Matter can exist in three states - solid, liquid, and gas. Solids have a definite shape and volume, liquids take the shape of their container but have a definite volume, and gases fill their container and expand to take up as much space as possible. All matter, regardless of state, has properties of volume, which is the space it occupies, and mass, which is the amount of matter. Matter can be natural materials from plants, animals and minerals, or artificial materials that are man-made like glass, plastic and paper.