* Solids: Have a definite shape and volume. This is because the particles within a solid are tightly packed together in a fixed arrangement. They vibrate in place but don't move around freely.

* Liquids: Have a definite volume but take the shape of their container. The particles in a liquid are closer together than in a gas but can move around each other. They flow easily.

* Gases: Have no definite shape or volume. They expand to fill whatever container they are in. The particles in a gas are far apart and move around randomly.

Here's an analogy to help understand:

* Solid: Imagine a tightly packed crowd of people standing still. They can't move much, and they take up a specific space.

* Liquid: Imagine a crowd of people pushing and bumping into each other, but still staying together. They can move around and take the shape of the space they are in.

* Gas: Imagine a crowd of people running around in all directions, completely spread out. They can move freely and fill up any available space.