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/Fi...)
Washout toilet - Flammingo (commons.wikimedia.org/wiki/Fi...)
Toilet diagrams - SouthHamsian (en.wikipedia.org/wiki/File:Fo...)
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[@SteveMould]

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.

[@flurgerbla7609]

but would it work with oil and water?

[@biggjiggins8987]

8:24 "gas is less dense than air” that almost slipped passed me. Shouldn't it be gas is less dense than liquid

[@larryscott3982]

@@biggjiggins8987 Yup. Wawa be heavier

[@rednammoc]

@@biggjiggins8987 unless the air is chilled somewhat heavily until it's no longer a gas, perhaps?

[@chrishill601]

Not something that would work in 2d, but I have noticed lately that lightly stirring (in a repeated pattern,) the water in a pot that's just starting to boil is a neat way of 'seeing' the currents. If you time it where bubbles are forming on the bottom, but not rising yet, because the water above them is still cool enough to act as a condenser, then when you stir, the faster moving currents will carry the heat away from the part of the pot under them faster than the slower moving ones, so you get lines of bubbles where the water is more still, and the heat can build up more. I don't know if there's enough there for a video, but I definitely thought of you when I noticed it.

[@kaisalmon1646]

You heard it here first folks: "Gas is less dense than air" 8:24 (edit: corrected time)

[@keco185]

Clearly he said “gas is less dense than hair” /s

[@guiorgy]

Also noticed that lol

[@phonn6935]

@@keco185 /sarcasm?

[@mathiasplans]

But steel is heavier than feathers!

[@Sean-pm2vd]

@@mathiasplans A tonne of feathers is the same weight as a tonne of steel.

[@NickMick9]

"The turd on the shelf", precisely the kind of insightful and intellectually stimulating content we come here for. Keep up the good work!

[@MrAndrewBeattie]

The turd on the shelf is so that you can EXAMINE your poo. Typically to look for worms.

[@keithfulkerson]

@@MrAndrewBeattie ahh, that makes sense. "Turd on the shelf" cracked me up, though.

[@BernhardVodicka]

We call it "Wurstbalkon" here. (sausage balcony)

[@Siska0Robert]

That toilet was pretty common in Czechia, but I'm glad to say that they're phasing them out.

[@Shrek_Has_Covid19]

i call it the shit on a shelf

[@maartenstriepe6893]

Definitely wasn’t expecting a 2 minute lecture on different kind of toilet bowls 🤣

[@hariman7727]

It was a shitty opening in multiple ways.

[@Keeps25]

I feel like this would've been very cool to see with two different density fluids. Say water and mercury. We would be able to see a fountain effect without any air.

[@grissee]

it's all fun and games until you got mercury poisoning

[@joshc5613]

a mercury fountain sounds more like something Qin Shi Huang would have come up with

[@andistansbury4366]

Fountain of youth.

[@bluesbest1]

@@andistansbury4366 Because you'll never grow old?

[@dgurevich1]

​@@grisseejust use cooking oil instead

[@veritasium]

Oh look it's Derek!

[@mikehawk37]

Cool to see you Here!

[@oRitchinal]

If anyone gets lost in this comment section, this is probably a good place to ask for derektions

[@mikehawk37]

@@oRitchinal pun patrol Here you're under arrest

[@oRitchinal]

@@mikehawk37 Guilty as charged, officer!

[@mikehawk37]

@@oRitchinal lol

[@wrongrabbit]

These visualisations and explanations are just fantastic. Keep them coming.

[@Skechi]

He made me visualise a turd on the shelf perfectly.

[@wraitholme]

@GROHAM official No. Once the blob of air in the system is moved enough, the system reaches equilibrium and the movement stops.

[@paulgrosse7631]

I remember seeing (and using) the German toilets when I went on tour there with a band in 1984. The sound engineer's theory was that it reduces the incidence of piles because people spend less time on the toilet (find somewhere else to read the paper) and the vocalist's theory was that it was so that you could look at what you had produced and have a greater chance of finding any indicators of bowel cancer (or other disease) there - they eat a lot of meat there. I also recall the same feeling of horror that you did when you see the fill-up-then-empty type. So, what to take away from this comment? If you want to see the toilets of the world, join a band and tour ;-)

[@sweetgirl070707]

Which band?

