* Solids: Particles in solids are packed tightly together, with very strong forces of attraction between them. This gives solids their rigid shape and fixed volume.

* Liquids: Particles in liquids are closer together than in gases, but they have weaker forces of attraction than solids. This allows them to flow and take the shape of their container.

* Gases: Particles in gases are far apart and have very weak forces of attraction between them. This allows them to expand to fill their container and be easily compressed.

In summary, the strength of the forces of attraction between particles determines the state of matter.