Илим жана Технология

A 2D Heron's Fountain Behaves Weirdly

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Heron's Fountain is a mind bending hydrodynamic mechanism. It appears to be perpetual motion but it fact it's a really clever mix of pneumatics and hydraulics. This 2D presentation helps to explain how it works.
Image credits:
Soxhlet extractor image - Vivi! (commons.wikimedia.org/wiki/File:Soxhlet.JPG)
Washout toilet - Flammingo (commons.wikimedia.org/wiki/File:Klo_flachsp%C3%BCler_mit_altem_Sp%C3%BClkasten.JPG)
Toilet diagrams - SouthHamsian (en.wikipedia.org/wiki/File:Four_types_of_pedestal_WC.svg)
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  1. Steve Mould

    Steve Mould

    4 ай мурун

    The object itself is 3D of course, but there's nothing interesting happening in one of those dimensions! What I'm saying is, there's a legitimate sense in which the mechanism is 2D. Don't @ me. The sponsor is CuriosityStream: Get a whole year for just $12 by going to curiositystream.com/stevemould and using the promo code stevemould at checkout.

    • Shane White

      Shane White

      2 күн мурун

      Ok we won't @ you

    • DD


      5 күн мурун

      Is it possible to make it flow continuously in a cycle by modifying the design?

    • Dan Loeb

      Dan Loeb

      18 күн мурун

      Could you make one with water in place of air and tungsten hexafluoride gas in place of water? The density difference is only 13x heavier for tungsten iv fluoride over the water, so I'm not sure it would work.

    • Jie Golang

      Jie Golang

      Ай мурун

      ramp pump in 2d

    • A. Azfar

      A. Azfar

      Ай мурун

      @Flurgerbla tycbx

  2. dileep_vr


    3 саат мурун

    How well to Tesla valves work in 2D with liquids?

  3. Tamal Paul

    Tamal Paul

    16 саат мурун

    Heres a challenge for you Steve, which will also be something very useful for the science and science education community: a cut of the vapor-refrigeration cycle. You might need to change the refrigerant fluid, since typical fluids can go down to negative 40s. Also need to build i to withstand the high pressures. It will explain something so important to the industrialized modern age: the heat pump.

  4. Akhil John

    Akhil John

    Күн мурун

    Amazing Visualisations of Hydrodynamic principles.

  5. Joseph DESTAUBIN

    Joseph DESTAUBIN

    2 күн мурун

    No! We can convince ourselves that none of the laws of physics are being violated because they are laws!!!

  6. Debasish Dey

    Debasish Dey

    2 күн мурун

    It's not UK, it's Indian

  7. Petar Doynov

    Petar Doynov

    3 күн мурун

    8:22 - the gas is less dense than air?😁😁😁

  8. Lloyd Stovall

    Lloyd Stovall

    4 күн мурун

    My name is Lloyd stovall from media library here in the US, don't know if this system is the same in your country but how does your kitchen sink system works is your water container in the basement and if so then how can water continuously run in your kitchen sink without eventually running out. Here in the US we did an experiment by leaving on a faucet and seeing if eventually the air would run out in this the water will stop flowing after a year the water was still flowing Non-Stop. I say this is because everyone explains this fountain but they never explain how the systems who used the theory in which you talk about in modern day systems to run continuously and all day long. Can you answer this question. And we know they're probably going to be a lot of jokesters out there seeing that I water bill had to be ignormous but this was a school project and the government flipped the bill sorry but you can't get out of answering the question that easily

  9. Garrett Rodgers

    Garrett Rodgers

    4 күн мурун

    I wont lie seeing the thumb nail kind of gave away how it works.

  10. Drew


    4 күн мурун

    Sounds like the music to Matt’s Off-road Recovery

  11. Fabian Girsch

    Fabian Girsch

    5 күн мурун

    OK it's official. I'm too dumb to understand toilets.

