Question

Describe an experiment to show the formation of convection currents in a liquid.

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Answer 1

Experiment to show the formation of convection currents in a liquid:

Aim of the experiment: To show the formation of convection currents in a liquid

Apparatus: Beaker, Bunsen burner, potassium permanganate crystals, wire gauge and water

Procedure: Take a beaker and fill half of it with water. Drop a few crystals of potassium permanganate into the beaker. This is done because potassium permanganate crystals add colour to the water and help in observing the convection currents easily. Heat the beaker and observe the movement of the solution.
The arrangement of the apparatus is shown below:


Observation: Due to the presence of potassium permanganate, the following movements of the coloured water are clearly visible:
(i) The coloured water at the bottom gets heated first and starts moving in the upward direction.
(ii) The cooler liquid on the top moves downwards, which in turn gets heated up and rises.

Inference: The transmission of heat from the hot water at the bottom of the beaker to the cold water at the top takes place by the actual movement of water.

Conclusion: Convection is a mode of heat transfer that takes place in liquids.