Experiment to Demonstrate Convection

Crystals of Potassium permanganate (KMnO₄) is dropped into a beaker filled with water.

The beaker is then placed on tripod stand and a flame from a Bunsen burner is set below it to gently warm the solution.

Observation:

A violet column from the crystals move up to clear regions of the water. This continued till the whole water is coloured.

Discussion:

The coloured column moved up when its molecules were heated up. They were then replaced by colder molecules from the clearer region. The heated coloured molecules also move up and are replaced by other clear colder molecules. This is what happened till the whole water became coloured.

Conclusion:

Heat was transferred through the water by convection.