In this lesson, students will learn that waterwheels are machines that convert the energy of falling water into power that can grind wheat into flour, saw timber, and make work easier. After investigating what this technology can do, students create a waterwheel using a plastic soda bottle, index cards, and a wooden dowel as they investigate the transformations of energy involved in turning the blades of a hydro-turbine. Students will also experiment with how weight affects the rotational rate of the waterwheel. In addition to a structured class activity, students can also be given the opportunity to use what they have learned to make and test waterwheels using different materials and designs.