Flushing out an equatorial fraud

By Phil Plait | March 27, 2012 11:00 am

On Twitter recently, I saw the following tweet:

[That tweet was from Minute Physics, a great channel on YouTube which does very short, informative, and fun animated physics videos.]

Intrigued, I clicked the link and watched this video. I describe it below. [You may have to refresh the page to get the video to load; if you see a blank spot beneath this then refresh.]

Amazing, right?

Not really. It’s totally bogus! And I’m happy to explain how.

Spinning the truth

Here’s the deal. The trick plays on the idea that people think water will drain (or flush in a toilet) one way north of the equator, and the other way south. Most people know hurricanes rotate one way (counterclockwise) in the north and the other (clockwise) in the south, so there’s some basis for this. The reason cyclones spin opposite ways in opposite hemispheres is due to the Coriolis effect, which I’ve explained in detail both on this blog and on my old website.

Read those explanations first if you’d like, but you don’t need to understand the Coriolis effect in detail here. All you need to know is that over the size of a water basin, the Coriolis force has no effect. I mean it: none. Any random eddy or movement of water in the basin is hugely more important than the teeny tiny effect of the rotating Earth on the basin.

Brain drain

So how does this work then?

Watch the guy working the ruse carefully. First he goes through a show of finding north, and locating the position of the Equator. This is all simply for show. As you’ll see in a second, this exact trick will work anywhere, not just on the Equator. I could do it in Boulder, at a latitude of 40° north!

He goes first to a basin on the Equator. It’s already filled, and the video jumped right before that, so I don’t know if he filled it right before draining it, or if it was sitting there for a while already filled. My guess is it had the water sitting for awhile — you’ll see why in a second. When he pulls out the plug the water drains straight down. OK.

He then grabs the basin and bucket and moves a few meters south. Watch very carefully what happens then: he pours the water from a bucket, making sure the water is flowing in to the left of the drain hole:

I’ve noted with an arrow where the plug is, and where he’s pouring the bucket.

When he does this, it sets up a natural clockwise spin to the water overall; it hits the back of the basin and will flow to the right from there. At least some of the people around him don’t notice this, though, since you can hear them talking excitedly about it.

Now watch again starting at 1:40 when he moves the basin to the north of the Equator. It’s hard to see, but you do very certainly see him pouring the water to the right of the drain hole:

See? That naturally sets up a counterclockwise rotation to the water! It has nothing to do with where the basin is; if he swapped the two locations but still poured to either side of the drain hole, the water would do exactly the same thing!

As for the water in the basin on the Equator, that’s why I think it was sitting for awhile first: he probably filled it carefully so there was no circular motion of the water. That way, when it drains, it drains straight down.

Flushed away

One thing I want to point out here: that guy knows exactly what he’s doing. He has to, to make it work. So at the very least, this is a trick. If he’s asking for money, though, and not explaining it, then in my opinion it’s just plain old fraud. Of course it’s not like he’s the first guy to take advantage of tourists! Caveat emptor, of course. But then, caveat venditor, too. Because there are folks like me who are fond of lux et veritas*.

My point is simply this: it’s easy to fool people, and it’s really easy to fool them if they already have some vague knowledge of how things are "supposed" to be. By coincidence, my friend James Randi wrote about this very topic for Wired magazine recently. It’s worth a read.

I’ll note — speaking of separating people from their money — that I have a whole chapter in my book Bad Astronomy debunking exactly this type of thing, though the person in the example I used had a slightly different technique.

But the bottom line is this: for hurricanes and shooting cannon and launching missiles, yeah, the Coriolis effect is important. For draining sinks and flushing toilets, though, it’s all a matter of spin.

Tip o’ the cyclone to Minute Physics.

* I’ll note, in the interest of full disclosure, that several people in the comments to the video debunk the method very well. however, I did not look at the comments before watching the video. In fact, the moment he picked up the basin the first time, my immediate thought was "He’s going to pour the water to the side of the drain!" So I didn’t cheat here. And hey! Would I lie to you?


Comments (51)

Links to this Post

  1. Coriolis Effect or Fraud? | CuleScience | March 27, 2012
  1. Rick J

    Cool explanation…thanks!

  2. Brian

    Can one of the more educated readers here enlighten the rest of us as to what is being said at the beginning of the video?

