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Q & A: Electromagnetic Induction and Windmills

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Most recent answer: 10/22/2007
Q:
I’ve been reading about how to make electricity using wind power and a generator. It said that the blade is connected to a magnet inside the generator. The magnet is wrapped by wire. As the wind blows the blades, the turning blades turn the magnet. Whenever a magnet passes the wire, electricity is produced. My question is "how" does the magnet moving past wire generate electricity? There has to be something to do with electrons, but I’m not sure what it is.
- Lesley Royce
Jacksonville, FL
A:
Lesley -

Great question! What you're talking about doesn't just have to do with windmills - any time you move a magnet near a wire, you will get electricity. This is how all electric generator works.

As you know, if you hold two magnets close together there will be a force between them. What you perhaps didn't know is that if you move a charge (like an electron) near a magnet, it will also experience a force. It is this kind of force that is used in your TV set to focus the electron beam and make the picture.

OK, if you believe that a moving electron experiences a force in a magnetic field, the rest is easy. A copper wire has lots of electrons in it that are free to move around inside the wire (copper is a good conductor). If you move a copper wire near a magnet in the right way, the magnetic field will try to push all of the electrons in the wire in one direction. This is how a generator works. You have lots of loops of copper wire that is moved (in a circle as it turns out) close to a bunch of strong magnets. This causes electrons to move in the wire. Since moving electrons are just electric current, presto, you are making electricity.

Tamara & Mats

(published on 10/22/2007)

Follow-Up #1: energy and electrons

Q:
but; but;but; energy can be niether created or distroyed iím confuzed now,-another point, take a/c 60/w light bulb use electron in lighting bulb-canít electron be re-charged,light another bulb,befor returned (compleat curcut)??
- joe ziviski
ocala ,fl ,-
A:
The problem isn't that there aren't enough electrons to go through both bulbs. It's that it takes some 'push'- a voltage - to make the electrons move through at a fast enough rate to light up the bulb. The energy that comes out as light is a part of the energy dumped into the bulb because that voltage push is doing work on the moving electrons. To get the electrons to flow through two bulbs at the same rate requires twice as much push, which in this case means twice as much work.

The energy that flows into the generator (from whatever source) ultimately comes back out of the bulbs as light, heat, etc.

Mike W.

(published on 10/22/2007)

Follow-up on this answer.