This guide was developed to provide children with an opportunity to prepare and collect several common gases and to discover and work with some of their properties. The guide is divided into five major sections: (1) introduction, (2) materials, (3) activities, (4) balloons aloft, and (5) an appendix. The introduction provides information concerning use of the guide, grade level, scheduling, and evaluation. The materials section lists materials needed for this unit. The activities section describes activities involving biomothymol blue, carbon dioxide, oxygen, hydrogen, and mystery gases. The Balloons Aloft section describes a concluding activity. The appendix provides information on safety precautions, preparations, recipes and techniques, and the yardstick balance. (DS)