Explore the wonders of the atmosphere with NCERT Solutions for Class 6 Science Chapter 11 - Air Around Us. Discover the secrets hidden in the air we breathe, from its composition to its role in maintaining Earth's climate and weather patterns. This chapter offers insights into the importance of air and its impact on our daily lives.

Q 1. What is the composition of air?

Ans: Air is mixture of nitrogen, oxygen, carbon dioxide, water vapour and a few other gases. Some dust particles may also be present in it.

Q 2. Which gas in the atmosphere is essential for respiration?

Ans: Oxygen is the gas in the atmosphere that is essential for respiration.

Q 3. How will you show that air supports burning?

Ans:

To demonstrate that air supports burning, we can perform a simple experiment:

1. Take a candle and light it.
2. Place a glass jar or a bell jar over the lit candle, ensuring that it completely covers the flame.
3. After a short while, you will notice that the flame begins to flicker and eventually extinguishes.
4. Remove the jar, and you may observe a slight smoke or residue inside.

Explanation:

• The candle flame requires oxygen from the air to sustain combustion. When you cover the flame with the jar, it consumes the available oxygen inside the jar.
• As the oxygen is used up, the flame begins to flicker and eventually goes out because there is no longer enough oxygen to support combustion.
• The smoke or residue inside the jar indicates incomplete combustion due to insufficient oxygen.

This experiment demonstrates that air (specifically, oxygen in the air) is necessary to support burning.

Q 4. How will you show that air is dissolved in water?

Ans:

1. Fill a clear glass with tap water.
2. Let the glass sit undisturbed for a while.
3. You'll notice tiny bubbles forming on the inner surface of the glass and rising to the top.
4. These bubbles are air that was dissolved in the water.
5. This happens because water naturally absorbs some air from the surrounding atmosphere.

This simple observation shows that air is dissolved in water.

Q 5. Why does a lump of cotton wool shrink in water?

Ans: A lump of cotton wool shrinks in water because the spaces between the cotton fibers fill up with water. Water makes it heavy to drown in the water.

Q 6. The layer of air around the earth is known as………………….

Ans: The layer of air around the Earth is known as the 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 (CO2).

Q 8.  List five activities that are possible due to presence of air.

Ans:

1. Breathing: We need air to breathe and stay alive.
2. Flying: Birds and planes fly because of the air pushing against their wings.
3. Wind Power: Wind turbines use air to make electricity.
4. Weather: Air makes wind and rain, which affect the weather.
5. Sailing: Sailboats move because of the air pushing against their sails.

Q 9. How do plants and animals help each other in the exchange of gases in the atmosphere?

Ans:

Plants and animals help each other in gas exchange:

1. Plants: They make oxygen (O2) and take in carbon dioxide (CO2) from the air during photosynthesis.
2. Animals: They breathe in oxygen and release carbon dioxide back into the air during respiration.

Plants produce oxygen that animals need, and animals produce carbon dioxide that plants need, helping each other in the exchange of gases.