Where does that power come from?

The transmission of energy to our homes and businesses is a multi-process event. Since we know that wind produces energy, scientists and engineers have figured out a way to take that energy and make electricity to power our lights, television sets and hair dryers!

• Wind power is a form of solar energy. About two percent of the sun's radiation that falls on the Earth is converted to wind energy through the heating and cooling of the earth's surface.
• When areas of the earth heat up, the hot air rises and cooler air rushes in, creating wind.
• When the wind blows, its energy can be used to turn the blades of a wind turbine.
• The spinning of the blades sends energy to the wind turbine's generator.
• The generator increases the voltage from 480 volts to 12,000 to 66,000 volts! (A volt is the measure of electromotive force in electricity.)
• Moving through underground cables, the electricity travels to a transformer that boosts the voltage even more, up to 400,000 volts! (They boost the voltage because it's more efficient to transport higher voltage electricity.)
• Still in cables underground, the electricity is moved to substations, where it is reduced to lower voltages.
• Near our homes, electricity goes through a transformer to convert the power to even lower levels for use in our homes.
• The electricity now moves above ground in electrical power lines to our homes.
• The voltages in your home are 110 volts for lights, television and hair dryers and 220 volts for larger appliances such as your clothes washer and dryer.

Discovery

Have the class take turns drawing this sequence of events on the chalkboard or a large sheet of paper for later display. Begin with the sun shining down on the Earth, and draw an arrow from that to a picture of a wind turbine, then draw an arrow from the turbine to a transformer box, and so on, or create a Wind to Electricity Transmission display. A picture or display helps bring the message home.

More windy facts:

• To create the amount of power necessary for home and business electrical use, wind farms must be built.
• A wind farm is many turbines grouped together.
• Wind farms are big! One turbine needs about two acres of land, but the land can still be used for farming and grazing.
• What do you think makes a good wind farm site?
• Wind speed increases with altitude. The taller the wind turbine, the more wind it can catch.

Have the class design a wind farm. Tell them to keep in mind that turbines do well on the tops of smooth hills, on open plains, near shore lines and in mountain gaps.

Why do you think the area you live in was chosen for a wind project?