Gases, liquids and solids are all made up of atoms, molecules, and/or ions, but the way the particles inside them differ.
In a gas, the molecules are spread wide apart and moves freely at high speeds
In a liquid, the more closer to each other and will vibrate or slip past each other
In a solid, the molecules are tightly packed, making no room for each other and harder to move. These molecules vibrate and jiggle but, don't move