[@the-quintessenz]

From experience with the splash and shelf system, I can tell that you need to use the toilet brush less often. Especially if you put a sheet of toilet paper on the shelf before you start your business, there is rarely anything left at the end.

[@toast6375]

@@sweetgirl070707 *_THE BAND_*

[@metrillbeats]

The Vocalist was right, Thats why some Hospitals still have some of those

[@Channeldyhb]

The absolute worst part is when it does actually keep rising when it's clogged 😨

[@wafikiri_]

I have built many Heron's fountains, for my children and for my students, using bottles. But I always much separated (a quarter or half a metre) the two bottom bottles, used long pipes with long visible lengths outside them, and topped the top end of the uppermost pipe with a strainer. Results: • The fountain had a surprisingly tall jet, reaching very high over the pile. • Water circulation through the pipes was very visible, at least if some air bubbles were present. Once the top pile is empty of water, just putting the artefact upside down empties the bottom bottle into the upper one, and the fountain is ready to work again once returned to its normal attitude.

[@ralexcraft990]

“Gas is less dense than air” That had me laughing

[@Psilocybism]

As someone famous would probably say: Gas doesn't have to be air, air is gas though. Unless your building a rocket or a quantum computer.

[@flinch6707]

Ah it happens lol

[@ralexcraft990]

@@graham741 Specific gases might be lighter or heavier than air, but for regular non super complex operations air=gas is good enough.

[@TheChzoronzon]

@@ralexcraft990 and the quantum computer?

[@ralexcraft990]

@@TheChzoronzon IDK, I’m not a computer scientist

[@helnami2281]

I love that you even made a 1 dimensional demonstration for completions sake

[@andrewcraig1074]

Where's the 4 dimensional version?

[@thetafritz9868]

@@andrewcraig1074 too hard to explain

[@rpyrat]

A true completionist would've made the 0 dimensional version as well...

[@p1nkfreud]

It's a 2 dimensional version, you cannot make a 1D Heron's cup

[@helnami2281]

@@p1nkfreud i was referring to the tube demonstration

[@FileCode1459]

this is so interesting!!! the 2d model really helped me understand what was going on, i really appreciate your effort into making this, i can't imagine how much thought it goes behind it. thank you for this video!!

[@haggleboggle]

You know, I actually really appreciate the brief toilet primer. It's always nice to know how one's things work.

[@Fleonwyn]

The "Turd on the shelf" is especially helpful in the medical sector. Its easier to control the stool for blood or something or to get stool samples. But why people (like my parents) decide to install it in their homes is a mystery to me.

[@rasalas91]

Those are basically normal in germany - I'd say that more than 50% of private toilets are like that. You can see a lot of health problems by "inspecting" your poop (more like a casual look while flushing) daily. The pee color is more visible too.

[@Fleonwyn]

@@rasalas91 I am German and 50% of the toilets in our house are built this way :)

[@Neysiriss]

The reason people would get the turd on the shelf at their home, is mostly because people are scared of "splash back". I know a lot of people in europe who wouldn't use a toilet if it's not a "turd on the shelf" one

[@yesihavereadit]

We first saw that toilet in Austria. We were on holiday skiing, 6 blokes and one poor girl. First breakfast someone mentioned the toilets, then someone said what if you Do a long one, cue 6 boys slowly rising from their seats, the poor girl!

[@Neysiriss]

@@yesihavereadit can confirm though a long one can get complicated

[@lavoyebonham9086]

I’d love to see a coffee percolator get the “2D” treatment.

[@morcogbr]

Oh god please don't use that devil mechanism to make coffee, just get yourself a Moka and enjoy

[@lavoyebonham9086]

@@morcogbr but it’s more convenient than a pour over. Although a Belgian siphon coffee maker would be fascinating to see as well.

[@wailingwarlie]

Yes!!!

[@beefymcskillet5601]

Wait till you taste properly made coffee

[@morcogbr]

@@beefymcskillet5601 Hope that one day he does

[@cerebrummaximus3762]

1:36 We had that one in our apartment in Bulgaria, but sadly our cousin broke something in the mechanism, and we had to replace the whole thing with a "normal" (UK or US, idk) toilet bowl. Fills me with nostalgia when I see this old design. Never thought I'd cry over a toilet bowl...

[@_..-.._..-.._]

I can’t watch this in HD, the eyes are too steely blue and seeing into my soul.

