The Truth About Toilet Swirl - Northern Hemisphere

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Some notes about this.
We each repeated the experiment 3 times, and got the same results every time. For those of you who might be skeptical, great! The good news is that right circularly prismatic kiddie pools are only $10 and you can do the experiment for yourself at your latitude. There's really no reason you shouldn't do this on your own, so before you criticize how we've done it, I'd strongly encourage you to do it for yourself.

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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 He also made still images of the earth from the top and the bottom.

Thanks to Jacob Vehrs for helping make the plywood pool platform.


There was a study performed at MIT years ago ( 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:

The Coriolis Effect influences the flight of a bullet.

We would love for someone to replicate this demonstration. Please tweet your results to us @SmarterEveryDay and @Veritasium.
Here's the link to puchase the exact same pool:

Tweet ideas to me @SmarterEveryDay

The thought is it will help educate the world as a whole, and one day generate enough revenue to pay for the kids' education. Until then if you appreciate what you've learned in this video and the effort that went in to it, please SHARE THE VIDEO!

If you REALLY liked it, feel free to pitch a few dollars towards their college fund by clicking here:

Warm Regards,


Views: 2392189
Runtime: 8:2
Comments: 5632

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Author Brian Smith ( ago)
what happens with the swirl on the equator or poles?

Author Zephree Zen Gold ( ago)
my comment is on veritassium

Author Farinhir ( ago)
Was already subscribed to you. Vertitasium got my subscription today. Like his name. Guessing it indicates something to do with truth.

Ah, I see in the video. An element of truth. Glad i figured out at least some of it.

Author Ethan Patane ( ago)
I experienced the change in flow rotation direction in real life. I went to the galapagos, but first stopped in Ecuador, where I went to the equator. The tour had a portable sink with him that had a removable plug in the bottom of it. He put the plug in, filled it up with water, and moved it perhaps a yard to the left of the equator. As the water drained, it spun clockwise. After it drained, he filled it back up and moved it one yard to the RIGHT of the equator. Sure enough, the water spun counterclockwise. But that's not the best part. He then filled it back up and drained it right on top of the equator. This time, when the water drained, it didn't spin AT ALL. It was really incredible!

Author ShadyNinjaGaming ( ago)
brilliantly made
Getting Smarter -(other vid)

Author Ajuran ( ago)
i thougth the earth was flat

Author Hunter McFarland ( ago)
i live there

Author bernardakoito ( ago)
snipers knew about this for a long time

Author Koenshakuable ( ago)
(cont'd from the other channel).. feeqin awesome!!!

Author Kwong Lung Ching ( ago)
Will you do the same experiment at the equator?

Author Emma ( ago)
That was so cool!

Author HOPEFOR TRUTH ( ago)
absolute nonsense the world is flat there is zero measurable curvature. vast bodies of water cannot conform to the outside of a shape in reality. water always finds level

Author Z_E_D ( ago)
Awsome Double video experience! The timing can't have been easy! =)
Great job! and fun to learn

Author shaheen eagle ( ago)
Well after watching like 20 videos you now have earned my subscription. congrats.👌👌👌👍👍👍

Author Max Davis ( ago)
I kept watching both videos at the same time when the synchronization ended...

Author Muhammad Zaidan ( ago)
squatting toilet> sitting toilet

Author Jørund Eldøy ( ago)
This explains stuff, not the swirling effect, but why the video was weird when i saw it two years ago.

Author Ananthan S Menon ( ago)
the second half of

Author The Porcupine ( ago)
if I drain my bath tub and start turning the water the other way with my finger it always ends up gowing the right way in the end.

Author Cakeman ( ago)
that was so cool when played side by side!

Author Ryo Ryo ( ago)
this video is creative...

Author Siberian Orange ( ago)
Wow! The whole synced videos thing was amazing!!! Hope that idea catches on!! Great job guys!

Author Alexandra M. Firebaugh ( ago)
But why do the actual major ocean currents and hurricanes rotate clockwise in the northern hemisphere, and vice versa for the southern hemisphere?....

Author Sam Peterson ( ago)
I love what you guy's did with this video!!!! So smart and awesome! I've been subscribed to both of your channels for some time now... glad to see two of my most entertaining choices working together.😁 thanks guys!

Author lol 231 ( ago)
awesome video

Author mac steven de villa ( ago)
what happens when a hurricane from the nothern hemisphere cross the equator?

