Explain Activity 1.2 NCERT Science Class 9

Activity 1.2 Explanation NCERT Science Class 9 Matter In Our Surroundings

Brief procedure:

Activity 1.2 asks us to dilute potassium permanganate solution.

Observation: 

When we add potassium permanganate in water, the colour of water changes to pink. DIlution decreases the colour intensity of the solution.

Explanation:

A visible particle may consist of smaller invisible particles like molecules and atoms.

A small amount of Potassium permanganate contain millions of its molecules.

When we dissolve potassium permanganate in water, its molecule spread uniformly in the solution and give a pink appearance.

Dilution lowers the amount of the particles in subsequent solution. As a result, we see a lower colour intensity.

 

Inference:

A visible particle may have a large number of smaller particles in it.

Related facts:

Potassium permanganate is a disinfectant and finds its use in many skin infection and purification of water.

Potassium permanganate reacts with chemicals in onion and removes the foul odour. It also increases the shelf-life of onion pieces, so restaurants put onion in potassium permanganate solution.

Next: Experiment to show particles in a medium are continuously in motion: Activity 1.3.

See also:

Why there is no Change in volume of water when we add salt: Activity 1.1.

Activity list Chapter 1 Matter In Our Surroundings.