Matter is anything that has mass and takes up space. The term matter refers to all the materials, or "stuff," making up the universe. Everything you see around you is matter. The computer in front of you, the trees outside your window, the food you ate for lunch, and even you are examples of matter.

Matter is characterized by its properties, which can be classified as being chemical or physical:

Chemical properties refer to the abilities of a substance to undergo chemical reactions and to form new substances.

Physical properties describe physical qualities such as color, smell, taste, texture, density, boiling and melting point, electrical conduction, and solubility.

Matter can exist in one of three physical states, or phases. These states are solid, liquid, and gas. As illustrated in the animations below, these states of matter can be changed by adding or removing heat energy.