Bringing together the atmosphere, hydrosphere, and the lithosphere can be a formidable challenge. This classroom activity created by H. Catherine W. Skinner of Yale University manages to do that quite elegantly, and it is one that geology teachers will want to try out in their own classrooms. In this activity, students will be presented with the opportunity to explore the natural processes that influence the geological distribution of materials, study elemental cycles, and also examine how they can affect human health. On this site, visitors can read about the pedagogical approach of this activity, download instructor notes, as well as the specific goals of the assignment.