The wind moves over the land. It sways the tall grass in meadows and rustles leaves on trees. It ruffles your hair. In a storm, it whirls and roars. Wind can change a cloudy day into a sunny one by pushing clouds along. Wind is moving air. And it is the sun that makes air move.
The earth spins around like a big top. As it spins, each part of the earth, in turn, comes into the sunlight. The sun’s light warms the earth, and the earth warms the air. The heat makes the molecules of gas in the air move faster and spread apart. This warm air rises up like a big, invisible cloud. It rises because warm air weighs less than cool air.
As the warm air rises, cool air from other places flows in to replace the warm air. This moving cool air is the wind. When you feel the wind blow, you are feeling the movement of cooler air pushing in to take the place of the warm air that rose up into the sky.
What happens to the warm air? It cools and then sinks back to the ground. There it takes the place of warmer air, and all the same changes happen over again!
Picture Credit : Google