Question

Solids expand on ______ and contract on_______.

Answer 1

1. As we know kinetic energy (energy possessed by virtue of motion) of molecules is directly proportional to the temperature.
2. When a solid is heated kinetic energy of its molecule increases which results in an increase in intermolecular space therefore the solid expands.
3. On the other hand, cooling decreases the kinetic energy of molecules, as a result, intermolecular space decreases, and solid contracts.

Hence, Solids expand on heating and contract on cooling.