The Truth About Toilet Swirl – Southern Hemisphere

The Truth About Toilet Swirl – Southern Hemisphere

Both videos on one page (for desktop):
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Some notes:
We each repeated the experiment 3 times, and got the same results every time. For those of you who might be skeptical, great! A right circular prismatic kiddie pool is only $10 and you can do the experiment for yourself at your latitude. There’s really no reason you shouldn’t 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 Vanessa for filming in Sydney:


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:…

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20 Responses

  1. Jaspii1 says:

    How does this take 3 years to make?

  2. Daeto B says:

    I loved the sinc videos 

  3. Justin Lloyd says:

    Finding the link has made me so frustrated I gave up on watching the

  4. Bryan Woods (Decolorido) says:

    Definitely one of the coolest things I’ve ever seen. Not necessarily super
    pumped about the Coriolis Effect (not that it’s not cool), but this
    synchronization and collaboration is absolutely mind blowing. Well done!

  5. ChappyHappy says:

    Sweet! Got the left/right side correct the first time. Sync was a bit off,
    but I was able to enjoy an ultra widescreen video.

    Already a sub on both channels though. I’d assume most subs follow the same
    channels (scishow, vsauce, asapscience, minutephysics, kurzgesagt, etc)


    that was an awesome video , both ok i am confused it is a single video or
    two different

  7. MoltenSwordGaming says:

    What’s the name of the music played during your videos, it’s awesome!

  8. carultch says:

    Derek, as an Australian, what was your reaction to the way that The
    Simpsons made fun of Australia?

    I love the inconsistency how Tobias has to bike all over the outback to
    check his neighbors’ fixtures, yet his dad in the same house can just shout
    out his window to speak to both his member of parliament and his prime

  9. BachBeethovenBeatles says:

    Damnit I watched it with Veritasium on the left and SmarterEveryDay on the

  10. Chandu S says:

    you guys are geniuses…the only annoying part is that i have to copy-paste
    the same comment to the other channel as well!!!

  11. Pierre-Olivier Cimon says:

    I easily managed to sync both videos and the result was epic! Awesome job
    guys !

  12. Marty.R Woodcock (Marty's Megapixels) says:

    Is it me or does destin’s smile look like Jim Carrey’s big mouth smile?

  13. Jashan Bola says:

    That sync was solo cool

  14. arc-mist says:


  15. Subham Roy says:

    In what direction water wl rotate in equator ?

  16. David Slattery says:

    awesome concept

  17. Michael Kentner says:

    if anyone is haveing a hard time with the sync just pause one video when he
    says 5 and pause the other at 1 then unpause the 5 and when he says 1 play
    the other thats how i did it

  18. karl McHugh says:

    You guys nailed it. the sync was really cool

  19. Danial Fitri says:

    This COLLAB made me use my tv & LAPTOP, so radical!

  20. Beliroz says:

    I love that the thumbnail is upside down. This was a really cool
    experiment, and the presentation was absolutely amazaing. I felt like I got
    smarter today, that’s the truth!