People post their opposite assertions, some claim to have tested it with opposite results and no one posts any sources for their claims. Word against word. The Wikipedia, however, must cite sources and can be corrected by knowledgeable scientists. The Wikipedia asserts that the coriolis forces does have an effect, and would cause the water to spin counter-clockwise in the northern hemisphere, and clockwise in the southern.
On the other hand, these effects are so small that they will rarely make a difference in real world situations, such as your own sink or toilet.
People post their opposite assertions, some claim to have tested it with opposite results and noone post any sources for their claims. John Kellett, Melbourne, Australia Why assume that the water has to go down the plug to be affected? It is movement relative to the earth across its surface that is acted upon. When you pull the plug the water moves towards the centre of the planet. The south side of the vessel always moves faster than the north side up here in the north but it doesn't make the water spin.
Why would you imagine that it suddenly makes a difference if the plug is pulled? As others said, the coriolis only effects big areas including winds and hurricanes and such.
I've experimented to check if all my sinks and toilets spin in the same direction and they really don't. It's not that big of a deal anyway, because is doesn't change anybody's life if it goes clockwise or counter-clockwise. I just wanted to tell everyone what I know because I'm learning about the coriolis effect at school right now and my science teacher is amazing. It has moved in both directions. I was always under the impression that it only went one way Stewart, Grimsby, England I don't know how old this thread is, but it should be allowed to die and be buried for good!
Most viewpoints express opinions based on "reasonable" arguments and "plausible" observations of highly controlled events. Rest assured that the Coriolis Effect has been objectively isolated in laboratory conditions not tourist traps and shown to be very small compared to all other local forces in our lives.
It is properly called an "Effect" and not a force, as it occurs only as a result of the observer's circular motion. The reason we have these ridiculous, pseudo-scientific discussions is because rotational motion is counter-intuitive. It is extremely difficult to visualize or explain!
You should see the coordinate transformation equations for the motion of a particle on earth's surface! As a first indicator of what it means to live on a rotating earth, check out this MIT video: techtv. Douglas Murray, Wiarton Canada Typical Everyones an expert and everyone else is wrong.
A few points to add something to think about. This I believe we can all agree with. Now, lets look at it from the opposite perspective Hmmmm, it would appear as though our point is now traveling clockwise around the earths circumference Interesting, no. What forces at play? Just one? No, I think not. So why does the structure of our atmosphere change north and south of the equator?
Solely the effect of Coriolis and centrifugal forces? Keep asking questions. Keep getting answers Many many more questions to be asked, many more to be answered; so few with so many answers.
The internet has given birth to such arrogance. Back in the 80's, a show called Mr. Wizard the original before Ben Nye did an experiment around this. They did the basin in the USA and the spin was counter clockwise every time. Then the cool part was they got on a merry go round turning clockwise and did it again and it did spin clockwise every time. Don't know. Just weird. Maybe a question we will never have an answer to. The earth spins counter clockwise on the Northern hemisphere, but from someone living on the Southern hemisphere, it appears to spin clockwise turn a globe upside down to see this.
Objects not attached to the surface of the earth water in a sink going down a drain will create a vortex going the opposite direction. So in the Northern hemisphere, it moves clockwise. In the Southern hemisphere, it moves counter clockwise. On the equator, water goes straight down. It isn't alway that simple since the earth is not a perfect sphere, but that is the general idea. This is a basic explanation of the Coriolis Effect. There are several different experiments you can do to see the effect many are in video form on the internet.
Calvin Roberts, Detroit. US The Coriolis acceleration definitely has an effect - how large it is, I am not sure, but the longer it takes to drain, the larger the effect. You have water going down toward the center of the Earth, and the Earth spinning around the North Pole. The "cross product" of velocity with spin gives the Coriolis acceleration.
This is an acceleration, so it would take time to build up, and cannot overcome preexisting powerful momentum opposing it before the water exits via the drain, i.
Reid, Huntsville, AL USA Please tell me that all or most of the people that have added their 5 cents worth to the above are under 5 years old. If not, there is a major blockage in education in you area! Clash, Dunston, UK" I mean really, are you living on the surface of the earth or inside? I can confirm that playing snooker in Australia is the same as playing in the UK; the balls don't curve in different directions. Do you drink snooker balls?
