invention of the ‘wheel’, the pace of human life increased. The usage of vehicles for transportation gained popularity. Also, from this phase, the man started exploiting nature for his own interests.

The invention of the wheel changed man’s relationship with nature. However, the human population was very low at that time and human activities did not cause any significant harm to the environment.

Question 8. What is meant by environmental pollution?
Answer:

Environmental Pollution:-

Soil, air and water are integral parts of our environment. When these components become contaminated or degraded due to natural or human activities, it causes environmental pollution. This, in turn, has adverse effects on living organisms.

Question 9. What are multipurpose river valley projects?
Answer:

Multipurpose River Valley Projects:-

Projects are undertaken to build large dams on various rivers to store the river water and use it for diverse purposes. These projects are known as multipurpose river valley projects.

Example- Damodar Valley Corporation.

Question 10. What are the main objectives of the multipurpose river valley projects?
Answer:

Main Objectives Of The Multipurpose River Valley Projects:-

The main objectives of these projects are

1. Irrigation,
2. Generation of hydro-electricity,
3. Flood control,
4. Pisciculture,
5. Tourism,
6. Transportation,
7. Distribution of drinking water,
8. Prevention of soil erosion,
9. Construction of roadways, railways, and bridges, etc.

Question 11. The main causes of environmental degradation are lack of education and poverty. Explain.
Answer:

The main causes of environmental degradation are lack of education and poverty:-

Illiteracy and poverty are the two main reasons why people exploit the environment. Collecting of wood from forests, grazing cattle, unplanned exploitation of mineral resources, lifting of excessive groundwater, etc., have adverse effects on the environment.

Again, poverty and lack of awareness are also responsible for the uncontrolled growth of the population. It is mainly through education that people will become aware of the importance of keeping the environment healthy and take up the path of sustainable development.

Question 12. Only environmental reform movements can protect the environment. Justify.
Answer:

Only environmental reform movements can protect the environment:-

Various movements have been initiated over the years in order to save the environment from being affected adversely.

Example

1. No trees were cut for about 10 years in the Himalayan region due to the Chipko Movement that was launched in Uttarakhand’s This region. the movement had a global impact.
2. Due to the Silent Valley Movement, the evergreen forest in the Palakkad district of Kerala has been declared a National Forest.
3. Narmada Bachao Andolan, Anti-Tehri Dam Movement, etc., have been equally effective in protecting the environment.

Question 13. How did the Bhopal Gas Tragedy which caused the death of about 4000 people and numerous birds and animals occur?
Answer:

On midnight of December 3, 1984, a tank of MIC (Methyl Isocyanate) gas exploded in Bhopal’s Union Carbide Factory, causing one of the most terrible industrial disasters ever.

This gas is used to produce pesticides. If not stored in a cold place and if it comes in contact with water, the gas undergoes a chemical reaction. This reaction between water and MIC was the main cause of the accident.

Question 14. What do you understand by eco-friendly forms of energy?
Answer:

Eco-Friendly Forms Of Energy:-

Environment-friendly or eco-friendly forms of energy are those that do not harm or pollute the environment when they are produced or used. These include solar energy, wind energy, tidal energy, etc.

These forms of energy are also known as green energy or sustainable energy or renewable energy.

Question 15. What is meant by biodiversity?
Answer:

Biodiversity:-

Biodiversity means the variety of living organisms, both flora and fauna, existing in a particular habitat. The Earth Summit. organised in 1992 put forth a comprehensive idea of biodiversity.

Question 16. Why is the idea of sustainable development gaining importance?
Answer:

The idea of sustainable development is gaining importance because

1. Wastage of resources can be checked;
2. The use of eco-friendly technology will increase;
3. Poverty and illiteracy will decrease;
4. Environmental pollution will be checked.

All these help in keeping the environment healthy. Hence, sustainable development is gaining importance at present.

Question 17. What do you mean by environment?
Answer:

Environment:-

The term environment indicates an organism’s surroundings including both living and non-living things, where plants and animals can co-exist.

Thus, the environment not only includes human beings but also other living and non-living things around them, each of which are co-related.

Question 18. What do you mean by physical environment?
Answer:

Physical Environment:-

Physical environment is equated with nature, which includes the physical components of the earth namely land, air, water, soil, etc. Human activities are not included in this environment.

Question 19. What is meant by economic environment?
Answer:

Economic Environment:-

The economic environment is the sum of those factors which directly or indirectly influence economic activity in an area. Agriculture and industry, are examples of the economic environment.

Question 20. What is meant by ecosystem?
Answer:

Ecosystem:-

A community of organisms living in association with the non-living components of the environment in a particular area, interacting as a system, forming an ecosystem. It may be as small as a cowshed or a tree.

The largest unit of an ecosystem is the entire biosphere. A.G. Tansley (1935) had first used the term ‘ecosystem.

 

Chapter 7 Topic A Consequences And Control Of Environmental Degradation Multiple Choice Questions Choose the correct option

Question 1. The activity of manufacturing goods is a

1. Self-service
2. Social service
3. Technology-based activity
4. Nature-based activity

Answer: 3. Technology-based activity

Question 2. The overall deterioration of the quality of the environment is known as-

1. Environmental pollution
2. Homeostatic mechanism
3. Environmental management
4. Environmental degradation

Answer: 4. Environmental degradation

Question 3. Which of the following is associated with environmental degradation?

1. Construction of reservoir
2. Loss of biodiversity
3. Smog
4. Bad odor from the fish market

Answer: 2. Loss of biodiversity

Question 4. The ‘Phailin’ had hit-

1. Assam
2. Odisha
3. Bihar
4. Maharashtra

Answer: 2. Odisha

Question 5. The destructive power of ‘Aila’ was felt in-

1. Jharkhand
2. West Bengal
3. Kerala
4. Gujarat

Answer: 2. West Bengal

Question 6. Arsenic pollution is a part of

1. Soil pollution
2. Groundwater pollution
3. Air pollution
4. Noise pollution

Answer: 2. Groundwater pollution

Question 7. Chemical fertilizers and pesticides pollute the-

1. Soil
2. Water
3. Air
4. Soil and water both

Answer: 4. Soil and water both

Question 8. The following is emitted due to the burning of fossil fuels-

1. H₂
2. CO₂
3. CH₄
4. bO₂

Answer: 2. CO₂

Question 9. Bhopal Gas Tragedy occurred in-

1. 1984
2. 1974
3. 1994
4. 2008

Answer: 1. 1984

Question 10. Chornobyl nuclear disaster occurred in-

1. 1966
2. 1976
3. 1986
4. 1996

Answer: 3. 1986

Question 11. The Fukushima Daiichi accident occurred in-

1. 1981
2. 1991
3. 2001
4. 2011

Answer: 4. 2011

Question 12. Environment-friendly energy is-

1. Thermal energy
2. Nuclear energy
3. Solar energy
4. None of these

Answer: 3. Solar energy

WBBSE Class 8 Geography Chapter 7

Question 13. World Environment Day is observed on

1. 5 June
2. 5 September
3. 5 March
4. 2 October

Answer: 1. 5 June

Question 14. The following may happen as a result of excessive deforestation-

1. Soil erosion and flood
2. Reduction of biodiversity
3. Desertification
4. All of the above

Answer: 4. All of the above

Question 15. Which of the following is directly responsible for the climatic change?

1. Indiscriminate use of resources
2. Deforestation
3. Unplanned development
4. Increase in temperature

Answer: 4. Increase in temperature

 

Chapter 7 Topic A Consequences And Control Of Environmental Degradation Very Short Answer Type Questions Fill In The Blanks

Question 1. Computer manufacturing is a _______-based activity.
Answer: Technology

Question 2. Environmental pollution accelerates environmental _______.
Answer: Degradation

Question 3. Unscientific agricultural methods reduce _______ of soil.
Answer: Fertility

WBBSE Class 8 Geography Chapter 7

Question 4. The full form of MIC gas is _______.
Answer: Methyl isocyanate

Question 5. Almost _______ people lost their lives in the Bhopal Gas Tragedy.
Answer: 4000

Question 6. The United Nations Conference on Environment and Development called the _______ was held in Rio de Janeiro, Brazil in 1992.
Answer: Earth Summit

Question 7. _______ is one of the primary factors responsible for increasing desertification of land.
Answer: Deforestation

 

Match The Columns

1.

Answer: 1. C, 2. A, 3. B, 4. E, 5. D

2.

Answer: 1. D, 2. E, 3. A, 4. B, 5. C

 

Answer In One Or Two Words

Question 1. Give an example of nature-based activity.
Answer: Agriculture.

Question 2. Give an example of technology-based activity.
Answer: Computer manufacturing.

Question 3. Name the system which compensates any disturbance caused to any part of the environment and thus maintains ecological balance.
Answer: Homeostatic mechanism.

Question 4. Give an example of environmental degradation caused by man.
Answer: Industrial toxic wastes are discharged into nearby waterbodies.

Question 5. What is the name of the type of cultivation that causes environmental degradation in India?
Answer: Jhum cultivation.

Question 6. Give an example of an earthquake in India caused due to the pressure of the reservoir of a dam.
Answer: Koyna earthquake, Maharashtra, 1967.

Question 7. What is the full form of MIC?
Answer: Methyl Isocyanate.

WBBSE Class 8 Geography Chapter 7

Question 8. What primarily caused the mishap in Fukushima, Japan?
Answer: Tsunami.

Question 9. Name eco-friendly non-conventional energy.
Answer: Solar energy.

Question 10. Which country hosted the ‘Earth Summit’ of 1992?
Answer: Brazil.

Question 11. Give an example of a natural disaster.
Answer: Tsunami.

Chapter 6 Topic B Mediterranean Climatic Region And Tundra Climatic Region Analytical Type Questions

Question 1. Account for the features of the climate of the Mediterranean region.
Answer:

Features Of The Climate Of The Mediterranean Region:-

Mediterranean climate prevails between 30° and 40° North and South latitudes in the western margins of the continents. The features of the Mediterranean climatic region are as follows-

1. Wet winters:

Moist westerlies from the seas blow over the region in winter and hence bring rain to the region.

2. Dry summers:

In summer, due to the northern journey of the sun (apparent), all the pressure belts shift to the north so the westerlies cannot influence the region. It comes under the influence of the dry northeast trade winds.

3. Scarcity of rainfall:

Though rainfall occurs in winter, its amount is not sufficient. It is only 25cm-150 cm on average annually. Rainfall gradually decreases when it goes towards the interior from the cost. As rainfall occurs in winter, this region is called the country of winter rainfall.

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4. Mild summer and winter:

The region, with its coastal location within the temperate zone, has both mild summers and winters. Summer temperature remains between 21°C and 27°C and winter temperature varies between 5°C and 10°C on average. The annual range of temperature is 17°C.

5. Sunny climate and cloudless sky:

This region gets a lot of sunshine for most of the year due to no cloud cover.

Characteristics of Mediterranean Climate

6. Low pressure in winter and high pressure in summer:

Sub-tropical high-pressure belt exists over this region in summer so air pressure remains high at that time. Again, in winter, due to the shifting of the pressure belts, the air pressure becomes low.

So, summers are marked by high pressure and winters by low pressure.

7. Winds:

Due to the shifting of the pressure belts, dry trade winds blow during summer and moist westerlies blow during winter.

Question 2. How will you identify the flora of the Mediterranean climate?
Answer:

Identification Of Flora Of The Mediterranean Climate:-

The flora of an area is closely linked with the climate of that area. The flora of the Mediterranean climatic type is not an exception.

Some of the major plants of the Mediterranean climatic area are cork, oak, olive, pine, far, cedar, eucalyptus, rosewood, beech, curry, maple, laurel, rosemary and lavender.

The ways of identifying the flora of the Mediterranean climate are

Since the summers here are warm and dry, the plants and trees have long roots.

1. Due to the occurrence of dry summers, the trees have thick barks and woody stems.
2. The leaves are broad and waxy to prevent the loss of moisture.
3. The trees in these areas bear juicy fruits.
4. These trees are not very high. Olive is the most commonly found tree in this region.
5. Coniferous trees like pine, fir, cedar, etc., grow in the areas where snowfall occurs during winter.

Question 3. Discuss the influence of the Mediterranean climate on the economic activities of the inhabitants of the region.
Answer:

The Mediterranean climatic region has the following characteristics

1. Wet winter and dry summer,
2. The average annual rainfall is 25 cm-150 cm,
3. Temperate condition prevails throughout the year,
4. Sunny, bright weather. These have, in turn, influenced the economic activities of the inhabitants of this region.

1. Agriculture:

Agriculture is the main occupation of this region with the following features-

Varieties of fruits grow here:

Tundra Climate Overview

The winter. rain and dry, sunny summer promotes the growth of different types of fruits like grapes, olives, apples, pears, peaches, oranges, pomelos, figs, walnuts, apricots and different types of citrus fruits. So, the region is called the ‘Fruit Basket of the World’.

 

Food items and other crops:

This region produces food grains like wheat (both in spring and winter), rice, maize and barley; vegetables like cabbage, tomato, peas, carrot, radish, etc., and also fibre crops like flax and cotton.

2. Abundance of minerals:

Iron ore is obtained from Algeria, Spain and Serbia; Natural gas is obtained from Algeria, Tunisia and Libya; Bauxite is obtained from southern France and Serbia; Mineral oil is obtained from California; Bauxite obtained from France; Marble and Sulphur are obtained from Italy and Gold is obtained from South Africa.

The abundance of minerals has helped in the development of mineral-based industries in this region.

Mediterranean Climate Regions

3. Fishing:

Fishes like sardine, tuna, herring and mackerel are caught here. California is called the sardine capital of the world.

4. Development of other industries:

Huge production of fruits has led to the development of the fruit processing industry (fruit preservation and making of jam, and jelly), wine-making, extraction of oil from olive (for soap, olive oil, perfume, etc.), orchard-based industry, flour industry, etc.

The sunny climate, clear sky and beautiful natural environment have helped in the growth of the tourism industry, and film-making industry. Among other industries of this region mention might be made of-

1. Engineering industry and
2. Aluminium industry.

5. Progress in trade and commerce:

Oranges from Spain, California, and Israel, Olives from Italy and grapes from France, Italy and California are all exported to foreign countries.

Italian olive oil, champagne from France, and squash from California are also exported in sufficient quantities.

Flora and Fauna of Tundra Regions

Question 4. Write a note on the Tundra climate.
Answer:

Tundra Climate:-

Tundra climate is noticed in the northern parts of Asia, Europe and North America in the northern hemisphere and also in several parts of Antarctica in the southern hemisphere. Its characteristics are as follows

1. Extremely cold, prolonged winters:

Winter lasts for about 8-9 months in the Tundra region, with biting cold and profuse snowfall. The ground gets entirely covered with a thick layer of snow and the temperature drops much below 0°C.

The minimum temperature in winter remains between -20°C and -40°C. This region has a continuous night for about six months and Aurora Borealis (northern hemisphere) and Aurora Australis (southern hemisphere) are visible at that time.

2. Short, cool summers:

The duration of summer in this region is only 2-3 months or even less. The sun is visible all through the summer, but due to its location near the horizon, the area receives very slanted/oblique rays.

As a result, summer temperature ranges from 0°C-10°C on average. Hence, summers are cool.

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3. Low rainfall but excessive snowfall:

The Tundra region receives very low rainfall, about 25 cm a year on average. Temperate cyclones in summer bring this rain. But snowfall in this region is long-lasting and excessive.

Snow particles accumulate to form dry snow and cause blizzards (or snowstorms). Due to the absence of vegetation cover, cold and strong winds blow unobstructed over the Tundra region.

Question 5. Discuss in brief the natural vegetation and animal life in the Tundra region.
Answer:

The natural vegetation of Tundra:

Snow melts for a short period in summer and during that time moss, lichen, sedge and other small shrubs with colourful flowers grow here. These are called ‘grass tundra.

In the southern part, which remains free from snow for a longer period, willow, birch, alder, juniper, etc., grow. These are called ‘bush tundra.

Seasonal Changes in Mediterranean Regions

Animal life in the Tundra:

The animal life in the Tundra region is discussed below- The animals of the Tundra, which live on land have thick fur, thick skin and a thick layer of fat under the skin to protect themselves from severe cold.

1. The animals generally found here are polar bears, reindeer, caribou, polar fox, lemming (a kind of rat), sable (a furry animal, black), hare, musk deer, etc.
2. Besides these, innumerable insects are born in the meltwater and varieties of migratory birds come here to feed on those.
3. Penguins are found in Antarctica, the Tundra region in the South Pole.
4. Seals, walruses, whales and different types of fishes are found in the cold waters of the Tundra region.

Question 6. How does the natural environment of the Tundra region influence the lifestyle of the inhabitants?
Answer:

Natural Environment Of The Tundra Region Influences the Lifestyle Of The Inhabitants:-

The Tundra region is completely different from the other climatic regions of the world for its unique climate and physiography.

The natural environment of the Tundra region:

Winter persists for about 8-9 months with a temperature of around -20°C to -40°C. Heavy snowfall and occasional blizzards are also common.

Sun remains almost invisible in the sky at that time and sometimes for 2-3 hours Aurora (Aurora Borealis in the northern hemisphere and Aurora Australis in the southern hemisphere) is seen here.

Summer temperature remains about 10°C on average and lasts for only 2-3 months. During this time, the sun is never seen to set, but its rays are always oblique or slanted and thus produce less heat.

So, moss, lichen and sedge-like shrubs and bush vegetation can grow here.

Human Adaptation to Tundra Climate

Influence of natural environment on the lifestyle of the people of the Tundra region:

People of this region live in very unfavourable climatic and physical conditions and so the population is sparse here. The people are mostly nomadic and usually settle in the coastal regions.

They are mostly wanderers with herds of reindeer and cannot practise any kind of cultivation. They usually hunt caribou, hare, reindeer, arctic fox, polar bear, seal, fish and various species of birds to obtain food.

Their summer residences are leather tents called topic and in winter they live in igloos, a type of snow house. Seal fat is used for lighting their lamps and they use umiaks (big boats) and kayaks (smaller ones) for fishing and hunting.

They use the skin of animals for clothing and bones for weapons. They stitch their leather dresses with needles made of bones. They use sledges, drawn by dogs (huskies) or reindeer.

Question 7. Discuss the recent changes in the lifestyle of the people of the Tundra region.
Answer:

Recent Changes In The Lifestyle Of The People Of The Tundra Region:-

Eskimos were hunters and gatherers previously, but of late, with the help of advanced technology and government aid, their living conditions have improved.

Some of these improvements are

1. They practise greenhouse cultivation.
2. They live in nylon tents or even brick houses now, instead of igloos and topics.
3. They have electricity in their homes now.
4. They use harpoons and rifles for hunting at present, instead of spears, bows and arrows.
5. They use speedboats driven by diesel, instead of kayaks.
6. Mineral oil, iron ore, coal, and gold have been recently found here giving a boost to industries. Roads and railways are being constructed for better transportation services. A railway network from Murmansk port of Siberia to Saint Petersburg has been established.
7. They use needles made of steel instead of bone needles that were used previously.
8. Inhabitants of this region import tea, coffee, and tobacco against fleece and feathers of animals.

Despite the unfavourable conditions of life in the Tundra region, the people there are progressing with time.

Class 8 Geography Solution WBBSE

Chapter 6 Topic B Mediterranean Climatic Region And Tundra Climatic Region Short Analytical Type Questions

Question 1. Give the location of the Mediterranean climatic region.
Answer:

Location Of The Mediterranean Climatic Region:-

The Mediterranean climatic region is experienced on the western margins of the continents lying between 30° and 40° North and South latitudes. 16 countries around the Mediterranean Sea occupy the most important position in this climatic belt.

Italy, Portugal, Spain and southern parts of France, Greece, Albania, and Former Yugoslavia in Europe; Turkey, Lebanon, Israel and Syria in Asia; the northern part of Egypt, Morocco, Libya, Algeria and Tunisia in Africa lie within this climatic region.

Though the Mediterranean coastal lands occupy the most important position, the Californian coast of the USA, central Chile in South America, Cape Town in South Africa, southwestern and south-eastern coast of Australia are also within this climatic region. This climatic region is within the warm temperate zone.

Comparison of Mediterranean and Tundra Climates

Question 2. Why does the Mediterranean climatic region receive rainfall in winter?
Answer:

Mediterranean Climatic Region Receives Rainfall In Winter:-

The Mediterranean climatic region receives rainfall in winter due to the following reasons-

1. As a consequence of the apparent southward journey of the sun in winter, the pressure belts shift towards the South Pole. As a result, in winter, the onshore southwest westerlies bring rain from the Atlantic Ocean to the Mediterranean region.
2. The pressure belts shift poleward in winter. Due to this, the Mediterranean climatic region becomes a meeting place of dry, cold polar winds and warm, moist westerlies from the tropics. In this way, temperate cyclones originate and cause rainfall in winter in the region. This rainfall is called ‘frontal rain’.

Question 3. Discuss the natural vegetation of the Mediterranean climatic region.
Answer:

Natural Vegetation Of The Mediterranean Climatic Region:-

The vegetation of an area is closely linked with the climate of that area. Since the summers here are warm and dry, the plants and trees have long roots, thick barks and woody stems.

Leaves are broad and waxy so as to prevent the loss of moisture. Three types of vegetation mainly grow here-

1. Coniferous vegetation: Pine, Fir, Ceder.
2. Evergreen vegetation: Oak, Cork, Eucalyptus, Rosewood.
3. Shrub-type vegetation: Maple, Laurel, Lavender, Rosemary, Matarrelli.

Olive is the most commonly found tree in this region. Hence, it is known as the signature tree. Besides these, many types of shrubs and bushes are found in this region like- California-Chaparral; Italy-Macchia; Chile-Maqui.

Question 4. Why is the Mediterranean region known as the ‘Fruit Basket of the World’?
Answer:

Mediterranean Region Known As The ‘Fruit Basket Of The World’:-

A huge quantity of fruits consumed all over the world is produced in the Mediterranean region. Winter rains and a sunny, dry climate in summer significantly promote the production of citrus fruits and nuts.

Due to bright and abundant sunny weather in summer, the fruits grow juicy flesh all around the seeds within, to protect them from the heat.

Some of the most important fruits that are grown here are olive, apple, plum, peach, fig, orange, grape and pear. The production of fruits is so high in this region that it is called the ‘Fruit Basket of the World’.

Olive trees are seen in the maximum number in this region. It is known as the signature tree of this region.

Class 8 Geography Solution WBBSE

Question 5. In the Mediterranean region, moist westerlies give rain in winter over the same latitude. In summer dry trade winds do not give any rain. Air pressure belts shift with the northerly and southerly annual apparent movement of the sun- What is the cause-effect relation between this and the above subject?
Answer:

The Mediterranean region receives rainfall in winter, whereas the same latitude in summer experiences dryness. There is a cause-effect relationship between this fact and the shifting of air pressure belts.

With the southward journey of the sun in winter, the pressure belts shift towards the South Pole. As a consequence, the southwest westerly wind blows over the Mediterranean region.

This wind comes from the Atlantic Ocean and causes rainfall in this region. On the other hand, in summer, the sun moves towards the North Pole and the whole air pressure belts shift towards the North Pole.

Then, the Mediterranean region comes under the northeast trade wind. This wind blows from the land towards the sea. This is a dry wind. That is why the summer in the Mediterranean region experiences dryness.

Question 6. Differentiate between Monsoon climate and Mediterranean climate.
Answer:

The differences between the Monsoon climate and the Mediterranean climate are

 

Question 7. Give the location of the Tundra climatic region.
Answer:

Location Of The Tundra Climatic Region:-

The Tundra climatic region lies roughly between 60° and 75° (approx.) North latitudes. The northern parts of Russia, Norway, Sweden, Finland, Iceland and Siberia in Asia in the northern hemisphere experience this type of climate.

Besides these, the eastern and western coastal areas of Greenland, the northern part of Canada and Alaska in the USA lie in this region.

The southern part of South America and the Falkland Islands in the southern hemisphere are also included in this region. The coastal strip of Antarctica is also influenced by this climate as well.

Impact of Mediterranean Climate on Agriculture

Question 8. How is Aurora produced in the polar region?
Answer:

Aurora Produced In The Polar Region:-

When polar regions have a continuous night for six months (from 23 September to 21 March in the North Pole and from 21 March to 23 September in the South Pole), the night sky has a faint light like a rainbow.

This is called Aurora or Polar Light. Aurora appears in the sky for just 2-3 hours. The charged particles released from the sun mix with various gases of the Ionosphere to produce a light called polar illumination.

This light is reflected on white ice and creates a brilliant illumination. It is called Aurora Borealis in the North polar region and Aurora Australis in the South polar region.

Question 9. Write a short note on Eskimos.
Answer:

Eskimos:-

Eskimos live in the southern part of Greenland, in the coastal region and some parts of Alaska in North America and the northernmost part of the Canadian Shield. The word ‘Eskimo’ means ‘raw flesh eater.

Due to the derogatory meaning of the term ‘Eskimo’, the natives prefer to address themselves as Inuits. They struggle hard and live under adverse natural conditions.

During the short summer (2-3 months), they collect and store food for the whole year. Their abode during summer is tupic, a leather tent of seal’s skin. In winter, they live in a dome-shaped house made up of snow called an igloo.

Class 8 Geography Solution WBBSE

 

For transportation purposes, they use wheelless sledges. They hunt bears, arctic foxes, reindeer, etc for livelihood. They use a type of boat called a kayak, made of seal skin, for hunting fish and seals.

Reindeer is their chief source of food as well as a mode of transportation. They get milk, and meat and use the skin of the reindeer. Milk of reindeer and berry fruits are their favourite food.

They use the skin of animals in making their clothing and bones for weapons. Lately, they have been making use of certain modern technologies for a better and easier way of living.

Question 10. Differentiate between the Mediterranean climate and the Tundra climate.
Answer:

The differences between the Mediterranean climate and the Tundra climate are-

 

Question 11. Differentiate between the inhabitants of the Equatorial climatic region and those of the Tundra region.
Answer:

The differences between the inhabitants of the Equatorial region and the Tundra region are-

 

Chapter 6 Topic B Mediterranean Climatic Region And Tundra Climatic Region Short Answer Type Questions

Question 1. Why is the Mediterranean climatic region economically developed?
Answer:

Mediterranean Climatic Region Economically Developed:-

This region is world-famous for growing fruits and nuts. Wine-making from fruits, extraction of olive oil and making squash, jam, jelly and pickles from various fruits are done here.

Fishing and cultivation of food crops are also practised here. Due to the enjoyable climate, film and industries have flourished here. So, this climatic region is said to be the most economically developed region in the world.

Educational Resources for WBBSE Geography

Question 2. Why is the Mediterranean climate the most favourable climate for recreational activities in the world?
Answer:

Mediterranean Climate The Most Favourable Climate For Recreational Activities In The World:-

In this region, the temperature difference between summer and winter and also days and nights is large. Cloudless, clear and bright skies and sunny weather during the day make it the most enjoyable climate.

Hence, film industries, theatres and other forms of entertainment have developed here. Thus, this region draws a large number of tourists from all over the world.

Question 3. Why has the film industry flourished in the Mediterranean region?
Answer:

Film Industry Flourished In The Mediterranean Region:-

The Mediterranean region, which includes Italy and France in southern Europe and world-famous Hollywood in California, USA is famous for its flourishing film industry.

This is because the sunny weather of this region in summer helps in the shooting of films. Sunshine and beautiful scenery have given the region a well-developed tourism industry as well.

Question 4. What is the significance of the name ‘Tundra”?
Answer:

Significance Of The Name ‘Tundra’:-

The northernmost parts of Asia, Europe and North America in the northern hemisphere remain snow-covered throughout the year. As a result, no tall trees can grow there.

During the short summers, when the ice melts, mosses, lichens, algae, etc., grow there. From the name of the algae, this region is named “Tundra.

Question 5. What are Aurora Borealis and Aurora Australis?
Answer:

Aurora Borealis And Aurora Australis:-

During winter, the night sky prevails for a continuous six months at both the Poles. In that time, a faint, colourful light like a rainbow appears in the sky for 2-3 hours.

It is called the light of the Poles or ‘Aurora’. It is called Aurora Borealis in the North polar region and Aurora Australis in the South polar region.

Question 6. The midnight sun is visible in Norway. Why?
Answer:

The midnight sun is visible in Norway:-

The sun is visible at midnight at Hammerfest port (70°30′ North), Norway in summer because the North Pole tilts towards the sun for six months (from March 21 to September 23) and the sun is almost vertically overhead on the Tropic of Cancer during this time.

It is for this reason that the area has long days of 20-22 hours in this period, although the sun remains a little towards the horizon all the time.

Question 7. Why are animals with thick fur found in the tundra climatic region?
Answer:

Animals With Thick Fur Found In The Tundra Climatic Region:-

To protect themselves from the extremely cold climatic conditions of the tundra region, animals are naturally provided with thick, long hair fur on their bodies.

This thick blanket-like fur does not allow cold to enter from outside and also prevents body heat from being discharged easily. The layer of air between the body and the fur also gives further protection from cold, making the animals perfectly suited to the environment.

Question 8. What is an igloo?
Answer:

Igloo:-

The round-shaped houses of Eskimos that are made of ice are called ‘Igloos. On the leeward side of the mountains, where biting cold winds cannot enter, Eskimos build their winter homes.

Stones, animal skin and fur are the materials used in it. Compacted snow is also used as a material to insulate their houses. When the houses get covered with ice or snow, they look like upside-down bowls and are called igloos.

Climate Change Effects on Tundra Regions

 

These do not have windows and one has to crawl through the low door to enter into it. Eskimos light up lamps with wicks of dry moss in seal fat lamps.

Question 9. What is a topic?
Answer:

Tupic:-

The conical leather tents in which Eskimos live in summer by the seaside are called tupics. When ice melts away in the summer, they make these types of tents. They use wood, whalebone or horns of deer to make the structure of these tents.

These are then covered with stitched skins of fifty to sixty seals. Tupics are pressed on the ground with heavy stones so that they remain firmly attached to the ground.

Question 10. What is a kayak?
Answer:

Kayak:-

The word ‘kayak’ means the boat for men or hunters. In summer, in coastal regions of Greenland and Alaska varieties of fish are found, with an abundance of seals.

Seal skin is used to make kayaks, which are used for hunting fish and seals during the summer months.

 

Chapter 6 Topic B Mediterranean Climatic Region And Tundra Climatic Region Multiple Choice Questions Choose The Correct Option

Question 1. The dry season in the Mediterranean region occurs in

1. Summer
2. Autumn
3. Winter
4. Throughout the year

Answer: 1. Summer

Question 2. Rainfall occurs in the Mediterranean region during-

1. Summer
2. Winter
3. Throughout the year
4. Autumn

Answer: 2. Winter

Question 3. The Mediterranean region experiences winter rain chiefly due to the

1. Polar wind
2. Monsoon winds
3. Westerlies
4. Trade winds

Answer: 3. Westerlies

Question 4. Local, hot wind Leveche blows over-

1. Egypt
2. Spain
3. Italy
4. Australia

Answer: 2. Spain

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 5. Among the following, the tree that grows in the Mediterranean region is-

1. Rubber
2. Cork
3. Sal
4. Mahogany

Answer: 2. Cork

Question 6. The density of the population in the Mediterranean region is-

1. High
2. Low
3. Medium
4. Very high

Answer: 3. Medium

Question 7. Winter in the tundra region continues for

1. Five months
2. Eight months
3. Four months
4. Three months

Answer: 2. Eight months

Question 8. The midnight sun is visible in the

1. Monsoon climatic region
2. Mediterranean climatic region
3. Tundra climatic region
4. Equatorial climatic region

Answer: 3. Tundra climatic region

Question 9. The predominant vegetation of the Tundra climatic region is-

1. Trees
2. Moss
3. Grass
4. Parasites

Answer: 2. Moss

Question 10. The only bird that can be found in the Tundra region of Antarctica is-

1. Penguin
2. Ostrich
3. Kiwi
4. Macaw

Answer: 1. Penguin

Question 11. The animal that is most abundantly found in the Tundra region is-

1. Reindeer
2. Elephant
3. Jaguar
4. Gorilla

Answer: 1. Reindeer

Question 12. Greenland in the Tundra region is inhabited by

1. Samoyeds
2. Finns
3. Eskimos
4. Lapps

Answer: 3. Eskimos

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 13. North European countries within the Tundra region are inhabited by

1. Yakuts
2. Samoyeds
3. Eskimos
4. Lapps

Answer: 4. Lapps

Question 14. The leather tents in which people of the Tundra region live in the summer are called-

1. Igloo
2. Kayak
3. Topic
4. Sledge

Answer: 3. Topic

Question 15. A boat made of seal’s skin leather is known as

1. Kayak
2. Igloo
3. Topics
4. Sledge

Answer: 1. Kayak

Chapter 6 Topic B Mediterranean Climatic Region And Tundra Climatic Region Very Short Answer Type Questions Fill In The Blanks

Question 1. ________ climate prevails in Greece.
Answer: Mediterranean

Question 2. The temperature of the Mediterranean climatic region is ________.
Answer: Mild/ moderate

Question 3. Dry ________ winds blow over the Mediterranean region.
Answer: North-east trade

Question 4. The Mediterranean climatic region is known as a region of ________ rainfall.
Answer: Winter.

Question 5. Olive trees are a part of the natural vegetation of the ________ climatic region and sandalwoods are common in the climatic region.
Answer: Mediterranean, Monsoon

Question 6. The Mediterranean climatic region is known as the ________ of the world.
Answer: Fruit basket

Question 7. The chief crop that grows in the Mediterranean region is ________.
Answer: Wheat

Question 8. Excellent wine is brewed from ________ in the Mediterranean region.
Answer: Grapes

Question 9. The tundra climatic region lies within the ________ zone.
Answer: Frigid/cold

Question 10. ________ climate is experienced in Greenland.
Answer: Tundra

Question 11. In winter, the Tundra region experiences strong ________.
Answer: Snowstorms/ blizzards

Question 12. The average temperature in the Tundra region in winter remains ________.
Answer: -20°C to -40°C

Question 13. Sometimes the Tundra climatic region experiences ________ cyclonic rainfall in small amounts.
Answer: Temperate

Question 14. ________ is visible at night in the Tundra.
Answer: Aurora

Question 15. The ground surface of the Tundra region is permanent ________.
Answer: Frozen

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 16. The scattered bushes in the Tundra are called ________.
Answer: Bush tundra

Question 17. During the short summer, the Tundra region grows ________ type of vegetation.
Answer: Moss

Question 18. Houses in the Tundra region made up of ice and snow, are called ________, and the mode of transport without wheels that is used there is called.
Answer: Igloo, sledge

Question 19. The main food of the inhabitants of the Tundra region are ________ and ________ of reindeer.
Answer: Flesh, milk

Write True Or False

Question 1. The Mediterranean climatic region receives rainfall in winter.
Answer: True

Question 2. The latitudinal extension of the Mediterranean climatic region is 50°-60° North and South of the equator.
Answer: False

Question 3. The main crops of the Mediterranean climatic region are wheat, maize, barley, etc.
Answer: True

Question 4. Coniferous forests are found in the Mediterranean climatic region.
Answer: False

Question 5. Northern Lights is also called the Aurora Borealis.
Answer: True

Question 6. The term Eskimo means ‘raw flesh eater.
Answer: True

Question 7. California is within the Tundra climatic zone.
Answer: False

Question 8. The Eskimos live in Greenland.
Answer: True

WBBSE Class 8 Geography Chapter 8 Question Answer

Match The Columns

1.

Answer: 1. C, 2. A, 3. D, 4. B

 

Answer In One Or Two Words

Question 1. Which area in North America experiences the Mediterranean type of climate?
Answer: California USA.

Question 2. Name two Asian countries which experience a Mediterranean type of climate.
Answer: Syria and Israel.

Question 3. Which climatic region experiences rainfall in winter?
Answer: Mediterranean climatic region.

Question 4. Which climatic region is at the top in terms of socio-economic status?
Answer: Mediterranean climatic region.

Question 5. In which climatic region, the film-making industry has developed predominantly?
Answer: Mediterranean climatic region.

Question 6. In which climatic region are moss and lichen found?
Answer: Tundra climatic region.

Question 7. Write the name of the climatic region in which the sun is visible even at midnight.
Answer: Tundra region.

Question 8. Which type of climate prevails in the North and South polar regions?
Answer: Tundra type.

WBBSE Class 8 Geography Chapter 8 Question Answer

Chapter 6 Topic B Mediterranean Climatic Region And Tundra Climatic Region Conceptual Questions And Answers Who am I?

Question 1. I am a vast region with uniform temperature, rainfall and natural vegetation. Who am I?
Answer: Climatic region

Question 2. ‘I experience high temperatures, damp and moist climate with heavy rainfall throughout the year and so I am covered with thick forests.’- Who am I?
Answer: Equatorial climatic region

Question 3. I am an Aboriginal of the Zaire basin. I am very short and live on fruits and hunt animals in the forest for meat.’- Who am I?
Answer: Pygmy

Question 4. I experience a combination of seasonal winds that blow over me in summer and change their direction to the opposite during winter. My location is in the central part of Southeast Asia.’- Who am I?
Answer: Monsoon climatic region

Question 5. ‘I move towards the northeast in summer after collecting abundant water vapour from the Indian Ocean. I mark the onset of the rainy season in India. I am a special wind. Who am I?
Answer: South-west monsoon wind

Question 6. ‘I have developed due to the sunny and beautiful weather conditions in the Mediterranean climatic region. I am the best centre of film-making in the world.’- Who am I?
Answer: Hollywood

Scrambled Words

1. GCIMOIL ATCERNI
2. D MAGSARACA
3. ERNEREVEG
4. SLVEA
5. NA FUA
6. NAGDREING
7. MP TERETAE
8. YULECAT PSU
9. LVADEREN
10. I UCT P

Answers:

1. CLIMATIC REGION
2. MADAGASCAR
3. EVERGREEN
4. SELVA
5. FAUNA
6. GARDENING
7. TEMPERATE
8. EUCALYPTUS
9. LAVENDER
10. TOPIC

 

Fill Up The Blanks In The Knowledge Hive

Question 1. Fill in the knowledge hive with information on the natural vegetation of the Equatorial climatic region.

Answers:

1. The trees of the forests in this region are evergreen in nature.
2. These trees grow up to 60 m in height.
3. Different species of trees (around 300) are found in these forests within just 2 sq.km of area.
4. Different types of creepers grow on forest floors.
5. The upper layers of the trees form a thick canopy.
6. The wood of the trees of these forests are very hard and heavy.

 

Chapter 6 Topic B Mediterranean Climatic Region And Tundra Climatic Region Answer Concerning The Illustration

Question 1. Write the names of the regions that experience a Mediterranean type of climate.

