Wind is reemerging as a clean and reliable source of energy--primarily for the production of electricity. This article discusses how to create a pinwheel to explore wind power. It presents a 5E learning-cycle lesson in which students construct a simple pinwheel-type windmill to test the power generated by different designs. Students compare three- and four-bladed pinwheels made from manila folders or plastic report covers. This lesson addresses the International Technology and Engineering Educators Association standard "energy is the ability to do work using many processes." (Contains 6 figures and 2 resources.)