Question

In a mercury thermometer the level of mercurary rises when it's Bulb come in contact with Hot object what is reason for this rise

Answer 1

This phenomenon is dependent on the motion of the molecules of the fluid which is the mercury.

The molecules move further from each other when they come in contact with the heat.

This is exactly what happens in expansion and contraction in liquids.

The liquid expands on contact with heat because of low molecular attraction.