Air Around Us | Science 6th | Chapter 15 | Questions and Answers

JANDKNCERT | Science 6^th |

Air Around Us | Science 6th | Chapter 15 | Questions and Answers

 

Chapter 15: Air Around Us

Dear Students, in Chapter 14, you learnt about Water, in which you learnt about the uses of water, sources of water, water cycle, evaporation, transpiration, condensation, precipitation, and rainwater harvesting. You also learnt that water is essential for all living organisms.

In this chapter, you will learn about the Air Around Us. The following points will help you to understand this chapter easily.

•     Air is found everywhere. We cannot see air, but we can feel it.

•     Air in motion is called wind.

•     Air occupies space.

•     Air is present in water and soil.

•     Air is a mixture of nitrogen, oxygen, carbon dioxide, water vapour and a few other gases. Some dust particles may also be present in it.

•     Oxygen supports burning and is necessary for living organisms.

•     The envelope of air that surrounds the earth is known as the atmosphere.

•     The atmosphere is essential for life on earth.

•     Aquatic animals use dissolved air in water for respiration.

•     Plants and animals depend on each other for the exchange of oxygen and carbon dioxide from the air.

 

Let us try to answer some questions taken from the NCERT Book of Science Class 6th. This Exercise is taken from the same book.

 

Exercises

Q1. What is the composition of air?

 

Answer.

Air is a mixture of many gases. It is composed of oxygen (O₂), nitrogen (N), carbon dioxide (CO₂), water vapour, dust, and smoke.

 

Q2. Which gas in the atmosphere is essential for respiration?

 

Answer.

Oxygen (O₂) gas in the atmosphere is essential for respiration.

 

Q3. How will you prove that air supports burning?

 

Answer.

It is the oxygen component in the air that supports burning. Let us do an activity to prove that oxygen supports burning. Take a burning candle and empty transparent glass. Cover the candle with an inverted glass. You will see that the candle burns for some time and then blows out. There was oxygen inside the glass that helped the candle to burn. The amount of oxygen inside the glass was limited which is why the candle burned for some time. When the amount of oxygen was utilized in burning the candle turned off. This shows that oxygen helps in burning.

 

Q4. How will you show that air is dissolved in water?

 

Answer.

Take some water in a glass vessel or beaker. Heat the water in the vessel. You will see tiny bubbles on the inner surface of the vessel. These bubbles come from the air dissolved in water. This shows that air is dissolved in water. Water is composed of oxygen and hydrogen. Animals living in the water use this dissolved oxygen to live.

 

Q5. Why does a lump of cotton wool shrink in water?

 

Answer.

When a lump of cotton wool is kept in water, it displaces the air present in it in the form of bubbles. The air that was present in the cotton had occupied the space and it was shrunk due to the displacement of air in the form of bubbles.

 

Q6. The layer of air around the earth is known as ___________.

 

Answer.

The layer of air around the earth is known as the atmosphere.

 

Q7. The component of air used by green plants to make their food is ________.

 

Answer.

The component of air used by green plants to make their food is carbon dioxide.

 

Q8. List five activities that are possible due to the presence of air.

 

Answer.

Activities that are possible due to the presence of air are as under:

(i) Air helps windmills to draw water from tube wells.

(ii) Air helps in the movement of boats, gliders, parachutes etc.

(iii) Air helps in the dispersal of seeds.

(iv) Air helps in the separate components of the mixture from grains by the method of winnowing.

(v) Air helps in the drying of wet clothes.

 

Q9. How do plants and animals help each other in the exchange of gases in the atmosphere?

 

Answer.

The plants and animals are interdependent, on each other. The balance of oxygen and carbon dioxide is maintained by the plants and animals through their respiration and photosynthesis in plants. During respiration, animals breathe in oxygen and breathe out carbon dioxide. Plants also consume oxygen but produce more oxygen than they consume. They use carbon dioxide in the process of photosynthesis. This is how plants and animals help in the exchange of gases atmosphere.

 

Q10. Plants need ________to make their food.

 

Answer.

Plants need carbon dioxide, water and minerals to make their food.

 

Q11. The moving air is called ____________.

 

Answer.

The moving air is called wind.