What is thermal expansion?

Thermal expansion is the tendency of matter to change in shape, area, and volume in response to a change in temperature. When a material is heated, its particles move more quickly and take up more space, causing the material to expand. Conversely, when a material is cooled, its particles move more slowly and take up less space, causing the material to contract. This phenomenon is seen in various materials, including solids, liquids, and gases.

Thermal expansion is the phenomenon where a material expands when it is heated and contracts when it is cooled. This is because heat causes the atoms and molecules in the material to move faster and spread out, making the material take up more space. The amount of expansion is determined by the coefficient of thermal expansion of the material, which is a measure of how much the material expands or contracts for each change in temperature.