Describe an experiment to demonstrate the thermal expansion in solids.
Experiment: [Gravesand’s ball and ring experiment
Take metallic ball and ring so that ball can pass through the ring easily. Now heat the ball. We see that the heated ball cannot pass through the same ring. This is because on heating the ball increases in size. Now on cooling the ball again, it can pass through the ring. This experiment shows that solids expand on heating and contract on cooling.