Hydro power has been used since days of yore (specifically and precisely). It was first used for grinding flour and other simple tasks that required mechanical movement, but little else. In the late 19th century, hydro power was first used to power an electrical generator, and hydroelectric power was born.
This simple demonstration will help you explain to kids (or anyone else who may be interested) the basic concept behind hydroelectric power.
You’ll need exactly four items for this little experiment: a scissor, a disposable plastic or foam plate, a pencil, and water source, such as a faucet or spigot.
With the scissor, cut a series of evenly-spaced, one-inch slits around the outer edge of the plate. Be sure to make an even number of cuts—it will work with an odd number, but it’ll be a bit wonky.
Carefully bend every other section of plate betwixt the cuts back until they’re at a 90° angle to the plate itself. You should have an equal number of bend-back “blades” and straight, unbent sections. Be careful not to bend them back too far (a danger especially with foam plates) as they may just break right off. If you do accidentally lose one or two, it will still work, but again it’ll be a bit wonky. Lose more than that and you’ll have to start over. Remember, disposable plates are a finite resource on this planet of ours.
Next, stab the pencil through the center of the plate. It may be easier to poke through with the scissor first. Either way, you should end up with the pencil piercing the plate. Work it through back-and-forth a few times until the pencil can move smoothly through the hole.
Then, hold the entire contraption (we’ll call it a “wheel” from here out) under the faucet/spigot/what-have-you with the water running, so that the water catches the blades and moves the wheel around the pencil-axle. It should start turning continuously; if not, adjust the wheel’s position until you find the sweet spot.
Wherefore Art Thou, Science?
The water pushing the blades of your wheel, and thereby moving the wheel itself around the axle, is a very basic recreation of a hydroelectric generator. The constant motion of a running river or waterfall can be used to turn large-scale waterwheels, which, when attached to generators, can produce large amounts of electricity.
Hydroelectricity was one of the first forms of electrical power generation, and is still widely used throughout the world. It is highly effective and relatively simple, though it can have a negative impact on the environment if not instituted and monitored properly.
- 365 More Simple Science Experiments with Everyday Materials, E. Richard Churchill, Louis V. Loesching, Muriel Mandell, and Frances Zweifel, 1998. ISBN 978-1579129675