1. Phase Changes Melting, Freezing, Vaporization, Condensation, Sublimation

2. Solid/Liquid Phase Changes Melting occurs when a substance absorbs heat energy changing a solid to a liquid. Melting point- temperature at which a solid changes to a liquid.

3. Solid/Liquid Phase Changes Freezing occurs when a substance loses heat energy and changes from a liquid to a solid. Freezing Point- Temperature at which a liquid changes to a solid.

4. Freezing Point = Melting Point Substances can freeze or melt at the same temperature depending on whether the substance is gaining heat energy or losing heat energy. Water will freeze or melt at 0 degrees Celsius depending on whether the water is gaining heat energy or losing heat energy.

5. Gas/Liquid Phase Changes Condensation occurs when a gas loses heat energy and changes to a liquid. Dew formed at night is a great example of condensation.

6. Gas/Liquid Phase Changes Vaporization occurs when particles in a liquid absorb enough energy to escape the liquid as a gas. Vaporization can occur in two ways: Boiling or Evaporation.

7. Boiling Boiling occurs when particles in a liquid are heated, thus changing the liquid to a gas. Boiling occurs at a specific temperature. Boiling occurs throughout the liquid.

8. Gas/Liquid Phase Changes Evaporation occurs at the surface of the liquid at various temperatures.

9. Solid/Gas Phase Changes Sublimation occurs when a solid changes directly to a gas or a gas changes directly to a solid. There is never a liquid stage when sublimation occurs. Frost is a good example.