what makes the wind blow?
Answers:
the rotation of the earth. imagine spinning a ball in a bowl of water. if you were standing on the surface of the ball, the water would be rushing past you, as the wind does. of course, it's much more complicated than that on a worldwide scale.
Other answers:
The sun warms the air, which expands it.
The sun warms the air, which expands it.
Both answer above are correct -- it is the combination of the two that causes the wind:
Wikipedia -- Wind is the roughly horizontal movement of air (as opposed to an air current) caused by uneven heating of the Earth's surface. It occurs at all scales, from local breezes generated by heating of land surfaces and lasting tens of minutes to global winds resulting from solar heating of the Earth. The two major influences on the atmospheric circulation are the differential heating between the equator and the poles, and the rotation of the planet (Coriolis effect).