States of matter

The kinetic particle theory explains the properties of the different states of matter. The particles in solids, liquids and gases have different amounts of energy. They are arranged differently and move in different ways.

The table below summarises the arrangement and movement of the particles in solids, liquids and gases, and shows simple diagrams for the arrangement of the particles.

Diagram of particle arrangement and movement

Solid: particles close together, regular pattern, vibrate on spot. Liquid: particles close together, random, move around each other. Gas: particles far apart, random arrangement, move quickly.

Solids

The table shows some of the properties of solids and why they are like this.

PropertyWhy
Solids have a fixed shape and cannot flowThe particles cannot move from place to place
Solids cannot be compressed or squashedThe particles are close together and have no space to move into

Liquids

The table shows some of the properties of liquids and why they are like this.

PropertyWhy
Liquids flow and take the shape of their containerThe particles can move around each other
Liquids cannot be compressed or squashedThe particles are close together and have no space to move into

Gases

The table shows some of the properties of gases and why they are like this.

PropertyWhy
Gases flow and completely fill their containerThe particles can move quickly in all directions
Gases can be compressed or squashedThe particles are far apart and have space to move into