Chapter - 15
Air Around us
NCERT MP Board Class 6 Science Chapter 15 Air Around us
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NCERT MP Board Class 6 Science Chapter 15 Air Around us
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NCERT MP Board Class 6 Science Chapter 15 Air Around us
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Q.1. What is the compositions of air?
Ans. The compositions of air is:
Nitrogen. : 78.08%
Oxygen. : 20.95%
Carbon dioxide : 0.034%
Argon. : 0.93%
Helium. : Traces
Water vapours : traces
Thus, we see that air contains mostly nitrogen and oxygen. From above, it is clear that these two gases together make up 98% of 5he air.
Q.2. Which gas in the atmosphere is essential for respiration?
Ans. Oxygen gas in the atmosphere is essential for respiration.
Q.3. How will you prove that air supports burning?
Ans. This can be shown by following experiment. Take a candle. Fix it on a table. Now light it. It starts burning. Then cover it with a glass cover so that all air supply is stopped. We will see that it stops burning after some time. As soon as air inside the glass is used up, the candle stops burning. This shown that air is necessary for burning.
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Q.4. How will you show that air is dissolved in water?
Ans. Take some water in a glass vessel or beaker. Heat it slowly on a tripod stand. We see that tiny bubbles are sticking on it. These bubbles came from the air dissolved in water. When we heat water, the air dissolved in water escape out in the form of bubbles. This shows that the air is dissolved in water.
Q.5. Why does a lump of cotton wool shrink in water?
Ans. A lump of cotton wool shrink in water because the air inside cotton wool is driven out by water. The layers stick together and hence the lump of cotton wool shrink.
Q.6. The layer of air around the earth is known as _________.
Ans. Atmosphere.
Q.7. The components of air used by green plants to make their food, is__________.
Ans. Carbon-dioxide.
Q.8. List five activities that are possible due to the presence of air.
Ans. Some activities that are possible due to the presence of air:
(i) Windmill
(ii) winnowing
(iii) Respiration
(iv) Flying of aeroplanes, birds, etc.
(v) Transpiration.
Q.9. How do plants and animals help each other in the exchange of gases in the atmosphere?
Ans. Plants use carbon dioxide to make their food and give out oxygen. The animals take oxygen, for respiration and ‘give out carbon dioxide. This makes the balance of oxygen and carbon dioxide in atmosphere. But if the green plants do not take in carbon dioxide and give out oxygen, after some time there will no more oxygen on the earth and all living beings will die. That means, say, no life on earth. Thus, we can say that plants and animals help each other in the exchange of gases in atmosphere.