Ima

Definition:Thermal expansion is the increase in the size (length, area, or volume) of a substance when it is heated. When things get hot, their particles move faster and push each other apart, making the object bigger.

Examples:

1. Railway tracks – They have small gaps so that they don’t bend in summer when they expand.

2. Bridges – They have expansion joints for the same reason.

3. Thermometer liquid – The mercury or alcohol rises when heated.

Fun fact:Not everything expands equally. Solids expand less than liquids, and gases expand the most when heated!