Roll-Back Can

It slows, stops, and rolls back by itself. Ask students to predict what will happen. Roll it away across the floor/table and let go. Key idea: A hidden weight twists a rubber band, storing energy that later unwinds. Ask: Where did the can get the energy to come back? Safety and cleanup: Keep internal weight secured. https://www.nsta.org/lesson-plan/why-does-can-come-back