How small are the particles of a matter? in Matter Around Us – Class 9 Science Experiment
Chapter Name: Matter Around Us
Activity Name: How small are the particles of a matter? in Matter Around Us
Activity Description:

In this experiment, we will investigate how small particles of a substance can disperse and color a large volume of water. We will use potassium permanganate and copper sulfate crystals to observe the changes in the color of water as the substances disperse.
Required Items:
- Beaker
- Water
- Potassium permanganate crystals
- Copper sulfate crystals
- Clear water
Step by Step Procedure:
- Take a beaker and mark the level of water.
- Add 1 or 2 crystals of potassium permanganate to the water and dissolve them, observing the change in the color of water.
- Take approximately 10ml of the solution from the first beaker and add it to 90ml of clear water in another beaker. Observe any changes in the color of water in the second beaker.
- Repeat the process by taking out 10ml of the solution from the second beaker and adding it to another 90ml of clear water. Repeat this step 4 or 5 times, noting any changes in the color of the solution.
- Reflect on whether the water is still colored and how two small crystals of potassium permanganate can color a large volume of water.
- Repeat the activity using a few crystals of copper sulfate instead of potassium permanganate to observe and compare the results.
Experiment Observations:
- Initially, the water in the first beaker turns a certain color upon dissolving the potassium permanganate crystals.
- When a small amount of this colored solution is added to clear water, the color spreads and the water in the second beaker also changes its color.
- Repeating the process several times results in the color continuing to disperse, eventually coloring a larger volume of water.
Precautions:
- Handle the chemicals (potassium permanganate and copper sulfate) with care and avoid direct contact with the skin or eyes.
- Dispose of the used solutions properly according to local regulations.
- Conduct the experiment in a well-ventilated area.
Lesson Learnt from Experiment:
The experiment demonstrates that even a small number of particles of a substance can disperse and color a large volume of water. This phenomenon is a result of the random motion of particles, known as diffusion. It also helps to understand the concept of concentration and how a higher concentration of particles in a small volume can disperse and spread to a lower concentration in a larger volume.