  3. JJ

    Perhaps more importantly, note his use of the leaves to get the motion he wants.

    In the “no vortex” case, the leaves are already in the water and he doesn’t touch them, for fear of getting enough coherent motion to start a vortex. In the last two cases, he tosses a couple leaves in the direction he wants to water to funnel down. In addition to the way he initially pours the water, these leaves appear too small to make a difference but really help get the bulk motion of the fluid going.

  4. Anonymosity

    I’m new in town, and I believe you Phil! Where do I send the money?

  5. Chris

    I think your use of the term fraud might be a bit too strong here. Those countries around the equator aren’t known for being economic powerhouses and many of the people living there are just trying to earn a living and I doubt most have even a high school education. So he gets $5 or $10 from some tourists passing through for what is essentially a magic trick. Now it would be nice if he would give a detailed explanation of the Coriolis effect and the fact that even though they traveled all this way, except for the GPS going between N and S, not much is really different. But if he did that, he’d be out of a job pretty soon. He has to put on a little show and get a few bucks from some gullible tourists, I’m OK with that. What we should be focusing on is the failure of the educational system which makes people fall for this trick.

  6. The Coriolis effect is very small and that is why it is apparent in large phenomena like tornados and hurricanes, but does not show up in small things like dust devils and sinks. Air currents alone need to settle for about a week in order to not influence the flow, assuming that no new currents are introduced.
    The amount of Coriolis effect a couple of steps away from the equator is so close to zero that this can only be a trick, as you have pointed out. Notice there is a swirl in the leaf at the equator, but he quickly tries to hide the moving leaf.
    He should set up Foucault Pendulums in these two spots and really bore the socks off of everyone.

  7. Frabjus


    I keep wondering about why people include the flushing of a toilet in this discussion. Toilets don’t just shoot water straight into the bowl. They are designed to spin the water into the bowl, as that’s the most effective way of transporting the contents down the drain. Yes?


  8. Daniel J. Andrews

    My grade 11 geography teacher told us that water would flow the opposite direction in the s. hemisphere. He was on a ship heading south, he said. He and his pals made a bet with other passengers that the water would flow the other direction once they crossed the equator. Once they crossed, they flushed the toilet but the water went the same way as before (“because we were only just across the equator”). A few days later, it started going the other direction and they collected their money.

    It wasn’t till I was in my early 20s that I began to figure out he’d probably been embellishing that story. He used to do a lot of work in the Arctic and Antarctic and points in between before he became a teacher. He would use his slides to add to the lectures. Even the other teachers were slightly in awe of him and would tell stories of his feats of strength and agility shown on field trips where he would spot something interesting and scale cliffs barehanded or crawl down into caves. He must have been mid-40s at the time yet would easily outlast the younger teachers. I can forgive him for embellishing that story—he was one of the rare teachers who inspires students.

    I saw him again two years ago. Still looks alert although nearing 90, and still has the bright orange wig (he lost all his facial and head hair when he almost froze to death in the Arctic–so the other other teachers told us). He drove his motorized wheelchair at high speed through the mall, pedestrians scattering to the side as he hummed along. It was a bit sad to see someone who once was so active now in a wheelchair, but the way he weaved around (and through) pedestrian groups made me smile–people still couldn’t keep up with him. I would have dearly wished to speak to him and thank him for inspiring me to take the pathway I did, but he had zipped by and gone before I could call his name. An amazing person. Great story teller. Best teacher ever.

  9. Didn’t Michael Palin show a similar huckster in “Pole to Pole”?

  10. Timmy

    Well there goes that myth down the drain! Now I want to watch that episode of The Simpsons where Bart gets kicked out of Australia.

  11. Alex

    Wow! I actually visited this very spot last October and was amazed by this trick. I am actually kind of sad to see that it isn’t true.

    For background: this is one of two paid tourist traps on the Equator near Quito, Ecuador. The first is a huge monument, built before GPS, that it turns out was a few hundred meters away from the real Equator. Oops. This museum is actually on the Equator as calculated by GPS. Hundreds of tourists pass through (and pay the $2 admission fee) every day. They also have other “tricks” that you “can only do” on the Equator, though now that I have seen this, I am skeptical…

  12. Dr.Sid

    Brian: he just says hello, we’re in city blabla (didn’t catch) in Equator, and we are now going to look at the equator, the line of equator. That’s all, nothing fancy ..

