Expand - GCSE Physics Definition

In the context of GCSE Physics, 'expand' refers to the increase in volume of an object or substance when it is subjected to heat. As particles within the material gain energy from the heat, they move more vigorously, causing them to occupy more space and push against each other. This process, known as thermal expansion, can happen in solids, liquids, and gases, where the degree of expansion can vary based on the material and the amount of heat applied. Understanding expansion is crucial as it explains various phenomena, such as the design of thermostats.