  12. mateusz1807


    5 күн мурун

    toilets with a shelf were popular in Poland years ago. nowadays it's hard to buy such

  13. Sarah Jane Smith

    Sarah Jane Smith

    5 күн мурун

    US toilets scared me the first time I used one, I thought I was going to flood the place. I even took a picture of it to take back home 😅

  14. prince aries

    prince aries

    5 күн мурун

    Idea of air valve and vacuum valve

  15. Hesley


    6 күн мурун

    Your "2D" is just genius! Thanks and congrats!

  16. 93NicoC


    6 күн мурун

    Okay... so gas is less dense than air? 😜

  17. Zenpai


    6 күн мурун

    If you could raise the viscosity a bit maybe the 2D versions would last a bit longer?

  18. Kevin Krug

    Kevin Krug

    6 күн мурун

    You are a very smart gentleman, thank you sir

  19. Francis M

    Francis M

    7 күн мурун

    Hi Steve i love your videos, one suggestion for your next video can you make toilet experiment that reduces the sound it makes when flushed..

  20. kyle lemonjello

    kyle lemonjello

    7 күн мурун

    How would the physics change if instead of our air, there was a fluid chamber like above but sealed with a different gas to see how it would react with different air density.

  21. Max Barton

    Max Barton

    7 күн мурун

    Can you explain how a ram pump works?

  22. Warren NZ

    Warren NZ

    8 күн мурун

    While we're on the topic of toilets has anyone tried coating the bowl with one of those hydrophobic coatings? Nothing (water based) will stick to things coated with that. I'll leave the rest up to your imagination. Here' s what I'm talking about. kgkey.info/block/qoCBcbS0bLhouXo/video.html

  23. Jacob On

    Jacob On

    8 күн мурун

    What would happen if you used two liquids with different densities?

  24. W i l d_F a Q

    W i l d_F a Q

    8 күн мурун

    2:13 nice bong ngl

  25. pokeface119


    8 күн мурун

    8:24 "Gas is less dense then air"?

  26. 114 Coolboy

    114 Coolboy

    9 күн мурун

    Here's a question, would this work with a container with oil replacing the air

  27. Ravi Kishan Daiya

    Ravi Kishan Daiya

    9 күн мурун

    would it work, If you move the middle part a bit low and also its right boundary ...

  28. Linus Franzoni

    Linus Franzoni

    10 күн мурун

    The ragged knee analogically grate because professor differently list toward a salty underclothes. exotic, alleged noise

  29. Issac Sparks

    Issac Sparks

    10 күн мурун

    Was a great video just one thing got me at around 8:30 you said gas is less dense than air instead of water

  30. Pepijn Holm

    Pepijn Holm

    10 күн мурун

    small thing though, what would happen if you would use a heavy liquid and a light liquid

  31. Unknown Variable

    Unknown Variable

    10 күн мурун

    curiosity stream honestly just looks like KGkey but for documentaries. sorry but I aint looking a listing of all 457 unique features of a bird species and how they express them throughout daily life, I'm just looking for quirky mechanisms and and such so I can apply them to some things for fun, like the tensegrity table I built using legos I had lying around, or other things I genuinely plan on making into something like an infinity mirror table, or just things to play around with in programs like this heron's fountain. or videos of people dancing and kicking or punching or swinging swords at notes for ridiculous songs in random rhythm games. or just songs in general, or blacksmithing random things into other random things, honestly from what I saw on that "curiosity stream" it looks like it should be renamed "research stream" I'm only interested in stuff I can have fun with or use, not the type of person to watch through several days worth of documentaries so I can catalog the sounds of a dozen bird calls, and if I did want to do that I would literally just walk outside with a pair of binoculars and a go pro. not even that dam hard.

  32. doubleT84


    10 күн мурун

    Flachspüler = instant health check

  33. Dominik Brdar

    Dominik Brdar

    10 күн мурун

    Gas is less dense than air 8:25

  34. Michael Janas

    Michael Janas

    12 күн мурун

    It strikes me that you could replace the air/water with other fluids of different densities to achieve similar effects with different geometrical proportions.

