Here's why:

* Solids: Particles in solids are tightly packed together in a fixed, rigid structure. They have very little freedom to move around.

* Liquids: Particles in liquids are closer together than in gases, but they can move around more freely than in solids. They are not fixed in a rigid structure, allowing liquids to flow and take the shape of their container.

Think of it like this:

* Solid: Imagine a tightly packed box of oranges. The oranges (particles) can't move much.

* Liquid: Imagine the oranges are now in a bag. They are still close together, but they can slide around and shift.

* Gas: Imagine the oranges are scattered all over a large room. They are far apart and move freely.