4.2 Text Questions :
Answer the following questions :
1. What is atmosphere ?
Ans: Atmosphere is a thin blanket of air that surrounds the earth. It protects us from the harmful rays of the sun .
2. Which two gases make the bulk of the atmosphere ?
Ans: Nitrogen and oxygen are the gases that make the bulk of the atmosphere .
3. Which gas creates green house effect in the atmosphere ?
Ans: Carbon dioxide creates the green house effect in the atmosphere .
4. What is weather ?
Ans: Weather is hour to hour, day to day condition of the atmosphere .
5. Name three types of rainfall .
Ans: The three types of rainfall are : Conventional rainfall , Orographic rainfall and cyclonic rainfall .
6. What is air pressure ?
Ans: The pressure created by the weight of air on the earth’s surface is known as air pressure .
Tick the correct answer :
1. Which of the following gases protects us from harmful sun rays?
(a) Carbon dioxide (b)Nitrogen (c) Ozone √
2. The most important layer of the atmosphere is _______ .
(a) Troposphere √ (b) Thermosphere (c) Mesosphere
3. Which of the following layers of the atmosphere is free from clouds?
(a) Temperature (b) Air pressure √ (c) Wind direction.
4. As we go up the layers of the atmosphere , the pressure ______ .
(a) Increases (b) Decreases √ (c) remains the same.
5. When precipitation comes down to the earth in the liquid form. It is called ______ .
(a) Cloud (b) Rain √ (c) Snow.
Match the following :
1. Trade winds (a) Seasonal wind.
2. Loo (b) Horizontal movement of air.
3. Monsoon (c) Permanent wind.
4. Wind (d) Local wind
Answers :
1. Trade winds — (c) Permanent winds .
2. Loo — (d) Local wind.
3. Monsoon — (a) seasonal wind .
4. Wind — (b) Horizontal movement of air.
Give reasons :
1. Wet clothes take longer time to dry on a humid day .
Ans: Wet clothes take longer time to dry on a humid day because the amount of water in the air is more on a humid day than on a sunny day. Due to which the rate of evaporation decreases and air soaks in less water from the clothes .
2. Amount of isolation decreases from equator towards poles .
Ans: Isolation is the incoming solar energy intercepted by the earth. Amount of isolation decreases from the equator to the poles, because the sun rays fall vertically on the equator and slant on the poles .
FUN TIME
Solve this cross word puzzle with the help of given clues :
Across :
1. In Indian tree having extraordinary quality of providing oxygen round the clock.
2. Gas present in atmosphere occupying only 0.03 by volume.
3. Outermost layer of atmosphere.
4. Mixture of many gases.
5. Life giving gas.
6. Air in motion.
7. An Indian tree valued highly for medicinal properties.
8. Gas protecting us from harmful sun-rays.
9. Low pressure area.
Down :
1. Amount of water vapour in air.
2. Condensation of water vapours around dust particles in atmosphere.
3. Example of local wind blowing in summer in northern India.
4. Short term changes in atmosphere.
5. Precipitation in liquid form.
6. Blanket of air around the earth.
7. Instrument to measure pressure.
8. Incoming solar radiation.
9. Reduces visibility in winters.
10. It is the time when sun is overhead.
Answers :
Across :
1. An Indian tree having extraordinary quality of providing oxygen round the clock – PEEPAL .
2. Gas present in atmosphere occupying only 0.03 by volume – CARBON DIOXIDE .
3. Outermost layer of atmosphere – EXOSPHERE .
4. Mixture of many gases – AIR .
5. Life giving gas – OXYGEN .
6. Air in motion – WIND .
7. An Indian tree valued highly for medicinal properties – NEEM. .
8. Gas protecting us from harmful sun-rays – OZONE .
9. Low pressure area – CYCLONE .
Down :
1. Amount of water vapour in air – HUMIDITY .
2. Condensation of water vapours around dust particles in atmosphere – CLOUD .
3. Example of local wind blowing in summer in northern India – LOO .
4. Short term changes in atmosphere – WEATHER .
5. Precipitation in liquid form – RAIN .
6. Blanket of air around the earth – ATMOSPHERE .
7. Instrument to measure pressure – BAROMETER .
8. Incoming solar radiation – ISOLATION .
9. Reduces visibility in winters – FOG .
10. It is the time when the sun is overhead – NOON .