Worksheet Chapter 4 Air Class 7
D.C.M.Senior Secondary School
Study Material 2018
Class VII
Chapter 4 Geography
Air Worksheet (July 2018)
Q1. Fill in the blanks:- 1. A wind blowing from the west is called ______. (Westerly winds)
2. Heavy air creates a _______ pressure area. (high)
3. Land and sea breeze are _____ wind. (local)
4. The heat energy received by the sun is known as ______. (insolation)
5. Air in motion called _____. (wind)
6. ______ reduces visibility in winters. (Fog)
7. ________tree having extra ordinary quality of providing oxygen round the clock. (Neem)
Q2. Multiple Choice Questions:-
1. On the Celsius scale the water freezes at_____. (c)
a. 1000C b. 98.40C c. 00C d. 1040C.
2. Cyclones originates in the ________. (c) a. Indian Ocean b. Arabian Sea c. Bay of Bengal d. Gulf of Khambat
3. Which of the following gases protect us from harmful sunrays? (c) a. Carbon Dioxide b. Nitrogen c. Ozone d. Carbon Monoxide
4. The most important layer of atmosphere is ______. (a) a. Troposphere b. Stratosphere c. Mesosphere d. Exosphere
5. As we go up the layer of atmosphere, the pressure_____(b) a. Increases b. decreases c. Remains the same d. none of these
6. Which of the following layers of atmosphere is free from clouds? (b) a. Troposphere b. Stratosphere c. Mesosphere d. Thermosphere
7. When precipitation comes down to the earth in the liquid from, it called (c) a. Cloud b. Snow c. Rain d. Hailstorm
Q3. Match the Column ‘A’ with the Column ‘B’:-
A B
1. Trade Winds Incoming solar energy
2. Loo Seasonal Winds [3]
3. Monsoon Horizontal Movement of the air [4]
2 4. Wind Layer of Ozone air Permanent Winds [1] Local Winds [2]
Q4. Answer the following questions in brief (in 1 or 2 lines):-
1. What is atmosphere?
Ans: Our earth is surrounded by a huge blanket of air called atmosphere. All living beings depend on the atmosphere. It provides us the air we breathe and protects us from the harmful effects of the sun’s rays.
2. What is weather?
Ans: Weather is the hour to hour and day to day condition of atmosphere in a place.
3. What is insolation?
Ans: Insolation is the incoming solar energy intercepted by the earth.
4. What is the standard unit of measuring temperature? Who invented it?
Ans: The standard unit of measuring temperature is ‘degrees Celsius’. It was invented by Anders Celsius.
5. What is air pressure?
Ans: Air pressure is defined as the pressure exerted by the weight of air on the earth’s surface. As we go up the layers of atmosphere, the pressure falls rapidly. The air pressure is highest at the sea level and decreases with height.
6. Name the three types of rainfalls.
Ans: The three types of rainfalls are: a. Cyclonic Rainfall b. Relief (Orographic) Rainfall c. Convectional Rainfall
7. What is the name of the instruments that are used to measure (i) rain (ii) temperature (iii) direction of wind and (iv) atmospheric pressure?
Ans: The names of the instruments are:
a. To measure rain - Rain Gauge
b. To measure temperature - Thermometer
c. To measure pressure – Barometer
d. To tell the direction of the wind – Wind Vane
8. What is the composition of the air? Also write the percentage of the main gases.
Ans: The air is a mixture of many gases. Nitrogen (78%), Oxygen (21%), Carbon Dioxide (0.03%), Argon (0.93%), other gases (0.04%). Apart from these gases, tiny dust particles and water vapours are also present in the air.
9. Which gas creates the green-house affect in the atmosphere?
Ans: Carbon dioxide creates a greenhouse effect by trapping the heat radiated from the earth.
Q5. Answer the following questions in detail (in 70 to 80 words each):
1. How does the increased volume of carbon dioxide affect the climate on the earth? Why is carbon dioxide called the green-house gas?
Ans: Carbon dioxide released in the atmosphere creates a green-house effect by trapping heat radiated from the earth. It is therefore called a greenhouse gas. Without it the earth would have been too cold to live in. When its level in the atmosphere increases due to factory smoke or car fumes, the heat retained increases the temperature of the earth. This is called global warming. This rise in temperature causes the snow in the coldest parts of the world to melt. As a result, the sea level rises, causing floods in the coastal areas. It can result in extinction of some plants and animals.
