Question

How small are the particles of substance and prove by an activity.

Answer 1

This can be proved by putting a small crystal of potassium permanganate in water. When you will put a small crystal of potassium permanganate in water in a transparent glass, you will see that the purple thread like structures start mixing with water and after some time all water becomes purple. The thread like structures is the particles of potassium permanganate, which start mixing with water because of the motion of particles of water. Because of continuous motion, all particles start colliding and finally potassium permanganate is mixed with water.

When you put a spoon of salt or sugar in a glass of water, it dissolved in water after some-times. This happens because of the motion of particles of sugar, salt and water.

Mixing of gases in nature is also the evidence of motion of particles. We get the scent of our favourite food sitting in the drawing room while food is being cooked in the kitchen. This happens because vapor coming out from the hot food mixes with air comes to your nostril because of the motion of their particles.

Answer 2

The particles of a substance are very small usually ranging between 0.3 A - 3 A.

To show their small nature we can try dissolving salt into water, it will be seen that it completely gets dissolved and the water starts tasting salty. This shows that the particles of salt are too small that they get adjusted in between the particles of water.

Hope it helps ^_^