[@goodguyjohn4625]

8:24 "Because gas is denser than air" I mean, you're technically right, sometimes...

[@viddork]

Saved me saying it!

[@orchdork775]

Yes, that confused me! Maybe he meant that air/gas is less dense than water? Idk haha

[@ShinichiroKururugi]

Yes, I think he meant to say the air is less dense than the water.

[@evildoctorporkchop6187]

Glad someone else caught it 🤣

[@AkanoWire]

and thats the best type of right q:

[@jamesgates1074]

“Let’s make a U shaped tube” Maybe we should call it a KZbin?

[@babeez1513]

Underrated comment

[@snazzy1050]

buh dum tss

[@Stickman_Productions]

UTube KZbin Human shaped tube if you are human

[@Thesupremeone34]

we actually call them U-tubes in fluids EX: google U-tube manometer

[@ANabih-uo3zy]

Get out

[@Cstolworthy]

Great video! Personally I would love to see a visualization of a waterhammer pressure wave. We often see the effects of them, but I don't believe I have ever seen someone visualize it well

[@thekornwulf]

Grady over at Practical Engineering has a really good video on water hammer with visual aids

[@cinnamonkittamon]

I wonder if this could be done with some sort of vegetable oil in place of the air, since it's about density

[@WJS774]

Maybe, though the density of oil is _way_ closer to water than air is. Oil is what, about 80% the density of water, while air is about 0.1%?

[@ross__mcl]

I remember seeing one of those crazy toilets with a platform when i was travelling around europe 10 years ago. I called it the poop deck

[@SteveMould]

Oh that's good

[@ross__mcl]

@@SteveMould I amuse myself sometimes

[@orbsphere-]

If WTF is a poop deck wouldn't the others be stool pool?

[@JanStrojil]

They used to be really common in Europe some 40 years ago.

[@rewardhole]

A perfect platform for post-mortem examination. 'One poop ex_cav_ation a day keeps the doctor away'. Enjoy.

[@Xsidon]

The shelf is there So you can appreciate your masterpice in full glory when you're done.

[@edeworabraham2761]

*chef kiss

[@johnjordan3552]

I usually take pictures of my works afterwards, so my friends can see my brilliant masterpieces and appreciate them as much as I do

[@nlb137]

If it's big enough to brag about, you'll be able to see it even in a normal toilet bowl.

[@Xsidon]

@@nlb137 True but it's not the ideal circumstance for review

[@duncanbowtell2607]

The goal is to fill it up till it kisses your cheeks…

[@stevievaughan5096]

this is my first video of yours and the bell siphon is definitely how my bong works

[@SusanoRipper]

Man, this channel and Your knowledge, accent, pure passion...its is all magnificent. Makes me look at the world in not-so-simple way but at the same time, a real way of how it works. Much obliged, sir.

[@jackdalton2538]

I really like the way you transformed yourself into a polistiren cube for the demonstrations with the tubes

[@unvergebeneid]

Haha, when I read this, I did not pronounce "polistiren" like "polystyrene" but like "po-LISS-terrin". Took me a while ;)

[@stephanjuvik6266]

Are you talking about the white cardboard screen?

[@luipaardprint]

I imagine filling that tube with an almost perfect 1/2 water, 1/4 air, 1/4 water took more time and effort than building the 2d heron fountain.

[@AdmiralStormy]

I would hope he had something to pinch it, otherwise it would have taken significant levels of witchcraft

[@veganjoy]

you could just fill it with some water from your mouth, not that complicated lol

[@TheWizardOfSand]

@@veganjoy water? You mean orange soda?

[@Weebdotexe]

submerge 3/4 of one side, then submerge 1/4 of the other, pushing 1/4 out, so u get a 2:1:1

[@mangouschase]

@@WeebdotexeI'm getting jetpack fuel club penguin mission flashbacks

[@douglasberger3908]

Have you ever done a video on the continuous cycle absorption system for refrigeration? It is used in a lot of RV refrigerators. A little pilot light can drive a beautiful combination of fluid dynamics and thermodynamics in one system.

[@Flamingtaint]

I like this idea. I'd love to know how a small flame makes my fridge cold.

[@noca7529]

Buenisimo! me encanto tu fontana de Heron en 2D, se entiende perfecto su funcionamiento y es muy inspiradora para ver como poder mejorarla. Saludos.

