Investigate the mysterious forces that affect the earth, using materials found around the house. Build an earthquake detector from a shoebox, pencil, paper, and string. Create a glacier model that melts, moves, and leaves behind sand and rock. Experiment with gravity, magnetism, plants and recycling. All are simple, safe, and guaranteed to work. 128 pages, 30 b/w illus., 5 3/8 x 8 1/4.