Does Water Swirl the Other Way in the Southern Hemisphere?

The definitive answer about the direction water swirls in two hemispheres
Sync the videos yourself: http://toiletswirl.com

For the record Destin and I repeated the experiment 3-4 times each in each hemisphere and got the same results every time.

The idea that water going down a drain or flushed down a toilet swirls in opposite directions in the Northern and Southern Hemispheres has a long history. But few have ever done the experiment. Destin from Smarter Every Day and I performed identical experiments in the Northern and Southern hemispheres. What we found is the direction of water swirl in a toilet, sink, or bathtub is determined by other sources of angular momentum. However if the body of water is big enough, e.g. a kiddy pool, and left still for long enough (at least 24 hours), then the Coriolis effect is observable with water swirling counterclockwise in the Northern hemisphere and clockwise in the Southern hemisphere.

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Twitter: http://twitter.com/smartereveryday

Gordon McGladdery did all of the sound design for the video. We used two songs from other artists (licensed of course). Derek split the first one up so it fades from video to video, and Gordon split the instruments up on the second one. There are violins on one video and percussion on the other for example. It's really neat.

The neat earth animation at the beginning and the synchronizing timer was made by http://eisenfeuer.com/. He also made still images of the earth from the top and the bottom.

Thanks to Vanessa for filming in Sydney: http://youtube.com/braincraftvideo


There was a study performed at MIT years ago (http://web.mit.edu/hml/ncfmf/09VOR.pdf) that explained the physics involved. We repeated some of these demonstrations, but on opposite sides of the globe…and in a way that can be easily understood.
This site is a great resource on the Coriolis effect and ways people have gotten it wrong:

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Автор life-of-sci ( назад)
I was at the equator in Africa and they did a demonstration where they put water in a funnel with a narrow opening, they blocked the opening with their finger - placed a wooden match stick on top of the water then let the water drain from the funnel. When they were on the North side of the equator the match rotated one way (counter clockwise) and when they stepped about 1-2 feet on the other side of the equator the match rotated the other way (clockwise). They did it again while straddling the equator and the match stick did not rotate at all. Amazing!

That demonstration was amazing to me not only because of the rotation but because the actual equator is so narrow!

Автор Ender586 ( назад)
I am not convinced. If I had to guess, this was all just a coincidence. No matter how many times you try, if you are using the same-shaped pool (in a room with the same air flow, vibrations etc), it may always produce vortex of the same direction and still be completely unrelated to the Coriolis effect.

Автор Rod Fell ( назад)
This experiment seems fairly sloppy and I wouldn't consider its results to be definitive.

Автор That One Weirdo ( назад)
I would like to point out that, when a toilet flushes, it spews e-coli into the air. That is why I close the lid when done.

Автор shimmer ( назад)
is this a re-upload??

Автор Kevin Velez De Villa Mejia ( назад)
Noooooo!!!!! It's boring like this, it's alot alot alot more fun to get 2 phones or tablets and making it yourself lol 😂

Автор De'Ja Nickle ( назад)
Thx for syncing videos

Автор ssundee85 ( назад)
i live in huntsville al

Автор Landon Lovette ( назад)
Glad they showed the clip from Long Way Down where they did it on either side of the equator

Автор Yashas ( назад)
What if a hurricane moves from the southern hemisphere to the northern hemisphere?

Автор Herbert Ramirez ( назад)

Автор 1chumley1 ( назад)
I wanted to see a nut-filled turd in one of those toilets.

Автор Cameron Sipka ( назад)
this is amazing <3

Автор po k ( назад)
Only one pool in each hemisphere doesn't prove anything. Thought I was on science channel :p

Автор Michael Covington ( назад)
Piss green from the sci show can suck it

Автор MDFlight ( назад)
and they only needed to try this 10 times to get their desired outcome, pretty good tbh

Автор Jacob chamberlain ( назад)
What about at the equator?

Автор Ryu Vincent ( назад)
this video could probably be the most beautiful video on YouTube just because of how entertaining 2 guys try to explain simple science (rocket science being the not simple one)

Автор Chinese Communist Party ( назад)
recycled footage much?

Автор Joel Shore ( назад)
It's interesting to note that at the level of a tornado, which is considerably bigger than a bathtub but still pretty small on the scale of the Earth, about 95-98% are said to rotate cyclonically (counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere), but there is that small fraction of anti-cyclonic tornadoes.

Автор Bryce William ( назад)
I literally heard the explosion of a flat earthers brain.

Автор Naranbaatar ( назад)
tell me about what will happen in the equator

Автор jiří ledvinka ( назад)
What if huricane move from one hemisphere to another? Will it dissolve?

Автор Lamanite Flarpleston ( назад)
It bothers me that they only conducted this test once. There is a 25% chance that the clockwise and counterclockwise rotations were completely by luck.

Edit: I just read the description and realized that they did multiple trials.
Ignore me.
I'm stupid

Автор ArtStone ( назад)
Now hang a pendulum from the ceiling and put a circle of wooden pegs on the floor to knock over

Автор Antoon Veeve ( назад)
Thank you two guys for doing this.. excellent - myth busted!