2. What is global warming?
ans: When the level of green-house gas increases due to factory smoke or car fumes, the heat retained increases the temperature of the earth. This is called global warming.
3. Name the layers into which our atmosphere is divided. Explain at least one layer.
Ans: The names of the layers of atmosphere are:
a. Troposphere
b. Stratosphere
c. Mesosphere
d. Thermosphere
e. Exosphere
Troposphere: This layer is the most important layer of atmosphere. Its average height is 13 km. The air we breathe exists here. Almost all the weather phenomena like rainfall, fog and hailstorm occur in this layer.
4. Why do wet clothes take longer time to dry on a humid day?
Ans: On a humid day, the humidity is very high, that is, the level of water vapours in the atmosphere is very high. Due to this, air is not able to carry away more water vapours and thus the clothes take longer time to dry on a humid day.
5. Amount of insolation decreases from equator towards poles. Give reason.
Ans: Insolation is the incoming solar energy intercepted by the earth. The sun is always vertical on the equator. So the sun’s rays fall directly on the equator whereas the poles remain away from the direct heat of sun and so the rays do not fall directly on the sun. Thus, the temperature decreases from the equator towards the poles
6. Why are cities warmer than the villages?
Ans: The following are the reasons for the same:
The buildings in the cities are made of iron, steel, concrete and cement, whereas the buildings in the villages are made of mud and straw.
The areas of the villages are wide open whereas the cities are crowded and congested. The villages have kutcha roads and the cities have metallic roads. The concrete, metals, asphalt etc. get heated during the day and the heat is released during the night.
Also the crowded high rise of the cities trap the warm air and thus raise the temperature of the cities.
7. Why do astronauts wear special space suits when they go to the moon?
Ans: On the moon there is no air and hence, no air pressure. Astronauts have to wear special protective space suits filled with air when they go to the moon. If they do not wear these space suits, the counter pressure exerted by the body of the astronauts would make the blood vessels burst. The astronauts would bleed.
Q6. Draw labelled diagrams of the Layers of Atmosphere and Types of Rainfalls.
Study Material 2018
Class VII
Chapter 4 Geography
Air Worksheet (July 2018)
Q1. Fill in the blanks:- 1. A wind blowing from the west is called ______. (Westerly winds)
2. Heavy air creates a _______ pressure area. (high)
3. Land and sea breeze are _____ wind. (local)
4. The heat energy received by the sun is known as ______. (insolation)
5. Air in motion called _____. (wind)
6. ______ reduces visibility in winters. (Fog)
7. ________tree having extra ordinary quality of providing oxygen round the clock. (Neem)
Q2. Multiple Choice Questions:-
1. On the Celsius scale the water freezes at_____. (c)
a. 1000C b. 98.40C c. 00C d. 1040C.
2. Cyclones originates in the ________. (c) a. Indian Ocean b. Arabian Sea c. Bay of Bengal d. Gulf of Khambat
3. Which of the following gases protect us from harmful sunrays? (c) a. Carbon Dioxide b. Nitrogen c. Ozone d. Carbon Monoxide
4. The most important layer of atmosphere is ______. (a) a. Troposphere b. Stratosphere c. Mesosphere d. Exosphere
5. As we go up the layer of atmosphere, the pressure_____(b) a. Increases b. decreases c. Remains the same d. none of these
6. Which of the following layers of atmosphere is free from clouds? (b) a. Troposphere b. Stratosphere c. Mesosphere d. Thermosphere
7. When precipitation comes down to the earth in the liquid from, it called (c) a. Cloud b. Snow c. Rain d. Hailstorm
Q3. Match the Column ‘A’ with the Column ‘B’:-
A B
1. Trade Winds Incoming solar energy
2. Loo Seasonal Winds [3]
3. Monsoon Horizontal Movement of the air [4]
2 4. Wind Layer of Ozone air Permanent Winds [1] Local Winds [2]
Q4. Answer the following questions in brief (in 1 or 2 lines):-
1. What is atmosphere?
Ans: Our earth is surrounded by a huge blanket of air called atmosphere. All living beings depend on the atmosphere. It provides us the air we breathe and protects us from the harmful effects of the sun’s rays.
