Solids, liquids & gases

The particles are always moving.

Solid: fixed shape and fixed volume. Particles are close together and vibrate about fixed positions.

Liquid: takes the container’s shape and has fixed volume. Particles stay close together and move past one another.

Gas: fills its container. Particles are far apart and move freely in all directions.

Melting: solid to liquid. Freezing: liquid to solid.

Evaporation or boiling: liquid to gas. Condensation: gas to liquid.

The particles do not grow or shrink when a substance changes state.

Particle models are not drawn to scale.