Ellen Jackson, age 8, of Monroe, Georgia, for her question:

Is it true that water can make electricity?

Electricity gives us lights and heat to do the cooking. A long time ago, a very clever inventor figured out how to use water to make the electric power that runs through the wires to our homes, cities and factories. The idea seems downright impossible. But it works. The water may be a big natural waterfall, like Niagara. Or it may be a spill from a man made dam. In any case, it must drop down from a steep height and there must be a lot of it. This falling water has a lot of strength    and its mighty force can be used to spin the parts of an electric generator.

A generator creates electricity by spinning magnets and copper coils around and around each other. The falling water is used to keep the parts spinning. This makes the electricity, and a system of wires is connected up to carry it for miles and miles. There are not enough waterfalls to make all our electricity, so some generators must be turned by steam from furnaces.