Answers:

1. California in North America
2. Chile in South America
3. Cape Town in South Africa
4. Southern and south-western regions of Australia

 

Strike The Odd One Out

Question 1. Equatorial rainforest: Tropical deciduous: Mediterranean forests: Mango orchard
Answer: 1. Mango orchard (it is not a forest in a specific climatic region)

Question 2. Rubber: Rosewood: Woodapple: Ironwood
Answer: Woodapple (it does not grow in the Equatorial evergreen forests)

Question 3. Pygmy: Yakut: Bantu: Semang
Answer: Yakut (they do not live in the Equatorial region)

Question 4. Lapp: Pygmy: Finn: Eskimo
Answer: Pygmy (they do not live in the Tundra region)

Question 5. Topic: Igloo: Railway carriage: Sledge
Answer: Railway carriage (it is not operative in the Tundra region)

Question 6. Kolkata: Rome: Cape Town: Adelaide
Answer: Kolkata (it is the only city that lies within the Monsoon climatic region)

Question 7. Greenland: Brazil: Alaska: Siberia
Answer: Brazil (does not lie within the Tundra region)

 

Correct The Following

1. Tropical winter prevails in the tropical Monsoon climatic region.
2. The Polar climatic belt receives convectional rainfall almost every day.
3. The Mediterranean climatic region is the most densely populated region of the world.
4. Only the Equatorial climatic region receives rain in winter.
5. Agricultural practice is carried on in steel houses in the Polar climatic region.

Answers:

1. Equatorial
2. Equatorial
3. Monsoon
4. Mediterranean
5. green

 

Chapter 6 Topic B Mediterranean Climatic Region And Tundra Climatic Region Crossword

 

CLUES

Down:

1. This city in Italy has a Mediterranean type of climate.
3. Snowstorms in the Tundra region.
5. Fibrous crop is grown in tropical Monsoon climate.

Across:

2. Tent made from sealskin.
4. A type of deer found in the Tundra region.
6. Glass structures used for growing crops in the Tundra region.

Answers:

Down: 1. Naples, 3. Blizzard, 5. Jute
Across: 2. Tupic, 4. Reindeer, 6. Greenhouse

 

Advanced Questions And Answers

Question 1. Write a short note on Pygmy.
Answer:

Pygmy:-

Pygmies live in the Congo or Zaire basin of the Equatorial climatic region. Bambuti, a group of Pygmies live in the forest of eastern Congo. They are very short in height, averaging only 137 cm.

They collect their food from the trees of the forests and cover themselves with barks of trees. Being broad-footed, the Pygmies are expert climbers. They live in groups and travel from one place to another in search of food.

Question 2. Write a short note on Bantu.
Answer:

Bantu:-

The Bantu groups mainly live in Central African countries like the Democratic Republic of Congo, Tanzania, Angola, Cameroon etc. Their lifestyle is a bit more developed than the Pygmies.

They practise shifting agriculture. They burn a portion of the forest and grow potato, maize, cassava, turnip, banana and yams in that cleared areas. Sometimes, they raise animals like goats and fowl.

They live on the outskirts of the forests. Sometimes, they employ Pygmies as labourers.

Question 3. Who are the Red Indians?
Answer:

Red Indians:-

Red Indians are the natives of the Selva forest of the upper Amazon basin, South America. They are mainly hunters and food gatherers.

Some groups practised primitive agricultural activities in the forest fringes. Red Indians wear light cotton dresses. They clear forest areas and build settlements there.

WBBSE Class 8 Geography Chapter 6

Question 4. Write a short note on Semang.
Answer:

Semang:-

The Semangs are the inhabitants of the Malaya Peninsula, Asia. They stay in groups of about 30 people and carry poisonous arrows, bows and horns and other instruments for making noise while hunting.

They wear the bark of trees and animal skins as clothes. They are nomadic by nature and live on tree-top stilt houses. At present, many of them work in rubber plantations.

Question 5. Discuss with examples how ocean currents can influence the climate of a place.
Answer:

Ocean Currents Can Influence The Climate Of A Place:-

There are two types of ocean currents, namely warm ocean currents and cold ocean currents. The temperature of a coastal area depends on the type of ocean current that flows there.

For example, the warm Kuroshio current passes by the eastern coast of Japan and as a result Japan enjoys a comparatively higher temperature and its coastal region remains free from snow throughout the year.

Question 6. How does distance from the sea regulate the climate of a place?
Answer:

Distance From The Sea Regulate The Climate Of A Place:-

Due to the phenomena of land and sea breezes, the temperature of the coastal margins is comparatively cooler than that of places situated far from the sea.

Again, the solid landmasses get quickly heated in summer while the water bodies take a longer time to get heated. Similarly, landmasses can discharge its heat more rapidly than water bodies.

This is due to differences in the specific heat of the landmass and water body. Due to these reasons, places away from the sea experience extreme climatic conditions.

Question 7. How do the winds influence climate?
Answer:

Winds Influence Climate:-

Winds cause a difference in the temperature of places. A wind blowing from the sea (onshore) brings a cooling effect on the land. Moreover, the planetary winds regulate the temperature of a place largely.

For example, in winter, polar winds from the northern polar region enter the continent of North America up to a great distance and so the central part of the USA experiences bitter cold and snowfall in winter.

Question 8. Discuss the influence of climate on the environment of a place.
Answer: Climate is of various types, depending on the latitudinal location and physical features of the land. Some regions are very hot, while some are very cold.

Again, some places might be very wet while others might be very dry. Moreover, some places receive rainfall during summer, while some get rainfall in winter.

For example, the Monsoon climatic regions, with wet summer and almost dry winter season, are covered with deciduous forests. On the other hand, in the Tundra region, it is extremely cold throughout the year and only mosses grow in a particular period.

Chapter 6 Topic B Mediterranean Climatic Region And Tundra Climatic Region Formative

Participation

This segment will indicate how much the students have actively participated and taken the initiative during the class.

The climate of a region is controlled by its latitudinal extent, altitude, proximity to the sea, ocean currents, wind movement, etc. With reference to these factors answer the following:

Question 1. Name some of the important climatic regions of the world.
Answer: Equatorial climatic region/Monsoon climatic region/Tundra climatic region/…

Question 2. Which natural and economic characteristics of a region are influenced by its climatic conditions?
Answer: Natural vegetation/Type of soil/Lifestyle of the people/…

Question 3. How does latitudinal extent influence climate? Give examples.
Answer: The Equatorial climatic region, being located near the equator, receives heavy rainfall throughout the year/the Tundra climatic region experiences an extremely cold climate all year round as it is located around the poles/…

Question 4. What are the characteristic features of the Monsoon type of climate?
Answer: Winds blow from opposite directions during winter and summer/summers are hot and humid but winters are dry/…

Question 2. See, some characteristics of the Mediterranean climate are just opposite to the Monsoon climate of our country. Compare the climate of the two types.

Answer:

 

Question 3. Observe the plants and animals in your surroundings. Write a report about the different characteristics and diversity of the natural environment. Prepare a survey report about the lifestyle (food, clothing, habitat, livelihood) of your neighbours.
Answer:

I am Titir Biswas. I am from Basirhat, North 24 Parganas. Different characteristics and diversity of the natural environment of my village are as follows-

1. Topography:

Basirhat is a perfect example of plain land. This area mainly belongs to the Ganga Delta region.

2. Drainage:

The rivers over here are tidal and thus saline. Navigation in these rivers synced with the occurrence of tides.

3. Climate:

This area is dominated by the Monsoon climate. Summer, monsoon, autumn and winter are distinct seasons here.

4. Soil:

This area is made up of sediments deposited by the rivers. Hence, this area is advanced in agriculture.

5. Vegetation or Flora:

Deciduous vegetation like Mango, Jackfruit, coconut, Palash, Mahua, Sirish etc and Mangrove vegetation like Gewa, Keora, etc are found here.

6. Fauna:

Cow, goats, street dogs, monkeys, snakes, foxes, a huge amount of birds and fishes, etc., are found here.

Lifestyle:

 

Interpretation And Application

This segment will test whether the students have understood the topics, or whether they are just mugging up.

Question 1. Write your explanation about the cause-and-effect relationship between the elements of the physical and socio-economic environment of four specific climate regions.
Answer:

The relationship among four important climatic regions in their physical and socio-economical environment is given in the next table-

WBBSE Class 8 Geography Chapter 6

Question 2. In your opinion which climatic regions are the most and the least socio-economically developed? Draw your opinion and cite the reason.
Answer:

The Mediterranean climatic region is the most developed region, and the Equatorial climatic region is the least developed one. This is because-

 

Question 3. Is there any effect of environment and climate on human lifestyle in your area?
Answer:

Effect Of Environment And Climate On Human Lifestyle In Your Area:-

Yes, the environment and climate affected the human lifestyle in my area. My homeland is located in the Duars region of the Himalayas, which is formed by the silt deposition of different rivers. During summer, rain occurs here, mainly influenced by monsoon wind.

It is an agriculturally prosperous area of West Bengal. This region produces rice, mustard, vegetables, etc. For that reason, most people choose agriculture as their occupation.

WBBSE Class 8 Geography Chapter 6

Question 4. Collect photos of Equatorial rainforests and other major forest type in the world. Also, collect information about the biodiversity of these regions and make a collage.
Answer:

1. Biodiversity of Equatorial climatic region:

1. Flora: Rubber, Rosewood, Brazil Nut, Ironwood, Cocoa, Bamboo, Palm, etc.
2. Fauna: Macaw, Toucan, Golden Monkey, Gorilla, Frog, Anaconda, Cheetah, Orangutan, poisonous insects, etc.

2. Biodiversity of Monsoon climatic region:

1. Flora: Sal, Sishu, Garjan, Teak, Palash, Mahua, Mango, etc.
2. Fauna: Elephant, Cheetah, Deer, Wolf, Tiger, Lion, Rhinoceros, etc.

3. Biodiversity of the Mediterranean climatic region:

1. Flora: Olive, Grapes, Rosemary, Pine, Oak, Maple, Lavender, etc.
2. Fauna: Jaguar, Rabbit, Sheep, Goat, Mule, Donkey, etc.

4. Biodiversity of Tundra Climatic region:

1. Flora: Moss, Lichen, shrub type Juniper, Alder, Birch, etc.
2. Fauna: Whale, Polar fox, Polar bear, Caribou, Seal, Walmus, Fishes, Sledge dog, etc.

5. Biodiversity of Mangrove forest region:

1. Flora: Sundari, Garan, Gewa, etc.
2. Fauna: Crocodile, Tiger, Deer, Hyena, Snake, Monkey etc.

 

 

Chapter 6 Climatic Regions Synopsis

The climate of a region is largely determined by its latitude, altitude, distance from the sea, wind movement, ocean currents, etc.

The areas with almost identical temperatures, rainfall, air pressure, latitudinal extent, humidity, amount of sun rays received, etc., are known as Climatic regions.

the climatic region has almost uniform natural vegetation, soil, biodiversity and lifestyle of the people.

There is a transitional zone between two different climatic regions, where the characteristics of both regions prevail.

The equatorial climatic region is found on both sides of the equator, up to 5°-10° North and South latitudes. This region experiences a hot and humid climate throughout the year.

Read and Learn More WBBSE Solutions For Class 8 Geography

The temperature at night is generally lower than the temperature in the Equatorial region. That is why nights in the Equatorial region are called ‘Winters of the Tropics’.

In the Equatorial region, rainfall with thunderstorms generally occurs from cumulonimbus clouds in the afternoon. This rainfall is known as 4 o’clock rain.

Due to high temperatures and rainfall over the Equatorial region, trees bear green leaves throughout the year. Hence, these forests are called Evergreen forests.

The dense forest cover of the Equatorial climatic region is also known as Equatorial Rain Forest.

Dense evergreen forests in the Amazon basin of Brazil are called Selva.

The trees of the evergreen forests have broad leaves. The trees are so close to each other that their leaves form an overhead layer or canopy.

The trees do not grow lateral branches in the lower part of the trunk, but form canopies with a thick growth of leaves on the top. That’s why forest floors do not receive sun rays and are called lands of ‘eternal darkness’.

Equatorial Climate Characteristics

The Selva forest in Brazil can have up to 300 different species of plants in just 2 sq. km. Creepers and bushes form thick undergrowth in the dark, damp forest floor and make the forest impenetrable.

There are several aborigines in the Equatorial region, e.g., Pygmies in the Zaire basin, Red Indians in the upper Amazon basin, and Semangs in Southeast Asia.

The word ‘Monsoon’ has been derived from the Arabic word ‘mousim’, meaning ‘season’. It is traditionally defined as a seasonal reversal of wind system accompanied by corresponding changes in precipitation.

The monsoon climatic region is found between 10 and 30° North and South latitudes on either side of the equator. The eastern parts of the tropical continents experience this type of climate.

The opposite direction of winds in summer and winter, hot and humid summer and dry winter, etc., are some of the characteristic features of Monsoon. climate.

When the Arabian Sea and Bay of Bengal branches of south-east monsoon enter into the Indian subcontinent, sudden and tremendous rainfall occurs. It is known as the ‘Burst of Monsoon’.

Due to the favourable climate and rapid development in agriculture, transport systems, etc., the Monsoon climatic region is the most populous part of the world.

The Mediterranean climatic region is experienced in the western parts of the sub-tropical continents between 30° and 40° latitudes in both hemispheres. Mediterranean climate is mostly found in the sixteen countries around the Mediterranean Sea.

Sunny weather, cloudless skies, dry summers and wet winters are the main characteristics of the Mediterranean climate. As rainfall occurs in winter, this region is called as ‘Country of winter rainfall’.

Olive is a characteristic tree in the Mediterranean climatic region. Due to bright and abundant sunny weather in this region grapes, figs, apples, pears, peaches, plum, walnuts, peanuts and different types of citrus fruits are grown here. Hence this region is called the ‘Basket of fruits.

The world’s best film-making industry has developed in Hollywood in California, USA due to pleasant weather, sunshine and other favourable conditions.

Tundra, a Russian word, literally means barren, mountainous land, but it also means a type of algae. Tundra type of climate is experienced in the regions around the Arctic and Antarctic Circles.

The Tundra Climatic region is found near the Arctic circle of the northern hemisphere and a very small part along the coast of Antarctica of the southern hemisphere.

Monsoon Climate Features

A short cool summer and a long severe cold winter are the major climatic conditions of the Tundra climate. Winter lasts for about 8-9 months in the tundra region.

During the continuous six months of night in the tundra region, sometimes a rainbow-like light appears in the sky for 2-3 hours. This is known as Aurora Borealis and Aurora Australis in the North Pole and South Pole regions respectively.

In northern Norway at Hammerfest, port (70°30′ North) and nearer areas sun remains visible at midnight according to the local time. Hence this region is called the ‘Land of Midnight Sun’.

Several groups of indigenous people live in the Tundra region. These arctic indigenous peoples include Eskimos and Red Indians in Greenland, Canada and Alaska; Samoyeds and Yakuts in Siberia; Lapps and Finns in the Scandinavian peninsula, etc.

In winter, the inhabitants live in Igloos- round-shaped houses made of snow. In summer, when ice melts away, they live in seal leather tents called Tupic.

Natives of the Tundra region use sledges without wheels over the snow-covered ground and the boat, and kayaks made of seal water skin over the bodies for transportation purposes.

Chapter 6 Topic A Equatorial Climatic Region And Monsoon Climatic Region Analytical Type Questions

Question 1. Define climatic region. Write the features of climatic regions.
Answer:

Climatic region:

The climate of a region is largely determined by its latitude, altitude, distance from the sea, wind movement, ocean currents, etc. The areas with almost identical temperatures, rainfall, air pressure, latitudinal extent, humidity, amount of sun rays received, etc., are known as Climatic regions.

A climatic region has almost uniform natural vegetation, soil, biodiversity and lifestyle of the people. Some of the important climatic regions are- the Equatorial climatic region, the Monsoon climatic region, the Mediterranean climatic region and the Tundra climatic region.

Distribution of Climatic Regions

Features of climatic regions:

The features of climatic regions are as follows-

1. Controlling elements:

Climatic elements such as temperature, rainfall, winds, air pressure, cloudiness, etc. control and determine the climate of a particular region.

2. Extension:

Each climatic region has a particular fixed extent (depending on latitudes).

3. Transitional zone:

There is a transitional zone between two different climatic regions, where the characteristics of both regions prevail.

4. Influence on vegetation and animal life:

The climate of a region influences the plants and animals living there. So, an idea about a climatic region can be made by studying the features of the flora and fauna in that region. For example, olive trees are representatives of the Mediterranean climatic region and polar bears are identifying features of the polar regions.

5. Influence on humans:

Climatic regions influence the socio-economic environment of man to a great extent. Food habits, clothes sense, houses, etc. are influenced by climate.

6. Sub-division of regions:

A big climatic region may have multiple sub-divisions for variation of climatic elements and location.

Question 2. Discuss the influence of climate on human lifestyle.
Answer:

Climate On Human Lifestyle:-

The climate of the dwelling place exerts the greatest influence on the inhabitants. Their food habits, dresses, house and all cultural and economic activities etc., are all dependent on the climatic conditions of the region they live in.

Clothes:

The clothes that people wear depend on the climatic pattern of that area. People living in the torrid zone wear light cotton clothes. In temperate and cold regions, people prefer woollen and leather garments.

Those living in the desert region have to wear long-covered dresses from head to toe to avoid the severe heat of the day.

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Dwelling places:

The roofs of the huts in the equatorial region are highly slanting and low. The floors of the huts are raised a few centimetres from the ground because of excessive rainfall and damp ground condition.

Again, Eskimos live in igloos to get protection from bitter cold and snowfall.

Livelihood:

People in the Equatorial region are mostly gatherers of forest products and hunters. As the climate is extremely hot and humid, agriculture is not practised in this region.

On the other hand, people living in tropical Monsoon climate regions and in temperate climate regions have maximum earnings from agriculture. In the cold tundra and the cool temperate regions, the main occupation of the people is fishing.

People in the wet and warm temperate climatic zones are now making rapid progress in industries.

Question 3. Discuss the special features of the Equatorial climatic region.
Answer:

Special Features Of The Equatorial Climatic Region:-

The Equatorial climatic region is found on both sides of the equator up to 5°-10° North and South latitudes. The following are the special characteristics of this region-

1. Temperature:

The annual average temperature of this region remains about 27°C. Temperatures generally vary from 25°C-30°C.

2. Range of annual temperature:

The annual range of temperature is 2°C-3°C and so it is summer all through the year.

3. Range of diurnal temperature:

The difference in temperature between days and nights is about 5°C-10°C and so nights are comparatively colder. Nights, here, are called tropical winters.

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4. Angle of sun’s rays:

The Equatorial region receives almost perpendicular sunrays throughout the year.

5. Air pressure:

The region has a permanent low-pressure belt and so convection currents are present. Thus doldrum’ (a region of calm) prevails here.

6. Humidity:

This region has a larger water surface than land and the vertical sun rays help in evaporation. So, the humidity of the air is very high and hence, damp weather prevails throughout the year.

7. Rainfall:

In this region, convectional rainfall occurs from cumulonimbus clouds, along with thunderstorms. It is known as 4’o clock rain or afternoon shower. There are about 250 to 300 rainy days in a year and the annual average rainfall is 200 cm to 250cm.

8. Cloudiness:

The sky is generally clear in the morning but gets heavily overcast with cumulonimbus clouds in the evening.

9. Absence of seasons:

The sun is overhead throughout the year so the region has only one season, that is summer.

 

Question 4. Discuss the variety of flora and fauna in the Equatorial region.
Answer:

Variety Of Flora And Fauna In The Equatorial Region:-

Due to excessive temperature, rainfall and other climatic features, various types of flora and fauna can be noticed in this region.

Variety of flora:

In the Equatorial region, hot and humid atmospheres have brought about diversity in the plant kingdom. The different varieties of trees found in this region are-

Impact of Climate on Biodiversity

1. Evergreen trees:

In the Amazon basin of Brazil and the Zaire basin of Africa, forests of evergreen, broad-leaved, and hardwood trees are found. In Brazil, these forests are called Selva.

It has been noticed that in some parts of the rainforests of Brazil, there are about 300 species of trees within just 2 sq. km of land. The trees are tall with a canopy on the top. Canopy does not allow sunlight to penetrate and reach the forest floor.

Creepers and bushes form thick undergrowth in the dark, damp forest floor and make the forest impenetrable. Rosewood, ironwood, mahogany, ebony, cocoa, brazil nut, cinchona, ablus and rubber are the important trees of this region.

2. Weeds:

Tall trees are covered with various types of parasites, creepers, ferns, etc.

3. Other trees:

Coconut, palm, betel nuts and palmyra are common in the coastal areas.

Variety of fauna:

Convectional rainfall and dense inaccessible forests with evergreen trees have encouraged a variety of animals to live here. Animals which can climb tall trees are mostly found in this region. Animals residing in these forests are as follows-

1. Animals residing in the uppermost parts: Golden monkeys, flying squirrels, macaw, toucan, orangutang, etc. live here.
2. Animals residing in the mid-parts: Gorillas, chimpanzees, monkeys, bats and various insects live here.
3. Animals living on the forest floor: Leopards, wild boars, cheetahs, deer, fox, rhinoceros, elephants, etc. live near the ground surface.
4. Animals in the water bodies: In swamps and rivers live crocodiles, poisonous snakes, hippopotami, anacondas, etc.

 

 

Question 5. Discuss the socio-economic condition of the people residing in the Equatorial climatic region.
Answer:

Socio-Economic Condition Of The People Residing In The Equatorial Climatic Region:-

Due to hot and humid climate and a dangerous environment, the population density of this region is very low. The density of the population is not even one on average in the Amazon and Zaire basins.

Socioeconomic status of the people (mostly tribes) residing in this region is discussed below-

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Gathering:

The aborigines of the Equatorial climatic region collect fruits and roots from the forests for their livelihood. Pygmies of the Zaire basin, Red Indians of the upper Amazon basin, and Semangs of south-east Asia collect flowers, roots, fruits, leaves, rubber latex and other materials available there, to live on. Some of them collect only latex for a living.

Hunting:

Tribes like Pygmy, Bantu and Moora hunt animals in the forest.

Agriculture:

Primitive methods of cultivation are still practised in the Equatorial region. Three types of agriculture are carried on here-

Shifting cultivation:

This is also called the ‘slash and burn’ method of cultivation. In this method of cultivation, the people clear a plot in the forest by cutting trees and burning the stalks.

Then they grow crops in that plot for a few years. When the fertility of the soil decreases, they just shift to another plot. Turnip, banana, sweet potatoes, yam, maize, etc. are grown in this way.

 

 

Plantation farming:

Rubber, cocoa, banana and palm are the important crops of plantation farming in the equatorial region.

 

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Intensive cultivation:

In Southeastern countries of Asia, intensive cultivation of paddy is practised.

 

Mineral resources:

Tin is obtained from Malaysia and Indonesia. Mineral oil and natural gas are obtained in large volumes from Sumatra, Java and Borneo.

Industrial production:

Industries have not developed in the Equatorial region due to unfavourable conditions. However, certain agro-based, forest-based and mineral-based industries have developed on a small scale.

Among these are-

1. Mineral oil refinery
2. Rubber production from latex
3. Palm oil production from palm trees
4. Coffee processing
5. Sugar processing from sugarcane
6. Timber industry with wood obtained from local forests.

Comparison of Equatorial and Monsoon Climates

 

 

Question 6. Discuss the features of the Monsoon climatic region.
Answer:

Features Of The Monsoon Climatic Region:-

Monsoon climate is found from 10° to 30° latitudes in both hemispheres, in the eastern part of the continent. Following are the special characteristics of this region-

1. Warm summers and mild winters:

Hot humid summer and dry mild winter are the main characteristics of this region. The maximum temperature of this region in summer is 30°C on an average, while it is 25°C on average in winter.

2. Winds blow from opposite directions season-wise:

Winds in summer and winter blow from opposite directions. For example, south-west monsoon winds from the seas bring rain to the Indian subcontinent in summer, while in winter, dry north-east monsoon winds (retreating monsoon) blow from land to sea.

3. Sufficient rainfall:

Monsoon climatic regions receive 150-200 cm of rainfall on an average, depending on physiography and distance from the sea. The amount of rainfall received also varies.

Monsoon rains are uncertain. Mawsynram is the wettest place in the world receiving more than 1200 cm of average annual rainfall, while the Thar desert of Rajasthan receives scanty or no rainfall.

Climatic Zones in India

4. Succession of various seasons:

Two opposite wind systems (south-west and north-east) have caused four seasons.

Example-In the northern hemisphere

1. A dry, cold season called ‘winter’ prevails from November to January.
2. A warm, dry season called ‘pre-monsoon summer’ prevails from March to May.
3. The wet season called the ‘monsoon rainy season’ prevails from June to September.
4. A transition of wet season to cold season called ‘autumn’ prevails from September to October.

Just the opposite seasonal conditions prevail in the Monsoon climatic regions of the southern hemisphere at the same time.

5. Air pressure:

An intensive low-pressure zone forms over the Tropic of Cancer in the northern hemisphere by the influence of the monsoon climate in summer. Hence, cold, high-pressure winds from the southern hemisphere come rushing towards the low-pressure zone. Opposite. conditions prevail in winter.

Question 7. Discuss the economic developments in the Monsoon climatic region.
Answer:

Economic Developments In The Monsoon Climatic Region:-

Economic condition of the Monsoon climatic region has developed remarkably. It has been discussed under the following points-

1. Agricultural development:

Favourable natural conditions (like- climate, and fertile soil) encourage the inhabitants to make progress in agricultural activities. They produce paddy, wheat, jute, tea, coffee, sugarcane, cotton, rubber, lentils, oilseeds, etc. in large quantities.

Out of this, paddy occupies the topmost position. This region is very important for producing fruits like mango, jamun, jackfruit, litchi, banana, pineapple, guava, etc.

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2. Abundant animal products:

Though grasslands for commercial grazing are not available in this region, domestic animals are reared everywhere. Cows, goats, sheep and buffaloes are mostly reared as domestic animals.

Milk and milk-based products, meat, etc. are the important animal products of this region. Silkworms and lac insects are reared, along with poultry farming.

3. Pisciculture:

Inland water bodies have helped in the development of fisheries. Fishing is also carried out in the coastal regions.

4. Mining of mineral resources:

This climatic region is rich in minerals. Mining iron ore, manganese, bauxite, coal, and mica from India; tin, lead, zinc, copper, and mineral oil from Thailand; bauxite and iron ore from Australia help many inhabitants to earn their livelihoods.

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5. Development of industries:

Various industries have developed in some places in this region, based on agricultural and mineral raw materials. For example-

1. Iron and steel, cotton textile, jute textile, sugar, engineering industries of India,
2. Jute textile industry of Bangladesh,
3. Mineral oil refining of Myanmar,
4. Electronics and engineering industry of Thailand,
5. Sugar, cotton textile and jute textile industries of China,
6. The cotton textile industry of Pakistan.

6. Density of population and urbanisation:

The Monsoon climatic region of Asia is the most densely populated region in the world due to favourable climate, fertile soil, enriched agriculture and advanced transport network.

Due to this, a large number of people have settled in the plains of the rivers Ganges, Indus, Brahmaputra, Irrawaddy, Sikiang, Mekong, Chao Phraya, etc. Many metropolitan cities have developed in these regions.

For example-

1. Mumbai, Kolkata, Delhi, Chennai, Hyderabad, and Bengaluru in India,
2. Karachi, Lahore in Pakistan,
3. Dhaka in Bangladesh,
4. Colombo in Sri Lanka,
5. Yangon in Myanmar,
6. Bangkok in Thailand,
7. Hanoi in Vietnam, etc.

7. Collection of forest products:

Some people living here earn their livelihood by collecting forest products and from the industries based on those products. Sal, teak, mahogany, etc., are used for furniture making and shipbuilding; bamboo and sabai grass for making paper pulp and paper.

Other important products obtained from these forests include rubber latex, honey, lac wax, medicinal herbs, etc.

Chapter 6 Topic A Equatorial Climatic Region And Monsoon Climatic Region Short Analytical Type Questions

Question 1. Where in the world can the Equatorial type of climate be found?
Answer:

The World Can The Equatorial Type Of Climate Be Found:-

Generally, the Equatorial type of climate is found between 5°-10° North and South latitudes. This type of climate is seen in the following regions-

1. South America: Amazon basin, i.e., the northern part of Brazil and western coast of Columbia.
2. Africa: Guinea coast, Congo or Zaire basin and eastern part of Madagascar.
3.  Central America: Panama, Costa Rica, Nicaragua, Honduras, Guatemala and some parts of Caribbean islands.
4.  Asia: Indonesia, Malaysia, Singapore, Philippines, south-western India, southern Sri Lanka, etc.

Question 2. The nights of the Equatorial region are called ‘tropical winters’-Justify.
Answer:

The Nights Of The Equatorial Region Are Called ‘Tropical Winters’:-

The Equatorial region remains very hot throughout the year as it receives vertical sun rays. The average day temperature generally records 25°C-30°C. As a result, excessive evaporation takes place.

This increases temperature, as well as humidity. At night the temperature drops about 20°C-25°C. The heat is distributed over a large area. Hence, the nights remain cold and are termed as tropical winters.

Weather Patterns in Equatorial Regions

Question 3. Discuss the characteristics of the Equatorial evergreen forest.
Answer:

Characteristics Of The Equatorial Evergreen Forest:-

The important characteristics of the Equatorial evergreen forests are as follows

1. The trees of the Equatorial rainforests are about 60m in height.
2. Trees do not grow lateral branches in the lower part of the trunk, but form canopies with thick growth of leaves on the top. Thus, the forest floors do not receive sun rays and are called ‘Lands of eternal darkness.
3. These evergreen forests are very dense and impenetrable.
4. Many types of valuable trees grow here.
5. A classfication according to the height of the trees can be noticed here.

 

 

Height-wise there are five distinct layers

1. Dominant or emergent layer- trees are 30-60 m in height.
2. Co-dominant or canopy layer trees are 25-30 m in height.
3. Understorey layer trees are 12-20 m in height.
4. Herbaceous or shrub layer- bushes and shrubs grow here.
5. Forest floor layer-creepers, fern, orchids, etc. grow here.

Question 4. Briefly write about Selva forest.
Answer:

Selva Forest:-

The denser forests of the world can be found in the Equatorial region. These forests are characterised by extreme heat, humidity and rainfall throughout the year.

These Equatorial rainforests in Brazil are called Selva. The trees growing in these forests compete with each other to get sunlight. So, the trees are very tall with broad leaves and form canopies in the upper layers of the forest.

 

These canopies do not allow sunlight to penetrate and reach the forest floor. They also have long trunks with large diameters that yeild hard and heavy wood.

Creepers and bushes form thick undergrowth in the dark, damp, forest floor and make the forest impenetrable. The trees of these forests are naturally arranged height-wise. In some places, about 300 species are found within just 2 sq.km of land.

These forests have trees like rosewood, ironwood,, cocoa, coffee, rubber, brazil nut, sandalwood and ebony.

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Question 5. Discuss the significance or uses of the forests of the Equatorial region.
Answer:

Significance Or Uses Of The Forests Of The Equatorial Region:-

The significance of the rainforests of the Equatorial region is discussed below-

1. Rubber, a tree of the Equatorial rainforest, is tapped to produce latex for making rubber, which is known as ‘Black gold’ in Brazil.
2. Brazil nuts, when crushed, produce oil and their shells are used for making buttons.
3. Chewing gum is extracted from the trees called japoti.
4. Edible oil, soaps, glycerine, etc., are produced from palm oil.
5. Quinine, an antidote of malaria, is extracted from the bark of cinchona trees.
6. Some of the hard wood of the forest are used in furniture making, ship building, construction of stages or in other structural works.

Question 6. Why has agriculture not developed much in the Equatorial region?
Answer:

Agriculture Not Developed Much In The Equatorial Region:-

Agricultural practices have not developed much in the Equatorial region, because-

1. Excessive rainfall:

Even though rainfall is required for cultivation, excessive rain damages crops. As it rains every day in the equatorial region, most crops get damaged.

2. Dense vegetation:

The Equatorial region is mostly covered with dense evergreen rainforests. If the land is left vacant for a few days, it gets covered with weeds and bushes.

3. Insects and pests:

The damp and moist climate of the Equatorial region facilitates the growth of insects and pests. These attack and damage the crops.

4. Use of primitive techniques for cultivation:

Since the countries on or near the equator are economically backward, they use primitive techniques for cultivation. The output by these methods of cultivation is very low.

Question 7. Why has lumbering not developed in the Equatorial climatic regions?
Answer:

Lumbering Not Developed In The Equatorial Climatic Regions

Equatorial climatic regions have dense developed there because of the following evergreen forests, yet lumbering has not factors-

1. Types of trees:

The trunks of evergreen trees are so hard that the felling of trees is very difficult in this region. In the Equatorial region, trees of different species grow together, making the forests very dense.

As a result, collection of wood from these forests become difficult. The collectors often have to wonder deeper into the forest in search of the exact products.

2. Inconvenience in transportation:

The ground or the forest floor of the Equatorial rainforest remains wet and humid. Hence, building of roads and railway tracks for transportation of logs is very difficult and expensive.

3. Disease-prone climatic conditions:

Accumulation of water on the forest floor leads to the growth of different types of poisonous insects, flies, mosquitoes, etc., which spread a number of diseases. So, it is very difficult to collect timber safely from these forets.

4. Unavailability of labourers:

Labour is not available in the Equatorial forest regions and so felling of trees, collection and transportation of logs, etc. are highly inconvenient processes there.

5. Inaccessible forest:

The Equatorial rainforests are so inaccessible that no one can enter in the forests easily.

Human Adaptation to Climatic Regions

Question 8. Give the location of the Monsoon climatic zone.
Answer:

Location Of The Monsoon Climatic Zone:-

The location of the Monsoon climatic region may be depicted as-

1. Latitudinal location:

The region lies roughly between 10°-30° North and South latitudes on either side of the equator.

2. Geographical location:

The geographical location of the Monsoon climatic zone is mentioned below-

1. India, Pakistan, Bangladesh, Mayanmar, Thailand, Laos, Vietnam, Cambodia, Taiwan, South China and some parts of the Philippines in south and south-east Asia record the maximum influence of the Monsoon climate.
2. Madagascar, Somalia and Mozambique in the eastern part of Africa are also influenced by this climate.
3. Florida and Mexico in North America lie within the Monsoon region.
4. The east coast of Brazil in South America experiences this type of climate.
5. Queensland in the northern part of Australia also records Monsoon climatic features.

 

Question 9. Why does the Monsoon climatic region receive scanty rainfall in winter?
Answer:

Monsoon Climatic Region Receive Scanty Rainfall In Winter:-

Generally seasons occur alternately in the two hemispheres. When there is summer in the northern hemisphere, it is winter in the southern hemisphere and vice versa.

But the monsoon region of both hemispheres receives negligible rainfall in the winter season. This is because, during winter in both hemispheres, the high pressure (due to low heat) develops over the landmass and the adjacent warmer water bodies have low pressure over them (water bodies take a longer time to discharge heat).

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So, the land breeze blows towards the seas. This dry wind cannot cause any rainfall. However, in some cases, the retreating monsoon winds from the land pass over water bodies and collect some amount of moisture from there.

These then cause rainfall in the area of land they blow over next. For example, in the Tamil Nadu coast, India scanty rainfall | snakes, insects, etc., due to their thick occurs in winter due to these winds.

Question 10. Describe the natural vegetation of the Monsoon climatic region.
Answer:

Natural Vegetation Of The Monsoon Climatic Region:-

A variety of natural vegetation is found in different parts of the Monsoon climatic region, depending on the amount of rainfall and temperature of that area.

For example-

1. Evergreen trees:

In the areas receiving 200 cm or more rainfall annually, grow mahogany, sishu, rubber, garden, etc.

2. Deciduous trees:

In the areas receiving 100cm-200 cm of rainfall annually, grow sal, steam, sirish, teak, palash, mahua, sagoon and fruit orchards of mango, blackberry, jackfruit, etc.

3. Shrubs and bushes:

In the areas receiving 50cm-100 cm of rainfall annually, grow pear, acacia, bushes and shrubs.

4. Desert vegetation:

In the areas where annual rainfall is less than 50 cm, grow desert vegetation that include cactus, babla, date, palm, and thorny bushes.

5. Mangrove forest:

In the sea coasts and deltas of rivers, where tides are active and keep the soil salty, mangrove forests are found. Trees like Sundari, garan, gewa, hentai, etc. are mainly seen in this forest.

Question 11. What do you know about the fauna of the Monsoon climatic region?
Answer:

Fauna Of The Monsoon Climatic Region:-

There are many animals like monkeys, deer, elephants, rhinoceros, cheetahs, tigers, wolves, bears, hyenas and foxes, which are found in the forests of Monsoon climatic region. Only in the Sundarbans of India-Bangladesh, the world-famous royal Bengal tigers are found.

Crocodiles are found near river estuaries of the coastal area. One-horned rhinoceros are found in the forests of Assam and North Bengal. Lions are found only in the Gir forest in Gujarat in India.

Apart from these, the dense forests that receive excessive rainfall have different types of birds, and vegetation growth. The grassland of the monsoon climatic region is used for rearing domestic animals like cows, goats and sheep.

Question 12. Why is the Monsoon climatic region? most densely populated?
Answer:

Monsoon Climatic Region:-

The Monsoon climatic region is most densely populated due to the following reasons-

1. Favourable climate:

In this region, the average temperature varies from 20°C-30°C and the annual average rainfall is 150cm- 200 cm. Hence, people prefer to live in this congenial climatic area.

2. Soil:

The alluvial soil (silt) of the river basins are highly fertile and suitable for agriculture. The black soil found in this region is also very good for cultivation.

3. Forest resources:

The timber from the evergreen and deciduous forests and other forest products are helpful for the livelihood of the residents.

4. Mineral resources:

This region has mineral resources like iron, copper, coal, manganese, bauxite, mineral oil, etc. which are important for the development of various industries.

5. Agricultural practice:

The favourable climate, fertile soil, and availability of water have made the region rich in the production of paddy, wheat, jute and other edible corn.

6. Industry:

The concentrated development of industries like iron and steel, cotton textiles, sugar, jute, oil refining, etc. has led to increased population density in this region.

Question 13. Name some areas of the world, which have the same climatic condition as your own country. 
Answer:

Some Areas Of The World, Which Have The Same Climatic Condition As Your Own Country:-

We live in India, a country dominated by the Monsoon climate. This climate influences the region lying between 10° and 30° latitudes in both hemispheres.

This type of climate prevails in some areas of the world apart from our country.

