There are three main states of matter: solids, liquids, and gases. Solids have a definite shape and volume, with particles that move but don't overcome attractive forces. Liquids have a definite volume but take the shape of their container, as particles can overcome some attractive forces. Gases have no definite shape or volume, as particles move quickly and are far apart. Matter can change states through processes like melting, freezing, evaporation, boiling, condensation, and sublimation which occur as the substance gains or loses energy.

1. Section 3 Three States of Matter Chapter 17 States of Matter States of matter are the physical states in which a substance can exist. The three most familiar states of matter are: solid, liquid, and gas.

5. Section 3 Three States of Matter Chapter 17 Changes of State A change of state is the change of a substance from one physical state to another. Each state of matter can change into other states by changing the amount of energy in the substance. Melting and Freezing Melting is the change of state in which a solid becomes a liquid when energy is added to a substance. Freezing is the change of state in which a liquid becomes a solid when energy is removed.

6. Section 3 Three States of Matter Chapter 17 Changes of State, continued Evaporation, Boiling, and Condensation Evaporationis the change of a substance from a liquid to a gas at the surface. Boiling is the change of a liquid to a gas throughout the substance. Condensation is the change of a gas to a liquid. Sublimation: Solid to GasSublimation is the change of state in which a solid changes directly into a gas.