What is Wind? You can’t see air, but it is all around us. You hear leaves rustling in the trees. You see clouds moving across the sky. You feel cool breezes on your skin. Wind is moving air.
The Sun Makes the Wind Blow
North Pole
The energy in wind comes from the sun. When the sun shines, it heats the Earth’s surface. The Equator gets more sunlight (radiant energy) than the North or South Poles. The Earth is not heated evenly. Dark areas of land, like forests, absorb a lot of solar energy. Areas of water reflect solar energy. Light colored desert sand, snow, and ice reflect the sunlight, too.
Equator
South Pole
As the Earth’s surface absorbs the sun’s energy, it turns the light into heat. The heat on the Earth’s surface warms the air above it. The air over the Equator is warmer than the air over the poles. The air over land is warmer than air over water. As air heats, it expands. Hot air rises. Cooler air rushes in to take its place. This moving air is wind. Wind is caused by the uneven heating of Earth’s surface.
How Wind is Formed
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RM A IR
CO O L A I
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1. The sun shines on land and water. 2. Land heats up faster than water. 3. Warm air over the land rises. 4. Cool air over the water moves in.
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Wonders of Wind