This two-week (~10-hour) module focuses on water and its importance to humans, both as a limited resource and in shaping Earth's surface. Water's flow through the hydrologic cycle is driven by Earth's external energy source – the Sun. Running water also moves and deposits sediment that ultimately becomes part of the rock cycle, whose energy source also includes Earth's internal heat energy. Students see that river systems change shape over time, are influenced by climate and by human activity, and affect human activity, for example through flooding. Students develop their understanding while working in small groups, through interaction with simplified physical models of complicated systems, with Google Earth images of stream profiles in different climates, and with real river flooding data sets. Activities within this module are aimed at content courses for pre-service teachers, but they also could be adapted to other undergraduate introductory geoscience or environmental science courses.