• Everything is made up of tiny particles.

• The properties of a substance depend on what its particles are like, how they move and how they are arranged.

• The particles in a substance are the same whether it's in the solid, liquid or gas state, but their arrangement and movement change.

How do solids, liquids and gases differ?

Everything is made up of tiny particles. The properties of a substance depend on what its particles are like, how they move, and how they are arranged.

Most substances can exist in three states: solid, liquid and gas. The particles of a substance are the same in each state, but their arrangement and movement change. This explains the different behaviour of a substance in its three states.

Solids

In the solid state the vibrating particles form a regular pattern. This explains the fixed shape of a solid and why it can’t be compressed or poured.

Liquids

In a liquid the particles still touch their neighbours but they move around, sliding over each other. This is why you can pour, but not compress, a liquid.

Gases

In the gas state, widely-spaced particles move around randomly. This explains why you can compress gases and why they flow.