This proves that a metal ball expands on heating. Note: It should be remembered that heat inside a metal ball or rod propagates through Conduction. As when a metal ball is heated then atoms vibrate and transfer their energy to neighboring atoms in exchange for phonons.

Does a metal ball expand when heated?

Q17) Describe an experiment to demonstrate the thermal expansion in solids. Take a metallic ball and ring such that the ball can pass through the ring easily. The ball is heated, and the ball cannot pass through the ring. This is because the solid ball expands in size.

Why the heated metal ball Cannot pass through the ring after heated?

Point out that when metal is heated, the atoms move faster and move slightly further apart. This makes the heated ball expand, which prevents it from passing through the ring.