  35. —lLEXl— ·.·XEL·.·

    —lLEXl— ·.·XEL·.·

    13 күн мурун

    _testi_ -dusti-

  36. Yusuf Maulana

    Yusuf Maulana

    14 күн мурун

    Hey, how to reset the process... You don't mention it. Should we

  37. Robert B

    Robert B

    15 күн мурун

    Steve, what would happen if you pull the line of the “tube” on the right a bit down and make the “tube” a bit narrower so that the liquid in the bottom (while still having the air “bubble” sitting on it) would start filling up the “middle” bucket/reservoir through the atmospheric pressure as soon as the bottom level catches the tube entrance, and since the topmost “reservoir” is higher than the middle reservoir entrance, it could keep on going... basically duplicate the exit of the middle reservoir on the bottom... what do you think? 🤔

  38. Ahmad on YT

    Ahmad on YT

    18 күн мурун

    3:00 unlimited power source?

  39. James Mackay

    James Mackay

    20 күн мурун

    I subscribed due to being totally waken to the power of gravity

  40. Eden England

    Eden England

    22 күн мурун

    tfw he cant even research a *toilet* then says its not actually a greedy cup: -_-

  41. CatGirl Nya

    CatGirl Nya

    22 күн мурун

    Dude wtf my brain just stopped working

  42. ODoyleRulz


    23 күн мурун

    What about a ram pump?

  43. Jiří Kajzar

    Jiří Kajzar

    23 күн мурун

    The WTF one is from Eastern europe...

  44. Gregory Marrone

    Gregory Marrone

    23 күн мурун

    Ok you seem to know alot about water and water fountains ....My question to you is how do the fountains in Europe keep going almost like perpetual motion machines??? All day long 24/7????

  45. Josh Reyes

    Josh Reyes

    23 күн мурун

    The wire you're talking about is Romex

  46. Emedan & Vmandin

    Emedan & Vmandin

    24 күн мурун

    Different pump wheels would be good 2D

  47. Emedan & Vmandin

    Emedan & Vmandin

    24 күн мурун

    Any reference to civil engineering will not work, like the “cable in the wall”. UK is unique. Thank god. Plumbing on the outside of houses.

  48. ZenoDovahkiin


    25 күн мурун

    1:48 Flachspüler, not "Flachstühle." Flachstühle would be flat chairs... or flat feces.

  49. EVPointMaster


    26 күн мурун

    To make the 2D version last longer, couldn't you change the volume ratio between the bottom and middle container?

  50. Tz'arkhan Besomar

    Tz'arkhan Besomar

    26 күн мурун

    then surely all you would need to acheive a semi perpetual motion with this system is a non powerred syphon which once started will constantly empty the lower reservoire and refill the top one, meaning that the constant over balance of gas would theoretically keep forcing water through the system. the only thing that would stop it being truly perpetual is the face that eventually gas would escape and the system would stop. Unless there was a way of retaking the escaped gas and passing it into the section where the fluid feed reaches the lower reservoire, but that leads the problem of a substance that would keeps releasing gas then there are two solutions, one that is insane and another that would just go flat. 1) (this is the insane one because it would mean you would have to store the system in a naturally cold environment like the north or south pole) you could make the system out of an insulator and then use liquid nitrogen as the fluid, because of the temperatures it would constantly be boiling and evaporating which would causea constant imbalance of gas forcing fluid to exitthe upper reservoire, and in the lower there would be a syphon to transfer the liquid back up to the upper to ensure a constant imbalance of fluid also, and to stop the escape of gas you would need a means to trap and transfer the escaped gas and transfer it to the point where the input connects with the lower reservoire, but this solution would need a naturally cold environment so it would be a daft idea for many reasons including that. 2) Use a carbonated fluid with a gas trap that connects to the point where the input meets the lower reservoire. however this solution would only work temorarily as the fluid would become inactive as there is no way to recarbonate the fluid without external means which would make it imperpetuallity and therefore a complete waste of time and soda. sorry for rambling like a mad man great video Steve.

