by Denby Bosley
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
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
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.
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
wind can make electiricity
When the wind blows, it pushes against the blades of
the wind turbines. The blades spin around. They turn a
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
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.