Question

If a thin aluminium disc with a hole in its centre is heated from one side , will that hole grow bigger or smaller

Answer 1

When the disc is heated on one side, the particles will start to vibrate at a random motion,this is due to the kinetic theory of matter.As they vibrate they create room for the particles near the hole making larger intermolleculer distance of which this tends to make the hole expand i.e (solid expands on heating)