In this activity, learners actually feel the difference in energy required to light two different types of light bulbs: incandescent light and LEDs. Learners will use a generator (hand crank) to provide the power and observe that the bulbs are equally bright. They will be surprised to learn that incandescent bulbs require more energy. This is a hands-on activity that works best if learners experience cranking the generator themselves, and works well at a learning station or center. This activity can be incorporated into a lesson on energy efficiency and/or used during winter holidays since it uses holiday lights.