Author Антон Леднёв ( ago)
You should make 100 attempts for clear experiment. ^_^

Author Ya Mi ( ago)

Author amateur gamer ( ago)
Children in African could have drank that water.

Author spawnage17 ( ago)
200,000 more people have watched Destin's video than Derek's video. This means that 200,000 people had no idea what was going on.

These two videos were so freaking cool.

Author CVE ( ago)
its the constellation of heaven/clouds, moon and the sun rotation that's causing it not the earth rotating....

Author Mahbub notoshu ( ago)
what is this science people were so pridefully competitive about...??

Author Anodos Arcade ( ago)
What happens if you drain it upside-down

Author Benjamin Hershey ( ago)
Protip: put Destin on the left and Derek on the right for proper orientation.

Author ERA ( ago)
its funny now people make big deals about small things like which way the water swirls xD Why does it matter which way it goes down? Just be gratefully that it actually goes down!

Author mian fazle razik ( ago)
I saw the video on both channels

Author Daniel Auen ( ago)
How about perfectly on the equator?

Author Mr Delaney ( ago)
Ecclesiastes 1:6 " The wind blows to the south and turns to the north; round and round it goes."

I love that you put bible verses at the end of your video

Author Omid Ganjavi ( ago)
The way he was sticking his face in the toilet was disturbing...,

Author Carmine Griego ( ago)
notice he put the water in clock wise thats so it would go clock wise this whole water thing is just a wives tail its just a myth its fake

Author ToastyRoland ( ago)
Sync these videos up.. it is extremely worth it. Cheers.

Author Cthulu Muramasa ( ago)
Haven't seen the vid but I know it's the coriolis effect

Author Michael Green ( ago)
Like this so Smarterevry day to awnser this!!

Whats the song that was playing durning to kitty pool?!

Author Everybody90 ( ago)
the other side

Author Snakezombie ( ago)
i told my friend on skype that lives in the northern hemesphere to screen share sync this up and it became wierd

Author RegularBrady ( ago)
Loved the syncing of the videos, super fun!!!

Author Rrroonald Weasly ( ago)
Perfect sync, first try. MVP.

Author instrumentalmane14 ( ago)
Who else got dizzy at 4:33

Author Antony Theriault ( ago)
Really cool videos guys, but geez do you not realize how hard it can be to sync two videos on the same computer?

Author Simon Ruszczak ( ago)
Wrong, the direction depends on the drain.

Dumbereveryday !

Author dilen noris ( ago)
Fake news.

Author The all knowing sause ( ago)
I am using my phone... can someone re upload this with it synchronized

Author Crazy Izzy ( ago)
So unfair I only have a phone to watch on

Author koplerio ( ago)
Sucks If I'm not able to make both go the same time. (southern Hemisphere)

Author Rohan N ( ago)
hey wait what about the equator??

Author CRaSHeCLiPs ( ago)

Author Johannes Kunder ( ago)
The syncro was awsome!
Pleasanton give us more!

Author Darth Chop ( ago)
YES! Thank you!

Author Mate Rodić ( ago)
soo cool

Author mattp1482 ( ago)
I think you should go to the southern hemisphere and do it again.. that would be proof

Author Dartnix ( ago)
One of the best ideas I've seen on youtube and very well put together!

Author Screaming Match ( ago)
Ya'll did great!

Author RCStormOrb ( ago)
When you get the timing right first time and the videos in the right order ... YEAHAHAHAHAA

Author Dj2xP ( ago)
Hahaha, I have a dual screen setup so synching these was not hard, but I chose to put Veritasium's video on my left screen, which broke the immersion at the end :D

Author Barnaby Jones ( ago)
This is one of the best uses I have ever had for my second monitor :)

Author anonymous bosh ( ago)
This could be faked or it could be coincidence. Either way it's an utterly ridiculous way to try to prove something that is theoretically true but in practice has been shown at least twice by universities with far more resources and patience than you to be impossible to prove or disprove on anywhere close to such a tiny scale. Attempting to do so using loose plastic kiddies pools in any old room is not only laughable but now casts serious doubt on your ability to inform us of anything with any certainty at all. Well done.

Author Oscar Jeans ( ago)
waiittt.... how does video have 200,000 more views?? but 1000 less likes?...

