NCERT Solutions for Class 6 Science Chapter 15 Air Around Us
NCERT solutions for class 6 science chapter 15 air around us : Solved Exercise Questions:
Q1. What is the composition of air?
Answer: Air contains some gases, water vapour and dust particles. The gases in air are mainly nitrogen, oxygen, small amount of carbon dioxide, and many other gases. We see that air contains mostly nitrogen and oxygen. In fact, these two gases together make up 99% of the air. The remaining 1% is constituted by carbon dioxide and a few other gases and water vapour.
Q2. Which gas in the atmosphere is essential for respiration?
Answer: Oxygen gas in the atmosphere is essential for respiration.
Q3. How will you prove that air supports burning?
Answer: By the following steps:
(i) Fix two small candles on a table. Light both the candles. Cover one of the candles with an inverted glass tumbler.
(ii) You must have observed that the candle covered with glass tumbler got extinguished after some time, whereas the other candle continued burning.
(iii) The candle got extinguished because the component inside of the glass tumbler, which supports burning, is limited. Most of the component is used up by the burning candles. However, the other candle is getting a continuous supply of air. This component of air, which supports burning, is known as oxygen.
Q4. How will you show that air is dissolved in water?
Answer: By the following steps:
(i) Take some water in a glass or metal container. Heat it slowly on a tripod stand.
(ii) Well before the water begins to boil, look carefully at the inner surface of the container. There are tiny bubbles, these bubbles come from the air dissolved in water.
(iii) When you heat the water, to begin with, the air dissolved in it escapes. As you continue heating, the water itself turns into vapour and finally begins to boil.
Q5. Why does a lump of cotton wool shrink in water?
Answer: Initially, air is present inside the lump of cotton wool but after adding water to it the air inside is driven out by water. This causes the layers of lump to stick together hence lump shrinks.
Q6. The layer of air around the earth is known as ___________.
Answer:
The layer of air around the earth is known as 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: Five activities that are possible due to the presence of air are:
(i) Flying of birds (ii) Respiration (iii) Cloud formation (iv) Burning something (v) Winnowing.
Q9. How do plants and animals help each other in the exchange of gases in the atmosphere?
Answer: It is obvious that animals cannot live without plants. The balance of oxygen and carbon dioxide in the atmosphere is maintained through respiration in plants and animals and by the photosynthesis in plants. In photosynthesis, plants take in carbon dioxide and give out oxygen that animals consume and give out carbon dioxide. This shows the interdependence of plants and animals.
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- HC Verma Part 1
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- RD Sharma Class 9
- RD Sharma Class 10
- RS Aggarwal Class 10
- Lakhmir Singh Class 9
- Lakhmir Singh Class 10
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