Roberta A. Mazzucco
The wind seems to be an obvious source of potential energy. It is a free and clean form of energy. The problem with this resource arises from the fact that there are few places on the earth where there is a steady and strong enough wind that could be relied on for more than a fraction of the energy we need. The United States is one of the leading proponents of this form of energy and we see proposals for wind farms in places like Rhode Island and Massachusetts. One of the main problems with the wind farms is that many people near these coastal areas fear the blockage of the natural beauty surrounding them. Likewise, the large fans like structures pose potential harm to birds. Many individuals around the world have small wind powered devices but, as has been stated, widespread use of this technology is not practical.
A local example of individuals utilizing this technology is the Phoenix Press of New Haven, Ct. They have a wind turbine near their shoreline business. Their turbine generates 165,000 kWh of power per year. They state in their literature that the turbine saves the equivalent of the greenhouse gas emissions of 23 passenger cars per year, or CO
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emissions from burning 276 barrels of oil annually, or the greenhouse gas emissions from 40 tons of yearly landfill waste.
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Many of us have made kites or simple pinwheels with our students. There are a few sites where students can also find directions to make an anemometer to observe wind speed, and of course, students can also work with kites. It seems important to me to show students how wind power actually works. I did come across directions for building a model windmill. That activity follows.
Activity 3: How to make a Windmill
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Materials: an empty milk carton, a drinking straw, a cork, a tack or paper clip, 2 3 feet of thread, a small pinwheel made from cardboard or paper, and sand
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1. Put a few inches of sand on the bottom of the milk carton
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2. Make a hole on either side of the carton so you can put the straw straight through the two holes.
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3. Put the cork on one side of the straw and the pinwheel on the other.
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4. Tie one end of the thread to the tack or paper clip and the other end to the cork.
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5. Blow on the pinwheel and as it turns the tack or clip will go up and down.
You might also use a small fan to make it turn. The point of the activity would be for students to see that to do work the wind must reach a certain level of intensity. Of course, even if the strength of the wind is reached, it must occur at the right time or the work cannot be accomplished. Since the wind is more predictable in certain areas of the world and only at certain times, it could never be a total solution to the energy problem.
Because the earth is unevenly heated by the sun, the air surrounding us varies in temperature, density, and pressure. These differences result in cool air masses dropping and warm air masses rising. This results in wind. Harnessing the wind to do work first occurred over 2,500 years ago in China when wind power was used to pump water. Over the centuries, windmills have been tremendously popular throughout Europe and in the United States. Unfortunately, there has to be a back up source of energy where wind energy is used. Ironically, if wind speeds are too high they can damage the turbine and so, they are usually constructed to automatically shut down under these conditions.
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There are certain geological areas where wind energy has been found to be most profitable. Ideal locations include formations that funnel wind through narrow passes, as in California, or continuous wind found along the ridge of the Rocky and Appalachian Mountains, and the central and northern portions of the Great Plains (Montana, the Dakotas, and Wyoming). There is also potential in Europe for off shore wind farms. There needs to be an annual average speed of at least 14 miles per hour. The ideal speed would be 25 to 35 miles per hour.
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