| Everything in the world is made up of solids, liquids and gases. These are known as the three states of matter. They are all substances that have mass and take up space because they have volume. All those things around you are made of matter, so are you, as are the Earth and stars in the sky. Solids, liquids and gases are made of molecules, which contain one or more atoms. In a solid, the molecules are bound together so strongly that its shape usually stays the same. In a liquid, the molecules are more loosely connected so that the liquid flows easily but has a level surface. In a gas the molecules move randomly in any direction so that the gas has no shape. |
