What happens to the particles of a substance as it heats up?

As a substance heats up, its particles gain energy, which causes them to move more vigorously. This increased energy leads to a higher rate of vibration and movement among the particles. The kinetic energy of the particles increases, resulting in them moving more rapidly compared to their state at lower temperatures. This phenomenon is fundamental in understanding the behavior of solids, liquids, and gases as temperature changes, illustrating that heat energy directly influences particle motion and arrangement.

In contrast, the other options do not accurately represent the behavior of particles when a substance is heated. The idea that they cease to move is incorrect; particles are always in motion, with the speed and nature of that motion varying with temperature. Claiming particles move closer together contradicts the behavior of most substances when heated since particles generally expand as they gain energy. Finally, stating they become colder incorrectly describes the temperature change, as heating inherently increases the temperature of a substance.