For example-

1. The Monsoon type of climate is mostly prevalent in countries which are located in south and south-east Asia, like Pakistan, Myanmar, Bangladesh, Thailand, Laos, Taiwan, South China, Taiwan, Cambodia and Vietnam.
2. Countries on the eastern coast of Africa (Madagascar, Somalia, Mozambique, etc).
3. Coasts of Florida and Mexico in North America.
4. The eastern coast of Brazil in South America.
5. Queensland in northern Australia.

Seasonal Changes in Monsoon Regions

Question 14. Write the differences between the Equatorial climate and the Monsoon climate.
Answer:

The differences between the Equatorial climate and the Monsoon climate are-

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Question 15. Is there any relation between origin of the monsoon and differences in air pressure and temperature over landmass and water bodies in the seasons of summer and winter?

Answer: During winter in the northern hemisphere, the sun becomes perpendicular over the Tropic of Capricorn in the southern hemisphere. High-pressure areas are developed over Asian landmass due to very low temperatures.

On the contrary, low-pressure areas are developed in the southern Indian Ocean owing to high temperatures. Consequently, wind blows from high-pressure areas to low-pressure areas, resulting the North-east monsoon or Winter monsoon.

The above conditions are reversed in summer in the northern hemisphere. The sun becomes vertical over the Tropic of Cancer and oblique over the southern Indian Ocean.

High-pressure area is developed over the water bodies and low-pressure area is formed over the Asian landmasses. Therefore, wind starts blowing from the southern Indian Ocean to the Indian subcontinent, resulting the South-west monsoon or Summer monsoon.

So, there is a close relation between the origin of monsoon and the differences in temperature and air pressure over landmass and water bodies in the seasons of summer and winter.

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Chapter 6 Topic A Equatorial Climatic Region And Monsoon Climatic Region Short Answer Type Questions

Question 1. What is a climatic region?
Answer:

Climatic Region:-

The climate of a region is largely determined by its latitude, altitude, distance from sea, wind movement, ocean currents, etc.

The areas with almost identical temperatures, rainfall, air pressure, latitudinal extent, humidity, amount of sun rays received, etc., are known as Climatic region.

A climatic region has almost uniform natural vegetation, soil, biodiversity and lifestyle of the people. Example-countries like India, Pakistan, Bangladesh, Myanmar, Thailand, Laos, Vietnam, etc. lie in the Monsoon climatic region.

Question 2. Explain how natural vegetation and climate change with the increasing altitude of a place.
Answer:

Natural Vegetation And Climate Change With The Increasing Altitude Of A Place:-

Due to the inverse relationship between temperature and altitude, there will be a drop in temperature by 6.5°C for every 1000m of ascent. There will also be changes in vegetation cover of the mountain slopes with increasing altitude.

As a result, evergreen forests grow on the foothills, the deciduous forests grow between 1000m and 2000 m of height, the coniferous forests grow within 2000m- 4000 m of height and above that grow the Alpine grassland.”

Question 3. What does a juncture of various climatic zone mean?
Answer:

A Juncture Of Various Climatic Zone Mean:-

Various climatic regions are separated by fine lines on maps, but actually it cannot be so, because one climatic area can slowly merge into the neighbouring one by natural process.

Thus, an area convergence or juncture is formed between two neighbouring climatic regions. This region is also known as transitional zone, where characteristics of both climatic zones may prevail. Such junctures extend almost up to 100-150 km.

Question 4. Why does the Equatorial region have continuous summer throughout the year?
Answer:

The Equatorial Region Have Continuous Summer Throughout The Year:-

The Equatorial region receives almost vertical rays of the sun throughout the year and so the temperature remains very high there. No change of temperature occurs even after northern and southern solstices or summer and winter solstices.

The annual difference in temperature is only 2°C-3°C. Here, the temperature can rise up to 30°C during the day. Besides these, the region has many water bodies and so its humidity is also high. Thus, the equatorial region has summer throughout the year.

Question 5. There is no change of seasons in the Equatorial region, yet it is cold at night. Why?
Answer:

There is no change of seasons in the Equatorial region, yet it is cold at night:-

The Equatorial region receives almost vertical rays of the sun during the day throughout the year, and so the difference in temperature is only 2°C-3°C annually.

But the difference between the day temperature and the night temperature is almost 5°C-10°C. This is mainly due to afternoon showers and radiation of heat at night from the earth’s surface. Thus, at night the temperature drops down.

Question 6. Why is rainfall a daily phenomenon in the Equatorial region?
Answer:

Rainfall A Daily Phenomenon In The Equatorial Region:-

The Equatorial region’s intense low-pressure zones develop due to extremely hot weather conditions. The region also has many water bodies, which increase the amount of moisture in the air.

The moist and hot air in this region rises (by convection), gets cooled and condenses in the upper layers of the atmosphere. This causes convectional rainfall almost every day in the afternoon.

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Rainfall occurs for about 250- 300 days a year in this region.

Question 7. Most of the people in the Equatorial region are hunters and gatherers of fruits. Why?
Answer:

Most Of The People In The Equatorial Region Are Hunters And Gatherers Of Fruits:-

The inhabitants of the Equatorial region are basically hunters and gatherers. Due to the extremely hot and moist climate, dense forests are found in this region.

Hence, agriculture is not practised in this region. The people here hunt animals and collect fruits and roots for food from these dense evergreen forests.

Question 8. What is the significance of the name ‘monsoon’?
Answer:

Significance Of The Name ‘Monsoon’:-

The word ‘monsoon’ has been derived from the Arabic word ‘mouse’, meaning season. Seasonality is a salient feature of the monsoon climate. It is also called a season-wise periodical wind system.

It is a larger-scale version of land and sea breezes. The climate of this entire region is under the influence of the monsoon winds and is hence called the Monsoon climatic region.

Question 9. What is a burst of monsoon?
Answer:

Burst Of Monsoon:-

In the month of June, the Tropic of Cancer receives vertical rays of the sun. So, the north-western part of India experiences extremely high temperatures and intense powerful low pressure develops over the region.

Due to this low pressure, moist winds from the Arabian Sea as well as from the Bay of Bengal enter into India rapidly. Consequently, the Indian landmass becomes cloud covered and torrential rain with thunder and lightning occurs.

This is called burst of monsoon. This system causes the first rainfall of the season in Kerala.

Question 10. Why are monsoon winds erratic in behaviour?
Answer:

Monsoon Winds Erratic In Behaviour:-

There is no consistency in the arrival and retreat of the monsoon winds. It can be timely or late in arrival and this uncertainty at times leads to droughts or conditions of flood.

Thus, the Monsoon winds are said to be whimsical or erratic in nature.

Question 11. Where in India do we find tropical evergreen and deciduous forests?
Answer:

We Can Find Tropical Evergreen And Deciduous Forests In India:-

The tropical evergreen forests are found in the western slopes of the Western Ghats, Meghalaya Plateau, Andaman and Nicobar Islands, Lakshadweep Islands, and foothills of the Himalayas.

The deciduous forests are found in The Tarai and Duars region of the Himalayas, Odisha, Chota Nagpur Plateau, Madhya Pradesh and other states like West Bengal, Bihar, Uttar Pradesh, etc.

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Chapter 6 Topic A Equatorial Climatic Region And Monsoon Climatic Region Multiple Choice Questions Choose The Correct Option

Question 1. The main determinant of the climate of a region is-

1. Latitudinal extension
2. Wind movement
3. Altitude
4. Human activity

Answer: 1. Latitudinal extension

Question 2. Convectional rainfall occurs throughout the year in-

1. India
2. Bangladesh
3. Spain
4. Indonesia

Answer: 4. Indonesia

Question 3. Degree of biodiversity is highest in-

1. Tundra region
2. Equatorial region
3. Mediterranean region
4. Monsoon region

Answer: 2. Equatorial region

Question 4. The regions stretching from 10°-30° North and South latitudes and situated in the eastern margins of continents experience-

1. Monsoon type of climate
2. Equatorial climate
3. Tundra climate
4. Mediterranean climate

Answer: 1. Monsoon type of climate

Question 5. A country situated in the Monsoon climatic region is-

1. Italy
2. India
3. Russia
4. Greece

Answer: 2. India

Question 6. Winds blow from opposite directions during winter and summer in the-

1. Monsoon climatic region.
2. Mediterranean region
3. Tundra region
4. Equatorial region

Answer: 1. Monsoon climatic region.

Question 7. The Monsoon climatic region receives maximum rainfall in-

1. Summer
2. Autumn
3. Winter
4. Throughout the year

Answer: 1. Summer

Question 8. A Burst of monsoon indicates-

1. End of the rainy season
2. End of winter
3. Consent of winter
4. The onset of the rainy season

Answer: 4. Onset of the rainy season

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Question 9. Different types of domesticated mammals are found in-

1. Tundra region
2. Equatorial region
3. Mediterranean region
4. Monsoon region

Answer: 4. Monsoon region

Question 10. The main crop that grows in the Monsoon climatic region is-

1. Paddy
2. Wheat
3. Cotton
4. Maize

Answer: 1. Paddy

Question 11. This amount of the world’s population lives in the Monsoon climatic region-

1. Fifty per cent
2. One-fourth
3. One-third
4. One-fifth

Answer: 1. Fifty per cent

Question 12. The ‘Rice Bowl’ of China is-

1. Hunan
2. Yangtze Kiang
3. Beijing
4. Hwang Ho

Answer: 1. Hunan

Chapter 6 Topic A Equatorial Climatic Region And Monsoon Climatic Region Very Short Answer Type Questions Fill In The Blanks

Question 1. Places situated on the same parallel of latitude have almost similar ________.
Answer: Climate

Question 2. The boundary between two different climatic zones is known as the ________.
Answer: Transitional zone

Question 3. Length of day and night is almost equal in ________ climate.
Answer: Equatorial

Question 4. ________ rainfall occurs predominantly in the Equatorial climatic region.
Answer: Conventional

Question 5. The overlay, made up of the overlapping branches and leaves of the trees of a rainforest, is known as ________.
Answer: Canopy

Question 6. Rosewood, ironwood and Brazil nut trees grow in the ________ climatic region.
Answer: Equatorial

Question 7. Rubber, cocoa, coffee, sugarcane and palm are ________ crops.
Answer: Plantation

Question 8. The main adverse effect of the construction of the Trans-Amazon Highway is loss of ________.
Answer: Biodiversity

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Question 9. Sandalwood trees grow in the ________ climatic region.
Answer: Monsoon

Question 10. The city of Shanghai in China is located in the ________ climatic region.
Answer: Monsoon

Write True Or False

Question 1. The climate is the average change of the weather conditions of a place over 40-45 years.
Answer: False

Question 2. Queensland, in the north of Australia, shows a slight influence of the Monsoon climate.
Answer: True

Question 3. The average annual rainfall in the Monsoon climatic region is 50cm-100 cm.
Answer: False

Question 4. One of the chief characteristics of the Monsoon climate is the periodicity of seasons.
Answer: True

Question 5. The deciduous forest of the Monsoon climatic region is called tropical Monsoon forest.
Answer: True

Question 6. There are four main seasons in a year of the Monsoon climatic region.
Answer: True

Match The Columns

1.

Answer: 1. C, 2. A, 3. B, 4. E, 5. D

 

Answer In One Or Two Words

Question 1. Mention a country in Central America, that experiences an Equatorial climate.
Answer: Panama.

Question 2. What is the average annual temperature of the Equatorial region?
Answer: 27°C.

Question 3. Which type of rainfall occurs in the Equatorial climatic region?
Answer: Convectional rainfall.

Question 4. Which climatic region records the maximum variety of animal life?
Answer: Equatorial climatic region.

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Question 5. Name two indigenous people from the Equatorial climatic region.
Answer: Pygmy of Zaire basin and Semang of South- east Asia.

Question 6. Which climatic region is not socio-economically rich?
Answer: Equatorial climatic region.

Question 7. Which area in Australia experiences a Monsoon type of climate?
Answer: Queensland of northern Australia.

Question 8. Which wind blows over India in winter?
Answer: North-east monsoon/Retreating monsoon.

Question 9. How many seasons can be found in Monsoon climatic region?
Answer: Four.

Question 10. Name two important plant species of mangrove forest.
Answer: Sundari, Garan, Gewa, etc.

Question 11. Name the world’s maximum paddy and jute-producing climatic region.
Answer: Monsoon climatic region.

Chapter 5 Topic B Precipitation Analytical Type Questions

Question 1. Explain the process of convectional rainfall with a diagram and examples.
Answer:

Process Of Convectional Rainfall With A Diagram:-

This type of rainfall is caused by convection currents generated in the atmosphere by the sun’s heat. So, it is known as convectional rainfall.

Some places on earth (especially the Equatorial region) have greater areas under waterbodies as compared to land and experience extremely hot climatic conditions due to perpendicular sun rays.

The air above land and water surfaces, being very hot and light, rises vertically, along with its moisture content. In the higher and cooler layers of the atmosphere, the air gets saturated due to a decrease in temperature and the water vapour in it cools and condenses into small droplets of water.

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The droplets gather around dust particles to form clouds. When the clouds get denser and the drops of water become bigger, they drop down as rain on Earth. This type of rainfall is known as convectional rainfall.

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Characteristics of convectional rainfall:

The characteristics of convectional rainfall are as follows-

1. Origin and another name:

Usually, cumulonimbus clouds cause convectional rain. It is also called ‘4 o’clock rain’ or ‘afternoon shower due to its occurrence in the afternoon or evening.

2. Area:

Convectional rainfall occurs on either side of the equator, up to 5°-10° latitudes and also in the tropical regions.

3. Type and nature:

This type of rainfall has a short duration but the amount is very high and the sky becomes completely clear after the rainfall.

4. Amount of rain:

It is about 200 cm-300 cm annually on average in the Equatorial region.

5. Time:

Rainfall occurs throughout the year in the Equatorial region, in the beginning of summer in the temperate regions and in the pre-monsoon or autumn season of the tropical regions.

Class 8 Geography Chapter 5 Types of Precipitation

6. Occurrence of thunderbolts:

Thunderbolts are very common along with convectional rain. Example-Thunderbolts are very common with Kalbaishakhi.

 

Example; The Equatorial region receives convectional rainfall every afternoon, while the tropical zone receives it at the beginning of summer. The state of West Bengal in India receives convectional rainfall occasionally during late summer afternoons.

Question 2. Explain orographic rainfall with an example and a diagram.
Answer:

Orographic Rainfall:-

When moist air from waterbodies blows towards land and is obstructed by a mountain in its path, it is forced to rise along the slope (windward side) of the mountain. This rapid rise helps the air to expand and cool.

Consequently, it condenses and gives plenty of rainfall on the windward slope only. This is called orographic rainfall or relief rainfall. After the rainfall, the wind becomes light enough to cross the mountain and blow downwards.

But now the wind is almost dry and cannot cause any rainfall on the other side (leeward side). Moreover, as the wind moves down the leeward side, which is also called rain shadow area, the temperature of air increases and its capacity to hold moisture also increases.

So, there is no chance of condensation or precipitation on that slope.

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For example,

1. The western slope of the Western Ghats receives a considerable amount of orographic rain, whereas the eastern slope of the same mountains is the rainshadow area.
2. Mawsynram and Cherrapunji record the highest amount of rain. Their location is on the southern windward slope of the Khasi Hills in Meghalaya. Cherrapunji receives about 11777 mm of rainfall annually, whereas Shillong on the leeward slope of the same hill and only 56km apart receives only 2207 mm of annual rain. (Mawsynram receives more than 1200mm of rainfall annually.)

 

Question 3. Which branch of the monsoon causes rainfall in Cherrapunji and why?
Answer:

Branch Of The Monsoon Causes Rainfall In Cherrapunji:-

Indian monsoon has two branches-the Arabian Sea branch and the Bay of Bengal branch. Cherrapunji, located in the northeastern part of India, receives relief rainfall from the Bay of Bengal branch of monsoon winds.

The sun is vertically overhead on and around the Tropic of Cancer in May and June. As a result, an intensely hot low-pressure zone develops in northern India.

To fill that vacuum, cold moist winds from the Bay of Bengal rush in through Bangladesh to reach north-eastern India. Here, the moist monsoon winds get obstructed by the Khasi Hills of the Meghalaya plateau and plateau and cause profuse orographic rainfall on the windward slope of the hills.

WBBSE Class 8 Geography Rainfall Types

Cherrapunji is situated on the windward slope of the Khasi Hills and so this place records the world’s highest amount of rainfall (about 11777mm).

 

Question 4. Explain the mechanism behind cyclonic rainfall in temperate regions.
Answer:

Mechanism Behind Cyclonic Rainfall In Temperate Regions:-

In the temperate regions (35°-65° north and south latitudes), air masses of different temperatures blow from opposite directions. Hot and moist air blows from the tropics in the southwest, while cold and dry air blows from the polar region in the northeast. These two meet along a line called ‘front. The front is of mainly two types- warm front and cold front.

A warm front is defined as a region in which there is an active movement of warm air over cold air. A cold front, on the other hand, is defined as a front along which cold air is invading the warm air zone.

A disturbance is created when the opposite air masses meet. The warm air mass overrides the cold air as the former is lighter. The moisture in the warm air condenses on coming into contact with the cold air and causes rainfall.

Rainfall during a temperate cyclone is drizzling and lingering, unlike tropical cyclones where thundershowers are seen.

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Question 5. Explain the phenomenon of cyclonic rainfall in the tropical region.
Answer:

Phenomenon Of Cyclonic Rainfall In The Tropical Region:-

Tropical cyclones originate on either. side of the equator (5°-20° latitudes). The extremely hot condition creates a severe low-pressure area (called the ‘eye’ of a cyclone).

The relatively cold, heavy winds from surrounding places rush to fill in the vacuum. Again, those cold winds rise, on being heated and in this process expand, cool and condense, finally to precipitate.

The speed of these whirling cold winds increases proportionately with the increasing intensity of the low-pressure eye. The eye is a smaller area that remains calm and quiet with clear skies, but the spinning cold winds outside the eye cause violent storms, along with rainfall.

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This cyclonic rain may develop into a more violent type of tropical storm. There is lighter tropical cyclonic rainfall also. Tropical cyclones are more powerful over water and lose energy while advancing landward. These cyclones usually occur in autumn.

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Question 6. What do you mean by the eye of a cyclone?
Answer:

Eye Of A Cyclone:-

The centre of a tropical cyclone, which has the lowest air pressure, is called the ‘eye’ of the cyclone.

The following are its features

1. If the eye of a cyclone has very low pressure, the cyclone becomes more powerful and devastating.
2. The eye has a clear sky and calm weather without any clouds.
3. As winds move towards the central low-pressure region, i.e., the eye, according to Ferrel’s law, they move in an anti-clockwise direction in the northern hemisphere and a clockwise direction in the southern hemisphere.
4. Winds converge at the eye.
5. The radius of this eye can be 20km-80km.
6. The region around the eye is generally covered by dense cumulonimbus clouds which cause strong cyclonic winds and heavy rainfall.

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Question 7. Classify precipitation.
Answer:

Classification Of Precipitation:-

Precipitation can be classified into- liquid form and solid form.

Liquid form of precipitation:

Hot and moist air cools and condenses on reaching the upper atmosphere and forms water droplets that float as clouds. Eventually, these are brought down as rain due to the gravitational pull of the earth.

Rainfall can be of three types

1. Convectional rainfall
2. Relief or orographic rainfall, and
3. Cyclonic rainfall.

Drizzle is another liquid form of precipitation when droplets of water less than 0.5 mm in diameter come down as rain.

The solid form of precipitation:

Solid forms of precipitation are as follows

1. Snowfall:

In cold regions, tiny droplets of water alter to specks of snow and fall as a powdery substance on Earth. This is snowfall.

2. Hailstorm:

Upward air current pushes the droplets of water to a great height. Here the temperature drops and water droplets form small particles of ice.

When more droplets of water gather around these ice particles, they expand in volume and fall on earth with rain. This is called a hailstorm.

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3. Sleet:

Combined precipitation of water- droplets and ice particles.

Question 8. Differentiate between fog and cloud?
Answer:

The differences between fog and cloud include

 

Chapter 5 Topic B Precipitation Short Analytical Type Questions

Question 1. Explain the cycle of rainfall. Or, Explain the various stages of rainfall.
Answer:

Cycle Of Rainfall:-

Rainfall is the final product of the following stages

1. Evaporation:

Solar energy causes surface water from seas, oceans, rivers, lakes, and ponds to evaporate to form water vapour, which is lighter than air and rises.

2. Condensation:

The water vapour ascends, expands and cools. It condenses and converts into tiny particles of water that join each other and become larger droplets.

Short Answer Questions on Precipitation for Class 8

3. Precipitation:

When these larger droplets coalesce with each other, they cannot remain suspended any more. They are attracted by gravitational pull and cause Clouds that may rainfall on the earth’s surface.

The size of droplets varies, based on the particles they combine with. This rainwater flows back to the waterbodies as surface run-off.

Question 2. What do you know about convectional rainfall?
Answer:

Convectional Rainfall:-

In the torrid zone (including the tropics and the equator) a convection current sets in due to extremely hot conditions during the day.

The air in these regions has a lot of water vapour in it because of

1. The greater surface area of water, and
2. Higher temperature.

This moist and hot air rises rapidly and cools down on coming into contact with the cold upper layers of the atmosphere. Ultimately, it condenses to cause heavy rainfall at the third quarter of the day (or afternoon). This is known as ‘convectional rainfall.

Question 3. Why is convectional rainfall common in the Equatorial region?
Answer:

Convectional Rainfall Common In The Equatorial Region:-

When the earth’s surface gets extremely heated, the air above it becomes hot and rises vertically with all its moisture content.

In the higher layers of the atmosphere, the hot, moist air expands, cools condenses and eventually falls on Earth as rainfall. As it is caused by convection currents, it is called convectional rainfall.

The Equatorial region has a lot of water bodies and also has high temperatures. throughout the year. So, convectional rainfall occurs nearly every evening or in the late afternoon. This is also called a 40’clock rain or afternoon shower.

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Question 4. Why does the amount of convectional rainfall increase in summer?
Answer:

Amount Of Convectional Rainfall Increase In Summer:-

Convectional rainfall is chiefly associated with temperature. In summer, during the day, the sun’s rays fall vertically on the land and consequently, the air above it becomes hot. Hot air has a greater capacity to hold moisture.

With increasing temperature, this hot and moist air rises vertically (due to convection current) expands, cools and finally condenses at higher levels of the atmosphere. This causes heavy rainfall (convectional) in the Equatorial region.

With an increase in temperature in summer, the amount of convectional rainfall also increases.

Question 5. Name the areas that receive heavy rainfall in India and explain why they do so.
Answer:

India receives rainfall mainly from the southwest monsoon winds, but these are highly irregular and sporadic. It has been observed after a thorough study that two regions receive the maximum amount of rainfall in India.

This is the western slope of the Western Ghats or Western coastal plains and eastern and Northeastern parts of India.

1. Western slope of the Western Ghats:

The western slope of the Western Ghats, being the windward side, receives plenty of orographic rainfall from the Arabian Sea branch of the southwest monsoon winds.

2. Eastern and north-eastern parts of India:

The entire region is located at the eastern and northeastern foothills of the Himalayas and receives heavy rainfall. The rain-bearing winds from the Bay of Bengal branch of the southwest monsoon get obstructed here and thus cause heavy rainfall.

Question 6. Think and comment on the relation between relative humidity and air temperature.
Answer:

Relative humidity and air temperature have an inverse relationship. The capacity of air to hold moisture depends on temperature. Thus, if air temperature increases, its capacity to hold moisture increases.

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Similarly, if the air temperature decreases, its capacity to hold moisture also falls. An increase in air temperature thus implies a fall in its relative humidity. Similarly, a decrease in air temperature results in an increase in relative humidity.

Question 7. What is a windward slope?
Answer:

Windward Slope:-

When moisture-laden winds blow from water bodies towards the land, at times, these are obstructed by mountains across their path. On striking the mountains, these winds rise the mountain slopes.

The rapid rise causes them to expand, cool, condense and ultimately to precipitate on these slopes only. The side of a mountain which receives relief or orographic rainfall is called the windward slope.

For example, the western slope of the Western Ghats is the windward side of the southwest monsoon winds (Arabian Sea branch).

Question 8. What is a rainshadow area?
Answer:

Rainshadow Area:-

The leeward side of a mountain is called a rainshadow area. After orographic or relief rainfall on the windward side of a mountain, when the wind crosses over the mountain and blows down the opposite or the leeward side, it has very little moisture left.

Its capacity to hold moisture also increases, as the air temperature increases. So, little or no precipitation occurs on this side. Hence, this leeward side is called a rainshadow area.

For example, the northern slope of the Khasi Hills in the Meghalaya Plateau is leeward and is therefore a rainshadow area.

Question 9. Why does the amount of rainfall received in Cherrapunji and Shillong differ drastically even though they are not very far away from each other?
Answer:

Cherrapunji is located on the windward slope of the Khasi Hills in Meghalaya, while Shillong is situated on the leeward slope of the same hill (just about 56km apart).

Due to this locational advantage, Cherrapunji receives very heavy rainfall from the southwest monsoon winds coming from the Bay of Bengal.

On the other hand, Shillong, being on the leeward side, is in the rainshadow area and remains comparatively dry even during the rainy season. The annual average rainfall at Cherrapunji is about 11777 mm, whereas Shillong records only about 2207 mm of rainfall annually.

Question 10. Why does the western slope of the Western Ghats receive heavy rainfall while the eastern slope remains dry?
Answer:

The Arabian Sea branch of the south-west monsoon winds on entering the Indian landmass, are first obstructed by the western slope of the Western Ghats.

The western slope receives plenty of orographic or relief rainfall from these moist winds. After the heavy downpour, the winds become lighter, cross the mountain and blow down the eastern slope into the interior of the Deccan Plateau.

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It causes little or an almost negligible amount of rain there. So, the eastern slope of the Western Ghats is a rainshadow area.

Question 11. Why is rainfall in Pune lower than that in Mumbai?
Answer:

Rainfall In Pune Lower Than That In Mumbai:-

The Arabian Sea branch of the southwest monsoon winds causes heavy rainfall in the western coastal plain of India due to its location on the windward side of the Western Ghats.

This plain receives about 500cm-700cm of rainfall, annually. Mumbai is situated on this side of the Western Ghats and thus receives sufficient relief rainfall.

When the same branch of south-west monsoon winds reaches the leeward side of the Western Ghats, it cannot cause any significant amount of rainfall in the Deccan Plateau region due to lack of moisture content, thus turning it into a rainshadow area.

Pune lies in this rain shadow area and thus rainfall here is lower than that in Mumbai.

Question 12. What is relative humidity?
Answer:

Relative Humidity:-

The ratio between the amount of water vapour present at a specific temperature and the amount of water vapour that the same volume of air requires to become saturated at that temperature is called relative humidity.

It is always expressed as a percentage. Relative humidity can be measured by the following formula-

For example, a definite volume of air absorbs 15 gm of water vapour at 25°C and it would be able to hold another 22.9 gm of water vapour before it becomes saturated. In that case

Question 13. What is absolute humidity?
Answer:

Absolute Humidity:-

The total amount of water vapour present in a definite volume of air at a particular temperature is called its absolute humidity. It is greater during the day than at night, in summer than in winter, in the Equatorial region than in the Polar zones.

For example, if 1 cc of air contains 5gm of water vapour, the absolute humidity of that volume of air will be 5 gm/cc.

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Question 14. Write the differences between the windward slope and the leeward slope.
Answer:

The differences between windward slope and leeward slope are as follows

 

Question 15. Write the differences between tropical cyclones and temperate cyclones.
Answer: The differences between tropical cyclones and temperate cyclones are as follows-

 

Question 16. Differentiate between precipitation and rainfall.
Answer: The differences between precipitation and rainfall are as follows-

 

Question 17. Why are dust particles necessary for the formation of clouds and rainfall?
Answer: Dust Particles Necessary For The Formation Of Clouds And Rainfall:

To start the process of condensation, there must be an abundant supply of microscopic dust particles in the air. Such particles are capable of attracting or absorbing water.

These are generally salt particles, pollens, etc. Water droplets become cool and condensed while moving in the upper air. These reside on the dust particles and form clouds. Later rainfall occurs from the clouds.

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Question 18. Why do evergreen forests grow in the Equatorial region?
Answer: Evergreen Forests Grow In The Equatorial Region:-

Evergreen rainforests are the characteristic feature of the Equatorial region. These forests generally grow in the Equatorial region because of the following-

1. High temperature:

This region has high temperature throughout the year. Temperature generally varies between 25°C to 30°C. This condition favours the growth of evergreen forests.

2. Abundant rainfall:

The average annual rainfall in this region is about 250 cm. Plenty of convectional rainfall promotes the growth of evergreen forests.

3. High humidity:

The humidity level always remains high in this region. High humidity in the atmosphere is a major factor that helps in causing plenty of rainfall.

These are the reasons why evergreen forests are found in the Equatorial region due to favourable climatic conditions.

Question 19. What disruption or inconvenience does fog cause in our daily lives?
Answer: Fog causes several problems in our daily lives. Some of these are as follows-

1. It obscures our visibility and hampers transportation via road, air and rail.
2. Fog, in combination with smoke and dust, creates ‘smog’, which is very harmful for our health.
3. Fog damages the crops.
4. Fog influences the weather conditions of places locally.

Question 20. What are the different types of rainfall in India?
Answer: India is blessed with almost all kinds of rainfall. The different kinds of rainfall prevalent in India are-

1. Convectional rainfall occurs in West Bengal during the early summer.
2. Orographic or relief rainfall is prevalent in the windward slopes of mountains across the path of southwest monsoon winds. South-west monsoon winds again have two branches-
3. The Arabian Sea branch that causes heavy rainfall along the western slope of the Western Ghats, and
4. The Bay of Bengal branch dashes against the southern slope of the Khasi Hills in Meghalaya and causes heavy rainfall there.
5. During autumn and the dewy season (called ‘Hemanta’ in Bengali), occasional cyclonic rainfall occurs in the coastal regions of India.
6. Winter rain occurs in the north and north-western part of India particularly in Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Uttar Pradesh and Punjab from the ‘western disturbances’ of the Mediterranean region.

Question 21. Why does it not rain from all the clouds?
Answer:

The following conditions are essential for the occurrence of rainfall from clouds-

WBBSE Class 8 Geography Chapter 8 Question Answer

1. To start the process of condensation, there must be an abundant supply of microscopic dust particles in the cloud, otherwise condensation will not occur.
2. The floating water droplets of a cloud are usually 0.01mm in radius. Unless these join together to become at least 0.5mm in diameter, these cannot be attracted by the gravitational pull of the earth and they cannot fall as raindrops.
3. The floating droplets of water, which form a cloud, cannot cause rainfall until they coalesce with each other.
4. The relative humidity of the atmosphere has to be 100%, otherwise, condensation and precipitation will not occur.

Question 22. Think and say why dew and fog are not classified as precipitation.
Answer:

Fog and dew are not regarded as forms of precipitation as these are not formed by the upward movement of air and do not earth’s surface due to the gravitational pull of the earth.

1. Dew:

The moisture deposited on objects such as grass, leaves and stones on the earth’s surface in winter nights is known as dew. Dew form when the sky is cloudless and when the radiation from the ground has cooled the lower layers of the atmosphere and the water vapour in it below the dew point.

2. Fog:

During winter nights, when the surface of the earth becomes very cold, the air just above it also cools and condenses, around dust particles, forming tiny droplets of water floating in the lower layer of the atmosphere appearing like smoke.

This is known as fog. Fog is essentially a type of cloud that forms at the surface of the earth, and is not any kind of precipitation.

Question 23. Different types of rainfall occur within West Bengal. Make a list of the different areas and different types of rainfall that occur there throughout the year.
Answer: The different types of rainfall occurring all over West Bengal are-

1. Convectional rainfall:

During early summer in every region of south and central Bengal, convectional rainfall occurs.

2. Cyclonic rainfall:

This type occurs in districts of North and South 24 Parganas, Kolkata, East and West Bardhaman, Bankura, East and West Midnapore, Birbhum, Howrah and Hooghly.

During the monsoon and autumn seasons, cyclonic rainfall occurs mainly in Digha, Sundarbans and Mandarmani areas.

3. Orographic rainfall:

Darjeeling, Jalpaiguri and other hilly areas in West Bengal experience this type of rainfall.

Question 24. Collect information regarding different types of rainfall that your locality experiences and note them down.
Answer:

The different types of rainfall that my locality (areas in and around Kolkata) experiences during different seasons are-

 

Question 25. Write a short note on snowfall.
Answer: Snowfall:-

If the air temperature at the higher levels of the atmosphere is below the freezing point (0°C) of water, condensation of water vapour into ice particles takes place.

Generally, as snow falls due to the gravitational pull of the earth, it passes through the warm air, melts and drops down as rain.

But in mountainous regions or cold climatic zones, where the air is very cold even near the earth’s surface, snow falls in shapes similar to sugar crystals or fluffy bunches of cotton. This is snowfall.

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 26. Describe the instrument used to measure the amount of rainfall.
Answer: Instrument Used To Measure The Amount Of Rainfall:-

Rainfall is measured by an instrument named a rain gauge. It consists of a funnel, usually 5 inches or 13 cm in diameter and a glass vessel or bottle of the same diameter. The funnel is fitted in such a manner that not a single drop of rainwater can escape. Rainwater is collected in the glass bottle for about 24 hours.

 

 

The instrument is placed about one foot above the ground to prevent the entry of water from outside by splashing. The water collected is then measured in a measuring glass or cylinder to get the amount of daily rainfall.

Question 27. What do you mean by hail?
Answer: When clouds or tiny droplets of water are forced to rise high up in the sky by convectional air currents, the water droplets freeze into small grains of ice.

When more droplets of water gather around these ice particles they expand in volume and fall on earth with rain. This is called hail. Hailstorms are observed in sub-tropical and temperate zones.

When more droplets of water gather around these ice particles they expand in volume and fall on earth with rain.

WBBSE Class 8 Geography Chapter 8 Question Answer

Chapter 5 Topic B Precipitation Short Answer Type Questions

Question 1. What is precipitation?
Answer:

Precipitation:-

When water vapour in the atmosphere condenses and falls on the earth as water droplets or ice particles, due to the gravitational pull of the earth, it is called precipitation.

Question 2. What is rainfall?
Answer: Rainfall:

The evaporated water rises with hot, light air and condenses after reaching the upper strata of the atmosphere to form tiny droplets of water that form clouds.

When these floating water droplets join together to become bigger (with a diameter of 2mm), they drop down as rainfall due to the earth’s gravitational pull. Rainfall is a liquid form of precipitation.

Question 3. Name two places that experience convectional rainfall throughout the year.
Answer: Two Places That Experience Convectional Rainfall Throughout The Year:

Two places that experience convectional rainfall throughout the year are-

1. Amazon Basin in South America and
2. Zaire Basin in Africa.

Question 4. Why does rainfall occur from cool air?
Answer:

Rainfall Occurs From Cool Air:-

If air loses heat and becomes cool, the relative humidity increases and the air gets saturated faster. After that, the water-holding capacity of the saturated air decreases and the water droplets come down to the surface as rainfall as a result of the earth’s gravitational pull.

Therefore, when the air cools down, the water droplets become denser and rainfall occurs.

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 5. What do you understand from the statement “relative humidity of an area is 70%”?
Answer:

Relative Humidity Of An Area Is 70%:-

The relative humidity of an area is 70% implies that the air at that place and at that given temperature needs 30% more water vapour to reach 100%, i.e., to become saturated.

Saturated air has 100% relative humidity while dry air has 0% relative humidity.

Question 6. What is orographic rainfall?
Answer:

Orographic Rainfall:-

Being obstructed by a mountain across its path, moist air rises very rapidly along the mountain slope and expands, cools and condenses there, precipitating only on that side of the mountain. This is called orographic rainfall (‘oros’, means ‘mountain’ and ‘graphy’ means to ‘rise’). For example, orographic rainfall occurs on the western slope of the Western Ghats in India.

Question 7. What is cyclonic rainfall?
Answer:

Cyclonic Rainfall:-

Low pressure over an area attracts cold air from the surrounding high-pressure areas towards it at a great speed. The lighter hotter air of that region rises.

It expands to cool and condense in the upper layers to form clouds, finally precipitating with thunder and lightning. This is called ‘cyclonic rainfall.

It is also called frontal rain in temperate areas because a ‘front’ or boundary is formed between the two contrasting air masses.

Question 8. What is ‘Aswiner Jhar?
Answer:

As winter Jhar:-

In the months of ‘Aswin’ and ‘Kartik’ (October-November) of the Bengali year Bangladesh, West Bengal and eastern India experienced a cyclonic storm. This is called ‘Aswiner Jhar’. It is caused by the retreating monsoon winds. This is more common in the coastal regions of the Bay of Bengal.

Question 9. Name any two recent cyclones in India.
Answer:

Two Recent Cyclones In India:-

The names of two recent cyclones in India are

1. Hudhud in 2014 and
2. Fani in 2019.

Question 10. Name the different forms of condensation.
Answer: Different Forms Of Condensation:                     

The common forms of condensation are dew, frost, fog, smog and clouds. Fog and clouds are the most important concerning atmospheric processes.

Question 11. What is acid rain?
Answer: Acid Rain:

When oxides of sulphur and nitrogen released in the air due to pollution react with water vapour in the atmosphere to form acid, which when comes down to rainwater is known as acid rain.

It has harmful effects on plants, aquatic life, as well as on buildings. Acid rains mainly occur as a result of air pollution.

Question 12. What is frost?
Answer: Frost:

In cold countries and at high altitudes of the hot or torrid zone, when the night temperature is minimal, dew freezes and becomes hard and solid. This is called frost.

Question 13. What is isohyet or equipluve line?
Answer:

Isohyet Or Equipluve Line:-

The imaginary line that joins places on a map, recording equal average annual rainfall at a particular time is called the isohyet equipluve line.

The characteristics of these lines are

1. These are usually curved lines.
2. The value of the lines is maximum in the Equatorial region, while it is minimum at the poles.
3. These lines never touch or cross each other.

 

 

Question 14. Why is less dew observed in dry regions?
Answer:

Less Dew Observed In Dry Regions:-

The air in dry areas has a lesser amount of water vapour in it. So, at night when the heat radiates back from the surface, the air near the surface becomes cooler but condensation does not take place due to lack of water vapour.

Thus, less dew is observed in dry regions.

Question 15. Why is fog mainly seen in winter and on waterbodies?
Answer:

Fog Mainly Seen In Winter And On Waterbodies

The amount of heat that a landmass can absorb during the day in winter, radiates back more heat than that during long winter nights.

Thus, when the layer near the earth’s surface gets cooled, the water vapour in it condenses around dust particles present in the air and leads to the formation of fog in winter.

