Kinetic particle theory

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

Particle arrangement and movement

Solid: Close together, regular pattern, vibrate on the spot. Liquid: Close together, random arrangement, move around each other. Gas: Far apart, random arrangement, move quickly in all directions.

Solids

PropertiesWhy they are like this
They have a fixed shape and cannot flowThe particles cannot move from place to place
They cannot be compressed or squashedThe particles are close together and have no space to move into

Liquids

PropertiesWhy they are like this
They flow and take the shape of their containerThe particles are free to move around each other
They cannot be compressed or squashedThe particles are close together and have no space to move into

Gases

PropertiesWhy they are like this
They flow and completely fill their containerThe particles can move quickly in all directions
They can be compressed or squashedThe particles are far apart and have space to move into