NCERT Solutions for Class 6 Science Chapter 15 Air Around Us

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Air Around Us NCERT Solutions for Class 6 Science Chapter 15

Class 6 Science Chapter 15 Air Around Us Exercise Questions and Answers

Question 1.
What is the composition of air?
Answer:
Various components of the air are:

• Nitrogen – 78.11%
• Oxygen – 20.95%
• Carbon dioxide – 0.03%
• Other gases
• Water vapours
• Dust particles

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

Question 3.
How will you show that air supports burning?
Answer:
We light a candle and cover it with a glass. We find after some time candle is extinguished as the amount of air inside the glass is limited.

Question 4.
How will you show that air is dissolved in water?
Answer:
To show that air is dissolved in water, we have to perform the following activity: Take some water in a glass vessel or beaker. Heat it slowly on a tripod. Look carefully at the inner surface of the vessel
We see that tiny air bubbles are sticking on it.
These air bubbles are mainly of oxygen gas present in the air, which is dissolved in water. When we heat up water, air dissolved in it escapes out in the form of bubbles.

Question 5.
Why does a lump of cotton wool shrink in the water?
Answer:
Air present in a lump of cotton wool gets dissolved in water and hence it shrinks.

Question 6.
The layers of air around the earth are known as?
Answer:
Atmosphere.

Question 7.
Which component of air is used by green plants to make their food?
Answer:
CO₂ (Carbon dioxide).

Question 8.
List five activities that are possible due to the presence of air ?
Answer:

1. We respire due to the presence of air.
2. Fuels are able to burn due to the presence of air.
3. Air helps in the movements of sailing yachts, gliders, parachutes, and aeroplanes.
4. Birds, bats, and insects can fly due to the presence of air.
5. Air helps in the dispersal of seeds and pollen of flowers of several plants.

Question 9.
How do plants and animals help each other in the exchange of gases in the atmosphere?
Answer:
Carbon dioxide along with water is used by green plants in the presence of sunlight. Oxygen is produced along with food during photosynthesis. Plants also consume oxygen for respiration, but they produce more of it than they consume. That is why we say plants produce oxygen.

Since plants produce oxygen, while animals consume it, thus it is obvious that animals cannot live without plants, since plants are their food. Moreover, plants could not survive for long without animals. They would consume all the carbon dioxide in the atmosphere. We can see that both need each other, as the balance of oxygen and carbon dioxide in the atmosphere is thus maintained. This is because of the interdependence of plants and animals on each other.

Class 6 Science Chapter 15 Air Around Us InText Questions and Answers

Activity 1

Take an empty glass bottle. Turn it, upside down.

Now, dip the open mouth of the bottle into the bucket filled with water as shown in fig. Observe the bottle.

Question 1.
Does water enter the bottle?
Answer:
No.

Question 2.
Now tilt the bottle slightly. Does the water now enter the bottle?
Answer:
Yes.

Question 3.
Do you see bubbles coming out of the bottle or hear any bubbles sound?
Answer:
Yes.

Question 4.
Can you guess what was in the bottle?
Answer:
Air was in the bottle.

Activity 2

Fix two small candles of the same size in the middle of two shallow containers. Now, fill the containers with some water. Light the candles and then cover each one of them with an inverted glass (one much taller than the other smaller) Fig. 15.2.

Question 1.
What happens to the burning candles and the water level?
Answer:
The burning candles go off. The water level rises in the two glasses.

Question 2.
Do you find any difference in your observation with the two glasses of different heights?
Answer:
Yes, the water rises higher in the taller glass.

Activity 3

Find a sunny room in your school/home. Close all the doors and windows with curtains pulled down to make the room dark. Now, open the door or a window facing the sun, just a little, in such a way that it allows sunlight to enter the room only through a slit. Look carefully at the incoming beam of sunlight.

Question 1.
Do you see some tiny shining particles moving in the beam of sunlight (Fig. 15.3) ? What are these particles?
Answer:
Yes, we see some tiny shining particles moving in the beam of sunlight. These are dust particles.

Question 2.
What does this activity shows?
Answer:
This activity shows that air contains dust particles.

Activity 4

Take some water in a glass vessel or beaker. Heat it slowly on a tripod stand. Well before the water begins to boil, look carefully at the inner surface of the vessel. Do you see tiny bubbles on the inside (Fig. 15.4)?

Answer:
Yes, we see tiny bubbles on the inside. These bubbles come from the air dissolved in water.