Also, the air above the waterbodies having more water vapour content than the landmass, causes the formation of fog mainly on waterbodies.

Class 8 Geography Solution WBBSE

Question 16. Why does a barefooted morning walk on the grass make your feet wet in winter?
Answer:

Barefooted Morning Walk On The Grass Makes Your Feet Wet In Winter:-

Dew is a form of condensation which consists of tiny droplets of water on the surface of objects rather than on dust particles in the air. It is produced when the heat radiation from the ground surface cools the lower layers of the atmosphere in night.

As a result, the water vapour in it condenses and gets deposited on trees and grass surfaces as droplets of water called dew. Thus, a barefooted morning walk on the grass makes our feet wet in winter.

Question 17. Briefly write about the drizzle.
Answer:

Drizzle:-

Often tiny droplets of water (0.5 mm or less in diameter) fall continuously on Earth from nimbostratus clouds over a large area.

It may be the result of low pressure in that region. These droplets are so light that they float along with the wind. This type of rainfall is called drizzle.

Question 18. What is mist?
Answer: Mist:

Water vapour, which condenses and descends as fine droplets, remains suspended in the air, and takes a smoke-like, appearance and is called mist. It is visible just above the earth’s surface. It is less dense and long-lasting than a fog.

Question 19. What is sleet?
Answer: Sleet:

Sleet is fine particles of ice mixed with rain. This form of precipitation occurs when the lower layers of the atmosphere are cooled down to almost the freezing point.

Question 20. What type of rainfall is generally observed in our country in the monsoon season?
Answer: Type Of Rainfall Is Generally Observed In Our Country In The Monsoon Season:

Our country receives two types of rainfall in the monsoon season.

These are

1. Orographic or relief rainfall in the mountain regions,
2. Cyclonic rainfall in many places at the end of the monsoon.

Question 21. Write a short note on moisture retaining capacity.
Answer:

Moisture Retaining Capacity:-

Moisture retaining capacity refers to the capacity of an air of a certain volume at a certain temperature to retain the maximum amount of moisture content. It is also known as humidity capacity.

It is positively related to temperature, i.e., the higher the temperature, the higher the retention capacity and vice versa. It is expressed in grams per cubic centimetre.

Class 8 Geography Solution WBBSE

Chapter 5 Topic B Precipitation Multiple Choice Questions Choose The Correct Option

Question 1. Rainfall is of-

1. 2 types
2. 3 types
3. 4 types
4. 5 types

Answer: 2. 3 types

Question 2. The most commonly occurring rainfall on the earth is-

1. Convectional rainfall
2. Orographic rainfall
3. Cyclonic rainfall
4. Sleet

Answer: 2. Orographic rainfall

Question 3. Rainfall that occurs when the sun’s heat causes water on the earth’s surface to rise as a vapour to form clouds, is known as

1. Convectional rainfall
2. Orographic rainfall
3. Drizzle
4. Cyclonic rainfall

Answer: 1. Convectional rainfall

Question 4. Convectional rainfall occurs in the Equatorial region during-

1. Summer
2. Winter
3. The entire year
4. Spring

Answer: 3. The entire year

Question 5. The type of rainfall that is observed in the Equatorial region is-

1. Convectional
2. Frontal
3. Orographic
4. Drizzle

Answer: 1. Convectional

Class 8 Geography Solution WBBSE

Question 6. Relative humidity is expressed in terms of-

1. Decimal
2. Degree
3. Percentage
4. Mass

Answer: 3. Percentage

Question 7. In comparison to cold air, warm air is-

1. Lighter
2. Of equal weight
3. Heavier
4. None of the above

Answer: 1. Lighter

Question 8. In comparison to dry wind, moisture-laden wind is-

1. Lighter
2. Heavier
3. Of equal weight
4. None of the above

Answer: 1. Lighter

Question 9. The relative humidity of saturated air is-

1. 0%
2. 100%
3. 50%
4. 150%

Answer: 2. 100%

Question 10. If the temperature of a volume of air increases, its capacity to hold moisture-

1. Increases
2. Remains the same
3. Decreases
4. None of the above

Answer: 1. Increases

Question 11. Rainshadow regions are formed along the

1. Slopes of the foothills
2. Leeward slope
3. Windward slope
4. Intermediate slope

Answer: 2. Leeward slope

Question 12. The branch of monsoon wind that causes rainfall in Mawsynram, India, is the

1. Bay of Bengal branch
2. Arabian Sea branch
3. Indian Ocean branch
4. Pacific Ocean branch

Answer: 1. Bay of Bengal branch

Question 13. The slope of the Khasi-Jaintia hills, on which Shillong is located, is the

1. Northern slope
2. Eastern slope
3. Southern slope
4. Western slope

Answer: 1. Northern slope

Question 14. The part of the hill that experiences relief rainfall is the

1. Windward slope
2. Speak
3. Leeward slope
4. Foothills

Answer: 1. Windward slope

Class 8 Geography Solution WBBSE

Question 15. Rainfall that occurs when a warm air mass meets a cold air mass, and the warm, less dense air is pushed up over the cold, dense air is called-

1. Convectional rainfall
2. Orogenic rainfall
3. Drizzle
4. Frontal rainfall

Answer: 4. Frontal rainfall

Question 16. Frontal rainfall is observed in the

1. Equatorial regions
2. Temperate regions
3. Polar regions
4. Tropical regions

Answer: 2. Temperate regions

Question 17. ‘Ashwiner Jhar’ in West Bengal is an example of-

1. Local rainfall
2. Relief rainfall
3. Convectional rainfall
4. Cyclonic rainfall

Answer: 4. Cyclonic rainfall

Question 18. The rainfall that is commonly associated with thunderstorms is-

1. Drizzle
2. Convectional rainfall
3. Cyclonic rainfall
4. Relief rainfall

Answer: 2. Convectional rainfall

Question 19. Rainfall due to the effect of temperate cyclones is observed in-

1. Western India
2. Central Europe
3. Eastern India
4. Southern India

Answer: 2. Central Europe

Question 20. Tropical cyclones are formed in-

1. 5°-20° latitudes
2. 35°-60° latitudes
3. 20°-35° latitudes
4. 60°-80° latitudes

Answer: 1. 5°-20° latitudes

Question 21. The Kalbaishakhi rain that occurs in April and May in India is an example of

1. Convectional rainfall
2. Orographic rainfall
3. Cyclonic rainfall
4. Rainfall due to the formation of the anticyclonic condition

Answer: 1. Convectional rainfall

Question 22. The unit that measures rainfall is-

1. Celsius
2. Millibar
3. Centimetre
4. Pascal

Answer: 3. Centimetre

Question 23. The instrument used to measure rainfall is known as

1. Altimeter
2. Barometer
3. Anemometer
4. Rain Gauge.

Answer: 4. Rain Gauge.

Question 24. A line on a map connecting places having the same amount of rainfall in a given period is known as-

1. Isotherm
2. Isobar
3. Isohume
4. Isohyet

Answer: 4. Isohyet

Question 25. ‘Ashwiner Jhar’ occurs in

1. January
2. April
3. July
4. October

Answer: 4. October

 

Chapter 5 Topic B Precipitation Very Short Answer Type Questions Fill In The Blanks

Question 1. _______ is the phenomenon by which water in its solid and liquid forms falls to the ground from clouds due to gravity.
Answer: Precipitation

Question 2. Tiny water droplets condense to form clouds, which keep growing till they become too heavy to remain suspended in the atmosphere and then fall from the sky as _______, due to gravitational pull.
Answer: Rain

Question 3. _______cyclones typically form over large bodies of relatively warm water.
Answer: Tropical

Question 4. A relative humidity of 100% indicates that the air is _______ with water.
Answer: Saturated

Question 5. _______ rainfall occurs when moist air rises as it moves over a mountain range.
Answer: Orographic

Question 6. The area to the north of Meghalaya Plateau is a _______ area.
Answer: Rainshadow

Question 7. West Bengal experiences spells of heavy convectional rain during the _______ afternoons.
Answer: Summer

Question 8. The highest amount of rainfall in the world is recorded in _______.
Answer: Mawsynram

Question 9. The foothills of the eastern Himalayas _______ experience rainfall.
Answer: Orographic

Question 10. The southwest monsoons strike the western coast of India and cause heavy rainfall on the _______ slope of the Western Ghats.
Answer: western

Question 11. The western slope of the Western Ghats experiences _______ type of rainfall.
Answer: Orographic

Question 12. A high _______ content is necessary for precipitation.
Answer: Water vapour

Question 13. The western disturbances over the northern Indian subcontinent are actually _______ cyclones.
Answer: Temperate

Question 14. One of the rainshadow areas in India is _______on the Meghalaya plateau.
Answer: Shillong

Question 15. _______ refers to a kind of fog that has soot or smoke particles.
Answer: Smog

Question 16. Most thunderstorms occur from _______ clouds.
Answer: cumulonimbus

Class 8 Geography Solution WBBSE

Write True Or False

Question 1. Rain helps to cool down the weather.
Answer: True

Question 2. Cyclonic rainfall in temperate regions occurs during the winter season.
Answer: True

Question 3. The moisture retention capacity of warm air is lower.
Answer: False

Question 4. Tropical cyclones become weak while moving on the landmasses.
Answer: True

Question 5. The wettest places on the earth are usually located in the Equatorial region.
Answer: False

Question 6. Cyclonic rainfall is most common in the Equatorial region.
Answer: False

Question 7. Rain is the most common form of precipitation.
Answer: True

Question 8. Convectional rain occurs on the earth’s surface when a conditionally unstable or moist atmosphere becomes heated more than its surroundings, leading to significant evaporation.
Answer: True

Question 9. All types of clouds lead to rainfall.
Answer: False

Question 10. Most of the rainfall in India is a result of orographic rainfall.
Answer: True

Question 11. Convectional rainfall is more common in high latitudes.
Answer: False

WBBSE Chapter 5 Topic B Precipitation Match The Columns

1.

Answer: 1. C, 2. D, 3. B, 4. E, 5. A

 

Answer In One Or Two Words

Question 1. By which process does the air heat up in case of convectional rainfall?
Answer: Convection.

Question 2. Name two countries that experience convectional rainfall throughout the year.
Answer: Uganda, Indonesia.

Question 3. Name a rainshadow region in India.
Answer: Deccan Plateau.

Question 4. Which slope of the mountain receives less rainfall?
Answer: Leeward slope.

Question 5. How many types of cyclonic rainfall are there?
Answer: Two.

Question 6. By what name is the autumn cyclone called in West Bengal?
Answer: Aswiner Jhar.

Question 7. What type of rainfall is observed in India during autumn?
Answer: Cyclonic rainfall.

Question 8. Which type of cyclone persists for a long time?
Answer: Temperate cyclones.

Question 9. Name the strongest tropical cyclone in the world.
Answer: Tornado.

Class 8 Geography Solution WBBSE

Chapter 5 Topic B Precipitation Conceptual Questions And Answers Who am I?

Question 1. I am the highest cloud. I look like a mare’s tail. I create a remarkable spectrum during the sunset. However, I do not cause rainfall.’ Who am I?
Answer: Cirrus cloud

Question 2. ‘I am a vertical, dome-shaped cloud. I cause rainfall with thunderstorms.’-Who am I?
Answer: Cumulonimbus cloud

Question 3. I am born from water due to insolation. I am light and I float in the air. I form clouds and fog.’ Who am I?
Answer: Water vapour

Question 4. I occur in the regions that have a higher percentage of water bodies and which receive vertical rays of the sun.’ -Who am I?
Answer: Convectional rainfall

Question 5. ‘I stay at the centre of a cyclone. The sky in my area remains clear and calm but my surroundings experience storms.’ -Who am I?
Answer: Eye of a cyclone

Question 6. I drop down as a solid substance from clouds instead of raindrops due to the extremely cold weather.’ Who am I?
Answer: Snow

Question 7. ‘You can see me in early winter mornings. I bar your visibility. I am almost like smoke.’ -Who am I?
Answer: Fog

Question 8. I stick on the blades of grass like tiny droplets of water, early in the morning. I am mostly seen in winter.’-Who am I?
Answer: Dew

Scrambled Words

1. MLUCO UNBIASED
2. UROICR MLUSUC
3. PEH CARURJNI
4. LFNWASLO

Answers:

1. CUMULONIMBUS
2. CIRROCUMULUS
3. CHERRAPUNJI
4. SNOWFALL

Fill Up The Blanks In The Knowledge Hive

Question 1. Fill in the knowledge hive with information on the cumulonimbus cloud.

 

Answers:

1. It is a vertical cloud.
2. It is dome-shaped and greyish or black in colour.
3. This cloud sometimes causes hailstorms also.
4. This cloud causes heavy rainfall along with thunderstorms.
5. This cloud is also called a thundercloud.

 

Chapter 5 Topic B Precipitation Strike the odd one out

Question 1. Cirrus, Cirrostratus, Cirrocumulus, Stratus
Answer: Stratus (not a high cloud)

Question 2. Stratus, Stratocumulus, Cirrus, Nimbostratus
Answers: Cirrus (not a low cloud)

Question 3. Convectional rainfall, Torrential rainfall, Cyclonic rainfall, Orographic rainfall
Answers: Torrential rainfall (not a type of rainfall)

Question 4. Snowfall, Dew, Sleet, Hailstorm
Answers: Dew (not a type of precipitation)

 

Correct The Following

1. The cirrus clouds appear like the scales of a mackerel fish.

2. Cumulus cloud is also known as a thundercloud.

3. The process by which water changes from liquid to vapour is known as condensation.

4. Hailstorm is a mixture of water droplets and snowflakes.

Answers:

1. Cirrocumulus
2. Cumulonimbus
3. Evaporation
4. Sleet

Crossword

 

CLUES

Down:

1. Place that gets the highest amount of rainfall in the world.
2. This type of cyclones occur in the mid-latitudes in winter.
3. Rainfall is produced when moist air moves up the sides of hills and mountains.

Across:

4. Phenomenon of moisture falling on ground from clouds due to gravity.
5. Cyclonic storm in the South China Sea.
6. Imaginary line joining places having equal amounts of rainfall.

Answers:

Down: 1. MAWSYNRAM, 2. TEMPERATE, 3. OROGRAPHIC
Across: 4. PRECIPITATION, 5. TYPHOON, 6. ISOHYET

 

Chapter 5 Topic B Precipitation Advanced Questions And Answers

Question 1. Write a short note on smog.
Answer:

Smog:-

Fog mixed with smoke is called smog. It is a consequence of air pollution and is very harmful for the living world. Industrial towns emit poisonous gases from factories which combine with the fog to form smog.

The cities of London and Los Angeles suffer from deadly smog during winter evenings.

Question 2. What are nor’westers?
Answer:

Nor’wester:-

It is a kind of abrupt or sudden wind that causes rainfall with thunder, lightning and hail at times, in the summer afternoons in eastern India, including West Bengal and its adjacent areas.

As the wind comes from the northwest, it is called the Nor’wester. This rainfall is also known as ‘Kalbaishakhi’.

Question 3. What are Western disturbances?
Answer:

Western Disturbances:-

During winter February), India enjoys sunny and pleasant weather conditions because of the sun’s apparent annual migration to the southern hemisphere after September 23.

Due to the shifting of wind belts along with climatic belts, the Mediterranean region comes under the influence of the westerlies that cause cyclones and heavy rain.

This rain and storm that comes from the west in winter is called ‘western disturbances. Under the influence of the western disturbances, Jammu and Kashmir, Himachal Pradesh, Uttarakhand, western UP, Haryana and Punjab receive this type of winter rainfall.

This winter rain is beneficial for the cultivation of wheat in Punjab.

Question 4. Why is the Bay of Bengal more prone to cyclones than the Arabian Sea?
Answer:

Bay of Bengal more prone to cyclones than the Arabian Sea:-

The reasons for Bay of Bengal being more prone to cyclones than the Arabian Sea are as follows-

1. The Arabian Sea has a greater expanse of water than the Bay of Bengal, which is rather restricted by land on three sides. So, the Bay of Bengal retains heat for a longer time. As a consequence, it creates a low-pressure zone, which gives rise to cyclones.
2. The water of the Bay of Bengal is denser than that of the Arabian Sea. Due to the lack of suitable conditions, the bay water cannot lose heat quickly. So, a higher atmospheric temperature leads to the formation of a low-pressure zone, which further leads to the occurrence of cyclones.

The Bay of Bengal is thus more prone to cyclones than the Arabian Sea.

 

Chapter 5 Topic B Precipitation Formative

 

Participation

This segment will indicate how much the students have actively participated and taken the initiative during the class.

The heat of the sun is responsible for the formation of water vapour from waterbodies. Since water vapour is lighter than air, it rises and accumulates to form clouds. With reference to this information, answer the following:

Question 1. Apart from the sun’s heat, what else is responsible for the formation of water vapour?
Answer: Moisture is added to the atmosphere due to the transpiration process in plants.

Question 2. What is the relation between cloud formation and rainfall?
Answer: Clouds filled with water vapour cause rainfall on Earth due to gravity.

Question 3. How many types of rainfall are there?
Answer: There are three types of rainfall.

Question 4. Which instrument is used to measure the amount of rainfall?
Answer: Rain gauge.

 

Interpretation And Application

This segment will test whether the students have understood the topics, or whether they are just mugging up.

Question 1. Take some water in a glass plate and a glass jar and keep them exposed to the weather. What change will be observed in the amount of water kept in the two vessels after two or three days?
Answer:

If we take some water in a glass plate and a glass jar and keep them exposed to the weather, we will see the amount of water has changed. Both the glass plate and the glass jar will have a lesser amount of water than it was kept in them earlier.

But the water in the glass jar will be more than the glass plate. The glass plate having a flat area, Fig. Set up for the experiment gets more sunlight, hence more water will evaporate from its surface.

 

 

On the other hand, the glass jar having a narrow mouth, less amount of water will be evaporated from it. Thus it can be said that the rate of evaporation depends on the area of the upper surface of the water bodies.

Question 2. Keep a few cubes of ice in a tumbler. After a while, droplets of water accumulate on the tumbler. Your hands get wet when you hold the tumbler. Air around the tumbler has cool down on its contact and the water vapour in it becomes a water droplets. Which process does this happen as a result of?
Answer:

It is observed that if some ice cubes are kept in a glass, water droplets accumulate outside the glass. When the air around the cold glass comes into contact with it, the water vapour accumulates on the glass surface as water droplets.

Thus, on holding the glass, our hands get wet. This process is known as condensation. This is how clouds form.

 

 

Question 3. Prepare a model of orographic rainfall and point out windward and leeward slopes. ▸ Materials required: Thermocol, knife, gum, cotton, colour, painting brush, several thin sticks, pen.
Answer:

Model-making:

With the help of these materials, the model can be prepared following the steps given below-

Stage-1:

A big sheet of thermocol is taken and cut into rectangular shapes. Then with the help of gum, they are fixed, one above the other.

Stage-2:

When the gum dries up, with the help of a knife, shapes of waterbody, landmasses and mountains are made on them. (As shown in the picture.)

Stage-3:

After that, blue colour for a waterbody, yellow for a landmass and grey for the mountain are used to paint the surface.

Stage-4:

Now using those thin sticks and glue, clouds are made with cotton. Those cotton are painted grey to make it look as original cloud.

Stage-5:

Small pieces of thermocouple are cut. ‘Ocean’, landmass’, ‘windward slope’ and ‘leeward slope’ are written on paper individually and fixed on the pieces of thermocol. Now with sticks those clouds are fixed where they are necessary.

 

 

Questioning And Experimentation

This segment will investigate the student’s understanding of the subject,

Question 1. Among all the clouds that you have come to know, note down the types you observe in the sky against the dates on which you see them.
Answer:

I am Samir Rehman, a resident of Howrah. The clouds that I could identify in the sky are-

1. Cirrus cloud: 26 October, 29 September.
2. Cirrostratus cloud: 11 July, 6 August, 21 September, 1 October.
3. Cirrocumulus cloud: 7 October, 10 October, 14 November, 19 November, 3 December, 4 December
4. Altostratus cloud: 7 July, 8 July.
5. Altocumulus cloud: 16 October, 19 October
6. Stratocumulus cloud: 12 October, 14 October
7. Stratus cloud: 29 June, 30 June, 1 July, 2 July
8. Nimbostratus cloud: 3 July-5 July, 14 August-16 August
9. Cumulonimbus cloud: 14 April-18 April, 26 April, 2 May, 11 May, 19 May

Aesthetics And Creativity

This segment will check the aesthetic sense and creativity of the students.

Question 1. Hand-made clouds: Try to form clouds in your own home.
Answer:

Materials:

1. A plastic bottle of 1-litre capacity,
2. Hot water (not boiling),
3. Matchsticks.

Process:

1. The lower portion of the bottle is filled with hot water.
2. A lighted matchstick is put inside the bottle and made sure that the bottle is filled with smoke.
3. Then the lid is put on the bottle and closed.
4. Finally, pressure is put on the bottle using hands a few times. Once that is done, it is observed that a cloud has formed within the bottle.

 

 

Reasons:

1. Hot water in the bottle increases the moisture-retaining capacity of the air within the bottle.
2. The temperature of the matchstick helps the air inside the bottle to saturate.
3. When air containing water vapour cools down a bit, the water vapour within it transforms into tiny water droplets and floats around. These together make up the cloud inside the bottle.

Chapter 5 Cloud And Rain Synopsis

Clouds are defined as the aggregate of numerous tiny water droplets around dust particles or a mixture of both in the air and the ground surface. Generally, the diameter of the water droplets in clouds is 0.02 mm or less.

The clouds which occur at an average minimum height of 20000ft are known as high clouds. This cloud group consists of cirrus, cirrostratus and cirrocumulus.

Cirrus clouds are whitish transparent, light and feathery clouds, through which the sun and the moon are visible.

Cirrostratus clouds are generally white and are spread in the sky like thin, white film. The clouds often form a halo around the sun or the moon.

Cirrocumulus clouds appear in the sky as cotton wool and make the sky look like the scales of a mackerel fish. The cloud indicates fair weather.

Read and Learn More WBBSE Solutions For Class 8 Geography

The location of medium clouds in the sky varies between 6500ft to 20000ft. This group consists of altostratus and altocumulus clouds.

Altostratus clouds, having a fibrous appearance, grey to bluish in colour yield widespread and continuous rainfall. The sun seems dull through these clouds.

WBBSE Class 8 Cloud Formation Overview

Altocumulus clouds are characterised by wavy patterns, flat, rounded structures and white to greyish colour. The sky is visible through the gaps in these cloud masses.

Low clouds are found up to a height of 6500ft from the ground. Stratocumulus, stratus, and nimbostratus clouds come under this group.

Stratocumulus clouds are layered clouds appearing like a heap. These are also called Bumpy clouds as the layers seem to be rolling along the sky.

Stratus clouds are low-altitude, grey-coloured, fog-like clouds. These clouds pose great difficulty to mountaineers and pilots. These clouds can sometimes cause drizzle.

Nimbostratus clouds are associated with continuous and copious precipitation. They are thick, dense, grey to black in colour and indicate bad weather.

Vertical clouds are usually found at an average minimum height of 16000 ft. They consist of cumulus and cumulonimbus clouds.

Cumulus clouds are thick, and dense with a high vertical extent. The top surface is white and irregular and the bottom part is black and flat. These clouds generally fair indicate fair weather.

Cumulonimbus clouds show great vertical development and produce heavy rains or hailstorms accompanied by thunderstorms. The clouds may be whitish-grey or black in colour and dome-shaped. The top and bottom parts of these clouds are flat.

The process of conversion of water into its gaseous form, i.e., water vapour is called evaporation.

When the temperature of moist air reaches the dew point, it becomes saturated. In other words, air having 100% relative humidity is called saturated air.

The temperature at which a mass of air becomes saturated is called its dew point.

The process of conversion of water vapour into water droplets is called condensation.

When water vapour in the atmosphere condenses and falls on the earth as water droplets or ice particles, due to the gravitational pull of the earth, it is called precipitation.

The major forms of precipitation include rainfall, drizzle, sleet, hail and snow.

During cloud formation, the water vapour present in the atmosphere condenses to form larger droplets of water. These droplets fall on the earth due to gravitational pull.

This is called rainfall. There are mainly three types of rainfall- convectional rainfall, orographic rainfall and cyclonic rainfall.

Relative humidity is defined as the ratio of the amount of water vapour present in a fixed volume of air at a particular temperature and the maximum amount of water vapour that the volume of air can hold at that temperature.

Cherrapunji in Meghalaya, being situated on the windward slope receives a mean annual rainfall of 11777mm.

Cyclonic or frontal rainfall is always associated with cyclones.

Class 8 Geography Chapter 5 Types of Clouds

A tropical cyclone generally occurs between 5 and 20° latitudes in both hemispheres. The innermost part (or centre) of this cyclone is known as the eye of the cyclone.

Aila, Phailin, Fani and Hudhud are some notable examples of tropical cyclones that have occurred in recent times.

A temperate cyclone occurs when two different air masses (warm and cold) converge in the temperate region. The mid-latitude countries experience rainfall mainly in winter due to this type of cyclone.

When very tiny droplets of water (less than 0.5mm in diameter) come down to the surface of the earth as rain, it is called a drizzle.

Sleet refers to the combined precipitation of water droplets and ice.

When clouds or tiny droplets of water are forced to rise high up in the sky by convectional air currents, the water droplets freeze into small grains of ice.

When more droplets of water gather around these ice particles they expand in volume and fall on earth with rain. This is called hail.

Snowfall is common in regions with cold climates or in high mountainous areas, where temperatures are below freezing point.

Dew falls on leaves and blades of grass mainly on winter nights. A cloudless sky and calm weather are the necessary conditions for dew formation.

When water vapour condenses around the tiny dust particles present in the air near the ground and appears like smoke, it is called fog. It generally occurs in winter and reduces horizontal visibility.

A rain gauge (also known as a udometer, pluviometer or ombrometer) is an instrument that is used to measure the amount of rainfall.

A line on a map (usually, a weather map) connecting points having an equal amount of rainfall in a given period is known as isohyet.

Chapter 5 Topic A Clouds Analytical Type Questions

Question 1. What are clouds? How are they formed?
Answer:

Clouds:

Clouds are defined as the aggregate of numerous tiny water droplets around dust particles or a mixture of both in the air above the ground surface. Generally, the diameter of the water droplets in clouds is 0.02 mm or less.

 

 

Stages of cloud formation:

According to climatologists, clouds form through various stages. These are discussed below-

1. Evaporation:

Water from various water bodies changes to water vapour by solar insolation. Water vapour, being lighter than air, rises to the higher layers of the atmosphere.

In addition to this, moisture discharged by trees and plants during transpiration is added to the atmospheric water vapour content.

Understanding Clouds for Class 8 Students

2. Condensation:

Condensation of water vapour takes place at this stage mainly at higher altitudes, when it comes into contact with cooler air. The cooler the air, the lower is its capacity to hold moisture.

Eventually, the temperature of the moist air mass reaches its dew point and the air gets saturated. When the temperature falls below the dew point, the finer water particles combine to form droplets of water or snow.

3. Clouds and precipitation:

The tiny droplets of water and snow, while floating in the sky, settle around existing. dust particles, pollen grains and other impurities in groups or patches and float in the air to form clouds.

Precipitation from these clouds occurs when they are unable to hold the moisture any further and the water flows back into the water bodies.

Question 2. Discuss the different types of high clouds or high-altitude clouds.
Answer:

Different Types Of High Clouds Or High-Altitude Clouds:-

Normally, high clouds or high altitude clouds are on average found at a minimum height of 20000 ft above the surface of the earth.

There are three subdivisions of high-altitude clouds

1. Cirrus
2. Cirrocumulus and
3. Cirrostratus.

1. Cirrus:

The features of these clouds are

1. This type of cloud are found at maximum height and resembles feathers or fluffs of cotton or at times the tail of a mare.
2. Cirrus, being formed of tiny ice crystals, is white and transparent.
3. This cloud creates a marvellous spectrum with the light of the setting sun.
4. These clouds do not cause rainfall and denote clear weather. But when these clouds accumulate into a compact mass the weather deteriorates. If cirrostratus clouds form after this, it may also indicate an approaching storm.

2. Cirrocumulus:

The features of these clouds are

1. They are spherical in shape.
2. Formed of very minute ice particles, these clouds look like waves or bunches of white sheets floating in the sky.
3. When the entire sky gets covered with such scale-like clouds, it is called ‘mackerel sky’.
4. This cloud indicates a clear sky without any hint of rain.

3. Cirrostratus:

The features of these clouds are

1. They are milky white in colour.
2. Sometimes, halos around the sun and the moon are formed by these clouds.
3. It floats high up in the sky, forming a thin white film.
4. It also forms the rainbow.
5. It indicates an approaching storm.

WBBSE Class 8 Geography Characteristics of Clouds

Question 3. Classify the medium clouds air, and middle altitude clouds.
Answer:

Classification The Medium Clouds Air, And Middle Altitude Clouds:-

Medium clouds or middle altitude clouds extend from 6500 ft-20000 ft in the sky.

There are two types of middle-altitude clouds

1. Altostratus and
2. Altocumulus.

1. Altostratus:

Another name for these clouds is layered clouds. The features of these clouds are

1. These may look grey to bluish in colour.
2. These clouds have a fibrous appearance.
3. These clouds are usually visible in the morning or afternoon. hours. The sun seems dull through these clouds.
4. Rainfall occurs for a long period and over a large area from these clouds.

2. Altocumulus:

The features of these clouds are

1. They look like round, rough-edged, soft balls of wool making wavy patterns in the sky.
2. The blue sky is visible through. the gaps in these clouds.
3. Their colour varies from white to grey.
4. The presence of these clouds in the sky indicates clear weather, but if they gather together, they may cause rain.

 

Question 4. Give a description of the different types of low clouds or low-altitude clouds.
Answer:

Different Types Of Low Clouds Or Low-Altitude Clouds:-

Low clouds or low altitude clouds are found up to a height of 6500 ft.

These are of three types

1. Stratocumulus
2. Stratus and
3. Nimbostratus.

1. Stratocumulus:

1. These are also called lower clouds. The features of these clouds are
2. Their colour varies from dark grey to black.
3. At the middle altitude, altocumulus clouds become heavier and darker and sink down to form stratocumulus clouds.
4. These are dome-shaped clouds arranged in layers looking like a heap. These are also called Bumpy clouds as the layers seem to be rolling along the sky.
5. These clouds are active and they keep moving.
6. During winter, in temperate regions, these clouds often cause heavy rainfall.

Cloud Types and Their Importance for Class 8

 

2. Stratus:

These are arranged in layers. The features of these clouds are

1. These are grey or white in colour.
2. These create visibility problems mainly for pilots and mountaineers.
3. These look like a thick fog.
4. This type of cloud sometimes causes drizzle.

Class 8 Geography WBBSE

Nimbostratus:

They are also called rain-bearing clouds. The features of these clouds are

1. These are grey or black in colour.
2. These are dense and thick clouds that cover the sky in the rainy season.
3. These clouds do not have any particular shape.
4. They cause heavy rainfall but without any thunder and lightning.
5. These may also cause hailstorms and continuous rain.

Cloud Classification for Class 8 Geography

Question 5. Describe the vertical clouds.
Answer:

Vertical Clouds:-

Vertical clouds are those which are. vertically developed to a great extent. The minimum height of these clouds is 16000ft on average. These clouds look almost like trees.

These are of two types

1. Cumulus and
2. Cumulonimbus.

1. Cumulus:

These are mound-like clouds. The features of these clouds are

1. These form as a result of the rising of water vapour and condensation in the higher layers of the atmosphere.
2. The bottom of these clouds are almost flat, but the tops are irregular and undulating and resemble a cauliflower.
3. The lower parts of these clouds are dark grey or black, but the upper parts are white.
4. These are dense, thick clouds.
5. These have a ‘silver lining’ on the top.
6. They indicate clear weather.

2. Cumulonimbus:

These are rain-bearing clouds. The features of these clouds are

1. Cumulus clouds become cumulonimbus after gaining height.
2. These clouds sometimes reach about a height of 12000ft from the surface.
3. The bottom and middle portions of these clouds are black, but the sides are white or grey.
4. These clouds are whitish-grey or black in colour and dome-shaped.
5. The top and bottom parts of these clouds are flat.
6. These clouds are visible at the time of Nor’wester in the north-western sky.
7. These cause heavy rainfall, violent thunderstorms and sometimes even hailstorms. Thus, they are also called thunderclouds. Usually, cloudbursts are associated with these clouds.

Chapter 5 Topic A Clouds Analytical Type Questions Short Analytical Type Questions

Question 1. Classify the different types of clouds.
Answer:

Clouds are classified

1. According to their heights and
2. According to their shapes and formation.

1. According to height, there can be

1. High altitude (20000 ft high from the earth’s surface) clouds,
2. Middle altitude (6500 ft-20000 ft high from the surface) clouds, and
3. Low altitude (up to 6500 ft high from the surface) clouds.

2. According to shape and formation

There can be four classes of clouds. These are

1. Cirrus, a high-altitude cloud that looks like feathers,
2. Stratus, a low-altitude fog-like cloud,
3. Cumulus, a cloud that looks like a mound of fluffy cotton,
4. Cumulonimbus, a rain-bearing cloud that gives plenty of rainfall.
5. These four types of clouds can be found in combined stages too. For example, cirrocumulus and cirrostratus belong to the high-altitude clouds group, altocumulus and altostratus belong to the middle-altitude clouds group, and stratocumulus and nimbostratus belong to the low-altitude clouds group. Cumulus and cumulonimbus can be found at any height.

Question 2. What do you understand by saturated air?
Answer:

Saturated Air:-

Air is said to be saturated when it contains the maximum amount of moisture it can hold at a given temperature. The upper limit of absorbing water vapour depends on the temperature of air.

If the temperature increases, the capacity of air to hold moisture also increases and vice versa. For example, at 25°C, 1cc air can hold 30gm of moisture at the most.

If it actually contains 30 gm of moisture at 25°C, then it will be called saturated air, but if that volume of air has 15 gm of moisture under the same conditions, it will be called unsaturated air.

WBBSE Class 8 Geography Chapter 5 Notes on Clouds

Features of saturated air include

1. It can hold the maximum amount of water vapour at a given temperature.
2. Atmospheric temperature needs to reach the dew point so that the air becomes saturated.
3. Saturated air plays a very significant role in causing rainfall and snowfall.

Question 3. Why is the amount of water vapour in air different in different areas?
Answer:

The Amount Of Water Vapour In Air Different In Different Areas:-

The variation in the amount of water vapour depends on the following conditions-

1. Waterbodies:

The location of a greater number of water bodies in an area helps in the rapid and widespread evaporation of water, if the temperature over there is favourably high.

Example-The equatorial region records maximum humidity.

2. Sun rays:

The angular distance of the sun’s rays is another important factor because the vertical rays of the sun heat up a particular place more intensely than the Islanting or oblique ones.

Example-The polar regions have very little evaporation.

3. Natural vegetation:

The extent of natural vegetation or forests is an important factor as well. Trees, shrubs and bushes transpire and a lot of vapour is emitted in this process.

Example-The equatorial evergreen forests have dense fog-like vapours in the atmosphere, while the deserts have very dry weather due to the absence of vegetation.

Question 4. Differentiate between evaporation and condensation.
Answer:

The differences between evaporation and condensation are

 

Question 5. Differentiate between dew point and freezing point.
Answer:

The differences between dew point and freezing point are-

 

Question 6. How important are clouds as a component of climate?
Answer:

Clouds As A Component Of Climate:-

Clouds are an important component of the climate of a region.

This is due to the following reasons

1. Rainfall is not possible without cloud cover even though all clouds do not cause rainfall.
2. If there are clouds in the sky during the daytime, the temperature decreases, since the sun’s rays cannot reach the earth’s surface.
3. The cloudless sky during day and cloudy sky at night cause a rise in temperature.
4. Clouds are responsible for maintaining a balance in the temperature of the atmosphere.

Question 7. Why is a cloudy night hotter than a cloudless one?
Answer:

Cloudy Night Hotter Than A Cloudless One

The earth’s surface receives solar energy during the day and gets heated by the processes of conduction, convection and radiation. At night, the atmosphere becomes cooler by discharging this heat to outer space (in the absence of the sun).

But if the sky has a cloud cover at night, it has a blanketing effect on the earth. This retains the heat inside the atmosphere, thereby making the night warmer than a cloudless one.

On the other hand, a cloudless sky allows the outward radiation of heat from the earth’s surface, making the night cooler.

 

Short Answer Questions on Clouds for Class 8

Question 8. What are the effects of the presence of water vapour in the atmosphere?
Answer:

Effects Of The Presence Of Water Vapour In The Atmosphere:-

The effects of the presence of water vapour in the atmosphere are-

1. Clouds are created from water vapour.
2. Air containing water vapour is lighter than dry air. Thus, it helps in creating regions of low air pressure.
3. Air filled with water vapour absorbs heat.
4. Excess water vapour in the atmosphere makes the air humid. This humid air makes human beings uncomfortable.
5. When water vapour in air condenses and causes rainfall, some amount of heat is released by it. This heat automatically leads to an increase in the temperature of the atmosphere.

Question 9. Put a kettle or container of water on the burner and heat it. After some time white steam will be seen coming out of the nozzle or top of the kettle or container. What actually is this steam?
Answer:

The water, on boiling, forms water vapour within the kettle, which rises and puts pressure under the lid of the kettle or comes out through the mouth of the kettle as white smoke.

If you put your palm over that smoke, you will see tiny water droplets accumulating on your skin.

Chapter 5 Topic A Clouds Analytical Type Questions Short Answer Type Questions

Question 1. What are clouds?
Answer:

Clouds:-

Clouds are defined as the aggregate of numerous tiny water droplets around dust particles or a mixture of both water droplets and dust particles, in the air above the ground surface. Generally, the diameter of the water droplets in clouds is 0.02mm or less.

Question 2. What is oversaturated air?
Answer:

Oversaturated Air:-

If, at a given temperature, a fixed volume of air contains more water vapour than what is required to make it totally saturated, it is called oversaturated air.

Question 3. What is unsaturated air?
Answer:

Unsaturated Air:-

When, at a particular temperature, a fixed volume of air contains less water vapour than what is required by it to become saturated, it is called unsaturated air.

This kind of air has the capacity to hold more water vapour if its temperature increases.

Question 4. When does air become saturated?
Answer:

Air Become Saturated:-

Air has the capacity to hold water vapour and its water-holding capacity depends on its temperature. The moisture content increases or decreases with an increase or decrease in temperature.

A volume of air becomes totally saturated when it holds moisture to its maximum capacity. Saturated air has 100% relative humidity.

