Question

what what is the main reason for thermal expansion in solids?​

Answer 1

Explanation:

Heat causes the molecules to move faster, (heat energy is converted to kinetic energy ) which means that the volume of a gas increases more than the volume of a solid or liquid.

Answer 2

Explanation:

When a solid is heated , it's atoms vibrate Faster abt their fixed points .

Heat causes molecules to move faster which means that the volume of a gas increases more than volume of a solid or liquid .