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Professor Quester Answers
Questions on Wind Energy

Dear Dr. Q:
I am doing a science report on wind energy and I have looked at your sight under this subject. The only thing that I don't think was made clear was exactly how the wind energy was turned into electricity in the generator located inside the wind turbine. Does the high speed shaft create heat that somehow turns into electricity? Please explain! Thank you.  (Alexandra, 8th grade, New York City.)

The Professor Answers:
Good observation ...actually the shaft does create some heat however that's not what makes electricity. A generator (attached to the shaft) produces electricity using electromagnetism. When metal moves through a "magnetic field," a voltage is produced. Voltage is a measure of electric energy. These types of generators (also known as dynamos) have a huge magnet surrounding many coils of wire. The shaft spins this coil of wire at very high speeds between the poles (positive and negative) of a magnet generating an electric "field" or current. The first dynamo was invented by Zenobe Gramme in 1870. Good luck on your science report.

Dear Dr. Q:
How and when did someone figure out that they could use wind as a type of energy? (Connor, 5th grade, Lafayette)

The Professor Answers:
I don't think it was a particular person that thought of using the wind as an energy source. Well, maybe it was someone particular but we don't know his or her name. Ancient people (we're talking several thousand years ago) could see that there was tremendous force in the natural motion of wind and water. Although they had no scientific understanding of energy, they realized they could harness these natural forces to do some heavy work. Early civilizations used "mechanical energy" to do work like lifting, grinding grain, building and transporting people and goods. This mechanical energy was from wind or water.

One of the earliest forms of wind power was used to move boats with cloth sails as long ago as 3500 BCE. On land, the first windmills seem to have been used in Persia (that's Iran and Iraq today) around 700 Common Era. Wind power was also used for irrigating dry land and draining wet land. More recently wind is used as an alternative energy source to generate electricity.

Dear Dr. Q:
How many lights can one wind mill light up?

The Professor Answers:
Wind turbines (people in the wind business like to call them wind turbines instead of windmills) usually produce about 50 to 300 kilowatts of electricity each. A kilowatt is 1,000 watts (kilo means 1,000). You can light ten 100 watt light bulbs with 1,000 watts. So, a 100 kilowatt (100,000 watts) wind turbine could light up 1,000 light bulbs that use 100 watts. More than are in your home. Thanks for asking and check out more wind information from The Energy Story.

Dear Dr. Q:
How do windmills work? (Nicole, 5th grade, Lafayette, CA)

The Professor Answers:
Very simply, blowing wind spins the blades on a wind turbine -- just like a large toy pinwheel. The spinning blades turn a generator that makes electricity. Check out The Energy Story (Chapter 16 on Wind Energy) for some pictures and more details on how a wind turbine makes electricity.

If YOU have a question about energy, send your question by e-mail to "Professor Quester."
Ask your parents or teacher first before sending an e-mail. Please tell us your grade level, the name of your school and your city. We will usually respond within four or five days.

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Page updated: May 17, 2002
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