Author Evan Tee ( ago)
Watched this with dual monitor one video on each. pretty cool idea

Author WheatWormStudios ( ago)
Too bad you made a video without doing any research. A toilet isn't big enough to be effected by by your made up effect and that has been documented. It has everything to do with the design of your toilet. Fail

Author Wynand Henderson ( ago)
Very cool experiment, but I would like you to at least test 3 times at the same place and replacing the nozzle at the bottom.

Author Bron Cinzah ( ago)
If you understand this video i think you

Author Seán Mercier ( ago)
Hey guys, wanted to say I've been watching both of your channels for a while now and just stumbled across this. Being from a Video making background, I found this synchronised fusion really exciting on top of your usual high quality content. Thanks for doing what you do!

Author williamstdog9 ( ago)
Awesome vid(s) bro(s)!

Author DR. NEO ( ago)
the sync was amazing

Author littleratblue ( ago)
If all the variables weren't cleared (and, given that one of the kiddie pools was outdoors, I'm finding that unlikely) and the results were random, then with only a single test case, there was still a 25% chance that you would get this result. You would really need to repeat it a few more times to call it science. (Though it is reasonable to think that the end result would prove the Coriolis effect).

Author Vincent Paul ( ago)
I synchronized the video and it was very interesting.

Author sranjesuper ( ago)
So u did this experiment in one hemisphere and ONE time to prove this is real? Do this experiment 50 times and if all 50 times the water goes the same way, then you may have proved something. Then change the pool size, and plug size and do it 50 times again. Then you may have proved it 100% You usually post good videos, but this is very very inconclusive

Author Will Bowie ( ago)
What if this was done on the equator

Author smoothy hack ( ago)
how about a pool on the equator. no spin?

Author sir FARTSalot ( ago)
Hey Destin,stin, i have something to say, at work every now and then I have to drain a sump of water and I've drained it onto concrete and then it goes down the concrete drain but when it goes down it goes anti clockwise but I am in Karratha Western Australia can you explain this thanks

Author KWSNinja ( ago)
Wrong. The Coriolis effect is not nearly strong enough to affect small kiddie pools. If it works on that sort of scale, hurricanes would be going over Mach 5. It depends which way the water is flowing, along with other microscopic interferences.

Author Death_Kenny ( ago)
Got it timed perfectly first try... Really amazing Idea of you both! Loved it!

Author Andrew Ivanov ( ago)
This is caused by Coriolis effect. Simple physics. Coriolis effect is responsible for many weather patterns and hurricanes.
Aren't they teaching this in schools? This is Middle school physics.

Author Maven Sony ( ago)
Now do this experiment in exactly midpoint of equator .Lets see what happens..

Author znatim ( ago)
You could mention Foucault experiment

Author CiPoint ( ago)
The result would be much more convincing if you repeated the experimemt e.g. 10 times. Otherwise it can't be considered as a proof.

Author ArcherSage ( ago)
it doesn't always spin the same direction

Author Amirnake ( ago)
Ok Destin, since you're vouching for the bearded guy can you explain to us how it is possible for the light of an object traveling away at faster than the speed of light relative to point A to reach point A? Point A relative velocity to object is more than speed of light. I forget his name no disrespect but the bearded guy on his channel said that's possible. I don't think point A will receive any information from the object.

Author Strike Eagle ( ago)
That... Was... AWSOME! The 2 vid idea was crazy cool!

Author Ray Grant ( ago)
That was a good explanation of the coriolis effect!

Author Big Nasty ( ago)
you should have measured the speed of the swirl, i bet it matches the speed of rotation of the earth, relative to its size.

Author Ethan ( ago)
whats happens when on the equator

Author Cole Peters ( ago)
mine doesnt swirl

Author Rodrigo Cavalcanti ( ago)
Best crossover ever! Love both channels

Author Kelby Bullard ( ago)
makes me wonder what it would do dead center on the Earth's axis

Author Karvák Ferenc ( ago)
i hate your idiot face

Author Ibakon Ferba ( ago)
This is seriously one (or rather two... 1 1/2? :D) of the most amazing videos on the internet! Just rewatched it and I wonder: what would happen if you would do this experiment exactly on the equator? would the be no swirling at all?

Author zazke girotron ( ago)
I wanna see what happens in the equator or exactly at the north pole with the same controlled variables, great video both of you

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