[@jimjohnson5739]

In Germany, a young lady told me the poo-on-a-shelf toilet became common 'way back in the day because of parasites; people had to frequently check their stool to know if they were worm-free.

[@winsomehax]

I read "2D heroin fountain behaves weirdly"... I need to sort myself out.

[@kaylakat9583]

i was worried i was alone

[@Casey-cy6ph]

Same

[@user-jc7hs1wd1d]

Same lmao

[@Speed001]

Yes, sort yourself out. Please don't string yourself out, lol.

[@Sparrow420]

you mean snort yourself out

[@assdan27]

You simplifying it down to a single tube was impressive. It intuitively makes sense but would be hard for most people to conceptualize in that way.

[@eliblay9973]

I never knew I wanted to know how a herons fountain worked, until 3am on this fine morning

[@maarten271]

I live in the Netherlands, and I never knew there were other toilets than these “turd shelve” types. Then I took a look at my own toilet and noticed it doesn’t even have a turd shelve. Conclusion: I never really paid much attention to toiletbowl layouts.

[@marcel9568]

You don’t give a shit about the layout. You should have noticed the wet ass.

[@tinnguyenanimations522]

lol

[@keysmiff7689]

These were a bit of shock when we moved to the Netherlands in the mid 1980s. 😮

[@smokey04200420]

7:46 Let’s all appreciate how he was able to get half air half liquid in the left column of that tube. Edit: I’ve added a timestamp.

[@lol-pk6jj]

That's actually very easy, just try to fill it all the way and you will get this

[@aissaouimohammedakram8640]

@@lol-pk6jj how?

[@lowbudgetname2745]

@@aissaouimohammedakram8640 git gud scrub

[@bubbahottep8644]

Spitballing: partially fill the tube, tape or hold the ends together, rotate until your air column is where you want it, pinch closed or put fingers over the ends, and rotate it to demonstration starting position.

[@asileginger8223]

Mhm.... there is a easier way hahahaha just think that the tube is a straw... have u ever played with a straw as a kid? well, as a kid, i would suck some juice, then pull the straw out of the juice to suck in air... and then put the straw back to the juice... so there would be air in between juice 😂 i guess u can do the same thing with that tube hahahaha

[@TheCentaury]

Steve. The more I watch your videos, the more I think you want to achieve (or are obsessed with) perpetual motion :D

[@BoggleWogglez]

1:50 We would call it a "prestatiepot" at home, Dutch for "pot to show your achievement"

[@psammiad]

It's just insane. Who in their right mind wants to admire and smell their own shit. Totally fucked up!

[@Bebop_2962]

@@psammiad The design allows you to check for colon problems/parasites.

[@cambridgemart2075]

@@Bebop_2962 Indeed, they're common in Austria, particularly in the Alpine regions, where pork makes up a significant proportion of the diet and the incidence of parasites is higher than other places.

[@TheGroundedCoffee]

Also there's no risk of splashback, A.K.A. Poseidon's Kiss. They're truly great.

[@RedHair651]

@@psammiad you don’t look at your poo?

[@brent_peterson]

8:25 “gas is less dense than air” I guess you learn something new everyday

[@h7opolo]

you can also learn something new everyday every day. ;)

[@thetafritz9868]

I noticed that too

[@Kram1032]

to be fair, certain gasses are less dense than the mixture of gasses in the air at sea level, whereas others are much denser

[@xuko6792]

In the context of talking about toilet bowls seems legit

[@ZEGTHEFISH]

A kilogram o Steel is heavier than a kilogram o feathers

[@rossstewart9475]

1:50 Washout toilets are used in the UK, too: That shelf is considerably easier to remove a stool sample from than most other designs, and (at least when I worked in the industry in the late 90s) they were common for hospital use, and also in 318 stainless steel; By order of HMPS. The greater distance through the trap also made it harder to use the u-bend to store stuff out of sight of staff, though there were other ways this was avoided.

[@adbarretttth]

My Dad, a plumber of 40 years' 2 laws of plumbing. 1. Shit always rolls downhill. 2. Water finds its own level.

[@nex]

8:13 Steve Mould, professional U-tuber.

[@arcm8725]

Funny

[@Knewman7777]

Underrated comment!

[@dr.redacted4492]

I don't understand

[@Knewman7777]

@@dr.redacted4492 from 7:40 to 8:20 he uses a U-shaped tube to simplify the demonstration.

