Diffusion in a solution
Molecules and ions in a liquid are continuously moving, and this movement increases with temperature. This explains why solutes eventually become equally distributed through a solution even though the solvent remains stationary.
The science behind this experiment
Molecules and ions in a liquid are continuously moving and this movement increases with increasing temperature.
Diffusion is the movement of matter in a system either liquid, solid or gaseous.
In a solid system the movements of molecules may be barely detectable, but in liquid or gaseous systems it is possible.
Equipment used
- Test tubes — PLA-007
- Test tube rack — PLA-012
- Spatula — PLA-024
- Tweezers — PLA-025
Chemicals and reagents
- Potassium manganate (VII) (permanganate)
- Distilled water
Questions for students
- Describe what happens as the crystal falls through the water and what happens when it comes to rest at the bottom of the test tube.
- What do you notice in the test tube as time goes by?
- Do you think the same phenomenon happens in gases? Give an example.
What to expect
As time goes by the very dark purple colour tends to diffuse into the remainder of the liquid and becomes less intense. Diffusion also occurs in gases but is very much faster, the smoke of fires is an example.
Disposal
Dispose of the solution into the liquid waste container.
Run this experiment in your classroom
This experiment is part of ATP Volta — a self-contained mobile science lab that turns an ordinary classroom into a working STEM laboratory, with over 200 experiments in physics, chemistry, biology, robotics and engineering. Gali, the AI tutor built into ATP Connect, guides students through each step and answers their questions at the bench.
See the ATP Volta mobile science labTalk to our team