WBBSE Class 8 Geography Study Guide on Clouds

Question 5. What is dew point?
Answer:

Dew Point:-

The temperature at which a mass of air becomes saturated is called its dew point. At the dew point, air gets totally saturated and cannot hold any more moisture, or rather, water vapour changes into water droplets to cause precipitation, at dew point.

Question 6. What is condensation?
Answer:

Condensation:-

The process of conversion of water vapour into water droplets is called condensation. When saturated air cools down further, the water vapour in it condenses to form small droplets of water.

Question 7. What is vaporisation?
Answer:

Vaporisation:-

The process by which water from oceans, seas, rivers, lakes, ponds, reservoirs, etc., changes into vapour due to solar insolation, is called vaporisation.

WBBSE Class 8 Geography Cloud Characteristics

Question 8. What is latent heat?
Answer:

Latent Heat:-

Latent heat is the heat required to convert the physical state of matter without any change in temperature, such as solid to liquid, liquid to gas, gas to liquid and again liquid to solid.

Example-Temperature of boiling water at 100°C remains constant until the last drop of water evaporates. This is because all the heat being added to the liquid is absorbed as latest heat of vapourisation and carried away by the vapour molecules.

Chapter 5 Topic A Clouds Analytical Type Questions Multiple Choice Questions Choose The Correct Option

Question 1. Cirrus clouds appear like-

1. Light feathers
2. Cotton wool
3. Clumpy layers
4. Mackerel sky

Answer: 1. Light feathers

Question 2. According to height, cirrocumulus clouds are grouped under-

1. High altitude clouds
2. Middle altitude clouds
3. Low altitude clouds
4. Vertical clouds

Answer: 1. High-altitude clouds

WBBSE Class 8 Geography Chapter 5

Question 3. According to height, stratocumulus clouds are grouped under-

1. High altitude clouds
2. Middle altitude clouds
3. Low altitude clouds
4. Vertical clouds

Answer: 3. Low-altitude clouds

Question 4. Thunderclouds are otherwise known as-

1. Altostratus
2. Cirrocumulus
3. Cirrus
4. Cumulonimbus

Answer: 4. Cumulonimbus

Question 5. The cloud that forecasts continuous rain is-

1. Altostratus
2. Altocumulus
3. Cumulonimbus
4. Cirrus

Answer: 1. Altostratus

Question 6. Nimbostratus clouds indicate whether that is-

1. Calm
2. Likely to drizzle
3. Bad
4. Likely to have heavy rainfall

Answer: 3. Bad

Question 7. The cloud known by Mackerel Sky is-

1. Cirrocumulus
2. Altocumulus
3. Stratus
4. Cumulonimbus

Answer: 1. Cirrocumulus

Question 8. The colour of Altostratus cloud is generally-

1. Yellowish
2. Violet
3. Milky white
4. Bluish-grey

Answer: 4. Bluish-grey

Question 9. The type of cloud generally associated with convectional rainfall is-

1. Cumulus
2. Cirrus
3. Cumulonimbus
4. Cirrocumulus

Answer: 3. Cumulonimbus

WBBSE Class 8 Geography Chapter 5

Question 10. The changing of water from gaseous form to liquid form is known as-

1. Rainfall
2. Condensation
3. Vapourisation
4. Precipitation

Answer: 2. Condensation

Question 11. Air that contains maximum amount of moisture that it can hold at particular temperature is known as-

1. Saturated air
2. Monsoon wind
3. Unsaturated air
4. Supersaturated air

Answer: 1. Saturated air

Question 12. The temperature at which air becomes saturated is known as-

1. Freezing point
2. Cthermal capacity
3. Dew point
4. Heat

Answer: 3. Dew point

Very Short Answer Type Questions Fill In The Blanks

Question 1. __________ is a visible mass of condensed water vapour floating in the atmosphere, typically high above the ground.
Answer: Cloud

Question 2. __________ clouds appear in the sky as sand ripples in the desert.
Answer: Cirrocumulus

Question 3. Clouds are mainly seen in the __________ layer of the atmosphere.
Answer: Troposphere

Question 4. The __________ cloud sometimes spreads out on top to form an ‘anvil head.
Answer: Cumulonimbus

Question 5. __________ clouds are sometimes called as ‘sheep clouds’ or ‘wool-pack clouds.
Answer: Altocumulus

Question 6. Cooler air has __________ capacity of retaining water vapour.
Answer: Less

Question 7. When air is __________, it cannot hold any more water vapour.
Answer: Saturated

WBBSE Class 8 Geography Chapter 5

Question 8. Water vapour in air __________ to form fog, a natural weather condition.
Answer: Condenses

Question 9. The process by which heat from the sun turns water from the surface of lakes and oceans into water vapour is known as __________.
Answer: Evaporation

Question 10. The __________ is the temperature at which the water vapour in a sample of air at constant barometric pressure condenses into water.
Answer: Dew point

Question 11. Water vapour releases latent heat into the atmosphere when it __________ to form clouds.
Answer: Condenses

Question 12. As water vapour condenses to form clouds, it releases __________ heat into the atmosphere.
Answer: Latent

Question 13. Water from the surface of lakes, rivers, seas __________ and oceans rises in the atmosphere.
Answer: vapourises

Question 14. When moisture-laden air moves up, its __________ and __________ decrease.
Answer: Temperature, pressure

WBBSE Class 8 Geography Chapter 5

Chapter 5 Topic A Clouds Analytical Type Questions Write True Or False

Question 1. Clouds are very significant because all forms of precipitation occur from them.
Answer: True

Question 2. Nimbostratus are high clouds with detached segments.
Answer: False

Question 3. Cirrus clouds are indicative of a long period of precipitation.
Answer: False

Question 4. Stratocumulus clouds are also known as bumpy clouds.
Answer: True

Question 5. Altostratus clouds are indicative of widespread, continuous precipitation.
Answer: True

Question 6. The process of condensation begins only when the relative humidity of ascending air becomes 50%.
Answer: False

WBBSE Solutions For Class 8 School Science Long Answer Type Questions	WBBSE Solutions For Class 8 School Science Short Answer Type Questions
WBBSE Solutions For Class 8 School Science Very Short Answer Type Questions	WBBSE Solutions For Class 8 School Science Review Questions
WBBSE Solutions For Class 8 School Science Solved Numerical Problems	WBBSE Solutions For Class 8 School Science Experiments Questions
WBBSE Solutions For Class 8 Maths	WBBSE Class 8 History Notes
WBBSE Class 8 History Multiple Choice Questions	WBBSE Solutions For Class 8 History
WBBSE Solutions For Class 8 Geography

 

Question 7. Generally, water droplets in clouds are macroscopic in size.
Answer: False

Question 8. Halos around the sun and the moon are visible due to the presence of cirrostratus clouds.
Answer: True

Question 9. Temperature and humidity of air are directly related.
Answer: True

Question 10. The process of conversion of solids directly to the gaseous state is called sublimation.
Answer: True

Match The Columns

1.

Answer: 1. B, 2. D, 3. E, 4. C, 5. A

WBBSE Class 8 Geography Chapter 5

Answer In One Or Two Words

Question 1. Name two components of clouds.
Answer: Water vapour and dust.

Question 2. Name the cloud that indicates an advancing storm.
Answer: Cirrostratus cloud.

Question 3. Which cloud is also known as ‘bumpy cloud’?
Answer: Stratocumulus cloud.

Question 4. Which type of cloud causes convectional rainfall?
Answer: Cumulonimbus cloud.

Question 5. Which cloud is also known as the ‘thunder cloud’?
Answer: Cumulonimbus cloud.

Question 6. What is the name of the potential heat energy in water vapour?
Answer: Latent heat.

Question 7. On which particle does water vapour condense to form clouds?
Answer: Hygroscopic nuclei.

Question 8. Give an example of hygroscopic nuclei.
Answer: Salt particle.

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Analytical Type Questions

Question 1. Explain briefly the relation between the pressure belts and the planetary winds.
Answer:

Relation Between The Pressure Belts And The Planetary Winds:-

There are seven pressure belts around the world which are very closely related to the planetary winds. As the earth rotates from west to east, the winds get deflected to the right in the northern hemisphere and to the left in the southern hemisphere.

Winds blow from high-pressure zones to low-pressure zones to maintain a balance between the air pressure of different regions. There are four high-pressure and three low-pressure belts on the earth.

Permanent or planetary winds arise from sub-tropical and polar high-pressure belts and move towards equatorial and sub-polar low-pressure belts. There are three planetary winds, namely trade winds, westerlies and polar winds.

Trade winds:

The permanent low-pressure belt of the equatorial region attracts winds from the sub-tropical high-pressure belts. This wind blows from the northeast in the northern hemisphere and south east in the southern hemisphere (by Ferrel’s law) and are called northeast trade winds and southeast trade winds respectively.

Read and Learn More WBBSE Solutions For Class 8 Geography

As per nautical expression the term ‘trade’ suggests blowing along a regular path. Trade winds shift more to the north and south of their normal paths following the annual migration of the sun.

WBBSE Class 8 Planetary Winds Overview

Westerlies:

These blow outside the tropics, in the temperate zone, mainly in the opposite direction of the trade winds between 35° and 60° north and south latitudes.

These also get deflected due to the rotational force of the earth and blow from the southwest in the northern hemisphere and the northwest in the southern hemisphere.

As these are western winds, they cause rainfall chiefly in the western parts of the continents, keeping the eastern sides dry. These winds do not follow a fixed direction or path either.

However, in the southern hemisphere, the westerlies are much stronger due to the absence of larger landmasses which obstruct their path and reduce the wind speed in the northern hemisphere.

Class 8 Geography Chapter 4 Planetary Winds Notes

Polar winds:

Scientists have established that there exist two permanent high-pressure belts in the south and north poles and two comparatively low-pressure belts along the sub-polar regions.

Due to this, icy polar winds blow from high-pressure zones of the poles to the sub-polar low-pressure zones regularly. These winds deflect towards the west in both hemispheres. These are called the polar easterlies.

Question 2. Classify the trade winds and discuss their characteristics and influence.
Answer:

Classification Of Trade Winds:-

The winds that blow from sub-tropical high-pressure belts of both the hemispheres to the equatorial low-pressure belt are called the trade winds. This is a permanent wind blowing regularly throughout the year in the same direction at a uniform speed.

There are two types of trade winds

North-east trade winds:

These winds blow from the sub-tropical high-pressure belt of the northern hemisphere towards the equatorial low-pressure belt. They deviate to the right and blow from the north-east direction according to Ferrel’s law. so these winds are known as the northeast trade winds.

South-east trade winds:

These winds blow from the sub-tropical high-pressure belt of the southern hemisphere to the equatorial low-pressure belt and deviate to the left as per Ferrel’s law. They blow from the southeast so these winds are known as the southeast trade winds.

Characteristics:

The characteristics of trade winds are

1. Velocity:

Having vast stretches of landmass in their path in the northern hemisphere, here the trade winds blow at a slower speed of nearly 16km/h. On the other hand, the southern hemisphere has less landmass compared to waterbodies.

So the winds travel here at a high velocity of 22-30km/h.

2. Extent:

The trade winds normally blow within 5°-25° north and south latitudes on either side of the equator.

Understanding Shifting Pressure Belts for Class 8

Influence:

The trade winds have contributed to the development of the hot deserts in the world. The deserts are situated on the western margins of the continents that are not benefited by the moisture brought in by easterly trade winds.

As a result, deserts such as the Kalahari, the Sahara and the Atacama have developed. On the other hand, the trade winds are blessings to the farmers in the eastern parts of the continents, where these winds cause sufficient precipitation for the cultivation of crops.

 

 

Question 3. Classify and mention, the features of Westerlies.
Answer:

Classification Of Westerlies:-

The westerlies are of two types

1. In the northern hemisphere, as per Ferrel’s law, the winds get deflected to the right while moving along their path towards the sub-polar low-pressure belt. So, they are known as the southwest westerlies in the northern hemisphere.
2. Similarly, they become the north-west westerlies in the southern hemisphere due to the rotation of the earth.

WBBSE Class 8 Geography Chapter 8 Question Answer

Features Of Westerlies:-

Some of the important features of the westerlies include

1. The speed and direction of these winds are not as constant and steady as the trade winds.
2. Having larger water- bodies along their way, the westerly winds collect sufficient water vapour to cause rainfall on the western margins of the continents.
3. Apparent migration of the sun also shifts the area that comes under the influence of the westerlies slightly to the north or south of the equator.
4. The southern hemisphere, having a larger percentage of water surface than landmass, records stronger and more constant westerly winds.
5. The westerlies around 40°, 50° and 60° south latitudes, are called the ‘roaring forties’, ‘furious fifties’ and ‘screaming
   sixties’ respectively.
6. In the regions over which the westerlies blow, cyclones and anti-cyclones often originate.
7. Westerlies are stronger in winter and weaker in summer.

 

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Question 4. What do you know about the polar winds? Classify and explain their features.
Answer: The winds that blow from the high-pressure belts of the polar region to the sub-polar low-pressure belts of both hemispheres, are called polar winds.

Classification Of Polar Winds:-

According to their path of flow, polar winds can be of two types

1. Polarwinds that blow from the North Pole towards the sub-polar belt in the northern hemisphere, get deflected to the right (as per Ferrel’s law) and are called north-east polar winds.
2. Similarly, winds blowing from the South pole towards the sub-polar belt in the southern hemisphere also get deflected to the left (as per Ferrel’s law) and are called south-east polar winds.

 

 

Features Of Polar Winds:-

Some important features of polar winds are

1. The Polar winds are very cold and heavy.
2. These are very dry and almost devoid of water vapour.
3. These are more active in the southern hemisphere than in the northern hemisphere.
4. Polar winds cause snowfall and blizzards at the poles.

Question 5. What are the effects of the planetary winds on Earth?
Answer:

Effects Of The Planetary Winds On Earth:-

Planetary winds blow in a regular pattern throughout the year in fixed directions from regions of high pressure to regions of low pressure on the Earth. There are three types of planetary trade winds, westerlies and Polar winds.

WBBSE Class 8 Geography Types of Winds

Effects of the trade winds:

After collecting a sufficient amount of water vapour while blowing over the seas, the trade winds cause rainfall on the eastern margins of the continents. This favours agricultural activities there. For example, northeast Brazil, northeast Australia, and the Islands of Hawaii have favourable climatic conditions and agriculture has flourished there.

The trade winds blow from northeast in the northern hemisphere and southeast in the southern hemisphere.

After causing rainfall in the eastern parts, when these winds reach the western part of the continents, they lose most of their moisture content. So, these regions get very little rainfall and major deserts have developed here, such as the Sahara, the Kalahari, the Atacama, etc.

With their constant and defined path and speed, in the earlier times, these winds used to help in the navigation of ships and trade, thus earning the name trade wind.

Effects of the westerlies:

1. The westerlies also collect sufficient moisture while blowing over the seas and cause precipitation on the western margins of the continents due to their direction of flow. These conditions also favour agricultural practices in those regions. For example, the land around the Mediterranean Sea.
2. The westerly winds blow from south-west in the northern hemisphere and from north-west in the southern hemisphere. These winds cause less rainfall on the eastern parts of the continents situated along their way; but the middle parts receive moderate rainfall and thus, temperate grasslands have developed in such regions of the world. For example, the Prairies in North America, Pampas in South America, Steppe in Central Asia, Veld in South Africa and Downs in Australia are such temperate grasslands.

Effects of the polar winds:

Polar winds blow over the eastern part of the continents. Thus, the climate of the eastern margins of these continents become extremely cold and they experience regular snowfall.

The cold polar winds also cause snowstorms in the polar regions, for example blizzards in Antarctica.

Question 6. Explain the shifting of pressure belts.
Answer:

Shifting Of Pressure Belts:-

The pressure belts follow the apparent annual migration of the sun to the north on the Tropic of Cancer (on June 21) to the south on the Tropic of Capricorn (on December 22), reaching its points of zenith twice on the Equator (on March 21 and September 23).

On June 21, the sun is directly overhead on the Tropic of Cancer and all the pressure belts shift towards the north by 5°-10°. On December 22, the sun shines vertically over the Tropic of Capricorn and similarly, all the pressure belts move southward.

 

 

Winds are largely influenced by this shifting of the pressure belts during the annual migration of the sun. The changes that occur are more prominent in the lower latitudes than in the higher latitudes.

Effect:

Maximum effect of this shifting of the pressure belts is observed between 30° and 40° north and south latitudes, where the regions remain under the influence of trade winds in summer and westerlies in winter.

The eastern margins of the continents receive precipitation due to easterly trade winds while the western parts of those regions remain dry.

Planetary Winds and Their Importance for Class 8

For example, the southern part of Argentina and Sudan get rain while the western parts of the Mediterranean regions (such as south Chile) remain dry.

On the other hand, the same western areas get heavy rainfall under the influence of the westerlies in winter, while the eastern margins remain dry. As the pressure belts shift with changing of seasons, the belts of precipitation also change their positions.

Question 7. Discuss the different types of periodic winds.
Answer:

Different Types Of Periodic Winds:-

Unequal air pressure between land and water surfaces at a particular place, at a particular time or period, gives rise to periodic winds.

There are three types of periodic winds

1. Sea breeze
2. Land breeze and
3. Seasonal winds.

1. Sea breeze:

The landmass, being warmer than the adjacent sea during the day, forms a low pressure area (almost a vacuum) above it. As a result, a comparatively cooler airblows over the sea.

This is called the sea breeze. The sea breeze often brings showers in the coastal regions.

2. Land breeze:

At night, the sea remains warmer than the adjacent land portion, which has already discharged its heat. The cool air over the land thus moves towards the warm sea.

This cool wind usually starts blowing at midnight or in the later part of the night and is called the land breeze.

3. Seasonal winds:

The difference temperature and air pressure on land and its adjacent water body causes winds to move towards land from the waterbodies or vice- versa. These winds change their direction season-wise, according to the prevailing conditions.

Hence, these are known as seasonal winds. They are also known as monsoon winds in India. The monsoon wind blows from south-west in summer and from north-east in winter.

In summer, the monsoon winds bring rain in India, while in winter, the monsoon winds are usually dry.

Question 8. What are local winds? Discuss some of the local winds.
Answer:

Local winds:

A difference in temperature and air pressure gives rise to certain winds that are influenced by the local topography and atmosphere of a particular place. These are called local winds. Example-Loo, Foehn, Chinook, Pampero, Sirocco, Khamsin, Andhi.

Some local winds:

Three local winds are discussed below

1. Loo:

It originates from the north-western landmass of India during the day. It is a very hot and dry wind that blows strongly over the land in a horizontal manner. Loo blows mainly over Delhi and parts of Rajasthan.

2. Foehn:

It is a dry and hot wind that blows down the leeward slope of the Alps in Europe. Foehn blows with great force. During spring, it melts the snow very quickly and thus helps in the luscious growth of pasture lands.

3. Chinook:

It is similar to Foehn, blowing eastward across the Prairies of North America from the eastern slope of the Rocky Mountains in the west. ‘Chinook’ in English means ‘snow eater’, as it increases temperature and melts the snow of the extended Prairie region. This wind strictly blows in winter.

WBBSE Class 8 Geography Wind Movement Explanation

Question 9. How have the names like Aila, Thane, Phailin, Helen, Lehar, Haiyan, etc., come to mean various cyclonic storms?
Answer: Meteorologists name the cyclonic storms that occur in various places around the world.

For example, cyclones are known as

1. Hurricane over the caribbean sea
2. Typhoon in japan and south china sea
3. Baguio in the philippines island, etc.

Similarly, the tropical cyclones in the Indian subcontinent are assigned different local names. These are Aila, Thane, Phailin, Helen, Lehar, etc. In the year 2000, the WMO (World Meteorological Organisation) decided to officially accept these local names.

It was decided that the cyclones originating in the Indian Ocean would be named by the countries around the ocean, including Bangladesh, India, Maldives, Myanmar, Oman, Pakistan, Sri Lanka, and Thailand.

Each country will submit a list of probable names for the storms which will be arranged alphabetically according to the first letter of the country’s name and the names of the cyclones in this region will be chosen from the respective lists.

Example ‘Aila’ came from Maldives, Phailin or Pilin’ came from Thailand, ‘Lehar’ from India, ‘Hudhud’ from Oman, ‘Fani’ from Bangladesh, etc.

Question 10. Explain briefly the variable winds. Or, What are cyclones and anti- cyclones? Explain in brief.
Answer:

Variable Winds:-

The winds that suddenly cease after blowing for a short span of time, depending on the local air pressure, are called variable or irregular winds.

A drastic, unpredictable rise or fall of air pressure in highly localised area gives rise to sudden or irregular winds. These winds are mainly of two types

1. Cyclones and
2. Anti-cyclones.

1. Cyclones:

A cyclone is a low pressure system with winds blowing anti-clockwise in the northern hemisphere and clockwise in the southern hemisphere. The pressure falls rapidly at the centre, with strong winds spiralling around it.

The isobars in this region are either circular or oval in shape. Cyclones can be of two types according to their origin and structure

1. Tropical cyclones and
2. Temperate cyclones.

Tropical cyclones:

Class 8 Geography WBBSE

Upward moving air that moves towards the centre of a low pressure area at a high velocity and in a spiral manner is called Tropical cyclone.

These cyclones originate over seas and oceans in the tropical regions, between 16° and 24° latitudes in either hemispheres. It is known by different names in different regions.

 

 

It is called ‘Cyclone’ in the Arabian Sea and Bay of Bengal, “Typhoon’ in South and East China Sea, ‘Hurricane’ in the Caribbean Sea.

Temperate cyclones:

The hot and cold winds blowing between 35° and 65° latitudes on both sides of the equator meet and gives rise to a ‘front. Cold winds being heavy, descend downwards and fill up the place of the hot wind.

The warm air mass overrides the cold air as the former is lighter. It rises up in a spiral manner and this is known as temperate cyclone.

2. Anti-cyclones:

An anti-cyclone is a weather condition having high pressure at its centre, associated with calm and fine weather. The winds blow clockwise in the northern hemisphere and anti-clockwise in the southern hemisphere.

Circular isobars prevail in these regions. They move very slowly, drifting or remaining stationary at times.

Class 8 Geography WBBSE

 

 

Question 11. Compare among trade winds, westerlies and polar winds.
Answer:

Comparison among trade winds, westerlies and polar winds are

 

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds  Short Analytical Type Questions

Question 1. What makes wind blow?
Answer:

Wind Blow:-

Difference in air pressure causes movement of wind. As per the natural tendency, winds always blow from high-pressure zones to low-pressure zones to maintain the pressure balance in the atmosphere.

The difference in pressure between two areas is the main factor what makes wind blow. Solar energy has great impact on the wind movement too. The sun’s heat increases the temperature of the air mass, making it expand, rise and form low-pressure regions.

 

 

 

For example, the equatorial low-pressure belt attracts cold and heavy winds from the sub-tropical high-pressure belts. On the other hand if the difference in pressure is negligible, calm weather conditions prevail.

Question 2. What is centrifugal force?
Answer:

Centrifugal Force:-

The rotational force of earth is felt maximum at the equatorial region and is almost nil at the poles.

This rotation tends to deflect all free flowing objects outward while the gravitational pull attracts everything towards the centre of the earth. The force the centrifugal force.

Characteristics of Planetary Winds for Class 8

Question 3. What is Coriolis force?
Answer:

Coriolis Force:-

G.D. Coriolis, a renowned scientist, first observed a kind of a deflecting or distracting force that originates due to the rotation of the earth.

Winds and ocean currents are mainly influenced by this force and get deflected to the right in the northern hemisphere and to the left in the southern hemisphere.

This force was named Coriolis force. Coriolis force has the maximum effect at the poles and the minimum at the equator.

Question 4. Define Ferrel’s law.
Answer:

Ferrel’s Law:-

As the earth is a sphere, its rotational force is not uniform everywhere. It tends to decrease gradually towards the poles from the equator. Thus, winds cannot blow straight on the surface of the earth and have to move in a curved manner.

This deflection occurs in a definite way. As a result, winds deviate to the right in the northern hemisphere and to the left in the southern hemisphere.

This was established by the famous American meteorologist William Ferrel in 1856 and is which deflects everything outwards is called known as the Ferrel’s law.

 

 

Question 5. Explain Buys Ballot’s law.
Answer:

Buys Ballot’s Law:-

In 1857, a Dutch meteorologist Buys Ballot found that in the northern hemisphere if you stand facing the wind, there will be low pressure to your left and high pressure to your right.

Class 8 Geography WBBSE

In the southern hemisphere, the situation is reversed. This relationship between wind movement and air pressure was first explained by him. Hence, it is known as Buys Ballot’s law.

 

Question 6. Classify the wind system.
Answer:

Classification Of Wind System:-

Wind system of the earth can be classified mainly into four broad categories, which are further of many types. This has been represented in the chart below-

 

Question 7. What are trade winds?
Answer:

Trade Winds:-

The planetary winds that blow from the sub-tropical high-pressure belts of both hemispheres constantly, following a definite path throughout the year, towards the equatorial low-pressure belts are called trade winds.

 

These tropical winds blow from north- eastern direction in the northern hemisphere and from south-eastern direction in the southern hemisphere.

Question 8. From which direction does the wind brings rain to our state? Or, Give an account of the direction of the rain-bearing wind in our state.
Answer:

Direction Of The Rain-Bearing Wind In Our State:-

The rain-bearing wind that brings showers to the state of West Bengal is the south-west monsoon wind. The Tropic of Cancer, which receives vertical sun rays during summer passes through West Bengal, making the state intensely hot in summer.

This heat forms a zone of extreme low pressure that attracts sea breeze from the adjacent Bay of Bengal which is called the south-west monsoon wind. These winds are very humid as they carry plenty of water vapour while blowing over the sea and cause heavy rainfall here.

The duration of the rainy season in our state depends on the period during which the south- west monsoon winds blow over the land.

 

 

Question 9. Why have deserts formed in the western margins of the continents which fall in the path of the trade winds, while the western margins of the continents which are under the influence of the westerlies receive heavy rainfall? Or, Why are most of the deserts situated in the western margins of continents in tropical areas?
Answer:

Most Of The Deserts Situated In The Western Margins Of Continents In Tropical Areas:-

The trade winds in both hemispheres blow from the warm tropics to the very hot equatorial region. As a result, they heat up further and absorb a lot of water vapour.

As they are easterly winds they cause heavy shower in the eastern margins of the continents. When the winds move from east to west in summer, they keep losing moisture constantly and the amount of rainfall goes on decreasing towards the west, where precipitation becomes almost nil.

So, large deserts have developed in these regions in the west. The westerlies, on the other hand blow from the west to the east. These cause heavy rain in winter in the western margins of the continents, while keeping the eastern regions dry.

Question 10. Briefly write about ITCZ.
Answer:

ITCZ:-

The permanent equatorial low-pressure belt attracts trade winds from sub-tropical high-pressure belts in both the hemispheres. Hence, the equatorial low-pressure belt becomes a meeting or converging point of north-east and south-east trade winds. This zone is called the Intertropical Convergence Zone or ITCZ.

The region always has a high temperature and so the air in this zone heats up and rises. So, no horizontal movement of air is experienced here, making it a region of ‘calm’ called the doldrums.

WBBSE Class 8 Geography Study Guide on Winds

Question 11. What is the relationship between air pressure belt and wind movement?
Answer:

Elationship Between Air Pressure Belt And Wind Movement:-

Air moves because of the difference in air pressure. There are seven pressure belts which exist on earth. Among these, three are low-pressure belts, while the rest are high-pressure belts.

To keep a balance among these pressure belts, air moves from high-pressure belts to low-pressure belts.

Example

1. Air from the sub-tropical high-pressure belts flows towards the equatorial low-pressure belt throughout the year. These are known as the trade winds.
2. A steady flow of air occurs from the sub-tropical high-pressure belts to the sub- polar low-pressure belts. These are known as the westerlies.
3. Cold and heavy air flows from the polar high-pressure belts to the sub-polar low-pressure belts. These are known as polar winds.

Question 12. Why are the higher slopes in Kullu and Kangra valleys of Himachal Pradesh more populated than the valley floors?
Answer:

Higher Slopes In Kullu And Kangra Valleys Of Himachal Pradesh More Populated Than The Valley Floors:-

At times slopes of mountains are found to be more densely populated than the valleys. Certain weather conditions produce a reversal of the normal rate of change in temperature with altitude and thus attract more people to settle there.

These conditions are as follows-

1. During the day, the sun heats up the mountain slopes more intensely than the valleys.
2. When the cold Katabatic wind descends and settles down in the valleys at night, the temperature of the valleys become colder than the mountain slopes.

For these reasons, the Kullu and Kangra valleys are less populated while the mountain slopes are more densely populated.

Question 13. Why have major grasslands developed in the eastern and central parts of the continents along the path of the westerlies?
Answer:

Major Grasslands Developed In The Eastern And Central Parts Of The Continents Along The Path Of The Westerlies:-

Usually waterbodies remain warmer than the landmasses in winter and the westerly winds collect abundant moisture from the seas while blowing over them and thus cause heavy rainfall in the western margins of the continents.

After this, they continue to become drier as they move towards the central and eastern parts of the continents. Due to less rainfall, temperate grasslands have developed on the eastern and central parts of continents along the path of the westerlies.

Question 14. Give the characteristics of the sea breeze.
Answer:

Some of the characteristics of sea breeze are as follows

1. It is a local wind.
2. The difference in temperature between land and adjacent waterbody generates sea breeze.
3. It blows during the day from sea to land.
4. The intensity of this breeze is usually strong and its intensity depends on the topography of the coastal region.
5. This breeze starts blowing about four hours after sunrise and picks up some speed in the evening.

 

 

Question 15. Mention the features of the land breeze.
Answer:

Land breeze has the following features

1. It is a local wind.
2. It blows as a result of the difference in temperature between sea and adjacent land.
3. It blows at night from land to sea.
4. It is weaker in intensity than the sea breeze.
5. It picks up speed at dawn.

 

WBBSE Class 8 Geography Pressure Belts and Wind Patterns

Question 16. Write the differences between land breeze and sea breeze.
Answer:

The differences between land breeze and sea breeze are as follows

 

Question 17. Write a brief note on monsoon winds.
Answer:

Monsoon Winds:-

The word monsoon is derived from the Arabic word mausim meaning ‘season. Monsoon wind is a seasonal wind and is associated with the rainy season in our country.

This wind develops due to the difference in temperature and air pressure between landmass and adjacent waterbodies (the Arabian Sea and the Bay of Bengal). In summer, these winds blow from south-west to north-east and cause rainfall in India.

In winter, the same wind blows from land to sea from north-east to south-west (retreating monsoon). But during this time, it cannot much all over the country cause rain, as it does not contain moisture.

Question 18. Why is monsoon wind classified as seasonal or periodic wind?
Answer:

Monsoon Wind Classified As Seasonal Or Periodic Wind:-

Monsoon winds are almost similar to land and sea breezes, except for the fact that these (monsoon winds) are seasonal, rather than being a daily phenomena. This is so because-

1. The monsoon winds depend on the apparent annual migration of the sun. The sun remains overhead on the Tropic of Cancer on 21 June and during that time, the northern hemisphere experiences summer, while the southern hemisphere experiences winter.

When the northern hemisphere experiences summer, cold winds blow from the south towards a low-pressure zone. After crossing the equator, these winds gets deflected to the right as per Ferrel’s law, become the south- west monsoon winds and bring rain to India.

 

 

2. Again, on December 22, the sun being overhead on the Tropic of Capricorn, the monsoon winds blow from the opposite or north-east direction under reverse conditions.

So, it can be seen that the monsoon winds change their direction according to seasons and so are called seasonal or periodical winds.

Question 19. In which season does north wind blow over our country?
Answer:

As the sun migrates to the southern hemisphere in winter, India remains comparatively cold because it does not receive perpendicular sunrays during this time. The southern hemisphere experiences summer then.

The high-pressure zone that develops over the Indian landmass causes air to blow towards the warm, low-pressure zone of the southern hemisphere.

In our country, this wind blows from land to sea in the winter and is know as the north-east monsoon (retreating monsoon) wind. This wind is dry and is also called the north wind.

Question 20. What do you mean by ‘inversion of energy, the temperature rises. Due to this, the temperature’?
Answer:

Altitude and temperature vary inversely. This means, temperature normally decreases with an increase in altitude or height (at the rate of 6.4°C per 1000m).

There are, however, some places where certain weather conditions produce a reversal of normal lapse rate in the lower atmosphere. In these cases, temperature increases with an increase in altitude.

Usually, on a calm night with no cloud cover, winds from the upper layers start blowing down along the mountain slope. By discharging heat, this wind already becomes cool and heavy.

This type of wind is called Mountain wind or Katabatic wind. On the other hand, during daytime a type of warm wind which moves upward is called Valley wind or Anabatic wind. In such cases, the lower slopes of a mountain record less temperature than the upper ones.

This happens due to the ‘inversion of temperature. So, farmers sometimes prefer mountain slopes for their agricultural activities than the lower altitudes of the valleys.

 

Short Answer Questions on Planetary Winds for Class 8

Question 21. Why does temperature of mountain slopes increase in spite of increase in altitude?
Answer:

Temperature Of Mountain Slopes Increase In Spite Of Increase In Altitude:-

Generally, temperature and altitude vary inversely. But in the valleys, if the sky has no cloud cover to prevent infiltration of solar air in the lower parts of the valley becomes warm and it starts to rise.

This warm air makes the mountain slopes warm. So, the temperature rises in the mountain slopes in spite of an increase in altitude.

Question 22. How do the winds get their names?
Answer:

Winds Get Their Names As Follows:-

A wind is named according to the direction from which it blows. Thus, a wind from the south blowing towards any direction is called a south wind.

For example, India receives rain from the monsoon winds that come from south-west and we call it south-west monsoon wind. Similarly, the westerlies have got their names from the direction from which they blow, i.e., the west.

Question 23. Write the differences between wind and air current.
Answer:

The differences between wind and air currents are

 

Question 24. Write down the hemispheres in which these places are located and the winds that they experience:

Answer: The hemispheres in which these places Beaufort Sea Northern are located and the winds that they experience are as follows

 

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Short Answer Type Questions

Question 1. What do you mean by planetary winds?
Answer:

Planetary Winds:-

The existing permanent belts of high and low pressure on the earth’s surface cause winds to move in a regular pattern throughout the year along definite directions. These winds are called planetary winds. These are also called invariable or permanent or primary winds.

They are constant and are of three types

1. Trade winds
2. Westerlies and
3. Polar winds.

Question 2. From which direction do the westerlies blow in the southern hemisphere and what is the name given to such winds?
Answer:

The westerlies in the southern hemisphere blow from the high-pressure belt around the Tropic of Capricorn to sub-polar low-pressure belt around the Antarctic Circle.

During their journey, they deflect towards the left as per Ferrel’s law and blow from the north-west. So, they are known as the north-west westerly winds.

Question 3. What are the westerlies?
Answer:

Westerlies:-

The winds that blow from the sub-tropical high-pressure belts to the sub-polar low-pressure belts in both hemispheres are called the westerlies.

Question 4. Why are the westerlies faster in the southern hemisphere?
Answer:

Westerlies Faster In The Southern Hemisphere:-

The westerlies are stronger or faster in the southern hemisphere as compared to the northern hemisphere. This happens because there are no large lamdmasses found in this region that can obstruct their path. So, here westerly winds are faster.

Question 5. Why is there almost no rainfall from the winter monsoon winds?
Answer:

There Is Almost No Rainfall From The Winter Monsoon Winds

In winter, monsoon wind blows from land to sea and it follows the direction from north-east to south-west (retreating monsoon).

As it blows from over the land, it does not contain much moisture to cause rainfall. Thus, there is almost no rainfall caused by the winter monsoon wind.

Question 6. From which direction does the polar wind blow in the southern hemisphere according to the Ferrel’s law and what is it called?
Answer:

The polar wind in the southern hemisphere blow from the Antarctic high-pressure belt to the sub-polar low-pressure belt of the southern hemisphere.

Along their path, they deflect towards the left as per Ferrel’s law and blow from the south-east. So, they are known as the south-east polar winds or polar easterlies.

Question 7. Why are trade winds also called ‘the winds of the traders or businessmen’?
Answer:

Trade Winds Also Called ‘The Winds Of The Traders Or Businessmen’:-

Trade winds blow between approximately 5° and 25° north and south latitudes. These winds rise from sub-tropical high-pressure belts and move towards the equatorial low-pressure belt. These are regular in terms of both speed and direction.

They seem to trace out a path in the sea for sailing in ancient times. Ships carrying goods for trading followed the path of these winds. So they are called ‘trade winds.

Question 8. What are the roaring forties?
Answer:

Roaring Forties:-

The north-west westerlies blow between 40° and 60° south latitudes uninterrup- tedly in the southern hemisphere because there are no large landmasses to obstruct them.

These winds blow with a great velocity and make loud noise while blowing over this region. Hence, these latitudes are known, by different names depending on the sound these winds make while blowing. The latitude of 40°S is known as the ‘roaring forties’.

Question 9. Why are the westerlies also called ‘anti-trade winds’?
Answer:

Westerlies Also Called ‘Anti-Trade Winds’:-

The rotational force of the earth has led to the formation of two low pressure belts along the sub-polar regions that attract winds from the sub-tropical high pressure belts in both hemispheres.

These are the westerlies, constant winds that blow in the opposite direction of the trade winds and are hence called the ‘anti-trade winds.

Question 10. Why do polar winds not cause rainfall?
Answer:

Polar Winds Not Cause Rainfall:-

According to meteorologists, both poles have two permanent high-pressure belts. Extremely cold and dry winds from the poles blow towards the adjacent sub-polar low-pressure belts, but these do not cause any rainfall because of the absence of considerable moisture in them.

However, the minimal moisture content of this wind gets precipitated as snow, instead of rain. Hence, polar regions have no rainfall but experience occasional snowfall.

Question 11. Why is the polar wind cold?
Answer:

Polar wind is cold, because

1. The poles have permanent ice caps.
2. The polar regions experience six months day and six months night alternately.
3. These regions receive very slanted rays of the sun, which do not produce enough heat.

Question 12. Which wind brings more rainfall to coastal areas?
Answer:

Wind Brings More Rainfall To Coastal Areas Are Given Below:-

Sea breeze, the kind of wind with maximum water vapour content, causes heavy rainfall in the coastal regions. Sea breeze blows during the day from the comparatively cooler water bodies towards the adjacent hotter landmasses.

This is because the air above the landmasses gets heated up and rises, thus creating a vacuum. The moisture-bearing winds from the sea fills in the vacuum and cause rainfall.

Question 13. From which direction would the cool breeze come in a coast or a river bank in the evening?
Answer:

Direction Of Cool Breeze Come In A Coast Or A River Bank In The Evening

In the evening, a cool, moist breeze blows from the river bank or coastal area towards the land.

