NCERT Science Class-VI Chapter-15: Air Around us Solutions
Exercises
Q 1: What is the composition of air?
Ans: Air contains water vapour, dust particles and gases. The gases in the air are mainly nitrogen, oxygen, small amount of carbon dioxide, and many other gases. In fact, nitrogen and oxygen together make up 99% of the air. The remaining 1% is constituted by carbon dioxide and a few other gases, water vapour and dust particles.
Q 2: Which gas in the atmosphere is essential for respiration?
Ans: Oxygen gas in the atmosphere is essential for respiration.
Q 3: How will you prove that air supports burning?
Ans: Place a burning candle upright in a tray having water. Cover it with a glass jar. Water will make it air-tight. During burning, oxygen is consumed and carbon-dioxide is released. After sometime no oxygen is left inside the jar and flame goes out. It shows air support burning.
Q 4: How will you show that air is dissolved in water?
Ans:
Step I: Take some water in a glass vessel or beaker.
Step II: Heat it slowly on a tripod stand and wait for water to boil.
Step III: We will observe tiny bubbles of water visible coming out from the bottom of the pan.
These tiny bubbles are coming due to the air dissolved in water. Thus, this proves that air is dissolved in water.
Q 5: Why does a lump of cotton wool shrink in water?
Ans: Sufficient volume of air is present in the cotton wool. When dipped in water, this air is replaced by less volume of water, so it shrinks.
Q 6: The layer of air around the earth is known as ___________.
Ans: The layer of air around the earth is known as atmosphere.
Q 7: The component of air used by green plants to make their food, is ___________.
Ans: The component of air used by green plants to make their food, is carbon dioxide.
Q 8: List five activities that are possible due to the presence of air.
Ans: Five activities that are possible due to the presence of air are as follows
- Living beings use air for respiration.
- Helps in seed dispersal and pollination.
- Blowing air (wind) is used for power generation by wind mills.
- Air helps in the scattering of seeds and pollens of plants.
- Air helps in burning of fuels and substances.
Q 9: How do plants and animals help each other in the exchange of gases in the atmosphere?
Ans: There is the interdependence of plants and animals.Plants take in carbon dioxide in during photosynthesis give out oxygen in the atmosphere while animals take in oxygen and breathe out carbon dioxide during respiration. In this way, plants and animals help each other in the exchange of gases in the atmosphere.
class vi science solutions
class vi science book solutions
class vi science mcq solutions
class vi science ncert solutions