Ever heard of Liquid, solid and gas? Guess which one water is. And by the way, if it is a scientific fact, then please show me to the uneducated, brainless scientist that proved that one! John Walker, Derby, UK" And you John, so you are saying that people in the South look at their watches from the back and in the North from the front, or vise verse or are you saying that watches turn the opposite way in the North and South?
What a retarded experiment!!! Everything that is measured on the earth is taken from the surface, looking at the surface and is measured for that particular area, not from above and below. Kirsty , Leeds, England" Kirsty girl, please don't become something that has anything to do with science or physics.
Maybe think on the lines of I don't know, housewife? Just e3liminate the problem of sink and plug hole issues and just pour the water people!! No one said anything about what happened to the water at the poles. I came into some money and, having nothing better to do, I took a cruise to Antartcia and managed to catch a ride to a camp very close to the South pole.
I took along a flat wash basin that had a hole and a rubber plug in it. I filled it about half full and took it outside so it would not be influenced by structural or gravitational fields of the buildings. I carefully pulled the plug and watched. Unfortunately the water froze before it could drain out so I guess this is why the effect is only seen at or near the equator. Land Waylamd, Chino. California ISA When you get drunk which way the room is spinning?
Seriously now, I think the water is just random, but is true for the tornados. The north hemisphere the tornados are spinning counter clockwise and on south hemisphere the tornados are turning clockwise. Dan the man, Bucharest Romania Unbelievable. The vortex only occurs when the water level is low so should in effect do the same to your half finished cup of tea. It doesn't because the force while exists is not strong enough.
People have talked of physics and shapes of bowl etc but nobody mentioned the real force of the waste pipe. Unromantic as it may be the swirl of a plug hole is simply due to the way the waste pipe is configured explaining the phonomenem of hand swirled sinks turning the other way. When you empty a bath there is no vortex as the pipe is full due to the pressure of the water. Only when the pressure reduces due to the volume of water does a swirl appear the direction of which depends on the shape of the pipe below.
Think not what you are told but what is physically happening otherwise you will end up stood on the equator listening to a charlatan with a bucket.
The effect of draining amplifies small movement as the water moves to the centre the same way a ballet dancer increases spin speed by putting arms in. Any chaotic system can be influenced by tiny changes, The butterfly effect.
Other effects such as basin shape may be larger but over a large number of tests on different set ups random factors should cancel out leaving any small consistant factor to show a measurable majority, or of course the most popular basin design could tip the balance. Steve Turner, Witham, Essex I have spent the last 15 years exploring this phenomena on a full time basis and I can now give the definitive answer.
Ideally one should consume a kebab prior to urination. I hope this answers the question once and for all. Baz l'hommedeleau, London UK Wow people, just wow. Some answers are way out there. Others are so convoluted that it's beyond reasoning. Only one person has come close to a logical answer to the apparent 'different' direction. Simple answer, the direction is the same, it's only the viewers point of observation that changes.
Anti-clockwise spin when viewed from the southern hemisphere, appears as a clockwise spin when viewed from the northern hemisphere. And guess what, vice versa applies regardless of the spin direction. Think about it, devise a simple test for yourself using you eyeline as the 'equator', test it for yourself, and prove to yourself it's simply your view perspective that 'changes' the direction, not the direction of spin suddenly stopping at the equator, and then miraculously reversing itself.
Paul Nankervis, Perth Australia I've studied this with many different tubs, kitchen sinks, bathroom sinks for many many hours with over a hundred tests and I concluded that what hemisphere you're in has nothing to do with the direction of the spin.
Joe Vortex, Montreal, Canada This is a common myth, and the previous comments settle it quite well. I only wish to add that the size or distance needed for Coriolis to have an noticeable effect is 10kms The Coriolis force tends to make things on the surface of the object to spiral a certain direction.
As the earth rotates, this motion causes everything on the surface to experience the Coriolis force, including the water in your sink. But, the Coriolis force is so weak that it doesn't really do anything until it acts on a lot of material. Your sink simply does not have enough water to be affected by the Coriolis force.
On the other hand, hurricanes usually spin counter-clockwise in the northern hemisphere and clockwise in the southern hemisphere because they have enough material to be affected by the Coriolis force, as detailed in the textbook " An Introduction of Dynamic Meteorology " by James R. Tornadoes are too small to be affected by the Coriolis force and spin in any direction. Reprints and Permissions. Whirlpools and Vortices. Nature , — Download citation. Published : 01 May Issue Date : 30 May Anyone you share the following link with will be able to read this content:.
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