This happens because of continuous incoming solar rays form a hot low-pressure zone over the landmass; whereas the waterbody, being comparatively less heated, has a high-pressure zone above it.

Therefore, by normal standards, winds blow from high-pressure to low-pressure zones.

Question 14. Which wind would help boats sail as they venture out into the sea or river at dawn?
Answer:

Wind Would Help Boats Sail As They Venture Out Into The Sea Or River At Dawn:-

Once the sun sets, both the land and waterbodies start discharging heat. The solid landmass can do it more rapidly than the liquid waterbody and as a result, high pressure exists over the land while low pressure prevails over the waterbodies.

So the wind blows towards the sea. This is known as land breeze. At dawn, the difference in temperature between land and sea is maximum. So land breeze is most intense at dawn.

Thus, this wind would help boats sail as they venture out into the sea or river.

 

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Multiple Choice Questions Choose The Correct Option

Question 1. Air movement chiefly depends on-

1. Atmospheric pressure
2. Temperature
3. Latitudinal location
4. Altitude of land

Answer: 1. Atmospheric pressure

Question 2. Coriolis invented the relationship between the earth’s rotation and centrifugal force of objects on earth in-

1. 1857
2. 1835
3. 1873
4. 1880

Answer: 2. 1835

Question 3. The relationship between air pressure and wind system was established by-

1. Ferrel
2. Buys Ballot
3. Magellan
4. Coriolis

Answer: 2. Buys Ballot

Question 4. Buys Ballot was a-

1. Dutch meteorologist
2. German geographer
3. French geologist
4. Russian meteorologist

Answer: 1. Dutch meteorologist

Question 5. The direction of wind is measured by a-

1. Barometer
2. Rain gauge
3. Wind vane
4. Hygrometer

Answer: 3. Wind vane

Question 6. The unit ‘knot’ is generally used to express-

1. Wind direction
2. Air pressure
3. Wind velocity
4. Chumidity

Answer: 3. Wind velocity

Question 7. The wind that blows regularly throughout the year from a definite direction between 5° and 25° north and south latitudes is called-

1. Polar wind
2. Trade wind
3. Westerlies
4. Monsoon wind

Answer: 2. Trade wind

Question 8. The trade wind usually travels at a speed of-

1. 10-12km/hr
2. 35-40km/hr
3. 16-30km/hr
4. 40-45km/hr

Answer: 3. 16-30km/hr

Question 9. The major deserts of the world lie in the-

1. Path of the planetary winds
2. Way of the westerlies
3. Direction of the trade winds
4. Path of the south-west monsoon wind

Answer: 3. Direction of the trade winds

Question 10. An example of a planetary wind is-

1. Westerlies
2. Sea breeze
3. Monsoon wind
4. Land breeze

Answer: 1. Westerlies

Question 11. Westerlies in the southern hemisphere blow from-

1. South-east
2. South-west
3. North-east
4. North-west

Answer: 4. North-west

Question 12. Polar easterlies blow in both hemispheres within-

1. 70° 80° latitudes
2. 5°-25° latitudes
3. 40°-45° latitudes
4. 35°-60° latitudes

Answer: 1. 70° 80° latitudes

Question 13. Portugal, Spain, Italy and France receive rain in winter due to the influence of the

1. North-west westerlies
2. South-west westerlies
3. South-west monsoon winds
4. North-east monsoon winds

Answer: 2. South-west westerlies

Question 14. The polar wind is-

1. Warm and wet
2. Cold and dry
3. Cold and wet
4. Warm and dry in nature

Answer: 2. Cold and dry

Question 15. A wind that blows seasonally is called-

1. Planetary wind
2. Sea breeze
3. Sudden/irregular wind
4. Monsoon wind

Answer: 4. Monsoon wind

Question 16. The cold heavy and moist wind that blows from the sea to land during the day is called

1. Abrupt or sudden wind
2. Land breeze
3. Sea breeze
4. Trade wind

Answer: 2. Sea breeze

Question 17. During the rainy season, India receives rain from-

1. North-east monsoon winds
2. South-east monsoon winds
3. South-west monsoon winds
4. North-west monsoon winds.

Answer: 3. South-west monsoon winds

Question 18. An example of a local wind is-

1. Monsoon wind
2. Sea breeze
3. Trade wind
4. Loo

Answer: 4. Loo

Question 19. Which of the following wind is known as ‘the Doctor’?

1. Foehn
2. Pampero
3. Harmattan
4. Bora

Answer: 2. Pampero

Question 20. The ‘Sirocco’ blows over-

1. Libyan desert
2. The alps
3. The rocky mountains
4. The himalayas

Answer: 1. Libyan desert

Question 21. The eye of an anti-cyclone has-

1. High pressure
2. Medium pressure
3. Low pressure
4. Equal pressure

Answer: 1. High pressure

Question 22. An example of a downslope wind is-

1. Anabatic wind
2. Trade wind
3. Katabatic wind
4. Monsoon wind

Answer: 3. Katabatic wind

Question 23. The warm and dry wind that blows down to the Prairies from the Rocky Mountains of North America is called-

1. Bora
2. Chinook
3. Foehn
4. Loo

Answer: 2. Chinook

Question 24. The cyclone that occurs in the islands of West Indies is known as-

1. Typhoon
2. Tornado
3. Hurricane
4. Phailin

Answer: 3. Hurricane

Question 25. A typhoon is-

1. An abrupt/sudden wind
2. Planetary wind
3. A seasonal wind
4. A local wind

Answer: 1. An abrupt/sudden wind

Question 26. The word ‘Chinook’ literally means-

1. Doctor
2. Season
3. Snow eater
4. Grass eater

Answer: 3. Snow eater

 

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Very Short Answer Type Questions Fill In The Blanks

Question 1. Winds usually blow from a _______ pressure belt to a _______ pressure belt.
Answer: High, low

Question 2. _______ wind is heavy and so the corresponding air pressure is high.
Answer: Cold

Question 3. _______ force is generated due to the rotation of the earth.
Answer: Centrifugal

Question 4. The rotation of the earth causes _______ effect.
Answer: Coriolis

Question 5. As per Ferrel’s law, winds in the northern hemisphere deflect to the _______ direction.
Answer: Right

Question 6. The vertical movement of air mass on earth is called _______.
Answer: Air current

Question 7. Air current in the equatorial region always moves _______.
Answer: Upward

Question 8. The winds that blow towards a definite direction throughout the year, are called _______ winds.
Answer: Planetary

Question 9. The meaning of the term ‘trade’ is _______.
Answer: Path/way that is steady

Question 10. North-east trade wind records a speed of _______ km/h on an average.
Answer: 16

Question 11. The _______ wind is considerably weaker in the northern hemisphere.
Answer: Trade

Question 12. _______ is a desert that has developed in the path of the trade wind.
Answer: Sahara

Question 13. The _______ blow in the opposite direction of the trade winds.
Answer: Westerlies

Question 14. Another name for the westerlies is _______.
Answer: Anti-trade wind

Question 15. _______ westerlies blow in the northern hemisphere and polar wind blows in the southern hemisphere.
Answer: South-west,south-east

Question 16. The westerlies cause more rainfall in the _______ season.
Answer: Winter

Question 17. The 50° south latitude is called _______.
Answer: Furious Fifties

Question 18. The places that lie along the pathway of the westerlies receive maximum rain in _______.
Answer: Winter

Question 19. The _______ wind causes blizzards.
Answer: Polar

Question 20. Sea breeze is a kind of _______ wind.
Answer: periodical

Question 21. Sea breeze blows during the _______.
Answer: Day

Question 22. Land breeze blows during.
Answer: Night

Question 23. Foehn is a type of _______ wind.
Answer: local

Question 24. A spiraling upward thrust of wind towards a low pressure eye at the centre is called _______.
Answer: Cyclone

 

Write True Or False

Question 1. Tornado is a local wind.
Answer: False

Question 2. With the change of seasons atmospheric pressure belts shift about 10°-15° in both the hemispheres.
Answer: False

Question 3. The major deserts in the world are locatedMatch the columns in the eastern margins of continents.
Answer: False

Question 4. Planetary winds are of four types.
Answer: False

Question 5. Shifting of planetary winds is noticed mostly in the region between 40° and 50° latitudes in either side of the equator.
Answer: False

Question 6. North-west westerlies are also called ‘brave west winds’.
Answer: True

Question 7. The direction of the trade winds depends on the equatorial low pressure belt.
Answer: False

Question 8. The polar winds. in the southern hemisphere are less forceful.
Answer: False

Question 9. ITCZ is the converging region of north-west and south-west westerlies.
Answer: False

Question 10. The trade winds are more forceful in the northern hemisphere than in the southern hemisphere.
Answer: False

Question 11. The Mediterranean climatic region is influenced by the trade winds in summer and the westerlies in winter.
Answer: True

Question 12. The westerlies cause rainfall in the western margins of the continents of the temperate region.
Answer: True

Question 13. Coriolis force is maximum at the poles and minimum at the Equator.
Answer: True

Question 14. Winds always blow from low-pressure belts to high-pressure belts.
Answer: False

Question 15. Winds are named after the direction from which they blow.
Answer: True

Question 16. Warm air has greater capacity to hold moisture and so is light or less dense.
Answer: True

Question 17. The horizontal movement of air, more or less parallel to the earth’s surface, is called wind.
Answer: True

Question 18. If moving wind in the northern hemisphere hits us from the back, we would feel more pressure on the right side than on the left side.
Answer: True

 

Match The Columns

1.

Answer: 1. C, 2. D, 3. A, 4. B

 

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Answer In One Or Two Words

Question 1. Which movement of the earth forces winds to get deflected?
Answer: Rotation of the earth.

Question 2. Which force is responsible for the deflection of winds?
Answer: Coriolis force.

Question 3. Which factor determines the moisture-retaining capacity of an air mass?
Answer: Temperature.

Question 4. Name the unit used to measure the velocity of wind.
Answer: Knot.

Question 5. Which planetary wind is known for maritime commercial activities?
Answer: Trade wind.

Question 6. What is the trade wind known as in the southern hemisphere?
Answer: South-east trade wind.

Question 7. Which part of the continents receives rain under the influence of the trade winds?
Answer: The eastern part.

Question 8. Under the influence of which wind system have the Sahara and Kalahari deserts come into existence?
Answer: The trade winds.

Question 9. Give the full form of ITCZ.
Answer: Inter Tropical Convergence Zone.

Question 10. Which wind would bring rain to Portugal, Spain, Italy and France and in which season?
Answer: The westerlies, in winter.

Question 11. How far do the atmospheric pressure belts shift seasonally?
Answer: 5°-10° to the north or south.

Question 12. Name the wind that causes rainfall in the coastal region.
Answer: Sea breeze.

Question 13. Which breeze will help a sailboat to move in the river or in the sea, early in the morning?
Answer: Land breeze.

Question 14. Which winds are considered to be a larger-scale version of the land and sea breezes?
Answer: Monsoon winds.

Question 15. From which direction does the cold breeze come in a coast or a river bank in the evening?
Answer: From the sea or a river to the adjacent landmass.

Question 16. Name the local wind that blows along the Adriatic Bay.
Answer: Bora.

Question 17. Hurricane is an example of what kind of wind?
Answer: A sudden or irregular wind.

 

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Conceptual Questions And Answers

 

Who am I?

Question 1. I am a belt that divides the earth into two equal hemispheres. I have upward air current but no horizontal movement of air is prevalent. I am a belt of calm.’- Who am I?
Answer: Doldrums

Question 2. ‘I occur in the tropical regions between 25°-35° North and South latitudes. I was infamous for obstructing the smooth passage of ships from Europe and Middle East. Who am I?
Answer: Horse latitudes

Question 3. ‘I am a deflecting force that can change the direction of all freely moving objects on the earth’s surface in accordance with the rotation of the earth. Who am I?
Answer: Coriolis force

Question 4. I am a region along the equator where the north-east and south-east trade winds meet.’-Who am I?
Answer: ITCZ

 

Scrambled Words

1. RDLUDOSM
2. LSWERTIESE
3. IARORGNTFROSIE
4. EABSEZREE
5. ABNATICA
6. W DLCIONLA
7. MTAHATRNA

Answers:

1. DOLDRUMS
2. WESTERLIES
3. ROARING FORTIES
4. SEA BREEZE
5. ANABATIC
6. LOCAL WIND
7. HARMATTAN

 

Fill Up The Blanks In The Knowledge Hive

Question 1. Fill in the knowledge hive with information on trade winds.

Answers:

1. It blows from the high-pressure belts of the tropics towards the Equatorial low-pressure belt throughout the year.
2. North-east trade winds blow at a speed of 16km/hr and south-east trade winds blow at a speed of 22-30 km/hr.
3. The convergence point of the northeast and south-east trade winds is known as Doldrums.
4. Deserts have formed in the western margin of the continents in the northern hemisphere due to the impact of northeast trade winds.

 

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Answer With Reference To The Illustration

Question 1. In order to travel from A (New York) to B (London) the pilot of an aircraft follows the path of movement of the south-west westerlies. So, can you tell which wind’s path of movement will a pilot from any temperate region follow to go from A (New York) to B (London)?

 

Answer: The pilot of the temperate region will follow the direct path of the south-west westerlies.

Question 2. Look at the pictures below and identify which one illustrates the effect of a cyclone and which one that of an anti-cyclone.

Answers:

1. Anti-cyclone (because of the calm atmosphere)
2. Cyclone (because of stormy weather)

Question 5. From the following two diagrams identify the wind direction in the northern and southern hemispheres during an anti-cyclone.

 

Answers:

1. The clockwise direction of winds in the northern hemisphere is found during anti-cyclone.
2. The anti-clockwise direction of winds in the southern hemisphere is found during anti-cyclone.

Question 3. From the two diagrams given below to determine the direction of the winds of cyclones in the northern and southern hemispheres.

WBBSE Class 8 Geography Chapter 4

 

Answers:

1. The anti-clockwise direction of winds in the northern hemisphere is found during cyclones.
2. The clockwise direction of winds in the southern hemisphere is found during cyclones.

 

Chapter 4 Topic B Planetary Winds Shifting Of Pressure Belts And Other Winds Crossword

 

CLUES

Down:

1. Severe tropical storm that forms in the Caribbean Sea.
2. A hot, dry wind local to Egypt and Saudi Arabia.
5. The region where north-east and south-east trade winds meet.

Across:

3. Force that appears to deflect winds.
4. Local wind in the Gulf of Guinea.

Answers:

Down: 1. Hurricane, 2. Khamsin, 5. ITCZ
Across: 3.Coriolis, 4. Harmattan

WBBSE Class 8 Geography Chapter 4

Advanced Questions And Answers

Question 1. How is the velocity or speed of wind measured?
Answer:

Velocity Or Speed Of Wind Measured As Follows:-

The instrument used to measure the speed or velocity of wind is called Anemometer. In this instrument, four semi-circular bowls are fixed on a tall pole in such a manner that the bowls can move freely, being attached to a pair of crossed sticks.

A measuring instrument, almost like a watch, is fixed at the bottom of the pole to measure the speed of wind. As the wind blows, the bowls move freely.

Question 2. Name the winds under the influence of which China in Asia, Ethiopia in Africa and Mexico’ in North America receive rainfall.
Answer:

Question 3. Dark clouds are looming over till late in the year! Do you think the advent of the rainy season is getting progressively delayed every year?
Answer:

Dark clouds are looming over till late in the year:-

The dark clouds during the month of October is indeed a matter of concern. The south-west monsoon wind should ideally return by September. According to experts, human beings are directly or indirectly responsible for this phenomenon.

The use of fossil fuels, deforestation, population explosion and an excessive increase in number of factories are some of the factors responsible for global warming as per expert’s opinion.

As a result of global warming, the atmosphere is getting heated up and temperature is increasing. Consequently, the polar ice caps are melting. Due to the melting of the polar ice caps, excess water vapour is being added to the air.

This results in chances of rainfall over a longer period of time. Thus the entire pattern of season change is getting affected. These are the reasons for the sighting of dark clouds even in October.

 

Empathy And Cooperation

This segment will determine the ability of students to cooperate, and help others within a group.

Question 1. The students will be divided into two teams, A and B. First, team A will ask questions and team B will answer them. Later, team B will ask questions and team A will answer them.

Answer:

 

Aesthetics And Creativity

This segment will check the aesthetic sense and creativity of the students.

Question 1. Collect information on recent cyclonic events in our state and our country and prepare reports on them.
Answer:

Name: Saswata Choudhury
School: Balagarh High School
Class: VIII
Sec: A
Roll: 10
Project: A report on a cyclone that has occurred recently

Introduction:

Temperature difference in different parts of the earth creates differences in air pressure. Since waterbodies are vast in number in the tropical areas as well as landmasses, change of air pressure is quite normal in this area and this region is prone to cyclonic storms.

A cyclonic storm is perilous to human beings as well as to any living being. Such a cyclonic storm, named Fani, lashed India’s east coast on 3 May 2019.

WBBSE Class 8 Geography Chapter 4

Description of the Cyclone:

Fani left a trail of destruction along the country’s east coast, mainly the coastal areas of Odisha and West Bengal. The velocity of wind in this storm was 215 km/h. Warnings in advance and proper evacuation saved thousands of lives.

However, homes were destroyed, trees and telegraph poles were uprooted and 89 people were killed by this storm among them 64 people was from Odisha. Odisha tourism and Puri temple faced severe destruction during this storm.

Electric supply was completely cut off in Fig. Collage related to cyclone Fani the coastal regions of Odisha. Drinking water got contaminated. The storm subsequently weakened while moving to West Bengal and Bangladesh.

The government and different NGOS did a splendid job by providing shelter and supplying food to the distressed people.

Question 2. Write down the names of the winds which have their paths traced by this arrows. Permanent wind blowing

Answer:

 

WBBSE Chapter 4 Pressure Belts And Wind Movement Synopsis

Air has weight and so it exerts pressure. This is called air pressure.

Belts of air of similar pressure stretching for thousands of kilometres, horizontally surround the earth. These are known as pressure belts.

The equatorial low-pressure belt is located between 5°N and 5°S latitudes, i.e., on either side of the equator.

The horizontal movement of air on the surface of the earth is called wind.

The vertical movement of air over the surface of the earth is called air current.

In the equatorial region, warm and light air moves upward. Thus, no wind movement parallel to the earth’s surface is noticed here. This leads to the prevalence of calm conditions here. So, this region is known as the belt of calm or doldrums.

Read and Learn More WBBSE Solutions For Class 8 Geography

Sub-tropical high-pressure belts extend between the latitudes 25° and 35° in both hemispheres.

During the sixteenth century, ships from the West Indies and Europe used to come to standstill conditions while sailing through the sub-tropical regions because of the presence of the calms. In such circumstances to save food and drinking water, the crew had to sacrifice their horses by throwing them into the Atlantic Ocean. So the sub-tropical regions are known as horse latitude.

WBBSE Solutions For Class 8 School Science Long Answer Type Questions	WBBSE Solutions For Class 8 School Science Short Answer Type Questions
WBBSE Solutions For Class 8 School Science Very Short Answer Type Questions	WBBSE Solutions For Class 8 School Science Review Questions
WBBSE Solutions For Class 8 School Science Solved Numerical Problems	WBBSE Solutions For Class 8 School Science Experiments Questions
WBBSE Solutions For Class 8 Maths	WBBSE Class 8 History Notes
WBBSE Class 8 History Multiple Choice Questions	WBBSE Solutions For Class 8 History
WBBSE Solutions For Class 8 Geography

 

WBBSE Class 8 Pressure Belts Overview

The sub-polar low-pressure belts are located between 60° and 70° latitudes in both hemispheres. These belts are called the Arctic sub-polar pressure belt and Antarctic sub-polar pressure belt in the northern and southern hemisphere respectively.

The polar high-pressure belts are located between 80° and 90° in both hemispheres.

Wind always blows from high-pressure to low-pressure areas to maintain the balance of pressure.

Due to the rotation of the earth, a force deflects the direction of winds. This deflective force is known as the Coriolis force.

Due to the Coriolis force, winds are deflected to the right in the northern hemisphere and the left in the southern hemisphere. This law is popularly known as Ferrel’s law.

According to Buys Ballott’s law, in the northern hemisphere, if you stand facing the wind, there will be low pressure to your left and high pressure to your right. In the southern hemisphere, the situation will be reversed.

The winds blowing almost in the same. direction at regular intervals throughout the year over a large area are called planetary winds or permanent winds.

Planetary winds are of three categories- Trade winds, Westerlies and Polar winds.

The winds blowing from the northern and southern sub-tropical high pressure belts to the equatorial low pressure belt constantly throughout the year are known as trade winds.

North-east trade winds and south-east trade winds meet at the equatorial low-pressure belt. Thus this region is also known as the equatorial calm region or Intertropical Convergence Zone (ITCZ).

The permanent winds that blow from the sub-tropical high pressure belts (25°-35°) to the sub-polar low pressure belts (60°- 70° in both the hemisphere) are known as the westerlies. These winds blow from 35°-60° latitudes in both the hemispheres.

The velocity of the westerlies is very high in the southern hemisphere. So, the westerlies blowing with a howl along the 40°S, 50°S and 60°S latitudes are called roaring forties, furious fifties and screaming sixties respectively.

The permanent winds blowing from polar high pressure belts to the sub-polar low pressure belts are known as polar winds. These winds blow from 70°-80° latitudes in both the hemispheres.

The winds that periodically change their direction diurnally or seasonally are called secondary or periodic winds.

The wind blowing from the sea towards the land during the day time is known as sea breeze. By mid-afternoon, when the temperature is maximum, the sea breeze blows at its maximum speed.

Land breeze, on the other hand, blows from the land towards the sea mainly at night, attaining maximum speed in the early morning.

Monsoon winds are the seasonal version of land breeze and sea breeze.

Class 8 Geography Chapter 4 Pressure Belts Notes

Summer monsoon wind comes from the south-western direction. It is hot and humid, so it brings rain.

The branch of the monsoon wind that blows from the northeast, is called winter monsoon wind. As it is a dry and cool wind, it does not cause rainfall in most parts of the country.

During the day, warm wind moves up along the slope of a mountain valley since the temperature in the valley is warmer than the surrounding air. This wind is called the Anabatic wind.

At night, cold wind moves down the slope of a mountain valley since the temperature in the valley is cooler than the surrounding air. This wind is called Katabatic wind.

Local winds are small-scale convection winds of local origin caused by temperature differences. Examples of some local winds are- Chinook (warm wind in the Rocky Mountains), Bora (cold and dry wind along the Adriatic Sea), Sirocco (warm and dry wind in Libya) and Loo (warm wind in India).

The winds that suddenly cease after blowing for a short period, depending on the local pressure differences, are called variable or sudden or irregular winds.

A cyclone is a large air mass that rotates around a strong centre of low atmospheric pressure. They can develop both in the tropical and temperate regions.

Anti-cyclone is a large-scale circulation of winds around a region of high atmospheric pressure. It generally develops in the high latitudes with clear sky, drier air and sunny weather.

Chapter 4 Topic A Pressure Belts And Winds Analytical Type Questions

Question 1. Discuss the factors responsible for differences in air pressure.
Answer:

Factors Responsible For Differences In Air Pressure:-

Several factors are responsible for the differences in air pressure.

Some of these are

1. Temperature:

Temperature and air pressure vary inversely. As temperature increases, air expands, becomes less dense and exerts less pressure. Thus, a low-pressure belt exists in the hot equatorial region, while high-pressure belts have formed in the cold polar regions of both hemispheres.

2. Presence of water vapour:

Temperature and moisture content of the air vary proportionately. The hotter the air, more its water vapour content. Hot, moist air has low pressure as it is lighter than dry, cold air.

A certain volume of dry air contains more nitrogen and oxygen while the same volume of humid air contains comparatively less nitrogen and oxygen, making the humid air lighter than the dry one.

Hence, the equatorial region, which receives almost vertical rays of the sun throughout the year has hot and humid weather. It is a low-pressure belt while the polar regions are high-pressure zones due to the absence of more water vapour.

Understanding Wind Movement for Class 8

3. Altitude:

Altitude and air pressure also vary inversely. As we move towards in the upward direction, we can feel less air pressure. This is because, with an increase in height, the air becomes thinner or less dense.

4. Rotation of the earth:

The difference in air pressure is also a result of the rotational force of the earth. For example, the rotational velocity of the earth is slightly higher in the sub-polar regions than in the polar regions.

This is why the winds from the sub-polar regions are deflected outward. As a result, the air in the said region is lighter and low-pressure belts have developed in these regions.

5. Density of the atmosphere:

Air pressure increases or decreases with the change in the density of the atmosphere. This density is not the same everywhere.

6. Distribution of land and water surface:

During the day, landmasses get heated rapidly and develop a low-pressure zone over there. At the same time high-pressure zone prevails over the seas where the temperature is comparatively cooler.

So the wind blows from the sea towards the land. In cold regions and at night, it is just the reverse.

Question 2. Explain with a labelled diagram the distribution of pressure belts in the world.
Answer:

Distribution Of Pressure Belts In The World:-

Depending on the differences in temperature, altitude, water vapour content, density of the atmosphere and rotational force of the earth, there exists a pattern of alternate high and low-pressure belts over the earth.

There are seven pressure belts-Equatorial low-pressure belt, a sub-tropical high-pressure belt of the northern hemisphere, sub-tropical high-pressure belt of the southern hemisphere, sub- polar low-pressure belt of the northern hemisphere, sub-polar low-pressure belt of the southern hemisphere, polar high-pressure belt of the northern hemisphere and polar high-pressure belt of the southern hemisphere.

Equatorial low-pressure belt:

This region between 5° north and south latitudes on both sides of the equator remains very hot throughout the year and thus developing a low-pressure zone. There is no horizontal movement of air.

The hot air rises upwards, making it a region of calm or doldrums.

Causes of formation:

1. This region receives more or less vertical sun rays throughout the year.
2. In the equatorial region, the area under waterbodies is greater than that of land surface. Thus, the air remains very humid.
3. Deflection of winds occur towards the right in the northern hemisphere and left in the southern hemisphere as per Ferrel’s law.

Sub-tropical high pressure belts:

Class 8 Geography Solutions WBBSE

This region lies between 25° and 35° north and south latitudes on either side of the equatorial low pressure belt.

Causes of formation:

1. The hot, moist and light air from the equatorial region rises upward; gets cooled down and becomes heavier. After that it descends on the sub-tropical belts due to the deflection caused by the rotation of the earth. Thus forms a high pressure belt around this region.
2. Air from the cold polar regions, while moving towards the equator, also descends here as a result of Coriolis force. This adds to the existing high pressure in this region.

Sub-polar low pressure belts:

These are sub-polar low pressure belts in the vicinity of 60°-70° north and south latitudes.

Causes of formation:

1. These are mainly formed due to the rotation of the earth. The velocity of earth’s rotation is greater here than at the poles. Thus, the air gets deflected to the polar and sub-tropical regions. So volume and density of air decreases over the sub-polar region.
2. These are the convergence zones of the cold Polar winds and warm Tropical winds, where the warm air is forced to rise and this causes low pressure.

Polar high pressure belts:

Beyond the polar regions, air pressure increases with increasing latitudes. So, high pressure belt exists in both the poles between 80° and 90° latitudes.

Causes of formation:

1. Polar regions havepermanent ice caps and temperature remains below freezing point throughout the year. Hence, the air is always supercool, dense and heavy there.
2. The rate of evaporation is almost nil as these regions get oblique rays of the sun. So, the air is not humid, but dry.
3. The air that rises from the sub-tropical low pressure belt gets cooled, becomes heavier and descends in the polar regions. This adds to the existing high pressure in this region.

 

Question 3. Substantiate the causes of formation of the equatorial low pressure belt and sub-tropical high pressure belts.
Answer:

Formation of the equatorial low pressure belt:

On either side of the equator, between 5° north and south latitudes, occurs this permanent low pressure belt.

This low pressure belt has formed due to three main reasons

1. The region receives almost vertical rays of the sun throughout the year. The hot and light air, in turn, forms a low pressure belt in this area.
2. The region has an extensive area under water surfaces and so the amount of moisture in the air of this region is high. The air pressure is less here due to high amount of moisture, which makes the air lighter.
3. Since the effect of the earth’s rotation is maximum at the equator, winds usually rise and get deflected to the right in the northern hemisphere and to the left in the southern. hemisphere. This process decreases its density and an area of low pressure is formed.

There is hardly any horizontal movement of air. Thus, the region is also called the equatorial doldrums.

Formation of the sub-tropical high pressure belts:

These permanent high pressure belts have formed between 25° and 35° north and south latitudes.

WBBSE Class 8 Geography Pressure Systems

The reasons behind the formation of these belts are

1. The hot and light winds from the equatorial low pressure zone rise, become cooler and heavier and sink down to settle. Due to the rotation of the earth, these winds get deflected to the right (in the northern hemisphere) or the left (in the southern hemisphere) and finally settle down around 25°-35° north and south latitudes, thus forming two permanent high pressure belts at the tropics.
2. Cold, dry and heavy polar winds which are moving towards the equatorial belt also settle between these latitudes due to the rotation of the earth. Thus the volume of the air increases over this region.

There is alomost no horizontal movement of air in these belts. Hence, they are also called sub-tropical belts of calm.

Question 4. Why is air denser in the tropics and at the poles?
Answer:

Air is denser in the tropics for the following reasons

1. The hot and light wind that rises from the equatorial low pressure belt gets cooled, becomes heavier and sinks down near the tropics.
2. A portion of the cold and dense polar wind also settles down in the tropics during their movement towards the equatorial low pressure belt.

Air is denser at the poles due to the following reasons

1. The poles have the perpetual ice caps, making these regions extremely cold with heavy air.
2. Slanting sun’s rays fall on the Arctic and and the Antarctic Circles (662° north and south latitudes), which cannot heat the air significantly. Moreover, the poles experience six months of day and six months of night alternately, and thus remain cold. Thus, the air is cold and heavy.
3. The rate of evaporation being very low here, the air remains dry and heavy.
4. The wind that rises from the sub-polar low pressure belts also sink down near the poles after getting cooled at higher levels of the atmosphere.

Chapter 4 Topic A Pressure Belts And Winds Short Analytical Type Questions

Question 1. How is temperature and air pressure related?
Answer:

Temperature And Air Pressure Related As Follows:-

Temperature and air pressure are inter- related. We find that an increase in temperature forces air to expand. Thus, the air becomes lighter and rises upwards. As a result, low pressure develops.

Example-The equatorial region experiences low pressure as it receives almost perpendicular sun rays throughout the year. So a permanent low pressure belt has developed there.

 

Similarly, a decrease in temperature causes air to contract, become cold and heavy and develop high pressure.

Example-the poles have permanent high pressure belts. This is because the regions have ice caps and receive highly slanted rays of the sun and that too for a very short period of time.

Question 2. Identify the world pressure belts on the following diagram and write down their names in your answer book.

Characteristics of Pressure Belts for Class 8

Mark the high and low pressure belts with different colours in a diagram and mention the latitudinal stretch of each pressure belt and locate them in the diagram.
Answer:

In this diagram the world pressure belts are as follows

1. Equatorial low pressure belt
2. Tropical high pressure belt of the northern hemisphere
3. Tropical high pressure belt of the southern hemisphere
4. Sub-polar low pressure belt of the northern hemisphere
5. Sub-polar low pressure belt of the southern hemisphere
6. Arctic high pressure belt and
7. Antarctic high pressure belt.

 

Question 3. Why are sub-tropical high pressure belts around the Tropic of Cancer and the Tropic of Capricorn called tropical doldrums? Or, Why are the sub-tropical belts of northern and southern hemispheres found to be calm?
Answer:

Sub-Tropical Belts Of Northern And Southern Hemispheres Found To Be Calm:-

The sub-tropical high pressure belts around the Tropic of Cancer and the Tropic of Capricorn are called tropical doldrums, because-

1. These two are high pressure belts and hot, rising winds from the equatorial region sink around these belts, after cooling and becoming heavier, when they reach higher altitudes.
2. Due to earth’s rotation, cold and heavy air moving from the poles to the equatorial low pressure belt, sinks partially at these high pressure belts of the tropics.

Horizontal movement of air is not much observed here. As the atmosphere is calm, these regions are called sub-tropical belts of calm or doldrums.

WBBSE Class 8 Geography Wind Movement Explanation

 

 

Question 4. Why are the sub-tropical high pressure belts called ‘horse latitudes’? Or, Why would ships come to a standstill in the horse latitudes?
Answer:

Ships Come To A Standstill In The Horse Latitudes:-

Sub-tropical high pressure belts are found in the regions lying between 25° and 35° latitudes in both northern and southern hemispheres. Cold and heavy winds sink and settle here. Thus, there is hardly any horizontal movement of air.

It is believed that in ancient times ships with horses used to sail from Europe and the Middle-East to North America and islands of West Indies through this region.

While sailing through this region of calm the ships got stranded here for the lack of favourable wind. In such cases, the sailors used to throw their dead or dying horses in the sea to make the ships lighter and to conserve food and drinking water for themselves. Thus, the name ‘horse latitudes’ came into being.

Question 5. Write about the major causes of high pressure in the higher latitudes.
Answer:

Major Causes Of High Pressure In The Higher Latitudes:-

There are two well known high pressure belts which exists around the north and south Poles between 80°-90° north and south latitudes. Following are the causes for which high pressure belts have been formed around the poles

1. The poles remain completely covered with snow. So, very low temperature (below freezing point) prevails throughout the year. Hence, high pressure prevails here.
2. These regions receive very slanted sun rays. Thus, they experience extremely low temperatures, along with high pressure.
3. The poles experience six months’ day and six months’ night continuously. This keeps the poles cold enough throughout the year, thus high pressure belts has develop here.
4. The rate of evaporation is very low because of extreme low temperature and so the wind does not rise and instead, settles.
5. As warm air rises from the sub-polar low pressure belts in both the hemispheres it sinks in the poles after being cooled. This contributes to the high atmospheric pressure in this region.

 

 

Question 6. Explain the relationship between air pressure and altitude.
Answer:

Relationship Between Air Pressure And Altitude:-

There exists an inverse relationship between air pressure and altitude.

Air pressure is maximum near the surface of the earth and at sea level because about 99% of the air mass prevails within 32 km of height above the earth’s surface.

Therefore, air pressure is higher at lower levels than at the higher layers of the atmosphere. Moreover, air becomes lighter with an increase in altitude and this lapse rate is about 0. 1inch or 3.4mb for every 600 feet of ascent.

Types of Pressure Belts for Class 8 Students

 

 

Question 7. If you visit Sandakphu, you might face certain problems while climbing up the mountain. Do you know what kind of problems you might face?
Answer:

Problems While Climbing Up The Mountain Like Sandakphu:-

Sandakphu is the highest point in West Bengal. It lies at a height of about 3630 m above the sea level. When we go there for trekking, we might face the following problems-

1. We might face difficulties in walking along the slopes.
2. As we go higher, we might face breathing problems because
3. With every 300m increase in height above sea level, pressure decreases by 34 mb. The air density decreases quickly and oxygen level falls sharply, thus causing problems in breathing.
4. The air is denser near the surface of the earth, but as height increases, the air becomes thinner. Thus the amount of oxygen in the air becomes less.
5. The difference between atmospheric pressure on the top of a mountain and the air pressure within the human body makes people breathe faster.

Chapter 4 Topic A Pressure Belts And Winds Short Answer Type Questions

Question 1. What is air pressure?
Answer:

Air Pressure:-

As the gravitational force of the earth pulls the air towards itself like all other materials, the weight of air exerts pressure on each and every material, even on our bodies. This weight of air is called air pressure or atmospheric pressure. It is an important element of weather and climate.

Question 2. Classify atmospheric pressure.
Answer:

Classification Atmospheric Pressure:-

Atmospheric pressure is observed to be either high or low, which actually indicates the amount of air molecules contained in the air.

If the air at a particular region contains a larger number of molecules, it is said to have high pressure and vice versa. So, air with higher pressure is denser, and air having low pressure is lighter.

Question 3. How many air pressure belts are there on earth and prepare a list including all of them.
Answer:

Types Of Air Pressure Belts Are There On Earth:-

The earth has different atmospheric pressure zones in different regions. These zones that surround the earth are called atmospheric or air pressure belts.

Class 8 Geography Chapter 4 Questions on Winds

There are seven pressure belts

1. Equatorial low pressure belt.
2. Tropical high pressure belt in the northern hemisphere around the Tropic of Cancer.
3. Tropical high pressure belt in the southern hemisphere around the Tropic of Capricorn.
4. Sub-polar low pressure belt in the northern hemisphere.
5. Sub-polar low pressure belt in the southern hemisphere.
6. Polar high pressure belt at the north pole.
7. Polar high pressure belt at the south pole.

Question 4. Atmospheric pressure is not the same all over the earth- Why?
Answer:

Atmospheric pressure is not the same all over the earth:-

Atmospheric pressure depends on several factors such as rotation of the earth, temperature, altitude, water vapour content of the air, topography and distance from the sea of a particular place.

For example, the equatorial region has developed a low pressure belt while polar regions have high pressure belts. Air pressure may also vary at different places the in different times depending on available weight of air there and the temperature of the region.

Question 5. What are equatorial doldrums?
Answer:

Equatorial Doldrums:-

The region on either side of the equator (0°) between 5° north and south latitudes is the hottest zone on earth, where the wind always moves upward, thereby creating a vacuum. Also, no significant horizontal movement of air is prevalent here.

Thus, a region of calm called the equatorial doldrums prevails here. This region actually represents the zone of convergence of north-east and south-east trade winds.

Question 6. Does the equatorial belt of calm extend over the earth continuously?
Answer:

The Equatorial Belt Of Calm Extend Over The Earth Continuously:-

The difference in temperature and air pressure on land and water surfaces obstructs the continuity of the pressure belt that forms at the equator. It thus gets divided into smaller divisions known as pressure cells.

Equatorial belt of calm is divided into three cells

1. The largest cell extends from the indian ocean to the pacific ocean
2. Over the atlantic ocean
3. Over the pacific ocean, in the west of south america.

Question 7. On which regions does air descend after deflecting from the Antarctic sub-polar belt?
Answer:

After rising from Antarctic sub-polar belt, air descends over two regions

1. Polar region of southern hemisphere and
2. Southern sub-tropical region.

Question 8. Mention the latitudinal extents of horse latitude and doldrums and point them out in the diagram.
Answer:

Latitudinal extents of horse latitude- 25° to 35° north and south latitudes. Latitudinal extents of doldrums-0° to 5° north and south latitudes.

Question 9. With the help of a diagram, illustrate which pressure belts witness vertical and displacement of air and which pressure belts witness convergence of air masses.
Answer:

Vertical displacement of air occurs in equatorial low pressure belt and sub-polar low pressure belts. Convergence of air masses occur in the sub- tropical high pressure belts and polar high pressure belts.

