Wheels in the Sky

Who can forget the exhilaration of walking through the rolling barrel at a carnival or in a modern theme park. Walking straight towards the opening on the other side was a guarantee for falling. Smartly walking against the oncoming rotating wall enabled us to cross. If our footprints were recorded on the inside of the barrel, they would have shown an interesting curved path and not a straight line. What happened with our path is that in a rotating system the direct path is not necessarily a straight line. The important discovery of Gaspard Gustave Coriolis in the early 19th century opened up an entirely new understanding of the rotating phenomenon. He proposed the force component of rotating system that now bears his name. The Coriolis force on the surface of the rotating Earth has far reaching consequences. Consider the atmosphere. It is controlled by a large number of parameters and it is very difficult to predict the motion of air-masses, i.e. the weather. Sometimes it appears totally random, but there is some order in that chaos intriguingly influenced by the Coriolis force. In the atmosphere, air flows from high pressure areas toward the lower pressure areas, just like heat moves to lower temperatures. Since our atmosphere happens to be on the rotating Earth, it is effected by the Coriolis force. The straight motion from higher to lower pressure areas will be modified by the Coriolis force resulting in the well known hurricane patterns.