Solids, liquids and gases
The particle theory is used to explain the properties of solids, liquids and gases. The strength of bonds (attractive forces) between particles is different in all three states.
Part of
Solids
Steel, plastic and wood are solids at room temperature. Ice is solid water. The particles in a solid are:
- close together
- arranged in a regular way
Strong forces, called bonds, attract the particles towards each other. This means that the particles in a solid:
- can vibrate in a fixed position
- cannot move from place to place
The table shows some of the properties of solids and why they are like this:
| Property | Reason |
|---|---|
| They have a fixed shape and cannot flow | The particles cannot move from place to place |
| They cannot be compressed (squashed) | The particles are close together and have no space to move into |
Solids such as concrete are useful for buildings and their foundations because they cannot be compressed.