Includes the following Great Explorations in Math and Science (GEMS) guides: Acid Rain; Animals in Action; Chemical Reactions; Convection; Discovering Density; Dry Ice Investigations; Earthworms; Environmental Detectives; Experimenting with Model Rockets; Global Warming and the Greenhouse Effect; Height-O-Meters; Learning about Learning; Mapping Fish Habitats; Math Around the World; More than Magnifiers; River Cutters; Stories in Stone and The Real Reason for the Seasons.