Air Around Us

When air comes in contact with a cool surface, it condenses and drops of water appear on cool surface.

There is less oxygen at high places like mountains, so they carry oxygen cylinder with them to breathe there.

Burning of some material releases smoke that contains few gases and fine dust particles that is harmful, thus we feel suffocation in a closed room, where some material is burning.

Chimneys take the harmful gases and smoke of factories away from our noses.

Fix two candles in middle of a container containing water. Light both candles. Now cover the candles with an inverted transparent glass, you will observe that candles goes off. This happens because of absence of air. Thus we can say that air is necessary for combustion.

Blow a balloon, air from your body enters balloon at it gets bigger because air occupies space.

The bottle contains air so when it was titled air came out in the form of bubbles.

Air is made up of mixture of gases like - Nitrogen, oxygen, carbon dioxide, water vapour, dust particles and other gases.

False, because our nose contains fine hair and mucus that trap all dust particles and prevent its entrance inside our body.

If we will breathe through our mouth then dust particles present in air will enter our body and will cause harmful diseases.

Through air present in soil.

Take water in a pan and heat it. After sometimes just before it boils we can observe some bubbles at the inner surface of the pan. This is because of the air dissolved in water.

When it rains heavily, water fills up all the spaces occupied by the air in the soil. Therefore organism living in soil has to come out for respiration.

A lump of cotton wool shrinks in water because water filled up the empty space that the air has occupied.

Respiration, burning, photosynthesis, movement of aeroplane and parachutes, generation of electricity by windmills.

Plants and animals help each other in the exchange of gases in the atmosphere Plants take carbon dioxide to prepare food and release oxygen during daytime. This oxygen is taken in by animals and carbon dioxide is released. Thus, plants and animals help in maintaining balance of oxygen and carbon dioxide.