Feel the wind

Feel the wind

Have you felt the wind blowing through your hair? Wind is moving air. Air is what we breathe. It is everywhere around us, even though we can't see it.

We can't see air. And we can't really see the wind. But we can see the wind move things. Wind pushes clouds across the sky. Wind flutters the leaves of trees and makes ripples on lakes. You can hear the wind, too. When wind blows through cracks in your house, it can sound like someone whistling. If the wind blows very hard, it can sound like a wild animal howling.

You can see the wind move things, you can hear the wind, and you can feel the wind too. Stand by an open window and let the breeze tickle your face. A strong gust or a light breeze-wind is moving air. But what makes air move? Yom make air with a fan, or by flapping a piece of cloth or paper. But fans don't make the wind. What makes the wind that blows across fields and forests and mountains? What makes the wind that whips around tall buildings in the city?

All of the Earth is surrounded by air. Earth and the air around it are heated by the sun. But some parts of the Earth heat up more than other parts. In the tropical parts of Earth, near the equator, the sun's rays strike the Earth directly. The air gets very hot. Near the Earth's icy poles, the sun's rays strike at a slant. So the air stays cooler. When hot air and cold air change places, wind is made.

Hot air is lighter than cold air, so hot air rises. People discovered this a long time ago and used hot air to make balloons float. The heated air in the balloons was lighter than the cooler air outside. The hot, light air made the balloons float upward. When heated air over the Earth rises, cooler, heavier air rushes in to take its place. The moving air is wind.