Students and crew on board the International Space Station (ISS) work as a team to test their windmills, determining speed and comparing results in microgravity to those recorded in the classroom to help prove their hypothesis. Students are then challenged to think of modifications to their windmill design that would allow the model to function as good, if not better, in microgravity as it does on Earth. Topics covered include gearing down, gearing up, ratchets, forces and motion, weight, force, time, and energy.