Most students have a very limited sense of where electricity comes from. In this activity, a hand-powered electric generator converts mechanical energy into direct current (DC) electricity that can be used to power a small lightbulb, run an electric motor, and do other tasks that require electricity. Electrical polarity can be reversed by switching the lead wires or by cranking the generator handle in the opposite direction. Computer simulations can be used to help students visualize how electrical generators convert kinetic energy into electricity to light a lightbulb.