Everything that you can see and touch is made up of matter. Even the stuff you can’t see or touch, like the oxygen you are breathing now, is made up of matter. Matter mostly exists in one of three forms: solid, liquid, or gas. Solids have their molecules tightly packed together and they hold their shape. The molecules in liquids are a little more spread out and they take the shape of whatever container they are in. Gases are very spread out and are constantly moving. Matter can change phase simply by changing the temperature or pressure in its environment.
The worksheets include the phases of matter (solid, liquid, gas), forms of substances, the action taken at each phase by the molecules involved.