Along-standing energy lab involves dropping bouncy balls and measuring their rebound heights on successive bounces. The lab demonstrates a situation in which the mechanical energy of a system is not conserved. Although students enjoyed the lab, the author wanted to deepen their thinking about energy, including the connections to motion, with a new version of this old favorite. A question asked in the activity was: "Where does the 'missing' energy go?" Addressing this question allowed students to practice evidence-based reasoning as called for by the Next Generation Science Standards (NGSS Lead States 2013; see p. 24). When answering the question, students often expressed the misconception that air resistance was the main culprit. So, the author reframed the lab around finding where the dissipated energy goes, focusing on how it could help students connect energy to the motion of the bouncy ball. This article describes the activity the author now uses in her 12th-grade physics courses. The revised lab takes roughly three 55-minute class periods.