Air Around us : Class VI Science Lesson 15

NCERT Class VI Science textbook: Lesson 15: Air Around us.


Exercise

1.Question. What is the composition of air?
Answer. Air contains some gases in air are mainly nitrogen,oxygen, small amounts of carbon dioxide, and many other gases.Air contains mostly nitrogen and oxygen. These two gases together make up 99% of the air. The remaining 1% is constituted by carbon dioxide and a few other gases, water vapour and dust particles.



2.Question. which gas in the atmosphere is essential for respiration ?
Answer. Oxygen.

3.Question. How will you prove that air support burning?
Answer. Two lighted candles are taken. one candle is covered a fixed in a tumbler containing water. This candle is covered by an inverted glass. After sometime, the covered candle gets extinguished and water rises upto 1/5th is oxygen. The candle extinguished as soon as all the oxygen was used up.                 

4.Question. How will you so that air is dissolved in water?
Answer.When a tumbler containing water heated, tiny bubles appear on the inner side. These bubles appear before the water starts boiling. So, these must be air bubles. This shows that water contains air.


5.Question. Why does a lump of cotton wool shrink in water?
Answer.a lump of cotton wool shrink in waterbecause the air inside wool cotton is driven out by water. They layer stic together and hence the lump shrinks.


6.Question. The layer of  air around the earth is known as:-
Answer.atmosphere.
           
                
7.Question. The comppnent of used by green plants to make their food, is :
Answer. Carbon doxide.


8.question. List five activities that are possible due to the presenmce of air.
Answer. (1) Winnowing.
              (2) Formation of clouds.
              (3) Respiration.
              (4) Photosynthesis.
             (5) Transpiration.
             (6) Flying of birds.