Solids, liquids and gases. In a solid like this brick, the particles are regularly arranged touching their neighbours and move only by vibrating. This explains why solids have a fixed shape.

The atoms of a solid are strongly attracted to each other. Solids keep their shape because of these strong attractions. The atoms vibrate but do not move past each other.

Dissolving a solid in a liquid depends on the interactions and attractions between the molecules of the liquid (solvent) and the particles of the solid (solute). Dissolving happens when the attraction ...