So as a volume of gas is heated, the addition of energy increase the particles' kinetic energy. This only means that they are now moving faster right? I cannot relate this increase of kinetic energy to expansion. Do the particles grow or something?
[Physics] Why do gas expand when heated
phase-transitionthermodynamics
Best Answer
A heated gas doesn’t expand if it is in, say, a steel container. Instead, its pressure rises due to the greater kinetic energy.
If it is in, say, a balloon, then the greater pressure pushes outward on the balloon and makes it expand.