Exhibit: Crank Power

Turn the crank to generate electricity. You can light up the bulbs or store electricity in a capacitor.

The generator is like a bike dynamo. When you turn a dynamo, a magnet spins around next to a coil of copper wire. The faster the magnet turns, the bigger the voltage generated between the ends of the coil, and the bigger the electric current the dynamo produces. In this generator however, a strong magnet remains stationary and the coil of wire spins around next to it, so a similar voltage is set up across the coil’s ends.

Once the capacitor is charges, you can leave it as long as you like, until you want to discharge it. Connect the capacitor to the bulb and the piled up electrons will flow through the bulb until there is no electrical pressure left.

There are two bulbs in the exhibit, which can be connected to the generator. You have to push the crank harder to light up the brighter of the two bulbs.