1. What is the composition of air?
Answer:
Air is made up of the following composition:
- Nitrogen
- Oxygen
- Argon
- Carbon dioxide
- Water vapor
- Dust and smoke
- Other gases
2. Which gas in the atmosphere is essential for respiration?
Answer:
Oxygen
3. How will you prove that air supports burning?
Answer:
The burning happens only in the presence of oxygen. If we put a burning candle on a closed glass vessel, after some time when oxygen exhaust from the vessel, candle burning will go off. By this experiment, we can say, air support burning.
4. How will you show that air is dissolved in water?
Answer:
- When we heat up the water from the vessel, we can see a bubble coming out from the bottom of the vessel to the surface, this bubble nothing but it is showing the escaping of dissolved air from water.
5. Why does a lump of cotton wool shrink in the water?
Answer:
The lump of cotton wool has lots of air in between the pore. When we dip the cotton wool into the water, air escaped from the pore of wool and that leads to the shrinking of wool.
6. The layer of air around the earth is known as __Atmosphere_________.
7. The component of air used by green plants to make their food, is ___Co2________.
8. List five activities that are possible due to the presence of air.
Answer:
- Buring of things
- Respiration of living organism
- Photosynthesis process
- Flying of birds
- Cloud formation
9. How do plants and animals help each other in the exchange of gases in the atmosphere?
Answer:
- Animals take oxygen through breathing and release Co2 by the respiration process.
- Plants take Co2 for photosynthesis and release oxygen as the by-product of photosynthesis.
- By the respiration and photosynthesis process, both plants and animals exchange the gases in the atmosphere.
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