[@dr.redacted4492]

@@Knewman7777 ohhhhh

[@dontaskquestions8721]

I saw this as “Heroin Fountain” and I was like “How the hell is this still on KZbin!?

[@doxasnike4789]

Same

[@verdetetto1814]

Same WTF

[@InservioLetum]

Because the algorithm doesn't have a drug problem, lol....

[@startube3629]

I read it as "Heroine Fountain" and was expecting some ancient greek myth... I was disappointed but amused.

[@tofikk]

I see heroin I click

[@honeyham6788]

the detail about tubes in the middle partitioning something in half reminded me of the brilliant novel "The Planiverse" about a world entirely 2D and how things would need to be constructed to allow such a thing to work

[@2259ninja]

Wish i had found this video sometime in school so I could explain what you have in this video as a science project of some kind.

[@muh1h1]

"The turd on the shelf". i've only ever known it as "Kacketeller", which would roghly translate to "poop plate" :D

[@DJCornelis]

The Pu Pu Platter! xD

[@Psilocybism]

This very same word in our language would mean someone/something that counts (like 1,2,3) turds.

[@ubernate860]

That earned him my like 🤣

[@amandarios448]

Kacketeller, sounds like poop counting/counter Which is about right

[@emperor_rat]

I alway thought that type of toilet is really good for hospitals... because there it is likely you have to monitor the looks of patients excrements 🤷‍♂️

[@totallynuts7595]

Ah, fluids. That subject which makes you remember air and void are two different beasts. (Because when you study rigid body mechanics and the likes, you consider everything to happen in a void)

[@TheDeadOfNight37]

When air and friction are not negligible 😔

[@wojtekpolska1013]

@@TheDeadOfNight37 actually it has nothing to do with friction, its the air pressure and surface tension

[@TheDeadOfNight37]

@@wojtekpolska1013 I know I was just making a joke bc most of the time in physics they're usually both negligible or neither are

[@nicreven]

you mean a vacuum?

[@heronscott6910]

It's fun that I think of my name as a really uncommon name but I see that Heron is a really well known math formula and that video's subject

[@lemonsneeker]

Uk usually aligns with Australia RE plumbing supplies, we have flushomatics if you want to go into some hydrodynamics seen in our toilets. They seemed cool to me, but it was part of my carrer, so that might have helped. Basically the valve breaks an air lock which alows a certain amount of water to pass and flush the toilet, then the airlocked equilibrium comes back and the flow stops again, giving you a flush that doesnt need time to refill between uses, which is ideal for public toilets. The valves are also mostly recyclable, the seals will need changing every so many years, but basically its a similar system to gas bottles, you trade an old leaking one for a refurbished valve, they refurbish yours and trade it on to someone else, you dont pay for a whole new valve, and the majority of it lasts decades before actually becoming waste.

[@odw32]

"The type of wire that's in your walls" is dangerously similar to the whole toilet situation. I'm convinced that World War 3 will start when someone asks an American, British and German electrician to wire up a house together.

[@siliciaveerah9327]

Honestly...a video I kind of want to watch now

[@DOSTalks]

Yeah but the type of wire they use is irrelevant. The difference between the electrical systems on those countries is related to sockets, voltage and frequency etc. You could wire an american home with british wire no problem (maybe not the other way round because of the earth but you could just use a separate cable of the same wire for that)

[@odw32]

@@DOSTalks There's also very different requirements regarding water damage safety and location/routing of the wires - in many european countries you're not allowed to wire horizontally through walls, and all wires must be isolated strands pulled through PVC conduit tubing of a certain diameter, which must be glued into wiring boxes. Putting the "flat" UK cables, or loose 8 inch service loops as is common in the US in a Dutch house would immediately void your fire insurance.

[@mortenhartvigkristiansen7760]

@@DOSTalks I don't think that would work though.. Since US runs on lower voltage, I'd expect them to run higher current, so they would require thicker wires compared to those used in Europe. No?

[@huuskari174]

@@DOSTalks they're bit more complicated and there is differences in wires and wiring. For example in great britain they use ring circuits where other countries don't.

[@Roedygr]

"gas is less dense than air" should be "air is less dense than water"

[@rpyrat]

You sure about that?