Автор yuuge biggly ( назад)
i knew this years and years ago. just by thinking. i thought it was aways common knowledge that there are too many disturbances and eraddic forces/ turbulants in a toilet or sink to prove the corriolous effect

Автор ChaosN ( назад)
Flat earthers be like...

Автор Mathias Reschauer ( назад)
Have you heared about foucaults pendulum? it is tze complete same thing, just that its easier to measure it zhat way. I have seen one in the Deutsches Musdum in Munich. Fascinating.

Автор Old Time Farm Boy ( назад)
Actually, water, hurricanes, tornadoes, etcetera, all turn in the same direction no matter what hemisphere they are in. It only appears different because of the perspective that humans see them in each hemisphere.

The proof can be found using the index finger of each hand. Let your left index finger represent the northern hemisphere, point it down and rotate it counter-clockwise. Let your right index finger represent the southern hemisphere, point it down and rotate it clockwise.

Now slowly, while maintaining its clockwise rotation, turn your right hand so that your index finger is pointing upwards towards the index finger on your left hand so that it assumes the perspective of someone in the southern hemisphere looking at the rotation. At that point you will clearly see that both index fingers are turning in the same direction.

Rotation of water, winds, hurricanes, and tornadoes are determined by the earth's rotation in both hemispheres. They only appear different because of human perspective.

Автор Maj Mat ( назад)
You'll have to go to the north pole and try it,see if it just dumps the water "or some other liquid that won't freeze" without rotation .

Автор Deilson Peres ( назад)
But Earth is flat :/

Автор Joe Rogan Tribute ( назад)
Veritasium are you interested in a collab?

Автор Reyner Godoy ( назад)
thats obvious
that's just a point of reference
for example ( just an example i dont know what's the direction of the rotation )
if you go to the north pole you will see it *spinning left*
and if you got to the south pole you will see it *spinning right*

but if you go to the north pole again and somehow become able to see the south pole water, in your perspective it is *spinning left and not right*

Автор Kearvin Brix Alano ( назад)
SO its true that the earth isnt flat??

Автор valaram chaudhary ( назад)
this thing blown my mind

Автор Faris Kazim ( назад)
Flat earthers just passed out

Автор Michael Kamat ( назад)
Next time try to add the coloring before you unplug the pool

Автор THATONEBACCA33 ( назад)
so this raises one question, what happens if you have a pool spilt through the equator 50/50 and drain it like that

Автор Black Profile Picture ( назад)
proof flat-earthers are wrong

Автор Dejan Kober ( назад)
Just for good measure I would repeat this experiment few more times.

Автор Omare Abadi ( назад)
i love those videos <3!

Автор pippaknuckle ( назад)
So right at the equator there is no swirl?
I remember being near the equator and thinking that sinks drained slower there.

Автор sam hansen ( назад)
i dont understand why the water nearest eh ecuator has a larger velocity and momentum than the water nearest the poles....

can anyone explain it simply?

Автор Ebony Maree ( назад)
Stargazing Live Australia really could have used you, Derek.

Автор Lachlan Hillard ( назад)
1:50 I like how the American uses the metric system, yet the Australian uses the imperial system.

Автор Rabik R ( назад)
But Derek, earth is flat, your theory is invalid!

Автор Fender Ignacio ( назад)
Still cool after a year 😎

Автор K 6 ( назад)
Science is real...

Автор Jared D ( назад)
Then it stands to reason that along the equator there would be no preferential direction.

Автор Ayyy Lmfao ( назад)
These two fucked after

Автор Liam Strand ( назад)

Автор Filip Wessman ( назад)
It is about size. The bigger the pool, the bigger the Corriolis effect. If the pool gets to slow, other factors like micro currents, friction, air draft, the shape of the container etc will determine the rotational direction.

Автор Stephen Kramer ( назад)
What does it take to PROVE something that is extremely subtle and sensitive to the factors that affect it? hmmmmmmmmm... Or, instead, what does it take to make something happen that confirms your pre-existing belief (that you actually know nothing about) so you can be happy and gay and make money making other gay people happy and gay about their pre-existing beliefs (that they actually know nothing about) so they can be happy and gay and make other gay people happy and gay about their pre-existing beliefs (that they actually know nothing about) so they can be happy and gay and make other gay people happy and gay about their pre-existing beliefs (that they actually know nothing about) so they can be happy and gay and make other gay people happy and gay about their pre-existing beliefs (that they actually know nothing about) so they can be happy and gay and make other gay people happy and gay about their pre-existing beliefs (that they actually know nothing about) so they can be happy and gay and make other gay people happy and gay about their pre-existing beliefs (that they actually know nothing about) so they can be happy and gay and make other gay people happy and gay about their pre-existing beliefs (that they actually know nothing about) ...

Автор 5Zaft Mohd ( назад)
so what happens at the equator? it just falls down then?

Автор CHICKENFACE411 ( назад)
my toilet doesnt swirl it just drains and the water comes back out

Автор Frank Harr ( назад)
That was pretty awesome.

