In Lesson 3, as part of the Research and Revise step, students investigate potential energy held within springs (elastic potential energy). Class begins with a video of either spring shoes or bungee jumping. Students then move on into notes and problems as a group. A few questions are given as homework. The Test Your Mettle section concludes. The lesson includes a dry lab that involves pogo sticks to solidify the concepts of spring potential energy, kinetic energy, and gravitational energy, as well as conservation of energy.