Diffusion - Mixing of a substance with water

The process by which a substance is mixed very slowly, without external intervention, with water is called diffusion.

In the following experiment you will investigate this process using crystals of potassium permanganate, a substance which is found in every chemical laboratory.


1.   Place with the pipette a large drop of cold water on the bottom of the experimental tray

2.    Bring the smallest possible potassium permanganate crystal to the edge of this drop. Make sure that the tray is not shaken or moved.                               more see below


1.     Write down your observations. Describe the changes seen after about 3, 10, 15 and 30 minutes, using words and drawings.

2.    Which factor affects the diffusion process?

3.    Explain your observations using the particle model.

4.    Find out about Brownian motion.

5.     Transfer the findings from your investigation to the example in the introduction. What happens at the particle level when the liquid is stirred with the spoon?

6.     Researching the web for examples of diffusion in everyday life.
Explain them using the particle model.

Erste Veröffentlichung: 20.12.2013                                                     Letzte Veränderung: 15.05.2014