2. What is weather?
Ans: Weather is the hour to hour and day to day condition of atmosphere in a place.
3. What is insolation?
Ans: Insolation is the incoming solar energy intercepted by the earth.
4. What is the standard unit of measuring temperature? Who invented it?
Ans: The standard unit of measuring temperature is ‘degrees Celsius’. It was invented by Anders Celsius.
5. What is air pressure?
Ans: Air pressure is defined as the pressure exerted by the weight of air on the earth’s surface. As we go up the layers of atmosphere, the pressure falls rapidly. The air pressure is highest at the sea level and decreases with height.
6. Name the three types of rainfalls.
Ans: The three types of rainfalls are: a. Cyclonic Rainfall b. Relief (Orographic) Rainfall c. Convectional Rainfall
7. What is the name of the instruments that are used to measure (i) rain (ii) temperature (iii) direction of wind and (iv) atmospheric pressure?
Ans: The names of the instruments are:
a. To measure rain - Rain Gauge
b. To measure temperature - Thermometer
c. To measure pressure – Barometer
d. To tell the direction of the wind – Wind Vane
8. What is the composition of the air? Also write the percentage of the main gases.
Ans: The air is a mixture of many gases. Nitrogen (78%), Oxygen (21%), Carbon Dioxide (0.03%), Argon (0.93%), other gases (0.04%). Apart from these gases, tiny dust particles and water vapours are also present in the air.
9. Which gas creates the green-house affect in the atmosphere?
Ans: Carbon dioxide creates a greenhouse effect by trapping the heat radiated from the earth.
Q5. Answer the following questions in detail (in 70 to 80 words each):
1. How does the increased volume of carbon dioxide affect the climate on the earth? Why is carbon dioxide called the green-house gas?
Ans: Carbon dioxide released in the atmosphere creates a green-house effect by trapping heat radiated from the earth. It is therefore called a greenhouse gas. Without it the earth would have been too cold to live in. When its level in the atmosphere increases due to factory smoke or car fumes, the heat retained increases the temperature of the earth. This is called global warming. This rise in temperature causes the snow in the coldest parts of the world to melt. As a result, the sea level rises, causing floods in the coastal areas. It can result in extinction of some plants and animals.
2. What is global warming?
ans: When the level of green-house gas increases due to factory smoke or car fumes, the heat retained increases the temperature of the earth. This is called global warming.
3. Name the layers into which our atmosphere is divided. Explain at least one layer.
Ans: The names of the layers of atmosphere are:
a. Troposphere
b. Stratosphere
c. Mesosphere
d. Thermosphere
e. Exosphere
Troposphere: This layer is the most important layer of atmosphere. Its average height is 13 km. The air we breathe exists here. Almost all the weather phenomena like rainfall, fog and hailstorm occur in this layer.
4. Why do wet clothes take longer time to dry on a humid day?
Ans: On a humid day, the humidity is very high, that is, the level of water vapours in the atmosphere is very high. Due to this, air is not able to carry away more water vapours and thus the clothes take longer time to dry on a humid day.
5. Amount of insolation decreases from equator towards poles. Give reason.
Ans: Insolation is the incoming solar energy intercepted by the earth. The sun is always vertical on the equator. So the sun’s rays fall directly on the equator whereas the poles remain away from the direct heat of sun and so the rays do not fall directly on the sun. Thus, the temperature decreases from the equator towards the poles
6. Why are cities warmer than the villages?
Ans: The following are the reasons for the same:
The buildings in the cities are made of iron, steel, concrete and cement, whereas the buildings in the villages are made of mud and straw.
The areas of the villages are wide open whereas the cities are crowded and congested. The villages have kutcha roads and the cities have metallic roads. The concrete, metals, asphalt etc. get heated during the day and the heat is released during the night.
Also the crowded high rise of the cities trap the warm air and thus raise the temperature of the cities.
7. Why do astronauts wear special space suits when they go to the moon?
Ans: On the moon there is no air and hence, no air pressure. Astronauts have to wear special protective space suits filled with air when they go to the moon. If they do not wear these space suits, the counter pressure exerted by the body of the astronauts would make the blood vessels burst. The astronauts would bleed.
Q6. Draw labelled diagrams of the Layers of Atmosphere and Types of Rainfalls.
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