Dust and Smoke

• Dust is always present in the air and smoke is produced by the burning of fuel.
• Smoke contains some gases and fine dust particles which are harmful.
• Burning of fuel produces smoke, smoke also enters air from vehicles and burning of coal in factories.

Activity to show the presence of dust particle in the air:

1. In a sunny room, close all the doors and windows, pull down all the curtain to make the room dark.
2. Allow sunlight to pass through slit.
3. Now look carefully through the slit.
4. We will see tiny shining particles moving in the sunlight.
5. These are dust particles.