NCERT Solutions for Class 6 Science Chapter 15 Air Around Us

Chapter 15
Air Around Us

1. What is the composition of air?
Ans- Air is a mixture of nitrogen, oxygen, carbon dioxide, water vapour and few gases. Some dust particles may also present in it.

2. Which gas in the atmosphere is essential for respiration?
Ans- Oxygen gas in the atmosphere is essential for respiration.

3. How will you show that air supports burning?
Ans- Take a small burning candle. Cover the burning candle with a glass jar. After few minutes the candle is extinguished. As the supply of air stopped due to glass jar the burning candle is also stopped. This experiment proves that air supports burning.

4. How will you show that air is dissolved in water?
Ans- Take a glass filled with water. On heating, bubbles are seen in the water. The bubbles are formed before water reaching its boiling point indicates dissolve air in water.

5. Why does a lump of cotton wool shrink in water?
Ans- Lump of cotton wool has air among gaps of cotton fibres. When water replaces the air from these gaps, the cotton lump becomes heavy and also shrinks due to removal of air gaps.

6. The layer of air around the earth is known as Atmosphere

7.The component of air used by green plants to make their food, is Carbon dioxide

8. List five activities that are possible due to presence of air.
Ans- Activities that are possible due to the presence of air are:
a) Winnowing
b) Photosynthesis
c) Respiration
d) Transpiration
e) Formation of cloud.

9. How do plants and animals help each other in exchange of gases in the atmosphere?
Ans- Animals and plants use oxygen from air during respiration and release carbon dioxide gas in air. But green plants also release oxygen gas by using carbon dioxide during photosynthesis. Thus, we can say that animals and plants help each other in exchange of gases.