Question

Explain with the help of a labelled diagram an experiment to show that liquids expand when heated.

Answer 1

Take a flask filled with a liquid up to its brim. Take a rubber cork with a hole in it and insert a glass tube in it. Now, fit the cork tightly on the mouth of the flask. You will notice that the the level of the liquid will rise in the tube. Note down the level in the tube and start heating the flask. Initially, the liquid level will drop, but after a few moments it will start rising. At first the liquid level will fall due to the expansion of the flask on heating; then when this heat reaches the liquid, it starts expanding. Only at this time you will notice that the level of liquid is rising in the tube. After cooling back the liquid to its normal temperature, the level will drop again.