  51. Blue Fire

    Blue Fire

    27 күн мурун

    Nile red has one 2:10

  52. Cory Clutterham

    Cory Clutterham

    28 күн мурун

    What would happen if the gas was replaced with a less dense liquid so that it doesn't escape into the atmosphere?

  53. Mony Bogoev

    Mony Bogoev

    29 күн мурун

    Ah yes the wtf type of toilets. Classic in Bulgaria

  54. Hemant Verma

    Hemant Verma

    29 күн мурун

    We all know he is a fan Mark Rober, Hack Smith, Backyard Scientist and Physics Girl .

  55. Albino Viper

    Albino Viper

    29 күн мурун


  56. Chainy Rabbit

    Chainy Rabbit

    29 күн мурун

    I hate European toilets. Put me off touring

  57. Chewy?


    29 күн мурун

    I feel like this could be a good answer to energy deficiencies with hydroelectricity

  58. Commandelicious


    Ай мурун

    The platform is so you actually can see your pop and possibly pee. Inspecting these from time to time is eh, let's say 'important'. Besides, your ass doesn't get wet which is nice.

  59. Anirudh Sawant

    Anirudh Sawant

    Ай мурун

    8:22 Gas is less dense than air 8:28 U funny 👉

  60. De Gueb

    De Gueb

    Ай мурун

    I was working as a labourer on a building site in Spain and we had to level and cement some waste land about 50 X 50 meters. I was wondering how they were going to get it flat, a laser level? a very very long spirit level?? No!!! a transparent hose was all we needed. We filled it with water, made sure there was no air bubbles and hammered some wooden sticks into the ground used the level in the hose to make the sticks. All at the same level!!

  61. george kurgansky

    george kurgansky

    Ай мурун

    I know how it works but it's satisfying to watch anyway! Great video, great explanation!

  62. Painfull Erection

    Painfull Erection

    Ай мурун

    1:36 the platform you poo on has another purpose.... when you get older your doctor might want you to bring a poo sample from home and that is way easier with a toilet like that.

  63. Sean Aguilar

    Sean Aguilar

    Ай мурун

    Is your intro music "Perfect Crime" by Guns N Roses, acoustic country version?

  64. Pig Daniel

    Pig Daniel

    Ай мурун

    I have the wtf toilet at home and it is the best, no splashes of toiletwater onto the as

  65. Jackson Morgan

    Jackson Morgan

    Ай мурун

    Better than any teacher I’ve ever had

  66. Kratos


    Ай мурун

    The wtf toilet design is to take samples of your stool easier

  67. paulflute


    Ай мурун

    a couple of word questions..? a system 'evolving' to equilibrium..? interesting.. perpetual motion 'mechanism'..? do you mean over unity mechanism..?

  68. b h

    b h

    Ай мурун

    it seem that the trompe effect might also have a role to play in your setup

  69. Christian Terrill

    Christian Terrill

    Ай мурун

    Good stuff, love using my brain I get to so little these days

  70. relentlessmadman


    Ай мурун

    welcome to plumbers school! Oh crap!



    Ай мурун

    Normal people: what wha? How? Engineers: hold my beer

  72. Michael Quigley

    Michael Quigley

    Ай мурун

    So if you changed the air for another fluid that is less dense than air would the fountain still work properly? like say oil, or does the air being compressible matter?

  73. Trophy Scars

    Trophy Scars

    Ай мурун

    I wonder if that would work in a game like terreria or starbound?

  74. Hermetic Hippie

    Hermetic Hippie

    Ай мурун


  75. Robert Hill

    Robert Hill

    Ай мурун

    Try two differently colored liquids with different densities that don't mix. Like an oil and water-based liquid!

