Great Explorations in Math and Science (GEMS) activities are designed to capture imagination while illuminating essential science themes, concepts and methods. Developed at the University of California at Berkeley's Lawrence Hall of Science and tested in thousands of classrooms nationwide, GEMS guides utilize children’s natural curiosity about their environment to teach mathematics as well as reading, social science, art, and, of course, science. Learning objectives are clearly summarized and activities are integrated across disciplines and grade levels. Each guide is complete and can stand alone as a unit of study or as a supplementary lesson.