Question

Describe one experiment to show that liquids expand on heating.

Answer 1

(i) Take an empty bottle with a tight-fitting cork having a hole drilled in its middle, a drinking straw, two bricks, a wire guaze and a burner.

(ii) Fill the bottle completely with water and add a few drops of ink in it to make it colored.

(iii) Fix the cork in the mouth of the bottle and pass the drinking straw through the cork. Put some molten wax around the hole so as to avoid the leakage of water.

(iv) Pour some more water into the drinking straw so that water level in the straw can be seen. Mark the water level in the straw as shown in the following figure.

Thermal expansion of a liquid

(v) Place the bottle on the wire gauze kept over the two bricks as shown in the following figure. Then heat the bottle by means of a burner.

(vi) Look at the level of water in the straw.

You will notice that as the water is heated more and more, the level of water in the drinking straw rises. This shows that water expands on heating.