* Heating increases molecular motion: When you heat a gas or liquid, you provide the molecules with more energy. This energy causes them to move faster and vibrate more intensely.

* Increased separation in gases: In a gas, the molecules are already relatively far apart. The increased motion from heating causes them to move even further apart, leading to an expansion of the gas.

* Less significant separation in liquids: In a liquid, the molecules are much closer together than in a gas. While heating does cause them to move more, they are still held together by attractive forces. The increased motion leads to a slight increase in the average distance between molecules, but the effect is less dramatic than in a gas.

Key point: Heating doesn't necessarily make molecules *move away* from each other in the sense of physically separating. It's more accurate to say that heating causes the molecules to move *faster* and *vibrate* more, which leads to increased average distances in gases and a slight increase in liquids.