The Coriolis Effect

Hurricanes, we’ve all heard of them. At least, I hope you have. An interesting fact you may not know about these dangerous phenomena is that they tend to move in different directions depending on what hemisphere they’re in. If they’re in the north, they spin counterclockwise, while in the south, they spin clockwise. But why is that? Why are north and south different? It’s all due to the Coriolis Effect.

To understand how the Coriolis Effect works, we must first imagine a sphere.

Imagine this sphere is going at a constant speed of 2 mp/h. But, the top and bottom of the spheres are smaller than the middle. If that’s the case, then for the sphere to move

at a constant speed, the middle of

the sphere needs to be moving faster than the top and bottom of the sphere, because the middle is larger. This applies to the Earth, too. Let’s pretend you are standing at the equator, and someone else is standing at, say, the North or South Pole, and you could see all the way to the other person. If you watch and wait, you will eventually pass the other person and they will leave your field of view because you are moving faster at the equator than the North/South Pole.

Let’s look at another example:

If we start with two points, one point A at the Nort

h Pole, and one point B at the equator, for them to travel to the same latitude on the other side of the planet, point B must travel a lot farther. Since the Earth is rotating at a constant speed, that means point B is traveling faster than point A. (The Earth has to average out to a constant speed, but points on the Earth can travel at independent speeds) When looking at the Northern Hemisphere, points will travel to the right relative to you, while when looking at the Southern Hemisphere, points will travel to the left.

Now, how does the Coriolis Effect affect hurricanes and other weather/wind patterns? It’s all because of air pressure. Low air pressure areas naturally cause high-pressure areas to flow toward them. But, thanks to the Coriolis Effect, the air moves in a curved path. Because of the opposite relative directions in the different poles, Hurricanes curve and spin in opposite directions. Counterclockwise for the north, clockwise for the south.

Wow! Now I know how something that will most likely never affect me in my life works at the cost of my time! Just kidding, it’s pretty interesting.