[@NielvanderWath]

@@rpyrat haha yeah tell Roedy Green

[@yusufat1]

Funny thing, "air" in indonesian language (pronounced a-eer) means "water". Thus as an Indonesian his statement is correct. 😅

[@angeluscollins2382]

i notice that to

[@nathanegbert977]

Intentional errors are used to boost comment counts. I assure you, the attention required to produce and edit this video did not miss such an obvious error.

[@dizfoster8726]

Design note- you may want to use less right angles on your drains, both for this and for the 2d Greedy Cup. Love your stuff.

[@ichliebebaeumeweilbaum]

The "turd on the shelf" one is horrific to me. It's kinda common here in Germany, but whenever I encounter one, I question the owner's mental stability... No, I DON'T need see my s**t in its full glory, thank you xD

[@GioBardZero]

I grew up with a "turd on a shelf" style toilet and when I moved to America, dealing with splashes was such a shock

[@shasan2393]

Poseidon's kiss

[@Graxu132]

I'm always putting a piece of toilet paper on the water to get rid of the splashes 🤣

[@trinesrensen560]

So the Netherlands? I don't think that style of toilets exist anywhere else.

[@GioBardZero]

@@trinesrensen560 nope, Georgia (the country). Funny thing is, I've never seen another toilet like it anywhere, even in other places in Georgia (the british style ones are the dominant ones there)

[@harleyspeedthrust4013]

What do u think of zandukeli lemonade

[@sampersonguy5337]

As I’m sure you can imagine, the rising of the water in toilets can be quite scary in the US as well if it doesn’t go back down

[@homagee296]

This man's videos are in top-notch quality and it's so much educational yet super enjoyable!

[@EVO1148]

What fluids do you use for these hydrodynamic models? I presume water with food colouring? Just curious to what extent factors like capillary action and other hydrostatic forces play a role. Have you tried these same models with oil for example?

[@TechyBen]

[Looks at toilet designs] OH!!! So *thats* why every other country in the world always gets "floaters" and I've never had a problem.

[@jasirkhan6513]

Steve: *Makes an amazing video* Everyone: 8:25 gAs iS leSs deNse thAn aiR

[@adfaklsdjf]

this is the best comment about it xD

[@sknt]

Best way to get the right answer to a question is to post the wrong answer on the internet.

[@dontneedtoknow5836]

Depends. Air itself contains a concentration of many gases. H2S no. Something about sulfer that really doesn't like to stay in gas and seems to be pretty dence. Have to check the table on that one.

[@Channeldyhb]

This is really my favorite series on KZbin tbh

[@ladderlappen4585]

this was actually quite trivial. thanks to you, i can feel smart now and my self esteem is raised.

[@hafizhmanaf1459]

Everyone after watched the video : "wow, that's amazing. Now i understand physics" Me : "I want to drink that orange syrup"

[@conmarsz]

Not if I get to it first

[@declantecho1717]

It is water

[@lucasanimations8636]

@@declantecho1717 r/wooosh

[@declantecho1717]

@@lucasanimations8636 Hydrate or dydrate, buddy. I didn’t say _don’t_ drink it. Of course we all wanna drink the Highlighted Hydrodynamic Science Fluid (tm)!

[@hindering4278]

I've moved to the Netherlands and the first time I encountered the poo on a shelf style toilet my first reaction was indeed: WTF... I have my own name for them though, I call them inspection shelf toilets.

[@giorgosvr09]

I believe "inspection shelf toilets" is a direct translation of the Dutch word used them or so I was told by a Dutch friend. Apparently in the old days it was very common for doctors to examine stool samples from sick people so the Dutch came up with this design to facilitate the sample collection process.

[@hin_hale]

I call it the trophy shelf toilet.

[@botsjeh]

vlakspoeler

[@t0k4m4k7]

He still missed it hahaha

[@Vasharan]

Those shelf toilets look like they would be very handy if you were smuggling diamonds or cocaine into a country.

[@marcellin1371]

I really love watching this kind of videos during sleeping time

[@BobbyParker784]

Well darn it I was looking for a way to make my own Perpetual Fountain watched about a million herons Fountain videos not a one of them said that it didn't keep running. You're the only one that mentioned that it would stop after a while

[@adammercer9679]

"Turd on the shelf" Or as I like to call it, a poo with a view.

[@chriss31]

Poo on the loo! Can’t believe he missed that....

