Learners study the properties of a rectangular solid and use geometric formulas to find volume and surface area.

In this well-illustrated object, learners examine the structures and properties of the four types of solids: molecular, metallic, ionic, and covalent network. Five interactive questions are provided.

Learners study the fundamental operation of a triac, particularly how it is turned on and off. A brief quiz completes the activity.

In this animated object, learners examine the fundamental operation of a diac including how it is turned on and turned off. A brief quiz completes the activity.

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 graphs and read that the heat of fusion is the heat energy absorbed by one mole of solid as it is converted to liquid, while the heat of vaporization is the heat energy absorbed by one mole of liquid as it is converted to gas.

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

Learners read an explanation of how the Magnetron Ignition System uses a solid state switching component, a step-up transformer, and magnetism to provide a high voltage spark in a one-cylinder combustion engine.

Vapor pressure is the pressure exerted by molecules in the gas phase in equilibrium with a liquid or a solid. Two examples are used to illustrate vapor pressure: the drying of clothes and the evaporation of ice.

In this animated and interactive object, learners examine the properties of liquids, solids, and gases.