There are three states of matter: solid, liquid, and gas. As you heat a substance, it goes from solid, to liquid, to gas. Some subsances bypass the liquid state, and this is called sublimation. In the solid states, the particles vibrate, but stay, as it were, in formation. As a liquid, they are slightly freer, and as a gas, they whizz around at random, bumping into each other at high speeds. The particles are always moving, however much, at any temperature. The one exception to this is particles which are at absolute zero (0K or -273oC). (see The Kinetic Theory)