Describe an experiment to demonstrate the thermal expansion in solids.

The thermal expansion in solids can be demonstrated by the following experiment:

1. Take a ball and ring set-up as shown in figure. It consists of a metal ball and a ring. The metal ball just slips through the ring when both are at room temperature
2. Now heat the ball on a burner and place it over the ring. We will observe that the ball does not pass through the ring.
3. Now allow the ball to cool by itself and after some time again place it over the ring. We will observe that the ball passes through the ring.

Conclusion — On heating the ball expands and becomes bigger than the diameter of the ring so it does not pass through the ring. But on cooling the ball contracts and passes through the ring.