  76. ZAC SMASH!


    Ай мурун

    Steve couldn't shake the smile he got after dropping the turd on the shelf lesson on us lol

  77. Deshitha Dhananjaya

    Deshitha Dhananjaya

    Ай мурун

    today meet this guy.. amazing

  78. Steven Harper

    Steven Harper

    Ай мурун

    Looking at toilet bowls ..., I’ve spent too much time on KGkey today

  79. Pyro Froyo

    Pyro Froyo

    Ай мурун

    I read this as a 2D heroin fountain

  80. Phillip Ellis

    Phillip Ellis

    Ай мурун

    I was ironically taking a piss at the beginning of this video..

  81. LaughingMute


    Ай мурун

    Gas is heavier than air? 8:25 (im sorry...)

  82. casesandcapitals


    Ай мурун

    I've lived in the U.S. my entire life and lemme tell you, the rising water in the toilet bowl still makes me anxious lol

  83. IronSimon X

    IronSimon X

    Ай мурун


  84. Jovan Janevski

    Jovan Janevski

    Ай мурун

    Heroin fountain... Wait, what did i just red?

  85. Enyetahip


    Ай мурун

    Can you daisy chain these?

  86. ***MaDuck***


    Ай мурун

    I dropped my phone on my face watching this

  87. Kanye Fuller

    Kanye Fuller

    Ай мурун

    I did this in Starbound, Terraria and minecraft

  88. De1taf1yer Lastname

    De1taf1yer Lastname

    Ай мурун

    “Because gas is less dense than air” 🤔

  89. Fruitographer


    Ай мурун

    The 2D version isn't a heron's fountain which is why it stops so fast. The pickup from the bottom chamber should be below the liquid level on the right side so the pressure will push the liquid from the bottom to the middle. Only air will push into the middle chamber the way this is setup so it isn't a proper heron's fountain. If this had a piece going down on the bottom right the same as it does on the left, it should actually work. Right now you are only pushing air into the middle layer and it should be pushing liquid. I would be very interested to see this with the changes to see how it works in comparison. You mention a gap that doesn't make sense at 6:00 and this is the reason there is a gap in why it ins't making sense. Hopefully this helps and I look forward to seeing what you come up with

  90. Man in the Park

    Man in the Park

    Ай мурун

    I love the music at 4:30.

  91. Samantha Maria Joan Hitipeuw Lius

    Samantha Maria Joan Hitipeuw Lius

    Ай мурун

    It's embarrassing how i Gasp every single time.. 😂 This is awesome!! Thank you so much!!

  92. Down The Rabbit Hole

    Down The Rabbit Hole

    Ай мурун


  93. Bill Pee

    Bill Pee

    Ай мурун

    I would like to see: reservoir of water, semipermeable membrane to column of saline solution, and spout some distance up with another semipermeable membrane and a spout. Osmotic pressure drives water across bottom membrane into column and head pressure drives water across upper membrane and out the spout and back to the reservoir.

  94. federico c

    federico c

    Ай мурун

    So much Talk makes me boring

  95. Tristan you

    Tristan you

    Ай мурун

    Im not the only one who read it as "2D Heroin" right?

  96. Bounty Hunter Master

    Bounty Hunter Master

    Ай мурун

    Okay so I haven't watched the video so I am going to see if I can get it right based on the thumbnail. Okay so water flows to the lowest point filling the bottom, since it's sealed the air between the two basins gets added pressure applied, that now compressed air wants to get out and equalize so it pushes down on the basin creating pressure in the water and since it doesn't like to compress it forces the water up out of the tube and thus the Cycle is complete.

  97. Isenmouthe 89

    Isenmouthe 89

    Ай мурун

    In a dramatic voice: 'The people behind "elf on a shelf" now brings you "dung on a rung", coming this summer!'.

  98. bohs2000


    Ай мурун

    I always called it the "continental shelf" because it's common on the continent.

  99. ObiWanShinobi1


    Ай мурун

    I wonder how that would look in a closed system with ether, or some other fast evaporating liquid.

  100. Detector de Gados

    Detector de Gados

    Ай мурун

    4:30 I was confused when that porn music kicked in