 

 

Question 10. Which one, between winter and rainy season, records less atmospheric pressure and why? 
Answer:

Water vapour is always lighter than air and so the lighter moisture-laden wind exerts less pressure than the dry wind.
For this, atmospheric pressure remains high in winter as the wind then is dry, cold and devoid of moisture.

On the other hand, the rainy season records maximum humidity and the lowest air pressure due to its very high moisture content.

Pressure Belts and Winds Study Guide for Class 8

Question 11. Why cannot we feel the air pressure?
Answer:

We Cannot Feel The Air Pressure:-

We cannot feel the air pressure due to the following reason-Our body has air inside it, which exerts outward pressure that is equal to to the atmospheric pressure exerted on our body from the outside.

The air pressure in our body, lungs, ears and stomach is the same as the air pressure outside of our bodies. For this reason, we do not feel the atmospheric or air pressure.

Question 12. Why do mountaineers use oxygen cylinders?
Answer:

Mountaineers Use Oxygen Cylinders Because :-

As we move higher up a mountain, there is a decrease in temperature and air pressure approximately at the rate of 34 millibar for every 600 feet of ascent.

Air pressure being less here, air becomes thinner and its oxygen content decreases. So, carrying an oxygen cylinder is necessary for the mountaineers in order to breath properly.

Question 13. What is an isobar?
Answer:

Isobar:-

An isobar is an imaginary line drawn on a map or weather chart, joining all places having equal atmospheric pressure at sea level at a given time.

As we know that air pressure decreases at the rate of 34mb per 600 feet of ascent, the isobars have to be converted to sea level before preparing a weather chart or map.

Isobars are expressed in millibars. These lines are more crenulated in the northern hemisphere than southern hemisphere.

 

WBBSE Class 8 Geography Wind Patterns

Chapter 4 Topic A Pressure Belts And Winds Multiple Choice Questions Choose The Correct Option

Question 1. The weight of air is called-

1. Air pressure
2. Air temperature
3. Humidity
4. Relative density

Answer: 1. Air pressure

Question 2. The total number of permanent pressure belts in the atmosphere is-

1. Three
2. Five
3. Six
4. Seven

Answer: 4. Seven

Question 3. Permanent low pressure belt in the atmosphere occurs in the-

1. Equatorial region
2. Sub-tropical regions
3. Polar regions
4. Desert regions

Answer: 1. Equatorial region

Question 4. Doldrums exist in the-

1. Equatorial region
2. Sub-polar region
3. Polar region
4. Desert region

Answer: 1. Equatorial region

Question 5. The regions between 25°-35° north and south latitudes are known as-

1. Aequatorial low pressure belt
2. Sub-polar low pressure belt
3. Sub-tropical high pressure belt
4. Polar high pressure belt

Answer: 3. Sub-tropical high pressure belt

Question 6. The high pressure belt/calm region. around the Tropic of Cancer is called-

1. Horse latitudes
2. Roaring forties
3. Furious fifties
4. Doldrums

Answer: 1. Horse latitudes

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 7. The tropical doldrums on the Atlantic Ocean is also called the-

1. Roaring forties
2. Doldrums
3. Horse latitudes
4. Equatorial belt of calm

Answer: 3. Horse latitudes

Question 8. Winds from the sub-polar belt of the southern hemisphere rise and move down to the-

1. Antarctic region
2. Equatorial region
3. Arctic region
4. Tropical region

Answer: 1. Antarctic region

Question 9. In comparison to the polar regions, the sub-polar regions of both the hemispheres record temperature which is-

1. Very low
2. Low
3. High
4. Same

Answer: 3. High

Question 10. Winds in both poles are-

1. Heavy and cold in nature
2. Warm and light in nature
3. Cold and light in nature
4. Heavy and warm in nature

Answer: 1. Heavy and cold in nature

Question 11. Which of the following regions has the highest air density?

1. Equatorial region
2. Polar regions
3. Sub-polar regions
4. Tropical regions

Answer: 2. Polar regions

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 12. The Antarctic region is dominated by-

1. Both high and low pressure
2. Nothing of the sort
3. Low pressure
4. High pressure

Answer: 4. High pressure

Question 13. Greenland is situated in the-

1. Equatorial belt or region
2. Tropical region
3. Temperate zone
4. Polar region

Answer: 4. Polar region

Question 14. The difference in isobars denotes-

1. Air pressure gradient
2. Deflection of air pressure
3. Areas of high air pressure
4. Areas of equal air pressure

Answer: 1. Air pressure gradient

Chapter 4 Topic A Pressure Belts And Winds Very Short Answer Type Questions Fill In The Blanks

Question 1. The equatorial region receives almost sun _______ rays throughout the year.
Answer: vertical

Question 2. The equatorial low pressure belt occurs between _______ and _______ both the hemispheres.
Answer: 0°,5°

Question 3. The _______ belt occurs between 5° north and south latitudes and _______ belts occur between 60°-70° north and south latitudes in both the hemispheres.
Answer: Equatorial, sub-polar

Question 4. An increase in air temperature causes a/an _______ in air pressure and a decrease in air temperature causes a/an in air pressure.
Answer: Decrease, Increase

Question 5. The regions lying between 25°-35° north and south latitudes are called _______.
Answer: Horse latitudes

Question 6. The maximum difference of atmospheric pressure occurs in the months of January and _______.
Answer: July

Question 7. The imaginary lines joining places with equal atmospheric pressure on a map are called _______.
Answer: Isobars

Question 8. The _______ hemisphere develops very definite air pressure cells.
Answer: Southern

Question 9. _______ is the instrument that is used to measure air pressure.
Answer: Barometer

Question 10. The Barometer was invented by _______ in 1643.
Answer: Torricelli

Question 11. The unit of measuring atmospheric pressure is
Answer: Millibar

Class 8 Geography WBBSE

Write True Or False

Question 1. Centrifugal force is a result of the rotation of the earth.
Answer: True

Question 2. The region between 0° and 5° latitudes is known as the equatorial belt of calm or doldrums.
Answer: True

Question 3. The sub-tropical belts of calm occur between 10°-20° north and south latitudes.
Answer: False

Question 4. A wind vane records the velocity of the wind.
Answer: False

Question 5. Water vapour content/humidity and air pressure vary proportionately.
Answer: False

Question 6. The sun is the chief source of heat or temperature in the atmosphere.
Answer: True

Question 7. Polar regions record low atmospheric pressure.
Answer: False

Question 8. The wind in the equatorial region is hot, humid and light.
Answer: True

Question 9. The greater the difference in atmospheric pressure between a high pressure and a low pressure belt, the lower will be the velocity of the wind there.
Answer: False

Question 10. Descending air current prevails in the equatorial region.
Answer: False

Class 8 Geography WBBSE

Match The Columns

Answer: 1. B, 2. C, 3. A, 4. D

 

Answer In One Or Two Words

Question 1. Name the different types of air pressure.
Answer:

1. High pressure and
2. low pressure.

Question 2. Name the type of pressure belt that has formed over the equatorial region.
Answer: Low-pressure belt.

Class 8 Geography WBBSE

Question 3. Name two countries and oceans over which equatorial low-pressure belt is found.
Answer:

1. Countries-Malaysia, Kenya.
2. Oceans- Indian Ocean, Atlantic Ocean.

Question 4. What type of pressure belts are formed over the sub-tropical regions?
Answer: Low-pressure belts.

Question 5. Think and say whether high or low pressure is prevalent in the sub-polar belts.
Answer: Low-pressure belt.

Question 6. What kind of pressure belt is located over both poles?
Answer: High-pressure belt.

Question 7. Write down the names of two countries and two seas in the Arctic polar region.
Answer:

1. Countries-Norway, Sweden.
2. Seas-Barents Sea, Laptev Sea.

WBBSE Topic B Rock Cycle, Rock-Forming Minerals And Importance Of Rocks Analytical Type Questions

Question 1. Discuss some important rock-forming minerals.
Answer: Minerals are essentially elements or compounds naturally occurring in rocks. These have specific chemical bondage, and atomic structures and are crystalline. A mineral can also be a compound of several elements.

Silicon, oxygen, iron, aluminium, magnesium, calcium, sodium, and potassium are eight elements that form the best part of most rock-forming minerals.

A few of the mineral-identifying properties are hardness, specific gravity, colour, cleavage, crack, chemical composition, etc. A few of the minerals are discussed in detail as follows-

Read and Learn More WBBSE Solutions For Class 8 Geography

Quartz:

The characteristics of quartz are as follows

1. Nature: It is a hard mineral having hexagonal crystals. Rocks composed of quartz become very resistant to erosion.
2. Colour: It is whitish.
3. Constituent rocks: Quartz is the main mineral of granite and basalt.
4. Uses: Quartz is used to make ornaments and as a glass and stone cutter.

Feldspar:

The characteristics of feldspar are as follows

1. Nature: It is smooth like a slate.
2. Colour: It is white or pink. The white variety is the Plagioclase Feldspar whose main chemical substance is sodium and the pink variety is Orthoclase Feldspar whose main chemical substance is potassium.
3. Constituent rocks: Feldspar is another main mineral of granite and basalt.
4. Uses: It is used in the ceramic industry and glass works for its smoothness.

Mica:

The characteristics of mica are as follows-

1. Nature: It is lustrous, smooth, flaky and brittle.
2. Colour: It may be white or black. The white variety is Muscovite and the black variety is Biotite.
3. Constituent rocks: Mica is present in many rocks, Granite being one. The lustre of granite comes from mica.
4. Uses: Mica, being a bad conductor of heat and electricity, is used in preparing electrical goods. It is also used as decorative glitter and for making paint.

Gypsum:

WBBSE Class 8 Rock Cycle Overview

The characteristics of gypsum are as follows

1. Nature: It is soft and light.
2. Colour: It is yellow.
3. Formation: It is a hydrated crystal of calcium sulphate.
4. Uses: In the cement industry, in making fertilizers and construction works huge amount of gypsum is used.

Question 2. Discuss the types of soil produced from different rocks.
Answer: The given list shows different types of soil produced from various rocks-

Question 3. List the different uses of the three kinds of rocks in our daily lives.
Answer: Three kinds of rocks are used by us differently in our daily lives.

The uses are as follows

Igneous rocks:

The uses of igneous rocks are as follows

1. Construction work is done using basalt and granite. For example- The temples of Rameswaram, Madurai, etc., are constructed from granite.
2. Stone chips used in railway tracks are made from basalt. Basalt is also used in laying tram lines, constructing roads, and footpaths, and making utensils and statues.
3. Granite is used to make floors, cooking table tops, etc.
4. Pestles used for grinding are made of basalt.

Sedimentary rocks:

Class 8 Geography Chapter 3 Rock Forming Minerals

The uses of sedimentary rocks are as follows

1. Fossil fuels like coal, mineral oil and natural gas are available from sedimentary rocks.
2. Limestone and dolomite (sedimentary rocks) are used in the iron and steel industry, and the chemical industry, as a raw material in cement-making and the construction of buildings.
3. Mudstone is the basic ingredient of clay modelling or pottery.
4. Rock salt from sedimentary rock layers is used as a cooking ingredient.
5. Regions formed of these rocks contain a sufficient amount of groundwater because of their greater permeability.
6. Silt, a product of sedimentary rocks, is very good for cultivation.
7. Some sedimentary rocks are used in building palaces and castles. For example, the Red Fort in Delhi is built of sandstone.

Metamorphic rocks:

The uses of metamorphic rocks are as follows

1. Valuable minerals like iron, copper, gold, silver, mica, manganese, etc., are obtained from these rocks.
2. The erosive process in metamorphic rocks is very slow, these are used in various construction works.
3. Slate is used to write on and also for making roof tiles. This is also used as a writing material.
4. Marble is used in architectural works like building houses, temples, memorials, etc.
5. Gneiss is used to build bridges and dams.
6. Graphite, when metamorphosed to diamond, is used to make valuable jewellery.
7. Amphi-bolite is used in constructing railway tracks.

Question 4. Discuss the importance and uses of rocks.
Answer: Economically rocks are very important. Some of the uses of rocks are

Architectural construction:

Various types of rocks are used to build temples, buildings, etc. For example, sandstone has been used to build the temple at Khajuraho and the dome at Sanchi.

Road construction:

Basalt is used for the construction of roads.

Groundwater retention:

The permeability of sedimentary rock layers helps in the preservation of groundwater. Areas formed. of granite also help in storing groundwater if there are cracks or faults oinit.

Understanding the Rock Cycle for Class 8

Minerals Production:

Igneous and Minerals metamorphic rocks contain metallic minerals and sedimentary rock layers are rich in deposits of mineral oil, natural gas and coal which are later extracted for economic purposes.

Agricultural practice:

Rocks weather to form soil which is used for agricultural purposes.

Clay products:

Fire clay heat-resistant clay and china clay are all products of mudstone. The inner lining of blast furnaces in the iron and steel industry is done with fire clay. China clay is used in the manufacture of porcelain.

WBBSE Solutions For Class 8 School Science Long Answer Type Questions	WBBSE Solutions For Class 8 School Science Short Answer Type Questions
WBBSE Solutions For Class 8 School Science Very Short Answer Type Questions	WBBSE Solutions For Class 8 School Science Review Questions
WBBSE Solutions For Class 8 School Science Solved Numerical Problems	WBBSE Solutions For Class 8 School Science Experiments Questions
WBBSE Solutions For Class 8 Maths	WBBSE Class 8 History Notes
WBBSE Class 8 History Multiple Choice Questions	WBBSE Solutions For Class 8 History
WBBSE Solutions For Class 8 Geography

 

Topic B Rock Cycle, Rock-Forming Minerals And Importance Of Rocks  Short Analytical Type Questions

Question 1. Differentiate between rocks and minerals.
Answer: The differences between rocks and minerals are

Question 2. How does the rock cycle work in nature?
Answer: The rock cycle is the process by which rocks of one kind change into another kind. It is the complete cyclic process of the formation of rocks and their change from one type to the other. The speed of different stages of this cycle varies.

 

 

Igneous rocks are formed by the cooling and solidification of magma or lava. Sedimentary rocks are formed by erosion, transportation, deposition and consolidation of sediments broken from igneous rocks, other sedimentary rocks and metamorphic rocks.

Metamorphic rocks are formed due to heat and pressure exerted on igneous or sedimentary rocks and at times on metamorphic rocks as well.

All these rocks may be thrust deeper into the crust to become magma again under high temperature and pressure. Thus, we can conclude that this cycle of formation and transformation of rocks is a continuous process.

Importance of Rocks for Class 8 Geography

Question 3. Discuss the role of rocks in the formation of landforms.
Answer: Rocks contribute much to the process of formation of various landforms. For example-

1. The hills and mountains formed of granite rock undergo exfoliation. As a result, their eroded tops are dome-shaped.
2. Basaltic plateaus are marked by their flat surfaces.
3. Rivers flowing over limestone and dolomite surfaces produce potholes or depressions on the crust.
4. Lava-formed regions near the volcanoes have conical features.
5. In the regions of sedimentary rocks, erosion gives rise to contrasting landforms. Hard, resistant rocks form higher or elevated lands while soft rocks turn into plains or lower plateaus due to constant erosion.

Question 4. Define karst topography. Write about the different types of karst landforms and give examples.
Answer:

Karst topography:

Karst topography is the landscape formed from the dissolution of limestone as a result of flowing river or rainwater. Carbonic acid (H₂CO₃) is produced when carbon dioxide (CO₂) dissolves in rainwater and this reacts with limestone.

Due to this reaction, limestone erodes and forms various types of landforms.

WBBSE Class 8 Geography Chapter 3 Notes on Rocks

Karst landforms:

The different types of karst landforms are as follows

1. When a column of lime hangs from the ceiling of a limestone cave, it is called stalactite.
2. When such a column rises from the floor of the limestone cave, it is called a stalagmite.
3. Stalactites and stalagmites join to form limestone pillars. Besides these, natural tunnels, natural bridges, terra rosa, lapies and sinkholes are also some examples of different types of karst landforms. Example-Some karst regions in India are Borra Guhalu, Andhra Pradesh, several caves in Mawsynram, a cave in Tapkeshwar temple, Dehradun, and caves in Panchmarhi, Madhya Pradesh.

 

Question 5. How does soil form from rocks?
Answer: Over time, big boulders are broken up and transformed slowly into soil. This process of soil formation from rocks is called pedogenesis. The following stages are involved in soil formation-

Weathering of rocks:

Rocks are disinter-rated and decomposed through the processes of mechanical, chemical and biological weathering. The agents of erosion. such as rivers, winds, and glaciers breaking down rocks.

Addition of organic matter:

The organic matter gets mixed with the disintegrated and decomposed rocks in this stage.

Class 8 Geography Solutions WBBSE

Removal of particles:

Agents of erosion (rainwater, rivers, sea waves, etc.) also remove a portion of the broken rocks, in this stage.

Regolith formation:

Materials left behind after the process of removal of particles form loose debris on the earth’s crust called regolith. Regolith is the basic constituent of soil. The debris then interacts naturally with water, air and organic matter to form soil.

Question 6. Mention some of the uses of igneous rocks.
Answer:

Igneous rocks:

The uses of igneous rocks are as follows

1. Construction work is done using basalt and granite. For example- The temples of Rameswaram, Madurai, etc., are constructed from granite.
2. Stone chips used in railway tracks are made from basalt. Basalt is also used in laying tram lines, constructing roads, and footpaths, and making utensils and statues.
3. Granite is used to make floors, cooking table tops, etc.
4. Pestles used for grinding are made of basalt.

Question 7. Mention the uses of sedimentary rocks.
Answer:

Sedimentary rocks:

The uses of sedimentary rocks are as follows

1. Fossil fuels like coal, mineral oil and natural gas are available from sedimentary rocks.
2. Limestone and dolomite (sedimentary rocks) are used in the iron and steel industry, and chemical industry, as a raw material in cement-making and cthe onstruction of buildings.
3. Mudstone is the basic ingredient of clay modelling or pottery.
4. Rock salt from sedimentary rock layers is used as a cooking ingredient.
5. Regions formed of these rocks contain a sufficient amount of groundwater because of their greater permeability.
6. Silt, a product of sedimentary rocks, is very good for cultivation.
7. Some sedimentary rocks are used in building palaces and castles. For example, the Red Fort in Delhi is built of sandstone.

Question 8. Mention some of the uses of metamorphic rocks.
Answer:

Rock Cycle Processes for Class 8 Students

Metamorphic rocks:

The uses of metamorphic rocks are as follows

1. Valuable minerals like iron, copper, gold, silver, mica, manganese, etc., are obtained from these rocks.
2. Erosive processes in metamorphic rocks are very slow, these are used in various construction works.
3. Slate is used to write on and also for making roof tiles. This is also used as a writing material.
4. Marble is used in architectural works like building houses, temples, memorials, etc.
5. Gneiss is used to build bridges and dams.
6. Graphite, when metamorphosed to diamond, is used to make valuable jewellery.
7. Amphi-bolite is used in constructing railway tracks.

 

Topic B Rock Cycle, Rock-Forming Minerals And Importance Of Rocks Short Answer Type Questions

Question 1. Are rocks and minerals the same things? Give reasons for your answer.
Answer: No, rocks and minerals are not the same things. Rocks are homogeneous or heterogeneous aggregates of one or more minerals. A rock may contain one or more minerals.

Minerals are elements or compounds of several elements which are found in rocks. These have a chemical bondage, and atomic structure and are crystalline.

Example-Granite and basalt are types of rocks, whereas, quartz and mica are types of minerals that are constituents of rocks.

Question 2. Why are landforms made of granite rock dome-shaped?
Answer: Magma which solidifies to form granite is viscous. As a result, the molten magma does not spread over extensive areas and solidifies in the shape of domes in the earth’s interior.

Eventually, after repeated exfoliation, these domes are exposed on the earth’s surface which further erodes to form rounded landforms. This type of landform is found in Malnad Plateau.

Question 3. Why is the Deccan Trap flat on the top?
Answer: The Deccan Trap, a part of the Peninsular Plateau of India, is formed of extrusive igneous rock-basalt. The lava that solidifies to form basalt is less viscous.

So the lava flow spreads over an extensive area before being solidified. As a result, the landform formed is flat-topped and not conical like hills or mountains.

Question 4. Which rocks are laid between and near a pair of railway tracks? Why are these rocks found here?
Answer: Basaltic igneous rocks are used between the railway tracks and these rocks are found here because these types of igneous rocks are formed of minerals like quartz, olivine, etc.

These minerals make the rock very hard and resistant to erosion. The rock can withstand the pressure of the heavy trains, thus preventing the tracks from getting damaged.

WBBSE Class 8 Geography Study Guide on Rocks

Question 5. Why does a piece of granite glitter?
Answer: The chief mineral constituents of granite are quartz, feldspar and mica.Granite rocks glitter due to the presence of mica. At times, the crystalline structure of granite also helps the rock to glitter.

Question 6. Define Moh’s scale.
Answer: Moh’s Scale of Hardness determines the hardness of minerals. This scale is graduated from 1-10. Talc is the softest mineral with a hardness value of only 1 on Moh’s Scale and diamond is the hardest mineral with a value of 10 on Moh’s Scale.

Question 7. What are minerals?
Answer: Elements or compounds that are crystalline, have well-defined atomic structures and chemicalbondagese and occur naturally in rocks are called minerals. Each mineral has its shape, colour, hardness, and structure.

Example-Quartz.

Question 8. Why is Chotanagpur Plateau called the ‘Storehouse of minerals’?
Answer: The Chotanagpur Plateau has huge reserves of minerals like iron, copper, bauxite, manganese, dolomite, mica, etc. So, the Chotanagpur Plateau is called the ‘Storehouse of Minerals’ of India.

Question 9. Name a plateau region in India, other than Chotanagpur, that is rich in mineral deposits.
Answer: The Deccan Plateau is a mineral-rich region in India. It is a storehouse of various kinds of minerals. Ratnagiri and Chandrapur of this region have a good concentration of iron ore, coal, manganese, limestone, bauxite, chromite, etc. This region provides the maximum amount of manganese.

Question 10. Why is the soil formed from basalt rock black in colour?
Answer: Basalt is an extrusive igneous rock. The soil that is formed from this rock is black as it contains titanium oxide and organic matter in sufficient quantity.

Question 11. Why is the soil formed from granite red in colour?
Answer: The soil formed from granite has more mineral content than organic matter and these minerals, which mostly contain iron oxide, make the soil red.

Question 12. Why does clayey soil have high moisture-retention capacity?
Answer: Clayey soil is a mixture of silt and clay and their grains are so fine and compact that these form impermeable layers, which prevent loss of water. Hence, clayey soil has a high moisture-retention capacity.

Question 13. Which part of West Bengal has saline soil and why?
Answer: The mangrove region of the Sundarbans in the southern part of West Bengal has saline soil due to the entry of tidal seawater into the coastal area. This soil is ideal for the growth of mangrove forests.

Question 14. What kind of rocks are mortar-pestle and slate-chalk?
Answer: Mortar is made of sandstone (sedimentary rock) and pestle is made of basalt (igneous rock). Slate is a metamorphic rock obtained from shale and chalk or the writing pencil on slate is limestone (sedimentary rock).

Topic B Rock Cycle, Rock-Forming Minerals And Importance Of Rocks Multiple Choice Questions Choose The Correct Option

Question 1. The hills of the Chotanagpur Plateau are round-shaped because they are formed of

1. Basalt
2. Limestone
3. Granite
4. Sandstone

Answer: 3. Granite

Question 2. In basaltic regions, landforms are generally

1. Flat-Topped
2. Conical
3. Rounded
4. Dome-Shaped

Answer: 1. Flat-Topped

Question 3. Rising limestone columns from the ground of the limestone caves are called-

1. Stalactite
2. Pillars
3. Stalagmite
4. None of these

Answer: 3. Stalagmite

Question 4. The main constituent minerals of granite and basal tares-

1. Gypsum
2. Mica
3. Quartz
4. Olivine

Answer: 3. Quartz

Question 5. Pink-coloured orthoclase feldspar has the following basiingredientsnt-

1. Calcium
2. Potassium
3. Sodium
4. Silica

Answer: 2. Potassium

Question 6. The ceramic industry uses-

1. Mica
2. Dolomite
3. Gold
4. Feldspar

Answer: 4. Feldspar

Question 7. The scale used to measure re hardness of minerals is the

1. Mercalli scale
2. Richter scale
3. Moh’s scale
4. Gutenberg scale

Answer: 3. Moh’s scale

Question 8. The soil of sandstone regions aisusually-

1. Saline
2. Acidic
3. Alkaline
4. Highly alkaline

Answer: 1. Saline

Question 9. Moh’s scale is graduated from-

1. 1 to 10
2. 1 to 5
3. 1 to 12
4. 1 to 100

Answer: 1. 1 to 10

Very Short Answer Type Questions Fill In The Blanks

Question 1. The cyclical process through which rocks transform from one type to another is called ____________.
Answer: Rock cycle

Question 2. Round-shaped landforms result from ____________ rock.
Answer: Granite

Question 3. Mountain tops made up of basalt are ____________.
Answer: Flat

Question 4. Karst regions are composed of ____________.
Answer: Limestone

Question 5. The shape of crystals of quartz is ____________.
Answer: Hexagonal

Question 6. Orthoclase feldspar is ____________ in colour.
Answer: Pink

Question 7. The hydrated crystal of calcium sulphate is known as ____________.
Answer: Gypsum

Question 8. The main occupation of the people in Chothe tanagpur Plateau region is related to ____________.
Answer: Mine

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 9. The loose debris formed from the weathering of rocks is known as ____________.
Answer: Regolith

Question 10. The stone chips used for the construction of roofs are made of
Answer: Basalt

Question 11. In the case of ____________ soil, there is practically no relation between the soil and the parent rock.
Answer: Alluvial

WBBSE Topic B Rock Cycle, Rock-Forming Minerals And Importance Of Rocks Write True Or False

Question 1. Minerals are compounds of basic organic materials of different types.
Answer: False

Question 2. Blackboards are made of quartzite.
Answer: False

Question 3. Karst landforms are found in areas of sandstone rock.
Answer: False

Question 4. Dams and reservoirs should not be built in limestone regions.
Answer: True

Question 5. Quartz is mostly used to cut glass and stone.
Answer: True

Question 6. The basic chemical in black plagioclase feldspar is sodium.
Answer: False

Question 7. Black mica is called biotite.
Answer: True

Question 8. Mica is a good conductor of heat and electricity.
Answer: False

Question 9. Gypsum is a moist crystal of calcium sulphate.
Answer: True

Question 10. The Chotanagpur Plateau is the storehouse of minerals in India.
Answer: True

Question 11. The soil formed from basalt has less capacity to hold moisture.
Answer: False

Question 12. Soil formed from granite is red.
Answer: True

Match The Columns

1.

Answer: 1. E, 2. C, 3. D, 4. B, 5. A

2.

Answer: 1. D, 2. H, 3. A, 4. B, 5. E, 6. F, 7. G, 8. C

WBBSE Topic B Rock Cycle, Rock-Forming Minerals And Importance Of Rocks Answer In One Or Two Words

Question 1. Which kind of rock constitutes the Chotanagpur region in India?
Answer: Granite.

Question 2. What are the limestone columns hanging down from the roof of a cave called?
Answer: Stalactite.

Question 3. Which region of India is known as the ‘storehouse of minerals’?
Answer: Chotanagpur Plateau.

Question 4. From which type of rock is black soil formed?
Answer: Basalt.

Question 5. From which rock is sandy soil formed?
Answer: Sandstone.

Question 6. What is the hardness value of topaz in Moh’s scale?
Answer: 8.

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 7. Which mineral in Moh’s scale bears a hardness value of 10?
Answer: Diamond

Question 8. Which soil is the best for growing cotton?
Answer: Black soil or regur soil.

Question 9. Which kind of soil is found in the Sundarbans?
Answer: Saline soil.

Question 10. Name the most fertile soil.
Answer: Alluvial soil.

Question 11. Give an example of metamorphism in which a metamorphic rock is involved.
Answer: Formation of phyllite from slate.

WBBSE Topic B Rock Cycle, Rock-Forming Minerals And Importance Of Rocks

Conceptual Questions And Answers

 

Who am I?

Question 1. ‘I am a constituent of the earth’s crust. I am composed of minerals.’-Who am I?
Answer: Rock

Question 2. ‘I am glittery, black or white. I am soft and malleable. I am a main constituent mineral of granite.’-Who am I?
Answer: Mica

Question 3. I have a smooth and attractive appearance. I am used to making floors. I have been used in constructing famous architectural landmarks including the Victoria Memorial.’-Who am I?
Answer: Marble

Question 4. I am a very hard, fine-grained grey-black rock. I am commonly used in constructing roads. Water can easily pass through me.’- Who am I?
Answer: Basalt

Question 5. ‘I am that branch of science that deals with rocks and their characteristics.’-Who am I?
Answer: Petrology

Scrambled Words

1. ERLEDTIO
2. SPH ASYLABY
3. RTGEANI
4. NLEMSITE O
5. HMROTEA MC PI
6. PFLDEAS R
7. YLPRTEO GO
8. CTRSAITFAINOTI
9. DETPRTIOIE
10. M COGNELATORE

Answers:

1. DOLERITE
2. HYPABYSSAL
3. GRANITE
4. LIMESTONE
5. METAMORPHIC
6. FELDSPAR
7. PETROLOGY
8. STRATIFICATION
9. PERIDOTITE
10. CONGLOMERATE

Fill Up The Blanks In The Knowledge Hive

Question 1. Fill in the knowledge hive with information on basalt.

Answers:

1. It is a volcanic igneous rock.
2. It cools down rapidly.
3. It is grey to black.
4. It is very heavy, hard and resistant to erosion.
5. It is formed by quartz, feldspar, olivine and pyroxene.

WBBSE Answer Concerning The Illustration

Question 1. The schematic representation of the rock cycle is given in the adjacent figure. Write the names of the rocks formed in the boxes marked 1, 2, and 3.

Answers:

1. Sedimentary rock
2. Metamorphic rock
3. Igneous rock

 

Crossword

CLUES

Down:

1. An example of a felsic rock.
3. Basalt is a rock.

Across:

2. It is widely used all over the world as a flooring material.
4. Common name of calcium carbonate.
5. ____ is used to make tram lines, roads, etc.

Answers:

Down: 1. Granite, 3. Volcanic
Across: 2. Marble, 4. Limestone, 5. Basalt

WBBSE Topic B Rock Cycle, Rock-Forming Minerals And Importance Of Rocks Advanced Questions And Answers

Question 1. The Himalayas are formed of sedimentary rocks.- Justify.
Answer: Due to the pressure of overlying layers of silt and water, the sediments deposited in water bodies become compact and hard. So, the mountains that rise from these seas are formed of sedimentary rocks.

Thus the Himalayas, are formed of sedimentary rocks since these are young fold mountains risen from the Tethys sea. The Tethys was a shallow sea with silt deposited on its bed over the ages.

Question 2. Classify igneous rocks based on their chemical composition.
Answer: Igneous rocks can be classified into four groups based on their chemical composition.

These are-

1. Acidic or felsic rock: This type of rock contains more than 65% silica. Examples- are granite, rhyolite, etc.
2. Intermediate rock: The silica content of this rock is almost 55%-65%. Examples- andesite, diorite, etc.
3. Basic or mafic rock: This type of rock contains 45%-55% of silica. Examples- are basalt, gabbro, etc.
4. Ultrabasic or ultramafic rock: The silica content of these rocks is less than 45%. Examples are peridotite, obsidian, etc.

WBBSE Class 8 Geography Short Answer Questions on Rocks

Question 3. What do you mean by palaeontology and mineralogy?
Answer: Scientists highly value the knowledge of fossils and a special branch dedicated to the scientific study of these has come into existence. This branch of science is known as palaeontology.

The branch of science that deals with all aspects of minerals in detail, is called mineralogy.

Topic B Rock Cycle, Rock-Forming Minerals And Importance Of Rocks Formative Participation

This segment will indicate how much the students have actively participated and taken initiative during the class.

Various types of rocks with different features can be seen around us. Based on that, answer the following:

Question 1. What are the features which can be used to differentiate various kinds of rocks?
Answer: Colour of the rocks/ hardness of the rocks/ texture of the rocks/…

Question 2. Name the various kinds of rocks based on their features.
Answer: Igneous rocks/sedimentary rocks/metamorphic rocks/…

Question 3. Give a few examples of different types of rocks.
Answer: Granite/ sandstone/ limestone…

Question 4. What are the commonly used rocks in your day-to-day life?
Answer: Slate (writing boards)/ lead (used in pencils)…

Interpretation And Application

This segment will test whether the students have understood the topics, or whether they are just memorising them.

Rock Cycle Diagrams for Class 8 Geography

CLUES

Down:

1. Molten rock material underneath the Asthenosphere
2. The type of igneous rock that forms after lava reaches the earth’s surface
5. Metamorphic rock formed from Shale
7. A porous and light rock formed from the consolidation of volcanic shale

Across:

1. The rock used in making Taj Mahal
3. Igneous rock that forms dome-shaped landforms
4. The softest mineral
6. The rock laid between railway tracks
8. Flaky mineral used to make decorative glitters

Empathy And Cooperation

This segment will determine the ability of students to cooperate and help others within a group.

Question 1. Ask your friends if they have seen any monument made out of stone while travelling. Make a list of such monuments. Do you know which stone they are made of? Find out and write down the type of stone from which these monuments are made and also their location. Try to find out how each type of stone was found at a particular location. Was the stone available in the local area or was it imported from another place?
Answer:

 

Aesthetics And Creativity

Question 1. Bring back some stones when you go for a trip. Discuss among yourselves and identify which rocks/minerals are they. Seek the teacher’s help if necessary.
Answer:

 

Question 2. If there is an object or place of interest and a work of architecture in your surroundings, try and find out which rock it is made of.
Answer:

Characteristics of Rock-Forming Minerals for Class 8

Question 3. If you have some pieces of rocks or minerals, expose them to some source of heat and observe which of them heats up faster or retains heat longer than the others.
Answer: Some rocks and minerals heat up quickly, while others take much longer to heat up and retain the heat.

Rocks and minerals that heat up quickly- Granite, Quartz, Feldspar, Sandstone, Diorite, Gneiss

Rocks and minerals that retain heat longer- Basalt, Gypsum, Shale, Mudstone.

WBBSE Chapter 3 Rocks Synopsis

Rocks are the homogeneous or heterogeneous aggregates of one or more minerals which are the complex of one or more inorganic elements.

Aggregates in which all elements remain in equal ratio everywhere are called homogeneous aggregates.

Aggregates in which all elements are formed in different ratios in different places are called heterogeneous aggregates.

The permeability of a rock is its ability or capacity to allow liquid and gaseous substances to pass through it.

The porosity of a rock is the ratio between the voids in a rock mass and the total volume of the rock.

Rocks are classified into three groups according to their origin-igneous rocks, sedimentary rocks and metamorphic rocks.

The rocks that form from cooled and solidified lava and magma on the earth’s crust or in the interior respectively, are called igneous rocks.

WBBSE Class 8 Rocks Characteristics

Extrusive igneous rocks are rocks formed due to the cooling and solidification of lava on the earth’s surface.

Read and Learn More WBBSE Solutions For Class 8 Geography

Intrusive igneous rocks are rocks formed when magma cools and solidifies below the earth’s surface.

When magma cools and solidifies just below the earth’s surface in the cracks, pores and hollow places the resultant rocks are called hypabyssal or sub-volcanic igneous rocks.

When magma cools and solidifies at a great depth within the earth the resultant rocks are called the plutonic or abyssal igneous rocks.

Granite is a hard, heavy, impermeable and erosion-resistant rock. The continental crust is mainly made of granite.

Basalt is a hard, heavy, erosion-resistant and permeable rock. The oceanic crust is mainly made up of basalt.

Sediments and debris derived by natural agents of erosion like rivers, glaciers, wind and sea waves through the processes of erosion and transportation are deposited regularly underwater.

These depositions are consolidated and compacted due to the continuous increase of weight and pressure of the overlying sediments to form sedimentary rocks.

Marine flora and fauna get buried within the beds of sediments during the formation of sedimentary rocks. Later, the solidified imprints of the dead remains of these organisms on rocks are called fossils.

Rocks formed due to cementing of disintegrated old rocks are called clastic rocks.

Chemically or organically formed sedimentary rocks are called non-clastic rocks.

Limestone is a calcareous sedimentary rock.

Sandstone is a sedimentary rock rich in sand.

Class 8 Geography Chapter 3 Rock Classification

Mudstone or shale is a soft sedimentary rock rich in clay.

Igneous and sedimentary rocks lose their physical and chemical characteristics over a long period and acquire new characteristics to form newly transformed rocks known as metamorphic rocks.

Marble is the metamorphic form of limestone.

Slate is the metamorphic form of mudstone or shale.

Gneiss is the metamorphic form of granite.

The rock cycle is the process by which rocks of one kind change into another kind. It is the complete cyclic process of the formation of rocks and their change from one type to the other.

Karst topography is the landscape formed from the dissolution of limestone as a result of flowing river or rainwater.

Elements or compounds that are crystalline, have well-defined atomic structures and chemical bondages and occur naturally in rocks are called minerals.

Some important minerals are quartz, feldspar, mica and gypsum.

Moh’s Scale of Hardness measures the hardness of minerals. It is graduated from 1-10.

The Chotanagpur plateau is known as the storehouse of minerals in India.

Natural agents like rivers, wind, rainfall, glaciers, sea waves, etc degrade rocks and minerals over a long period to form loose debris of rocks. This debris is called regolith.

Chapter 3 Topic A Characteristics And Classification Of Rocks Analytical Type Questions

Question 1. What is a rock? Classify different types of rocks.
Answer:

Rocks:

Rocks are the homogeneous or heterogeneous aggregates of one or more minerals which are the complex of one or more inorganic elements.

Geologists believe that the materials which form the earth’s crust can be called rocks in general. Hence, pebbles, stones, clay, gravels, sands, etc., are all included in the category of rocks. Some of the rock-forming minerals are quartz, feldspar, mica, olivine and pyroxene.

Classification:

According to the origin, rocks are classified into three categories

1. Igneous rocks
2. Sedimentary rocks and
3. Metamorphic rocks.

1. Igneous rocks:

The rocks that form from cooled and solidified lava and magma on the earth’s crust or in the interior respectively, are called igneous rocks. These are also known as primary rocks as these were the first rocks to originate on Earth.

When the earth first cooled from a burning mass, the hot molten materials or magma slowly radiated heat to cool down and formed a solid, hard crust on the surface.

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WBBSE Solutions For Class 8 Geography

 

Later on, lava was ejected through craters or fissures and over time, it cooled to form igneous rocks.

