The library of physical science

Describes solid, liquid, and gaseous salts, explains how salts are formed, and discusses how the body uses salt.

Introduces the atom, elements, compounds, and mixtures and discusses related concepts including chemical reactions, chemical equations, and photosynthesis.

Explains what elements are, identifies the common elements in organisms, and provides scientific descriptions of different compounds.

Explains the difference between the physical and chemical properties of substances, and provides scientific descriptions of mixtures, compounds, and solutions, and how they behave.

Examines the various properties of gases and their relationship with other properties.