  13. Mike Torr

    @8 John, I seem to remember that Palin was taken in at first, unfortunately! But to be honest, I’m not sure I wouldn’t have been fooled as well, in those days – my knowledge and critical thinking skills have improved since.

  14. todor

    @ Brian. He says:
    Hello. We’re in Quito, the capital of Ecuador. We’re going to catch a trolley bus and go to the bus station where we’ll get on a bus which will drive us to the equator to see the equator line.

  15. hudasx

    I’ve lived in both hemispheres, and I’ve also gotten tired of correcting people about this. FYI, most new toilets in Australia don’t even swirl. The water just tends to fall in, as they are designed to use less water per flush than typical toilets in North America.

  16. I remember a spot in Kenya where they do a very simmilar trick, except the “sink” is already filled, and a guy holds it in his hands. What he does then is walk north of the equator, turns around to face the audience, pulls the plug, and viola it drains counterclockwise. Then he repeats it by starting at the equator, moves south, turns to face the audience and pulls the plug, and voila, it drains clockwise.

    Of course, it has nothing to do with the direction he turned to face the audience. 😉

  17. I was at this place just last October. It is located about an hour north of Quito, Ecuador.

    The guide I had did the same experiment with the water basin and they also do egg balancing and other gimmicks.

    Right after she did the water trick I knew what she was doing and I called her on it. She (very quickly) fessed up and said it was just a demonstration. She said nothing about it being a demonstration, however, during the demonstration.

    Also, it should be noted that I’m not entirely sure that what they have labeled as the equator is actually the equator.

    There is large 100-year old monument nearby which was erected by a French survey team who marked the equator in the 19th Century. They were pretty close considering the tools they were using, but they were off by about 100m.

    I took out my iPhone and pulled up the GPS app I had installed and tried to get a lock on where 0°.00.0000 was located.

    According to my GPS, it was actually located where the driveway to the facility met the road, which was probably 30m north of where they do the demonstration.

    The GPS claimed an accuracy of 5m. Here is the screenshot I took: http://travelphotos.everything-everywhere.com/photos/i-W3FtPjc/0/L/i-W3FtPjc-L.jpg

  18. I tried to explain this to my family a few years ago, after watching the Michael Palin episode – and got laughed at when I said that water has a certain amount of “memory” as to how it was poured into the bowl, in the form of residual circular motion. I was NOT referring to the so-called “water memory” that homeopathists claim enables water to “remember” what was dissolved into it, which is utter nonsense. Funny how certain members of my own family (who will remain nameless) laughed at me for trying to explain this simple trick, but at the same time think homeopathy is a real phenomenon.

  19. VinceRN

    It always amazes me that so many people, probably most people, fall for this. It’s especially ridiculous that school teachers, even science teachers, tell kids this.

  20. jem

    Elwood, if only you had said momentum, because you were of course correct. Someone better than me at fluid mechanics could probably even work out how long it takes for the viscosity of the water to damp out the momentum and hence how long he needs to let the first basin sit there before pulling the plug.

  21. Worlebird

    #5 Chris – “But if he did that, he’d be out of a job pretty soon. He has to put on a little show and get a few bucks from some gullible tourists, I’m OK with that.”

    So it’s ok for poor people to lie to tourists for money because they are poor? Rich people lying for money is fraud, but poor people lying for money is just business? Does that apply to all moral behavior, or do you have an imaginary line drawn somewhere? Perhaps your rule of thumb is “poor people can do anything for money, as long as they don’t kill anyone”? Or maybe it’s just something as simple as “poor people can do anything for money, as long as it’s something I can feel superior for not falling for”?

  22. Chris

    @ 22 Worlebird

    I don’t have a specific cutoff when you earn too much and become a fraudster. All I was saying was to look at the context of where this was occurring. He is essentially performing a magic trick. In my opinion it’s no different than having the kids sit on Santa’s lap. You get a few nice memories and you help out someone less fortunate with your donation. Even though that person is not the real Santa so he is essentially committing identity theft and (spoiler alert) there is no Santa, so it is fraudulent. It’s fine to let everyone know how the magician does his tricks, but don’t so easily demonize them till you’ve walked in their shoes.

