Learners observe that the melting of a solid and the freezing of its liquid occur at the same temperature. The melting point is an intrinsic property and is used to identify a substance.

Learners examine phase diagrams that show the phases of solid, liquid, and gas as well as the triple point and critical point.

In this animated and interactive object, learners examine kinetic and potential energy as well as the first law of thermodynamics and the flow of energy between a system and its surroundings. Students also answer questions about exothermic and endothermic reactions

In this animated object, students examine the role equilibrium plays in everyday life. Formulas are presented in an interactive way.

Learners examine the periodic table to identify metallic elements that have either fixed or variable oxidation states.