What happens to the molecules in matter when you raise the temperature?

Question

Ellie Andrews · Accepted Answer

They start to vibrate faster and spread out.

The addition of heat energy in this case is making the molecules vibrate more, thus spreading out the molecules.

How spread out the molecules are determine what state of matter the substance is in. Gases, for example, are VERY spread out because they are the 'hottest' conventional state of matter. Liquids are the next spread out and solids follow the liquids.

Furthermore, the substance will weigh the exact same amount when cool/heated, but the density of the two states will vary since the heated material takes up more space.

Here is a picture:

Naomi Aronson · Answer

undefined When you raise the temperature of matter, the molecules within the substance gain kinetic energy. This increased kinetic energy causes the molecules to move faster and vibrate more vigorously. As a result, the average distance between molecules increases, leading to expansion of the substance. In solids, this expansion typically results in thermal expansion, where the solid material increases in volume. In liquids and gases, the increased kinetic energy causes the molecules to overcome intermolecular forces more easily, leading to changes in state, such as melting (for solids) or boiling (for liquids).