Using a graph, teach how the addition of heat causes ice to heat up and change from a solid to a liquid, and then to a gas. The graph shows how heating the ice causes the temperature to rise and how phase changes relate to this. Definitions of freezing point, melting point, boiling point, evaporation, condensation, and sublimation are included. This worksheet asks questions about changes in the graph and about the definitions of the phase changes. Four pages are included, two worksheet pages and two key pages. Bluebird Teaching Materials.