  23. Number 6

    @Worlebird….I agree both are wrong, but when rich people lie or take advantage it’s more revolting, because they already have more than enough, yet they want more….in other words, they are greedy. Yet, if someone does this because it puts food on the table for his family especially if it’s the only way he can get food on the table for them, I don’t get all that bent out of shape over it.

  24. MadScientist

    Ah, an age old trick which had been debunked numerous times before. I think Randi mentions it in one of his books. It’s a great scam – most of the time it’s performed pretty far from the equator and yet the dodos who flock to see it don’t seem to notice. I remember experimenting with water swirling down the sink when I was about 8; I noticed that sometimes it went straight down and sometimes it swirled one way or the other – I played around until I could get it to swirl whichever way I wanted. If you’re carrying the tub you don’t even need to pour in the water from any particular direction – you can leave the water sitting there; all you have to do is turn to your right or turn to your left and this imparts enough motion to the water (thanks to friction with the container – so this will even work for round bowls, not just rectangular sinks) to make the vortex swirl in the desired direction.

  25. Maria

    @22 Eh… It’s an act. Entertainment. I think the comparison to a ‘magic trick’ or a ‘street act’ is a lot more apt then saying this is fraud. It’s like doing the find the ball under the cup trick. The definition has little to do with poverty or richness.

    I guess there’s fraud (this, tricks, stories) and then there’s Fraud (Madoff, election rigging, prescription pad printing). Like fraud, tricks fail or succeed on information the mark, or audience, doesn’t have. But, isn’t calling street acts ‘fraud’ a bit hyperbolic?

    Tourists pay to be entertained for a few minutes.

    I give the dude doing a one man band skit my change because he’s entertaining me, not because I believe he’s actually 5 different people playing 5 instruments.
    The “magical gypsy” band gets my money because they cut a decent rug, not because I believe they are magical gypsies.
    The Elvis impersonator gets a few bucks because they do a mean lip curl, not because I think they are The King.
    A mime gets my money because he does a great box skit, not because I think he’s really trapped in an invisible box.

    Ok no, never mind, I don’t give money to mimes.

  26. @Maria and others regarding fraud. A magician does not actually claim he is using supernatural forces and everyone in the audience knows it’s just a neat trick.

    In this case the fraud is convincing people of something he knows to be untrue in order to take their money. The very definition of fraud.

    It’s more akin to three card Monte, the mark is being tricked out of money, not paying to be entertained.

  27. JB of Brisbane

    @Alex #11 and others questioning the actual location of the Equator in this instance –
    A bit off topic, but related – the spire marking the Tropic of Capricorn in Rockhampton, Queensland, Australia is located about three kilometres north of the actual Tropic. There was a marker in the correct location on the old Bruce Highway, but both the road and railway into Rockhampton were deviated in the 1980s, and I guess the government department concerned didn’t want a traffic snarl 3km out of town from tourists getting photos there, so they moved the spire and part of the marker to the Tourist Info Centre at the southern end of town. I think that almost qualifies as fraud.

  28. Brian Too

    The funny thing is, imagine this demonstration being performed with accurate information. People would still pay! Show them how the incorrectly described demo is wrong, let the tourists interact with it. The tourists still get a show, they still see something interesting, and they learn a little something.

    I’ve seen these kinds of setups before. A good guide can earn a nice living and gain the trust of the people in his/her care. A very good guide, you remember for a long time.

  29. Steve D

    The reason toilets spin is because they’re engineered to do so – the water comes in from the side. I can explain why we want the water to spin as graphically as you like. But the toilet will spin the same way anywhere on Earth.

    My wife saw a similar gimmick in Uganda, complete with spirals painted in the basins.

    The Tropics actually move, by about 10m a year, because the earth’s axis tilt oscillates by +/- a degree in a 40,000 year cycle. Right now the tilt is decreasing and will decrease to 22-1/2 degrees before increasing again in 10,000 years. So there are all sorts of tropic monuments that were accurately placed but are off now. A degree is about 110 km or over 60 miles, so the discrepancy can get to be pretty big.

  30. Maria

    @27 VinceRN I don’t know…. I’m still not convinced one could call this fraud. Even if the guide was being paid to show the trick to the group.

