When matter heats up, dose the molecules close together?

Yes because when they heat up you sweat, and when they cool down they would probably separated because you are at your normal temperate

Ok don't look at the bottom answer, that's incorrect. When matter heats up, molecules start to separate. That's why gas has no physical form, unlike solids. Ice, for example, is solid, but when it heats up, the molecules strat to move apart and become a liquid and then a gas. Hope I helped!