* Liquids: Liquids take the shape of their container. For example, water will fill a glass or a bottle, taking on the shape of the container it's in.

* Gases: Gases also take the shape of their container. Air, for instance, fills the room it's in.

* Plasma: Plasma is a superheated gas that is ionized, meaning its atoms have lost electrons. It behaves similarly to a gas and takes the shape of its container.

While solids have a definite shape, liquids, gases, and plasma do not.