Wind Power

by Denby Bosley

wind

wind

is moving air. We can use the energy in wind to do work. Early

Egyptians used the wind to sail ships on the Nile River. People still use

wind to move sailboats. In the Netherlands, people used windmills to grind

wheat. The Pilgrims used windmills to grind corn, to pump water, and to

run sawmills. Today, we use wind to make electricity.


The Sun makes the wind move

The energy in wind comes from the sun. When the sun shines, some of its light reaches the

Earth’s surface. The Earth near the equator receives more of the sun’s energy than the North

and South Poles.

Some parts of the Earth absorb more solar energy than others. Some parts reflect more of the

sun’s rays back into the air. Light-colored surfaces and water reflect more sunlight than dark

surfaces. Snow and ice reflect sunlight, too.

Some types of land absorb more solar energy than others. Dark forests absorb sunlight, while

light desert sands reflect it. Land areas usually absorb more energy than water in lakes and

oceans.

When the Earth’s surface absorbs the sun’s

energy, it turns the light into heat. This heat

on the Earth’s surface warms the air above it.

The air over the equator gets warmer than

the surface air near the poles. The air over

the desert gets warmer than the air in the

mountains.

The air over the land usually gets warmer

than the air over the water. As air warms,

it expands. The warm air over the land

becomes less dense than the cooler air and

rises into the atmosphere. Cooler, denser air

nearby flows in to take its place. This moving

air is what we call wind. It is caused by the

uneven heating of the Earth’s surface.

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wind is renewable

As long as the sun shines, there will be winds on the Earth. We will never run out of wind

energy. It is a


renewable energy source. It is also free since no one can own the sun or the air.

we can capture wind

Some places have more wind than others. Areas near the water usually have a lot of wind. Flat land

and mountain passes are good places to catch the wind, too.

Today we use big


wind turbines to capture the wind. Sometimes, there are hundreds of wind

turbines in one place. This is called a


wind farm. Some wind turbines are as tall as 20-story

buildings!

wind can make electiricity

When the wind blows, it pushes against the blades of

the wind turbines. The blades spin around. They turn a

generator



to make electricity. The wind turbines don’t

run all the time though. Sometimes the wind doesn’t

blow at all. Sometimes the wind blows too hard. Most

wind turbines run between 65 and 90 percent of the

time.

Today wind energy makes a small amount of the

electricity we use in the United States. Most of the big

wind farms are in Texas. There are plans for many more

all over the country and the world.

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