Автор Rajan Rangarajan ( назад)
Justin, derrick: why didn't you find some to do one more setup at equator at the exact same time?

Автор BubbleGuy92 ( назад)
I didn't realise that this was both videos synchronised, so I clicked the link in the description to do it myself.

Автор Lejon Van Rhee ( назад)
i love this vid

Автор Hans-Joachim Bierwirth ( назад)
But: If you view a photograph showing a flock of flatearthers made through a filter polarized clockwise on the northern hemisphere through a filter polarized counterclockwise on the southern hemisphere the flatearthers are gone!

Автор RoScFan ( назад)
so what happens if you put the kiddy pool right in the middle of the north or south pole? im not joking. This could be used to pinpoint the exact north/south pole to within a few hundreds of a milimeter. and it is something that should be done.

Автор JmmiP 20 ( назад)
2:06 "anti-clockwise"

Автор This guy ( назад)
It's not the same but if it's your only choice, it suffices.

Автор raju pittu ( назад)
True scientists...

Автор Ihab Karim ( назад)
can u help by telling if i rotates water in vertical clyinder ,,what would happend in high speed rpm

Автор Sol RT ( назад)
So much water wasted 🤔👎

Автор MorningCrafter ( назад)
You are wrong. The water still has a lot of momentum in it. Those tiny movements can snowball and create that whirl. You should have done more tests than one.

Автор Unknown Entity ( назад)
Don't ask the question you dingus. Just say it does. I can't even be bothered to watch.

Автор Spacemole ( назад)
I love how the American measured the pool in Meters and the Australian-Canadian measured it in Feet. Maybe the world is spinning backwards :D

but what if you drain it in the equator? will it drain sideways?

Автор Logan Luther ( назад)
So we just need a really big toilet to see it...

Автор Nathan Scott ( назад)
On the count of three everyone flush your toilet.....
1...... 2......

..3! Ahhh your not even at your toilet.

Автор Proletário ( назад)
thats insane

Автор Sgipon ( назад)
lmao! it's flat and unmovable. that's the truth

Автор diGritz1 ( назад)
Clearly another attempt by NASA to hide the truth about poopy swirling vortexes of death. WAKE UP SHEEPLE!

Автор upplsuckimcool16 ( назад)
if you try this exeriment precicely on the equator......... the water will explode.

Автор upplsuckimcool16 ( назад)
This is what I've hear as well, however, I always just thoguht it had to do with which way the jets in the toilt bowl shoot out....

Автор Marcus Ellis ( назад)
So what if half the pool is north of the equator and half is south of the equator?

Автор Barti ( назад)
I enjoyed it back then...Enjoy it now...awesome.

Автор Arnab Animesh Das ( назад)
Awesome speech sync. Gr8 vid as always.

Автор QueenDaisy ( назад)
Two data points isn't really sufficient to prove anything; let's say that the direction of draining was completely random, there'd be a 50-50 chance one would conclude (from only two data points) that water always drains in the same direction no matter which hemisphere one is in, and a 50% chance one would get a false positive result that the direction does depend on the hemisphere one is in even if it doesn't.

Автор BloodTar ( назад)
But I thought the earth was flat?

Автор mc vid's ( назад)
In England our toilets don't spin the water

Автор Ramazan Samat ( назад)
2 displays have better effect

Автор Alain ( назад)
3:19 Coriolis effect

Автор TheOriginalJoneser ( назад)
I have been subscribed to you BOTH of you, for Years, and this is one of the best collaborations of science on Youtube, EVER.

Автор GG2K7AU05 ( назад)
Please also do a video about the weight difference at places like Finland (closer to pole) vs places like Brazil (at the equator).

Автор Umberto Fournier ( назад)
so much science

Автор MineGAGGER ( назад)
If this were totally random there would be a 25% chance that you would get this result so the experiment isn't really proof.

Автор Master Of memez ( назад)
what about on the equator ( ͡o ͜ʖ ͡o)

Автор Toveri Juri ( назад)
Never thought that a video about toilet water would be this interesting...

Автор Alexander Provias ( назад)
*Question:* How big should an object be in order for us to see it if, theoretically, it's moving with the speed of light.

Автор TheRadical Gamer ( назад)
What if you're ON the equator?

Автор ironcityblue ( назад)

Автор pyroguyman096 ( назад)
Can hurricanes cross the equator as they are forming and swirling, and if so, what happens? Does it disperse, like stirring a pot of water and then immediately switching directions, or would it maybe split off into two masses swirling opposite one another?

Автор Pratik Patil ( назад)
+Veritasium Maybe you could do a video on the cooling of water in an earthen pot with infrared cameras and also a video on the wringing of the slip gauges ☺

Автор Christopher Lusher ( назад)
For fun, sometimes I convince a person that only specialized helicopters can fly across the equator. First, talk about the Coriolis effect on draining water. Then say something like, "Due to the Coriolis force, the aircraft must be equipped to instantly reverse blade rotation to continue flying." haha, see if you can do this with a straight face!

Автор givememore4free ( назад)
Thank God you did this video. It was really hard to sync the videos together.

Автор dfjshjkd ( назад)

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