Why does the wind blow?

Wind is something everyone has felt, from a gentle breeze to a powerful gust. It can turn the pages of a book, push sailboats across the water, or knock down trees in a storm. Yet wind is invisible. We only see its effects, never the wind itself. So what exactly is wind, and what makes the air start moving? The answer lies in the air pressure of our atmosphere and the heat of the Sun.

The air around us is a real substance, made of gases, and it has weight. The weight of all the air pressing down creates what we call air pressure. Air pressure is not the same everywhere, though. In some places the air presses down more strongly, creating an area of high pressure. In other places it presses down less, creating an area of low pressure. These differences in pressure are the engine that drives the wind.

In nature, things tend to even out, and air is no exception. Air naturally flows from where there is more of it, the high-pressure areas, toward where there is less of it, the low-pressure areas. This moving air, flowing from high pressure to low pressure, is exactly what we experience as wind. The bigger the difference between the two pressures, the faster the air rushes to balance them out, and the stronger the wind blows.

What creates the pressure differences in the first place? The main answer is the Sun. The Sun does not heat the Earth evenly. Some areas, like land, heat up quickly, while others, like water, heat more slowly, and the equator receives far more heat than the poles. When air is warmed, it becomes lighter and tends to rise, leaving lower pressure behind. Cooler, heavier air creates higher pressure. Because the Sun constantly creates these uneven warm and cool spots, it constantly creates the pressure differences that keep the wind blowing all around the planet.

This article was written using information from Wikipedia.