* Solids: Molecules are tightly packed and arranged in a highly ordered, rigid structure. They vibrate in place but don't move freely. This strong attraction between molecules gives solids their fixed shape and volume.
* Liquids: Molecules are close together but can move around each other. They have less order than solids and can flow, taking the shape of their container. However, they still maintain a fixed volume.
* Gases: Molecules are far apart and move freely in all directions, colliding with each other and the walls of their container. They have no fixed shape or volume, expanding to fill whatever space they occupy.