    Three Card Monte itself isn’t actually fraud either, the act of taking bets and involving shills to fleece a mark is fraud. The card trick itself is just an extremely old “stage magic” trick, a staple of traveling showmen and con artists alike; it’s included in most magic books. Stage magic tricks are either confidence or misdirection tricks. They are illusions in direct partnership with the audience and the magician usually doesn’t step back after and explain the trick to the audience.

    What this guy seems to be engaging in is illusion or maybe even theater? He’s not saying it’s supernatural magic or forces. And he’s not taking bets like in many card/cup tricks. At most he’s playing a misdirection trick, both physical (the set up and process) and mental (knowledge gaps and preconceptions / assumptions). All in all, it IS a rather silly one.

    @29 Yeah. It’s funny isn’t it. You’re right it wouldn’t be that hard to make a demo that’s educational and memorable while debunking the whole swirling water myth.

    Missed opportunities and all that.

  31. Infinite123Lifer

    So…Santa is not at the North Pole?

    And really? 0• 00.0001′ N? I think this implies that the equator is unattainable on a small scale.

  32. Daniel Speyer

    I’ve been there. Yes, the water is left sitting a long time before the demonstration.

  33. Georg

    Just a remark on the “no rotation” on equator.
    This is the main trick, because even on equator
    the water will start a swirl, given enough time and/or
    the right proportions of the basin.
    In this case the basin is rather flat, thus there
    will be more friction in the water.
    This results in less rotation or longer time until the swirl
    Some swirl (either left or right 1:1 statistically)
    always will develop.

  34. James

    Also worth pointing out that the Coriolis effect is miniscule (relatively) any small distance from the equator anyway (as should be obvious, since it is actually zero precisely on the equator).

  35. Nigel Depledge

    John W Kennedy (9) said:

    Didn’t Michael Palin show a similar huckster in “Pole to Pole”?

    Yes, but Palin fell for it hook, line and sinker. He’s a comedian / writer / comic actor, not a scientist.

  36. Nigel Depledge

    This makes me want to go there and paddle in the “on the equator” bowl . . .

  37. Werner

    For those having trouble picturing how big (small) the corriolis effect is on small bodies of water, imagine holding a bucket full of water in front of you and spinning around. Make sure each revolution takes 24 hours. How much does that make the water in the bucket swirl??? It doesn’t, I hear you say. Too right. No effect other than sore arms.

  38. What you CAN see in your (kitcen) sink, though, is a really neat depiction of a standing shockwave, similar to what happens at the heliopause of our solar system. Run the water onto a relatively flat part of the sink, and you’ll see a region around the point of impact where there is only a thin layer of water, with a shockwave surrounding it and then a region with more, but gradually decreasing water. The point of impact is like the sun, the region with the thin layer of water is the solar system and the solar wind, and the shockwave is the heliopause. Pretty cool for just running water, eh?!

  39. K

    When I moved from the US to South Africa I was disappointed to see that the water still went clockwise. The Simpsons & my high school science teachers had lied.

  40. Ben

    I think it’s worthwhile to point out, that this little trick is about 3 minutes worth of a 45 minute guided tour that has a whole heap of information on the Amazon, the tribes there, the history of Ecuador, use of sun dials, etc etc. It costs about $2 (from memory) for entry and the guided tour.

    Taking money by trickery? Not so much

  41. blagos

    Actually, it is possible to show the effect of Coriolis force in an experiment like this (but not this experiment), and it has been done before. First, performing the test at the equator is out — this minimizes the effect of the force. You need to be much further north and south. Second, you need a tub that is vibrationally isolated to eliminate the effects of induced currents. Third, you need as large a tub as possible to further produce stability (I don’t see how the amount of water in the tub would in theory affect the test) Forth, you need to develop a method of openning the drain that does not induce a favored direction for the water flow/rotation. Fifth,, you need to run the experiment many, many times (like a thousand). The Coriolis effect will show up as a statistically meaningful difference between the number of times the water rotates in one direction other than the other.

  42. blagos

    . . .And, KSays, I loved that Simpsons episode. Especially that part when Homer flushes the specially equipt toilet and the water rotates counterclockwise, bringing a tear to his eye as he sings the Star Spangled Banner.

