What makes the air move? --- John, Beirut, Lebanon
Marshall Brain Answered:
There are several things that can make air move. For example, a fan moves air around. A car going down the highway will move air out of the way as it passes. When you open a refrigerator door, the cold air will spill out onto the floor. But in the simplest, most fundamental terms, the air is moving because of pressure differences. Air moves from areas of high pressure to areas of low pressure.
At the scale of the earth, the pressure differences are caused by the sun. We feel the pressure differences as wind, with the wind flowing from a high pressure area to a low pressure area. The pressure differences are often caused by uneven solar heating.
This video demonstrates how convective currents can cause wind in the atmosphere: