Susan Fulks, Age 10, Of Ravenswood, W. Va., for her question:

How does water make electricity?

The magic of electric current is generated when a copper coil moves through a magnetic field. A magnetic field is the invisible band of energy which hovers around the outside of a magnet. If the two ends of a copper wire are fixed to the generator, a current of electricity is sent through the wire circuit. In order to keep the current going, the copper or the magnet must whirl around and around.

Tumbling water has great pushing power. A waterfall may be used to push around the moving parts of a generator. If it falls upon a wheel hung with little buckets, the wheel turns, and as it turns, it turns the generator to keep the electric current flowing through the circuit of copper wires.