  43. DennyMo

    As a tourist in many places around the world, I’ve been lied to so many times by locals that I pretty much expect it now. Anywhere there’s a concentration of “rich” tourists, some local shill will prey upon their ignorance and/or generosity. It’s not a big deal, and if you go in to the encounter armed with this assumption you’ll be entertained instead of cheated.

    If I were in the audience at this particular demonstration, I’d enhance the show for the guy. I’d pull out my Droid with a sufficiently techy-looking-and-sounding app, pass my new “anti-graviton emitter” over the tub, then demonstrate how I’d temporarily reversed the Coriolis effect…

  44. There is another reason this change in swirl direction is rigged. The Earth’s axis is not fixed. It exhibits a wandering motion known as Chandler’s Wobble in which the axis moves a few meters from time to time at the poles. This has been well documented at the South Pole. It would seem that the equator would move the same way. When the equator is painted on the ground it may or may not be accurate. The corollary of this change in swirl direction is that, if true, it could be used as a surveying tool to locate the equator. Tourists being fleeced by the locals? So what? That is what tourists are for.

  45. Joe

    Ah, for the good old days (1962) when you could get a letter into Nature publishing almost this exact result: http://www.nature.com/nature/journal/v196/n4859/pdf/1961080b0.pdf

    It turns out that a broad (~2 m) shallow pan, when stilled for 24 hours in a temperature stable room, will reliably experience a slight, but measurable coriolis force on the drain direction.

  46. mike burkhart

    May be the guy should be on stage ,this is what slight of hand magic is all about ( as Phils friend James Randi can tell you ) . about the desk top project on my computer I have a picture of the Hubel Deep feild as my wall paper .

  47. icemith

    I wonder what the effect would be at the (exact) North or South Pole? I’m talking about the Coroilis Effect, not the so-called clockwise/anti-clockwise flow of small bowls of water, or any other fluid, draining out.

    I guess keeping the water from freezing would be an added problem, but then even Glaciers DO flow, and are forced to “swirl”. It may not happen over night, but………………..?


  48. To entertain people at a wine tasting, demonstrate the direction of the Coreolis Effect by having people use both hands to rotate wine in opposite directions. One direction will be much easier to accomplish, and that direction will probably be common to everyone in the group. The direction more difficult for everyone can be concluded to be so due to being opposite the Coreolis Effect.

    What seems to be actually happening is a combination of coincidences. The biomechanics of our arms, hands and muscles, being left and right and not symmetric, do simply seem to be better suited for opposite rotation in opposite hands. As for agreement that one is easier than the other, the vast majority of people are right-handed, so doing anything with that hand will be more coordinated and feel more natural. When a left-handed person turns up, they can be concluded to be “over powering” the weak Coreolis effect that everyone else clearly identifies. Few people actually know which way the Coreolis effect makes things rotate, so it’s not every time that people will notice that what appears on the surface to be a simple process of experimentation and observation actually yields exactly the wrong result in the Northern Hemisphere (counterclockwise in the dominant right hand, clockwise in the left).

    Performing this “test’ In the Southern Hemisphere, where the group’s conclusion matches the direction of Coreolis-induced cyclonic rotation, and you’ll have even the most dedicated skeptics scratching their heads as to what’s going on to produce a correct result in a random group of people. Like the Equator-pouring example, a test performed a certain way can repeatably yield a correct result for the wrong reasons.

  49. Ignore what I said about the hemispheres and cyclonic rotational direction. According to Wikipedia:
    “In the Northern Hemisphere the direction of movement around a low-pressure area is anticlockwise. In the Southern Hemisphere, the direction of movement is clockwise because the rotational dynamics is a mirror image there. At high altitudes, outward-spreading air rotates in the opposite direction.”
    I was thrown off by the opposite depicted direction of the directional circles drawn in the globe graphic captioned, “Schematic representation of inertial circles of air masses in the absence of other forces, calculated for a wind speed of approximately 50 to 70 m/s.”

  50. Goldie

    Shapiro, Ascher H. (1962). “Bath-Tub Vortex”. Nature 196 (4859): 1080. Bibcode 1962Natur.196.1080S.

    Effect can be reproduced under lab controlled conditions. But not on small scale.


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!


See More

Collapse bottom bar