[@orbsphere-]

OK can't resist a poo with a view or a poo with a phew

[@Bezzer1975]

"Elf on the shelf" has some opposition this Christmas.

[@ForumCat]

Crap on a lap?

[@Gastell0]

Despite never seeing or hearing this before, I immediately understood how it works the 2D version in the very beginning of the video, this is awesome work in making it so much easier to understand!

[@mmmdananananone]

Really interesting and top-notch presentation.

[@dtyle1890]

It would be interesting to see with two liquids of different densities ie water and oil

[@riatorg]

This was my thought as well. Does the compressibility of the gas play into the effect?

[@dontneedtoknow5836]

@@riatorg only the the compression of water. The lesser of the two is restricted by the greater only to the point of the greater. Then it becomes mass over volume.

[@triste4-21]

@@dontneedtoknow5836 water cant compress. Well, liquid water cant compress

[@BloodyHaemorrhoids83]

Step 1: Cover yourself in oil

[@dontneedtoknow5836]

@@triste4-21 is there any liquid that can compress?

[@KarnBlueEarring]

I grew up with the WTF toilet. I'm from Germany and I always assumed it was normal as a kid. Until eventually I got into school and visited other kids and realized that our toilet was kind of unique...

[@nova290r]

Jo die nennen es oft auch german toilet.... sagt alles

[@LinKueiDragon]

Sure, false Furry

[@KarnBlueEarring]

@@LinKueiDragon wat

[@abdullahyousef3481]

same

[@tylerspaeth1885]

Thanks you! I’ve been curious how this works. Optional question: could you make an invertible version (think hour glass) with the right combination of tubes and one way valves or something?

[@dwaynemadsen964]

I chuckled sensibly about "The Dribble!" Thank you for sharing, and stay safe.

[@qybl]

the "turd on a shelf" toilet was invented by Germany. as a German, I think this is the second worst thing we have ever done.

[@jcmick8430]

I would say exterminate them all with fire, but they say 2 wrongs don't make a right...

[@labradoor3884]

If that’s the second worst then what’s the worst...

[@paleoleft]

@@labradoor3884 hmmm I wonder

[@gohunt001-5]

Third worst thing being whatever the heck the H&K G11's mechanism is

[@kayq_]

@@labradoor3884 worst thing germans have ever done is the creation of gummy bears

[@jacko2131]

I'll admit, as interesting as this was, I was expecting a lot more when I read the title as "Heroin fountain"

[@erinhowett3630]

Me too...

[@scandinerdian1961]

Indeed my thoughts exactly. I would think that Steve would've been quite the popular guy in the 80s of this was his legacy.

[@Android-jz2yh]

I would have loved to see instead of air, oil or some other liquid that is less dense as water as an example to show it working, this is all very interesting stuff, keep up the good work

[@spankedbywife1018]

Thanks so much very well illustrated.

[@lumbiniashutoshtambat5871]

I wanted to know this since a decade and finally got the chance now in the best way!!

[@theoct0525]

8:20 "Gas is less dense than air" - Steve Mould, 2020

[@michaeljacobdelossantos]

Maybe he meant by moist air which is wet air is less dense than air of what we breathe which is dry air.

[@theoct0525]

@@michaeljacobdelossantos I think he meant that gas is less dense than liquid, considering the context, but just had a slip of the tongue ;)

[@reezek3956]

In dorms we call old "turd shelf" toilets simply "the stage" xD

[@obanjespirit2895]

Those labels on that chart showing different types of toilet mechanism are very accurate. Especially the 'wtf' at the top right of the chart. Exactly what i was thinking.

[@zyanidwarfare5634]

I wonder if you made something like this, but super elaborate and maybe the entire thing sealed in a container, if it would actually become a perpetual motion machine since the pressure inside of the vessel is always the same, and gravity causes the water to flow in areas which shifts other water. Just a really elaborate and large series of sealed siphons

[@ryushi5]

It would be interesting to see this done with two liquids of different density. Of course, it would be very tricky to fill.

[@paulopereira47]

It would stop when the liquid of lower density gets the role of pushing the liquid of higher density up

[@YourCRTube]

It will spoil it as it will reveal the mechanics. It will be easier to "connect the dots".

