Wind

Wind is air that is moving from one place to another. It happens because the Sun heats Earth's surface unevenly. Warm air rises and cool air rushes in to take its place. This movement of air is what we feel as wind. Wind can be a gentle breeze or a powerful storm force.

What Causes Wind

The Sun heats land and water differently. Warm surfaces heat the air above them. Hot air rises because it is lighter. Cooler air rushes in along the ground to replace it. This creates wind. The bigger the difference in temperature between two areas, the stronger the wind blows.

Wind Power

People have used wind power for thousands of years. Windmills once ground grain and pumped water. Today, giant wind turbines use the wind to make electricity. Wind power is a clean energy source because it does not create pollution. A single large wind turbine can power about 1,500 homes.

Fun Facts

• The fastest wind speed ever recorded on Earth's surface was 253 miles per hour during a tornado.
• Sea breezes blow from the ocean toward land during the day, and land breezes blow from land toward the sea at night.
• On Neptune, winds can reach speeds of over 1,200 miles per hour.

Did You Know?

The jet stream is a river of fast-moving air high up in the atmosphere. It flows from west to east at speeds of 100 to 200 miles per hour. Airplanes flying east use the jet stream to save fuel and arrive faster. Flying west takes longer because the plane fights against the wind!