Air Arounds Us
Chapter 15
Exercises (অনুশীলনী)
1. What is the composition of air?
Ans:- The components of air are nitrogen, oxygen, carbon dioxide, water vapor, other gases and dust particles.
2. Which gas in the atmosphere is essential for respiration?
Ans:- Oxygen gas.
3. How will you prove that air is dissolved in water?
Ans:- A candle was placed in the middle of a shallow pot the candle was lit. Now the candle that is burning in the container has been covered with a glass of glass.
It was found that after a while of burning, the candle remained switched off. The reason for this is the presence of oxygen gas, one of the components of the air. A limited amount of oxygen was trapped inside the container to cover it and it was used to light the candle. As soon as that was over, the candle turned down. This proves that air is needed to ignite a fire.
4. How will you show that air is dissolved in water?
Ans:- Some water is taken in a glass container or disorder. Now that water has been heated in fire or gas. As the water boils, numerous small bubbles will appear on the surface of the pot. This bubble is derived from the air dissolved in the water. It converts into steam when the water is continuously heated. This proves that the air is dissolved in the water as well.
5. Why does a lump of cotton wool shrink in water?
Ans:- When a cotton jar or a pile is placed in an open space, the gaps in the middle of it are filled with air, if the cotton is soaked in water, water enters the airy areas in the middle of it and the air in it is drained out.
6. The layer of air around the earth is known as ___________ .
Ans:- Atmosphere.
7. The component of air used by green plants to make their food, is __________ .
Ans:- Carbon dioxide.
8. List five activities that are possible due to the presence of air.
Ans:- 1) Paltara boat moves in the presence of air.
2) Feathered flight material (Gliders), it takes air to use parachutes.
3) Aircraft run in the air only.
4) The spread of seeds and flowers requires air.
5) Electricity generation, windmills have to be used to lift water from the well, to pour the flour mills.
9. How do plants and animals help each other in the exchange of gases in the atmosphere?
Ans:- Plants prepare their own food through photosynthesis. Oxygen gas is produced while preparing this food. Plants absorb oxygen gases while inhaling but produce more than they consume. This oxygen gas is used by organisms for respiration. In the same way, plants take part of the carbon dioxide gas released by organisms through inhalation to carry out photosynthesis. This shows the interdependence of animals and plants.
