David Leon Triska, age 8, of Buckeye, Arizona, for his  question:

How can water make electricity?

This seems impossible    but it can be done. It works because moving water can push. Even a small flowing stream can push along bits of gravel. When a river dashes over a cliff, the water tumbles down with force mighty enough to be used to create electricity. The fob is done inside a great turbine, or generator. It has a giant magnet and a mighty arm of copper coils    and the parts are connected to a circuit of copper wires. The magic happens when the copper or, the magnet swings around and around.

An electric generator must keep whirling around to send current through the wires. The push of falling water can keep it turning. The generator is set near a waterfall or near a dam, where they let out the falling water as they need it. It is set so that the force of the water keeps spinning parts of the generator around and around. By some mysterious magic, this sends electricity through the wires.