Example-granite and basalt.

2. Sedimentary rocks:

Sediments and debris derived by natural agents of erosion like rivers, glaciers, wind and sea waves through the processes of erosion and transportation are deposited regularly underwater.

These depositions are consolidated and compacted due to the continuous increase of weight and pressure of the overlying sediments to form sedimentary rocks.

Example-sandstone, limestone and mudstone.

3. Metamorphic rocks:

Igneous and sedimentary rocks lose their physical and chemical characteristics over a long period and acquire new characteristics to form newly transformed rocks known as metamorphic rocks.

Example-Gneiss, marble, quartzite and slate.

Question 2. Classify igneous rocks according to their origin and structure and define them.
Answer:

Classification of Igneous Rocks According To Their Origin And Structure:-

Igneous rocks, according to origin and structure, are divided into two classes-extrusive igneous rocks and intrusive igneous rocks.

Understanding Rock Types for Class 8

Extrusive igneous rocks:

Rocks formed due to the cooling and solidification of lava on the earth’s surface are called extrusive igneous rocks. The grains or crystals formed in this rock are fine.

Example-Basalt, obsidian, etc.

Classification:

Based on their origin, extrusive igneous rocks are further divided into two types

Lava rocks:

When hot, molten magma reaches the surface of the earth through holes, cracks or fissures and gets solidified, it is called lava rock.

Example-Basalt.

Pyroclastic rocks:

As a volcano erupts, it also throws out lava that had previously solidified in and around the craters or vents along with cinder ash. All these together are ejected out with the erupting lava and they form rocks known as pyroclastic rocks.

Example-Tuff.

Intrusive igneous rocks:

Rocks formed when magma cools and solidifies below the earth’s surface are called intrusive igneous rocks. The grains or crystals are bigger than the extrusive rocks.

Example-Granite, are dolerite, etc.

Classification:

Intrusive igneous rocks are further sub-divided into two types

Abyssal rocks:

When magma cools and solidifies at a great depth within the earth the resultant rocks are called plutonic or abyssal igneous rocks. The size of the grains or crystals is the biggest.

Example-Granite.

Hypabyssal rocks:

When magma cools and solidifies just below the earth’s surface in the cracks, pores and hollow places the resultant Plutonic rocks are called hypabyssal or sub-volcanic igneous rocks.

The grains or crystals of these rocks are not as fine as the extrusive igneous rocks and neither are these as big as those of the abyssal rocks.

Example-Dolerite.

 

Question 3. What are sedimentary rocks? Classify different types of sedimentary rocks.
Answer:

Sedimentary rocks:

Sediments and debris derived by natural agents of erosion like rivers, glaciers, wind and sea waves through the processes of erosion and transportation are deposited regularly underwater.

These depositions are consolidated and compacted due to the continuous increase of weight and pressure of the overlying sediments to form sedimentary rocks.

WBBSE Class 8 Geography Characteristics of Rocks

Examples— are sandstone, limestone and mudstone.

Classification of sedimentary rocks:

Based on the origin of sediments, sedimentary rocks can be divided into two types

Clastic rocks:

Rocks formed due to cementing of disintegrated old rocks are called clastic rocks.

Example-Conglomerate, breccia. Clastic rocks are mechanically formed when sediments bind together due to the immense pressure of the overlying layers.

They can be further subdivided into the following

1. Argillaeceous sedimentary rocks, with a grain diameter size of less than 0.06mm. Example-Mudstone.
2. Arenaceous sedimentary rock, with a grain diameter size of 0.06 mm-2 mm. Example-Sandstone.
3. Rudaeceous sedimentary rock, with a grain diameter size of more than 2 mm. Example-Conglomerate.

Non-clastic rocks:

Chemically or organically formed sedimentary rocks are called non-clastic rocks. Example-Limestone, rock salt.

Types of Rocks for Class 8 Geography

Sub-divisions of the non-clastic rocks are as follows

1. Chemically formed sedimentary rocks:

Running water contains chemical materials in suspension. When this water comes in contact with rocks on its way, the soluble materials from the rocks are removed. These materials are known as chemically derived or formed which gradually settle under water to form chemically formed sedimentary rocks.

Examples- Dolomite, rock salt, etc.

2. Organically formed sedimentary rocks:

Sediments derived from the disintegration and decomposition of plants and animals when deposited and compacted form organically formed sedimentary rocks.

Example-Limestone from marine organisms, and coal from plants.

Question 4. What information can be gathered from fossils?
Answer:

Information Gathered From Fossils:-

Fossils can rightly be called pages from history. A lot of information might be gathered from fossils.

Some of these are

1. Finding the time to which the fossil belonged by testing the C14 isotope.
2. Understanding the climatic condition of the time to which the fossil belonged by observing the shapes of leaves, branches, etc.
3. Getting to know the species to which the organism belonged by knowing the age of the fossil.
4. Finding the origin of an organism by studying the fossil.
5. Getting to know about the condition of the place where the fossil has been found. A fossil also indicates the contemporary condition of the place (where it is found) at that age.

 

Question 5. What are metamorphic rocks? Classify different types or methods of metamorphism.
Answer:

Metamorphic rocks:

Igneous and sedimentary rocks lose their physical and chemical characteristics over a long time and acquire new characteristics to form newly transformed rocks known as metamorphic rocks.

Example-Granite changes to gneiss, limestone to marble and phyllite to schist.

 

 

Methods of metamorphism:

The types or methods of metamorphism are

Thermal metamorphism:

Rocks change their forms when they come in contact with the hot molten magma from the interior of the earth. This metamorphism occurs during volcanic activities.

Class 8 Geography WBBSE

Example-Peat coal changes to graphite.

1. Local or contact metamorphism:

The change of rocks over a small area on the earth’s surface under the influence of heat is called local metamorphism. This method is also known as contact metamorphism because the rocks come in contact with the magma.

Example-Limestone to marble.

2. Pressure-induced metamorphism:

When pressure plays a dominant role in the alteration of the rock form to form new rocks the process is known as pressure-induced metamorphism.

Example- Mudstone to slate.

Regional metamorphism:

Large-scale mountain building or orogeny causes extensive areas to undergo temperature and pressure changes. Rocks thus formed over extensive areas mainly due to pressure changes are said to have formed by regional metamorphism.

Example-Shale or mudstone to slate.

3. Chemically induced metamorphism:

Geologists believe that groundwater or reactive gaseous substances sometimes react with rocks to change their present forms. The resultant rocks thus formed are due to the chemically induced processes.

Example andalusite to silimenite.

 

 

Question 6. Compare igneous, sedimentary and metamorphic rocks.
Answer:

Comparison Of Igneous, Sedimentary And Metamorphic Rocks:-

The comparison among igneous, sedimentary and metamorphic rocks are as follows

 

Chapter 3 Topic A Characteristics And Classification Of Rocks Short Analytical Type Questions

Question 1. How did igneous rocks form?
Answer: Formation Igneous Rocks:-

Geologists believe that the earth was formed from a fiery gaseous state. It gradually cooled down to a solid body and the hard cover on the surface further hardened and became solid to form rocks, called igneous or primary rocks.

Not only at the time of the earth’s inception, but even now lava flows out, cools and solidifies on the earth’s surface to form igneous rocks. These are extrusive igneous rocks.

Example-Basalt.

Similarly, when magma cannot come out onto the surface, it cools and solidifies inside the earth over a long period to form igneous rocks. These are intrusive igneous rocks.

WBBSE Class 8 Geography Study Guide on Rocks

Example- Granite.

Question 2. Discuss the characteristics of igneous rocks.
Answer:

Characteristics Of Igneous Rocks:-

The characteristics of igneous rocks are as follows

1. Crystalline structure: All igneous rocks have a crystalline structure.
2. Stratification: The absence of stratification is an important feature of these rocks.
3. Mineral content: Igneous rocks contain various molten metallic substances. They are heavy because of their mineral content.
4. Hardness and weight: These rocks are hard, heavy and compact.
5. Fossils: The absence of fossils is another important feature of igneous rocks.
6. Resistance to erosion: These rocks are less fragile and highly resistant to erosion.
7. Nature: These rocks can be both acidic and basic or alkaline.
8. Permeability: These are usually impermeable rocks. However, the presence of cracks and joints makes them permeable.

Question 3. Distinguish between hypabyssal and abyssal rocks.
Answer:

Differences Between Hypabyssal And Abyssal Rocks:-

The differences between hypabyssal and abyssal rocks are as follows

 

Question 4. What do you know about granite?
Answer:

Granite:-

It is a kind of abyssal intrusive igneous rock. The continental crust is mainly formed of granite. The characteristics of granite are as follows

1. Grain size:

The cooling process is very slow, so the grains formed are big, coarse and distinct. The diameter of the grains are more than 3mm.

2. Mineral content:

This rock is mainly composed of quartz, feldspar, mica and hornblende.

3. Resistance to erosion and hardness:

This rock is very hard and thus very resistant to erosion.

WBBSE Class 8 Geography Rock Types Overview

4. Colour:

Its colour varies from white, and grey to pink.

5. Permeability:

This is an impermeable rock, but the presence of cracks and joints may allow water to enter into it.

6. Landforms:

Landforms made of granite are usually dome-shaped.

Question 5. What do you know about basalt?
Answer:

Basalt:-

It is a kind of extrusive igneous rock. The oceanic crust is mainly composed of basalt.

The characteristics of basalt are as follows

Grain size: Molten materials from the earth’s interior flow over the surface of the earth and cool down rapidly after coming into contact with air so these rocks are fine-grained. The grain size is less than 1mm.

Mineral content: The chief mineral constituents are feldspar, olivine and pyroxine.

Resistance to erosion and hardness: This rock is very hard and thus very resistant to erosion. It is also a heavy rock.

Colour: It is grey to black.

Permeability: Due to the presence of many cracks and joints this rock is highly permeable.

Landforms: Flat-topped plateaus formed in regions composed of basalt.

Question 6. How are sedimentary rocks formed?
Answer:

Formation Of Sedimentary Rocks:-

The rock materials on the earth’s crust are constantly getting eroded by natural agents (running water, wind, glaciers, sea waves, etc.) and are also undergoing constant chemical reactions.

These eroded materials like pebbles, sands, silt, clay, etc., get deposited in layers on the beds of the water bodies. As water and the upper layers of silt exert pressure on the lowest layers, the sediments get compacted and hardened to form sedimentary rocks.

Examples- are limestone, sandstone, etc.

Question 7. What are the characteristic features of sedimentary rocks?
Answer:

Characteristic Features Of Sedimentary Rocks:-

The characteristic features of sedimentary rocks are as follows

Stratification:

Distinct layers are found in sedimentary rocks. Hence, these rocks are also known as stratified rocks. Mudcracks are found on these rocks.

Classification of Rocks for Class 8 Students

Hardness:

Sedimentary rocks get easily eroded due to a lack of hardness. These rocks are soft and fragile.

Porosity and permeability:

Sedimentary rocks are porous and highly permeable.

Fossils:

These are the only rocks with fossil content.

Mineral content:

Only sedimentary rocks bear deposits of coal, mineral oil, natural gas, etc.

Crystalline structure:

Sedimentary rocks do not have a crystalline structure or the presence of cracks or joints.

Resistance to erosion:

Although different rocks have different capacities to resist erosion, these rocks are less resistant on a general basis.

Question 8. Why do sedimentary rock layers bear mineral oil?
Answer:

Sedimentary Rock Layers Bear Mineral Oil:-

During the process of sedimentation, minute sea organisms, bacteria, plant cells, phytoplankton, etc. get trapped between the layers of sediments.

Gradually, the pressure of the upper layers of silt, internal heat of the earth and chemical reactions lead to the formation of petroleum after being transformed into the solution of hydrocarbons and other organic compounds.

 

 

Thus, sedimentary rocks have mineral oil-bearing rock strata. Petroleum is also called a type of hydrocarbon for excessive hydrogen and carbon content.

Question 9. Why is mineral oil not found in igneous rocks?
Answer:

Mineral Oil Not Found In Igneous Rocks:-

Mineral oil was formed when dead animal bodies got deposited between layers of sedimentary rocks and were transformed into a solution of hydrocarbon and another organic compound due to overlying weight, pressure and high temperature.

Igneous rock formation on the other hand involves hot molten magma and lava which destroys the dead bodies of all living organisms. Thus, mineral oil formation is never possible in the igneous rocks.

Question 10. What are fossils and why are they found in sedimentary rocks?
Answer:

Fossils:-

Marine flora and fauna get buried within beds of sediments during the formation of sedimentary rocks. Later, the solidified imprints of the dead remains of these organisms on rocks are called fossils.

The impressions or remnants of living organisms and plants left within the layers of sedimentary rocks are called fossils. Sedimentary rocks are formed when sediments deposited on the river or seabed get compacted under the influence of pressure from the overlying layers.

At the time of sediment deposition marine flora and fauna may get buried within the sediment layers. Later dead remains of these organisms leave their imprint solidified.

WBBSE Class 8 Geography Chapter 3

Thus, fossils are formed and found in the layers of sediments after being sedimentary rocks.

Question 11. Why are fossils not found in igneous rocks?
Answer:

Fossils Are Not Found In Igneous Rocks:-

There are several reasons why igneous rocks do not contain fossils.

These are as follows

1. During the time of formation of igneous rocks, the heat of the molten magma and lava destroys the presence or evidence of all organic matter buried in it. Hence, no impression of fossils is found here.
2. Igneous rocks are not deposited in layers like the sedimentary rocks and so remnants of organic life cannot be found there.
3. Igneous rocks are the parent rocks that existed even before the beginning of life on Earth. Hence, these cannot have any fossil content in them.

Question 12. Write a short note on different kinds of sedimentary rocks.
Answer:

Sedimentary rocks:

Sediments and debris derived by natural agents of erosion like rivers, glaciers, wind and sea waves through the processes of erosion and transportation are deposited regularly underwater.

These depositions are consolidated and compacted due tothe continuous increase of weight and pressure of the overlying sediments to form sedimentary rocks.

Example— sandstone, limestone and mudstone.

Classification of sedimentary rocks:

Based on the origin of sediments, sedimentary rocks can be divided into two types

Clastic rocks:

Rocks formed due to cementing of disintegrated old rocks are called clastic rocks.

Example-Conglomerate, breccia. Clastic rocks are mechanically formed when sediments bind together due to the immense pressure of the overlying layers.

They can be further subdivided into the following

1. Argillaeceous sedimentary rocks, with a grain diameter size of less than 0.06mm. Example-Mudstone.
2. Arenaceous sedimentary rock, with a grain diameter size 0of .06 mm-2 mm. Example-Sandstone.
3. Rudaeceous sedimentary rock, with a grain diameter size of more than 2 mm. Example-Conglomerate.

Non-clastic rocks:

Chemically or organically formed sedimentary rocks are called non-clastic rocks. Example-Limestone, rock salt.

Sub-divisions of the non-clastic rocks are as follows

1. Chemically formed sedimentary rocks:

Running water contains chemical materials in suspension. When this water comes in contact with rocks on its way, the soluble materials from the rocks are removed. These materials are known as chemically derived or formed which gradually settle under water to form chemically formed sedimentary rocks.

Examples- Dolomite, rock salt, etc.

2. Organically formed sedimentary rocks:

Sediments derived from the disintegration and decomposition of plants and animals when deposited and compacted form organically formed sedimentary rocks.

Example-Limestone from marine organisms, and coal from plants.

Question 13. Write the differences between clastic and non-clastic rocks.
Answer:

The differences between clastic and non-clastic rocks are

Question 14. What do you know about limestone?
Answer:

Limestone:-

It is a calcareous sedimentary rock. The characteristic features of limestone are as follows

WBBSE Class 8 Geography Chapter 8 Question Answer

Nature:

Limestone is organically formed. Calcium carbonate (CaCO₃) or limestone is not soluble in water. But when it is transformed into calcium bicarbonate it readily dissolves in rainwater or acid solutions.

Colour:

Limestone may be white, grey, green and blackish.

Permeability:

It is highly permeable.

Hardness:

It is a type of soft rock and thus has very little resistance to erosion. Uses: It is used as a raw material in making cement and in the iron and steel industries.

Landforms:

Regions composed of limestone form karst landforms.

Question 15. What do you know about sandstone?
Answer:

Sandstone:-

It is a sedimentary rock rich in sand.

The characteristics of sandstone are as follows-

Nature:

It is a mechanically formed sedimentary rock. The soil in regions dominated by sandstone is saline and infertile.

1. Resistance to erosion: It is resistant to erosion.
2. Permeability and porosity: It is highly rocks are as follows porous and permeable.
3. Colour: It is yellow, orange, red, pink, white or grey in colour.
4. Uses: Many architectural wonders have been built out of sandstone, for example, the Red Fort, the temples in Udaygiri-Khandagiri.

Question 16. What do you know about shale?
Answer:

Shale:-

It is a sedimentary rock rich in clay.

The characteristics of sedimentary rock are as follows

1. Presence of strata: Thin layers of stratification are seen in this rock.
2. Grain size: It is a fine-grained rock.
3. Porosity: It is highly porous.
4. Hardness: It is soft and brittle and thus all construction work should be avoided in regions formed of shale.
5. Colour: It is blackish grey in colour.
6. Uses: It is used in making roof tiles of buildings as they can be separated along thin layers or foliation.

Question 17. What are metamorphic rocks?
Answer:

Metamorphic Rocks:

Igneous and sedimentary rocks lose their physical and chemical characteristics over characteristics to form newly transformed rocks for a long time and acquire new known as metamorphic rocks.

Example-

1. Metamorphosis of igneous rock-Granite to gneiss.
2. Metamorphosis of sedimentary rock- limestone to marble.
3. Metamorphosis of metamorphic rock-Phyllite to schist.

Question 18. What are the different methods of metamorphism?
Answer:

Metamorphic rocks:

Igneous and sedimentary rocks lose their physical and chemical characteristics over a long period and acquire new characteristics to form newly transformed rocks known as metamorphic rocks.

Example-Granite changes to gneiss, limestone to marble and phyllite to schist.

WBBSE Class 8 Geography Chapter 8 Question Answer

Methods of metamorphism:

The types or methods of metamorphism are

Thermal metamorphism:

Rocks change their forms when they come in contact with the hot molten magma from the interior of the earth. This metamorphism occurs during volcanic activities.

Example-Peat coal changes to graphite.

1. Local or contact metamorphism:

The change of rocks over a small area on the earth’s surface under the influence of heat is called local metamorphism. This method is also known as contact metamorphism because the rocks come in contact with the magma.

Example-Limestone to marble.

2. Pressure-induced metamorphism:

When pressure plays a dominant role in the alteration of the rock form to form new rocks the process is known as pressure-induced metamorphism.

Example- Mudstone to slate.

Regional metamorphism:

Large-scale mountain building or orogeny causes extensive areas to undergo temperature and pressure changes. Rocks thus formed over extensive areas mainly due to pressure changes are said to have formed by regional metamorphism.

Example-Shale or mudstone to slate.

3. Chemically induced metamorphism:

Geologists believe that groundwater or reactive gaseous substances sometimes react with rocks to change their present forms. The resultant rocks thus formed are due to the chemically induced processes.

Example andalusite to silimenite.

Question 19. What are the characteristics of metamorphic rocks?
Answer:

The characteristics of metamorphic

Resistant to erosion:

The constituent minerals become more compact and hard during the process of metamorphism which makes the resultant rock harder. So, the process of erosion is slower in metamorphic rocks than in igneous and sedimentary rocks.

Presence of bands:

During metamorphism, the minerals recrystallise and similar minerals tend to get together. As a result, bands appear in metamorphic rocks. Igneous rocks after metamorphism become more crystalline and more lustrous.

WBBSE Class 8 Geography Chapter 8 Question Answer

Example- granite, when metamorphosed to gneiss, develops bands on it.

Stratification:

Igneous rocks do not have strata so when they are metamorphosed, there would be no stratification; but in the case of sedimentary rocks, which are always stratified, their layers are lost after metamorphosis due to tremendous pressure and heat.

Fossils:

Fossils in sedimentary rocks also disappear after metamorphosis under heat and pressure.

Question 20. Write a short note on the marble.
Answer:

Marble:-

It is the metamorphosed state of limestone.

The characteristics of marble are as follows

1. Nature: Marble is a very smooth, glittery and attractive rock.
2. Colour: It has a variety of colours like white, green, grey, yellow and blue.
3. Erosion: Marble erodes rapidly when it comes into contact with acid. So, it has to be kept away from acidic solutions.
4. Uses: Marble is soft and so can be cut and shaped according to requirement. Hence, it has been used in architecture and sculpture. The Taj Mahal, the Victoria Memorial, etc. have been built out of marble.

Question 21. Write a short note on the slate.
Answer:

Slate:-

It is the metamorphosed form of mudstone or shale.

The characteristics of the state are as follows

1. Nature: It is smooth and arranged in thin layers that can be easily broken.
2. Colour: It is bluish-grey to black.
3. Uses: It is used in making roof tiles, and blackboards and is also used as a surface for writing.

Question 22. Briefly describe the rock gneiss.
Answer:

Rock Gneiss:-

It is the metamorphosed form of granite. It is also called banded gneiss’.

The characteristics of gneiss are as follows

1. Nature: It is a hard rock and resistant rock.
2. Colour: It can be greyish, blackish or whitish in shade.
3. Presence of circular band: In gneiss, minerals are arranged in circular bands or layers. Thus, extracting a certain mineral from this is convenient.
4. Uses: It is used in constructing roads and other construction works.

Question 23. Compare sedimentary rocks and metamorphic rocks.
Answer:

 

Chapter 3 Topic A Characteristics And Classification Of Rocks Short Answer Type Questions

Question 1. What are homogeneous aggregates?
Answer:

Homogeneous Aggregates:-

Aggregates in which all elements remain in equal ratio everywhere are called homogeneous aggregates.

Question 2. What are heterogeneous aggregates?
Answer:

Heterogeneous Aggregates:-

Aggregates in which all elements are formed in different ratios in different places are called heterogeneous aggregates.

Question 3. What are the permeability and porosity of a rock?
Answer:

Permeability And Porosity Of A Rock:-

The permeability of a rock is its ability or capacity to allow liquid and gaseous substances to pass through it. The porosity of a rock is the ratio between the voids in a rock mass and the total volume of the rock.

Question 4. Are porosity and permeability of rocks the same thing? Give a suitable example.
Answer: No, porosity and permeability of rocks are two different properties, but these are closely related. Porosity is the ratio between voids in the rock mass and the total volume of the rock.

Permeability means a rock’s capacity to allow liquid and gaseous matter to pass through Greater the porosity of a rock, the lesser its permeability and vice versa.

WBBSE Class 8 Geography Chapter 8 Question Answer

Example- Mudstone is porous and thus is poorly permeable.

Question 5. Why are igneous rocks also called primary rocks?
Answer:

Igneous Rocks Also Called Primary Rocks:-

The rocks that were formed first on the earth were igneous rocks and sedimentary and metamorphic rocks came into existence in later stages from these igneous rocks. Hence, igneous rocks are also known as primary rocks.

Question 6. Why are sedimentary rocks also called stratified rocks?
Answer:

Sedimentary Rocks Also Called Stratified Rocks:-

Sedimentary rocks have been formed by the deposition of a large amount of silt on the beds of waterbodies in layers or strata. So, they are also called stratified rocks.

In sedimentary rocks, one layer is separated from another layer by a stratification plane.

Question 7. What is a stratification plane?
Answer:

Stratification Plane:-

Sedimentary rocks are generally formed of pebbles, stones, sand, clay, etc. During the formation of these rocks, comparatively heavier and older sediments get deposited below, while the lighter and newer ones settle above.

As a result, a stratification is noticed. Thus, the plane that separates one strata from the other, is called the stratification plane.

Question 8. Why are the sedimentary rocks porous?
Answer:

Sedimentary Rocks Porous:-

Sedimentary rocks are formed as a result of deposition of silt, clay, etc. on seabeds. As compared to igneous and metamorphic rocks there are pore spaces present in between the components of sedimentary rocks. Thus these rocks are porous.

Question 9. Why is coal considered to be a type of sedimentary rock?
Answer:

Coal Considered To Be A Type Of Sedimentary Rock:-

About 300-350 million years ago, as a result of earth movements, large forest tracts got buried deep under the ground. Due to the pressure and temperature of the earth’s interior, the plants and trees were stratified.

The carbon content of the stems of the trees gradually transformed into coal. Thus, coal is a type of organically formed sedimentary rock.

Question 10. What are clastic rocks?
Answer:

Clastic Rocks:-

The agents of erosion like rivers, winds, sea waves, etc. constantly break the rocks into pebbles, sand, silt and clay. The sedimentary rocks that are formed due to the cementing of disintegrated old rocks are called clastic rocks.

Example-Sandstone, mudstone, conglomerate.

Question 11. What are non-clastic rocks?
Answer:

Non-Clastic Rocks:-

Chemically or organically formed sedimentary rocks are called non-clastic rocks.

Example-Limestone, rock salt.

Question 12. What is a conglomerate?
Answer:

Conglomerate:-

Conglomerate is a kind of compact, mechanically formed, stony sedimentary rock. These are formed of comparatively bigger and rounded pebbles and coarse sand, which are deposited in coastal regions. These pebbles or sand grains are more than 2 mm in diameter.

Question 13. What are the different types of metamorphic rocks?
Answer:

Different Types Of Metamorphic Rocks:-

Metamorphic rocks can be classified in the following ways based on the origin of rocks

1. Metamorphism of igneous rocks, for example, Granite to gneiss;
2. Metamorphism of sedimentary rocks, Example-Mudstone to slate;
3. Metamorphism of metamorphic rocks, Example-Slate to phyllite and then to schist.

Question 14. What is regional metamorphism?
Answer:

Regional Metamorphism:-

Large-scale mountain building or orogeny causes extensive areas to undergo temperature and pressure changes. Rocks thus formed over extensive areas mainly due to pressure changes are said to have formed by regional metamorphism.

Example-Slate.

Question 15. What is contact metamorphism?
Answer:

Contact Metamorphism:-

Rocks change their forms when they come in contact with the hot molten magma from the interior of the earth. This metamorphism occurs during volcanic activities over a small local area. This process is known as thermal local or contact metamorphism.

For example- Limestone changes into marble due to contact metamorphism.

Question 16. Why are crystals not formed in sedimentary rocks?
Answer:

Crystals Not Formed In Sedimentary Rocks:-

Molecules of water combine with different minerals to form crystals. When igneous rocks form, some amount of water remain in it taking the shape of veins.

Crystals are formed from the atoms of mineral water which evaporates while the rock cools. But in the case of sedimentary rocks, this water disappears due to the tremendous pressure of the overlying layers. As a result, crystals do not form in sedimentary rocks.

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 17. From which type of rock is mineral extraction convenient and why?
Answer: Mineral extraction is convenient from metamorphic rocks. The position of minerals within a rock is altered due to excessive heat and pressure in the process of metamorphism.

Similar minerals tend to get together. Thus, the extraction of minerals becomes convenient.

Question 18. Try to know which rock is used to make a pencil lead and to which type of rock it belongs.
Answer: Pencil lead is made from graphite which is a metamorphosed form of peat coal.

Question 19. Why are the basic features of original rocks not found in their metamorphosed state?
Answer:

Basic Features Of Original Rocks Not Found In Their Metamor-Phosed State:-

Rocks metamorphose under the influence of great heat, pressure and even chemical reactions on the surface of the earth. As a result, the basic features of the original rock are lost in the process and the resultant rock formed has new characteristics altogether.

Chapter 3 Topic A Characteristics And Classification Of Rocks Multiple Choice Questions Choose The Correct Option

Question 1. When the porosity of a rock increases, its water retention capacity

1. Decreases
2. Increases
3. Remains moderate
4. None of these

Answer: 2. Increases

Question 2. The ratio between the space of a rock and its total volume is known as its-

1. Porosity
2. Cleavage
3. Permeability
4. Texture

Answer: 1. Porosity

Question 3. An example of primary rock is-

1. Granite
2. Shale
3. Sandstone
4. Limestone

Answer: 1. Granite

Question 4. Igneous rock is also called-

1. Stratified rock
2. Unstratified rock
3. Metamorphic rock
4. Incoherent rock

Answer: 2. Unstratified rock

Question 5. An example of a hypabyssal rock is-

1. Basalt
2. Dolerite
3. Granite
4. Gabbro

Answer: 2. Dolerite

Question 6. An example of an abyssal or plutonic rock is-

1. Basalt
2. Granite
3. Dolerite
4. Gneiss

Answer: 2. Granite

Question 7. The oceanic crust is mainly composed of-

1. Granite
2. Basalt
3. Limestone
4. Mudstone

Answer: 2. Basalt

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 8. The mineral found in granite rock is-

1. Quartz
2. Aragonite
3. Calcite
4. None of these

Answer: 1. Quartz

Question 9. Which of the following is a sedimentary rock?

1. Mudstone
2. Graphite
3. Augite
4. Tuff

Answer: 1. Mudstone

Question 10. Chalk is a type of-

1. Extrusive rock
2. Sedimentary rock
3. Lava
4. Metamorphic rock

Answer: 2. Sedimentary rock

Question 11. Carbon deposits in the trunks of trees get stratified to primarily form-

1. Coal
2. Graphite
3. Mineral oil
4. Dolomite

Answer: 1. Coal

Question 12. Natural gas is available in

1. Igneous rocks
2. Metamorphic rocks
3. Sedimentary rocks
4. None of these

Answer: 3. Sedimentary rocks

Question 13. Fossils are found in

1. Igneous rocks
2. Sedimentary rocks
3. Metamorphic rocks
4. None of these

Answer: 2. Sedimentary rocks

Question 14. A sedimentary rock formed from organic matter is-

1. Coal
2. Shale
3. Gneiss
4. Granite

Answer: 1. Coal

Question 15. Conglomerate is a type of-

1. Igneous rock
2. Sedimentary rocks
3. Metamorphic rock
4. None of these

Answer: 2. Sedimentary rocks

Question 16. A kind of sandy sedimentary rock is-

1. Haematite
2. Kimberlite
3. Sandstone
4. Phyllite

Answer: 3. Sandstone

Question 17. The permeability of sandstone is-

1. Medium
2. High
3. Low very
4. Low

Answer: 2. High

Question 18. Graphite is a/an-

1. Igneous rock
2. Metamorphic rock
3. Sedimentary rocks
4. None of these

Answer: 2. Metamorphic rock

WBBSE Class 8 Geography Chapter 8 Question Answer

Question 19. The rock formed due to zonal/regional metamorphism is-

1. Phyllite
2. Schist
3. Slate
4. Granite

Answer: 3. Slate

Question 20. The type of rock with the highest resistance to erosion is-

1. A sedimentary rock
2. Metamorphic rock
3. Igneous rock
4. Pyroclastic rock

Answer: 2. Metamorphic rock

Question 21. When igneous rocks metamorphose, their roughness-

1. Decreases
2. Increases
3. Remains the same
4. None of these

Answer: 1. Decreases

Question 22. Granite metamorphoses into-

1. A hornblende
2. Marble
3. Gneiss
4. Slate

Answer: 3. Gneiss

Question 23. The metamorphic form of basalt is-

1. Amphibolite
2. Hornblende
3. Phyllite
4. Gneiss

Answer: 1. Amphibolite

Question 24. The metamorphosed form of sandstone is-

1. Gneiss
2. Quartzite
3. Chalk
4. Marble

Answer: 2. Quartzite

Question 25. The metamorphic state of peat coal is-

1. Bituminous
2. Bentonite
3. Graphite
4. Peridotite

Answer: 3. Graphite

Question 26. An example of the metamorphosed form of a metamorphic rock is-

1. Amphibolite
2. Hornblende
3. Phyllite
4. Gneiss

Answer: 3. Phyllite

Question 27. Kimberlite is a type of-

1. Extrusive rock
2. Abyssal rock
3. Hypabyssal rock
4. Pyroclastic rock

Answer: 3. Hypabyssal rock

Question 28. The branch of science that deals with rocks is-

1. Pedology
2. Orology
3. Petrology
4. Cryptology

Answer: 3. Petrology

Question 29. An example of a non-crystalline rock

1. Basalt
2. Chalk
3. None of these
4. Graphite

Answer: 2. Chalk

Question 30. The moisture retention capacity of silt is-

1. Low
2. High
3. Very Low
4. Medium

Answer: 4. Medium

Question 31. A type of pyroclastic rock is-

1. Tuff
2. Graphite
3. Ilmenite
4. Basalt

Answer: 1. Tuff

Question 32. An example of an ultra-alkaline rock among the following is-

1. Granite
2. Peridotite
3. Diorite
4. Pegmatite

Answer: 2. Peridotite

WBBSE Chapter 3 Topic A Characteristics And Classification Of Rocks Very Short Answer Type Questions Fill In The Blanks

Question 1. When hot molten magma from the interior of the earth gushes out to the surface, it is called _________.
Answer: Lava

Question 2. Igneous rocks were the first rocks to form on the surface of the earth and so they are called _________ rocks.
Answer: Primary

Question 3.  _________ rock is the parent rock of all other rock.
Answer: Igneous

Question 4. Basalt is a type of _________ igneous rock.
Answer: Extrusive

Question 5. Basalt is made up of fine grains while granite is made up of _________ grains.
Answer: Coarse

Question 6. Dolerite is a type of _________ igneous rock.
Answer: Hypabyssal

Question 7. Abyssal rocks are also called _________ igneous rocks.
Answer: Plutonic

Question 8. Crystals are chief characteristics of _________ rocks.
Answer: Igneous

Question 9.  _________ is the chief constituent of the continental crust.
Answer: Granite

Question 10. Granite is a combination of quartz, hornblende,  _________ and mica.
Answer: Feldspar

Question 11. Igneous rocks on the crust of the earth constantly _________  and transform into sand, gravel and pebbles.
Answer: Erode

Question 12. Stratification and formation of _________ are characteristics of sedimentary rocks.
Answer: Fossils

Question 13. Sedimentary rocks are more _________ igneous rocks.
Answer: Brittle

Question 14. An example of clastic rock is _________.
Answer: Breccia

Question 15. A combination of pebbles, cobbles, granules, etc forms _________.
Answer: Conglomerate

Question 16. Gneiss is an example of _________ rock.
Answer: Metamorphic

Question 17. Quartzite is a metamorphosed form of _________.
Answer: Sandstone

Question 18. Limestone gets metamorphosed into _________.
Answer: Marble

Question 19. Phyllite metamorphoses into _________.
Answer: Schist

Question 20. Limestone or _________ is generally not soluble in water.
Answer: Calcium Carbonate

Question 21. Igneous rocks containing more than 55% of silica are called _________ rock.
Answer: Acidic

Question 22. Tuff is an example of _________ rocks.
Answer: Pyroclastic

Question 23. Igneous rock is classified as _________ or basic depending on its silica content.
Answer: Acidic

Question 24. Dolomite is a type of _________ rocks.
Answer: Sedimentary

Question 25. The plane that separates one layer of silt from another in a sedimentary rock is called a _________ plane.
Answer: Stratification

Question 26. Rock containing excessive _________ is called an acidic rock.
Answer: Silica

Question 27. Based on chemical composition, igneous rocks can be subdivided into acidic, intermediate, _________ and ultrabasic rocks.
Answer: Alkaline

Question 28. Diorite and dolerite are _________ rocks.
Answer: Irneous

Question 29. Rhyolite is a type of _________ igneous rock.
Answer: Extrusive/Acidic

WBBSE Chapter 3 Topic A Characteristics And Classification Of Rocks Write True Or False

Question 1. Layers of silt harden to form sedimentary rocks.
Answer: True

Question 2. Another name for metamorphic rock is stratified rock.
Answer: False

Question 3. Both igneous and sedimentary rocks change to metamorphic rocks due to heat and pressure.
Answer: True

Question 4. The upper crust of the earth is made up of granite and the lower one of basalt.
Answer: True

Question 5. Igneous rock is the source of all other rocks.
Answer: True

Question 6. Fossils are found in sedimentary rocks.
Answer: True

Question 7. Igneous rocks are stratified.
Answer: False

Question 8. Porosity is the chief characteristic of sedimentary rocks.
Answer: True

Question 9. Coal is a type of igneous rock.
Answer: False

Question 10. Sandstone is a kind of stratified rock.
Answer: True

Question 11. Sedimentary rock layers contain a sufficient amount of metallic minerals.
Answer: False

Question 12. Coal, mineral oil, etc. are available in igneous rock layers.
Answer: False

Question 13. Limestone is composed of either calcite or aragonite.
Answer: True

Question 14. Another term for sedimentary rock is primary rock.
Answer: False

Question 15. Dolerite is a kind of abyssal rock.
Answer: False

Question 16. Permeability is more in igneous rocks than in other rocks.
Answer: False

Question 17. Granite is generally dark in colour.
Answer: False

Question 18. The amount of silica in acidic rocks is more than 65%.
Answer: True

Question 19. Porphyry is a kind of hypabyssal rock.
Answer: True

Question 20. Regions formed of basalt are dome-shaped.
Answer: False

Question 21. Sedimentary rocks are called unstratified rocks.
Answer: False

Question 22. If the permeability of a rock increases, its capacity to hold moisture will decrease.
Answer: True

Question 23. Porosity is one of the characteristics of igneous rocks.
Answer: False

Question 24. Only sedimentary rocks contain natural gas.
Answer: True

Question 25. An example of contact metamorphism is a marble.
Answer: True

Question 26. Peat transforms into a diamond.
Answer: False

Question 27. Water mixed with acid does not react chemically with marble.
Answer: False

WBBSE Chapter 3 Topic A Characteristics And Classification Of Rocks Match The Columns

1.
Answer: 1. B, 2. A, 3. E, 4. C, 5. F, 6. D

 

WBBSE Answer In One Or Two Words

Question 1. How many types of rocks are there?
Answer: Three.

Question 2. What is the capacity or ability to let liquid or gaseous substances pass through in a rock called?
Answer: Permeability.

Question 3. Name the igneous rock that comes out to the surface of the earth.
Answer: Extrusive igneous rock.

Question 4. Which type of rock mainly forms the continental crust?
Answer: Intrusive igneous rock (granite).

Question 5. In which rock are fossils found?
Answer: Sedimentary rock.

Question 6. Name à sedimentary rock that is made up of organic matter.
Answer: Coal.

Question 7. Which type of rock has been used to build the Red Fort?
Answer: Red sandstone.

Question 8. Which rock metamorphoses to form graphite?
Answer: Peat coal.

Question 9. What is a blackboard made of?
Answer: Slate.

Question 10. Give an example of acidic rock.
Answer: Granite.

Question 11. Which rock has a stratified plane?
Answer: Sedimentary rock.

Question 12. Which rock contains petroleum?
Answer: Sedimentary rock.