Did you ever take a ride on a Merry-Go-Round with a friend and while the ride was spinning you tried to toss something, let’s say a piece of candy to them? Well I bet the candy took off in a sharp turn and you missed by a mile! You’re left with a surprised look on your face as the candy flies off as if it had a mind of its own!
Think about it, because of the motion of the Merry-Go-Round both you and your friend are moving in a circle! That means that by the time the candy gets to where your friend was when you threw it, they’re not there anymore! And because of the circular motion of the Carousel your candy appears to you to take a sharp turn in the opposite direction of the spin of the Merry-Go-Round! Click on the link below to be taken to a youtube video of a very nice demonstration of what I’m describing from a freshman physics course at MIT.
This effect is commonly known as the Coriolis “Force” although any physicist will point out that there’s really no force acting on the candy. Technically what’s happening is that you are in a rotating frame of reference, the Carousel, but once you let go of the candy it no longer is. This makes the candy’s straight line motion look to you as if it’s curved. That’s right the candy is moving in a straight line, you’re on the Merry-Go-Round, you’re the one going in a circle!
Now we all live our lives on a great big Merry-Go-Round, better known as the spinning globe of the Earth, so the coriolis effect has a major influence on many of the phenomena we see every day. (That’s right you flat Earth loonies, the Earth is a spinning globe and the phenomena I’m about to talk about are demonstrations of that fact!!!). Since the Earth’s equator is 40,000 km in circumference and the planet rotates once every 24 hours that means that a person standing on the equator is actually moving at 1666.6 kilometers per hour (40,000km / 24 hours=1666.6 kph). On the other hand someone standing at the north or south pole isn’t moving at all (relative to the center of the Earth at least) but simply turning around once every 24 hours. In between you can calculate your speed if you know your latitude using the formula:
v=1666.6 x sin(Latitude)
For example I live in Philadelphia at a latitude of 40º N so I’m moving at a speed of 1071 kph. The image below illustrates this.
Your speed due to the Earth’s spin depends on your latitude.
This difference in velocities has a major effect on our weather and to see how let’s look at how a LOW pressure system behaves. Now I hope you remember that a low pressure system is also a storm system because it pulls in and condenses moisture laden air leading to rain and strong winds.
Looking at the image below we see that a super strong Low Pressure system is sitting right over me in Philadelphia. This low is so strong it’s pulling in air all the way from the equator and the north pole. Now as I said above Philadelphia is moving at 1071 kph and so is the air above it. The air at the equator is moving much faster however, 1666 kph so when it get pulled toward the low it misses, going in front of the low, to the east. The air at the pole however is moving much slower so it misses the low to the rear, the west. The result is a counter-clockwise flow of air around the low pressure system giving hurricanes and tornados their familiar spiral shape, see image of a hurricane below. That is why you often hear your local meteorologist, in the northern hemisphere, talk about storms having a counterclockwise motion while a fair weather system has a clockwise spin.
The mirror image of this happens in the southern hemisphere. The air from the equator still misses to the front of the low and the air from the pole misses to the rear but because the equator and pole have flipped positions, see image below, the low now has a clockwise flow. The very movements of the weather systems on Earth are due to our planet being a spinning globe.
Before I go I’ll mention one more example of the coriolis effect that you probably see several times a day, whenever you flush your toilet in fact. Think about it, isn’t all that water flowing out causing a low pressure system, and doesn’t the water spin counter-clockwise north of the equator and clockwise south of it. That’s the coriolis effect right inside your own home.
And you don’t have to be very far north or south of the equator to see the spinning. Click on the link below to be taken to a youtube video shot at the equator in Uganda. The presenter demonstrates the coriolis effect just a few feet north of, right on and a few feet south of the equator.
https://www.youtube.com/watch?v=_xqtXBnuXiA
So remember, the next time some you arguing with a flat Earth idiot just flush the toilet and tell them the spinning globe of the Earth is causing the spin in the water. Then you can flush their nonsense down the toilet as well.