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.

Students read brief descriptions of atoms, molecules, elements, and compounds, and complete a matching exercise that pictures these particles and molecules as pieces of taffy.

Learners examine the method for calculating the atomic weight of copper from the natural percent composition of each of its two isotopes.

In this animated and interactive object, learners examine the inverse proportionality of wavelength and frequency and their relationship to the speed of light.