Overview

Thermal expansion is an increase in material’s volume when its temperature increases. As the temperature increases, the average kinetic energy of the particles increases and they speed up and spread out thereby increasing the volume of the material. Thermal contraction is a decrease in a material’s volume when its temperature decreases. As the temperature decreases, the average kinetic energy of the particles decreases and they slow down and get closer together thereby decreasing the volume of the material. Thermal expansion and contraction are most noticeable in gases, less noticeable in liquids and the least noticeable in solids.

Learning objectives