This book, addressed to students for their independent use as well as to teachers as a supplement to the standard texts, contains nearly 100 practical science experiments that cover a wide range of subjects at different grade and ability levels. It is designed to involve students in active scientific experimentation, demonstrations, and projects for school and home. Each experiment provides safety precautions, an introduction, procedures, time and materials needed, data tables, and an analysis where applicable. Topics included are: (1) "Earth Science" (which covers such areas as acid rain, pollution, water currents, surface area and erosion, air movement, rocks, and the solar system); (2) "Biology" (covering the formation of a classification key, trees, insects, soil, tidal pools, ecological survey of a marsh, the effect of food supply on fruit fly density, and other topics); (3) "Physical Science/Chemistry" (including testing powers of observation, plant indicators for acids and bases, atmospheric pressure, and salts as neutralizers); and (4) "Physics" (including experiments with uniform motion, gravity, friction, sound waves, circuits, and plane mirrors). Following the experiments, a section called "Our Findings" supplies possible answers to questions cited in the activities, and this is followed by lists giving grade level, supervision required, setting (school or home), and number of participants for each experiment where relevant. Experiments that can be completed in less than an hour are also listed, as are sources for materials and supplies. A list of contributors and an index complete the document. (RT)