Particle Model (Cambridge (CIE) O Level Physics): Revision Note

Arrangement & Motion of Particles

• In a solid:

  • The molecules are very close together and arranged in a regular pattern

  • The molecules vibrate about fixed positions

• In a liquid:

  • The molecules are still close together (no gaps) but are no longer arranged in a regular pattern

  • The molecules are able to slide past each other

• In a gas:

  • The molecules are widely separated - about 10 times further apart in each direction

  • The molecules move about randomly at high speeds