This resource book introduces sixth-grade children to the physical and chemical properties of gases. The unit begins with an investigation of acids and bases. Students then generate carbon dioxide, oxygen, and hydrogen, and investigate the properties of each. The unit culminates with an activity involving an unknown gas. Students conduct tests to determine the identity of the unknown gas by observing its properties and comparing them with the properties of known gases generated earlier. The lessons include investigations into the following concepts: (1) acids and bases; (2) neutralization; (3) flame tests; and (4) using limewater to test for carbon dioxide, and studying carbon dioxide, oxygen, and hydrogen. Each lesson includes objectives, materials needed, materials to be prepared, student procedures, and a worksheet. Reference materials include a listing of materials needed, supplementary audiovisual materials, a listing of correlated texts, vocabulary, an overview of unit objectives, safety precautions, and instructions for preparing solutions. A unit evaluation is also provided. (MVL)