A hydro-electric power station uses the force of moving water to make electricity.

First a dam is built to hold a deep lake of water. The lake is filled by streams of rivers flowing into it.

A large pipe near the bottom of the dam allows a stream of water to leave the lake. The stream flows through the blades of a turbine. The turning blades are joined to a shaft and to machinery that makes electricity. The electricity is taken to homes, offices and factories along thick electric wires.

In a hydro-electric power station it is easy to control how much electricity is made. When a gate at the entrance of the large pipe is closed, no water reaches the turbine and so no electricity is made. When the gate is partly closed, less water flows into the pipe so the turbine blades spin more slowly

and make less electricity.

© 2005 Al Bawaba (www.albawaba.com)