[@janseta5162]

@@YourCRTube not really, it cottons be WAY sneakier if the two fluids were the same color, so then you can't see any change over time other than liquid coming out the top

[@skyrotechnics3245]

I think it would be great to fill it up with lots of water, then use a syringe to fill the middle reservoir, then pour mercury on top, which would recreate the effect

[@GA1313E]

This really makes me want to see one where a greedy cup mechanism empties the bottom container when its done so you can reuse the water to refill the top and start it over. I think might work if the base water level at the bottom seals off the air from escaping into the greedy cup mechanism

[@YuBeace]

The “shelved” toilet also helps for those who need to keep an eye on their health via their stool. Yes, really, certain health conditions can be tracked really well by checking the changes in how the stool looks.

[@SamuelLiJ]

"Gas is less dense then air" 8:24

[@SteveMould]

Oh damn

[@user-bl4oq7fd8d]

@@SteveMould didn't even notice it either, my brain somehow made total sense of that xD

[@tassiehandyman3090]

@@SteveMould Relax, man - it's just more evidence that you should never let the director edit his own stuff... 😂

[@thetafritz9868]

Lol

[@xuko6792]

helium gas is, so

[@ThZuao]

You gave me an idea to use this principle for my cat's drinking fountain (cats love fresh, moving water). So I'll give you an idea for a video: Water locks with water saving basins. I'll refer you to look up how the Panama Channel water saving basins work. Water locks may be simple in principle, but Water is such an important resource for the Panama channel they invested billions into water saving basins that save up to 60% of the water used per crossing. Because if it rains too little or they use up too much water, the depth of the cannal may render it impassable for shipping. The way they work is that when a boat has to be lowered, instead of discharging the lock's water into the lower level of the waterway, it instead drains into a separate basin that is at a higher level than the lower channel. The water level at the lock and the basin will level off, at that point the valve between the lock and the basin is closed and the rest of the water has to drain into the lower level of the waterway. When a ship has to be raised, the water from the basin drains into the lock, then the basin valve is closed and the lock fills the rest of the way with water from the higher level. A one basin design can save roughly 20-25% of water (it depends on the area covered by the basin). Panama channel uses 3 basins per lock. each at one height. When one levels off, the valve closes and the next one gets filled and so on. It's a really simple and clever piece of engineering. And I've made one in Algodoo, so I can definitelly tell you it can be made as one of your models. Also, just for curiosity's sake, I calculated how much each cubic meter of water costs to be moved on the panama channel based on how much water is drained and the cost of traversing the whole thing. They charge $60 dollars per empty 20 foot container and $90 for each full container. The largest Panamax class ships can carry 15000 20 foot containers, so based on that, the height of the cannal and the size of the locks (there are six and they're all the same size), I calculated that each cubic meter of water in the panama channel costs between $0.16 and $0.25 if we don't take into acount the water saving or $0.40 to $0.60 if we do. Where I live, the cost per cubic meter of treated tap water is roughly $1.

[@supersonictumbleweed]

Grady from Practical Engineering has a great video on the locks

[@edwardblair4096]

Here is the link to the Practical Engineering video. He actually has several videos demonstrating hydrodynamic properties. kzbin.info/www/bejne/iXPZlJ-MmMqme6c

[@engihere5434]

My friend has a cat Titan and he bought one of those fancy cat water fountain bowl things for him which cost like 50 bucks and Titan dumbass just goes to his new watering bowl and proceeds to destroy the whole damn thing within an hour lmao funniest shit

[@AnnaMorimoto]

Ideas for hydrodynamic systems: shishi-odoshi (found in Japanese gardens), water drinking bird, ancient water clocks, fluid valves, the Panama canal.

[@mohangurunathan8634]

Brilliant explanation, bravo!

[@mario387mario6]

The shelf is the old style, had to do with being able to inspect the stool to spot illness.

[@meafanaronelbuzon]

"The turd on the shelf" just got me 😂 excellent content as always! thanks!

[@ettorefassina356]

this explains it kzbin.info/www/bejne/qKu7gax5jpydmNU

[@gondebas]

7:46 That is marvelous part of your video. I managed to grasp how coil pump works. Thanks:-)

[@Aquaponic0]

I’m a high school science teacher in a high-needs area in Savannah,Ga. I am so glad I’ve found your videos because this is helping me learn how to break down complex interactions into visual demonstrations. I’ve got access to a 3d printer, which helps in many ways for more revolutionary/interesting designs and general manufacturing for class project, but I lack the fabrication process which I am learning from people like you! I appreciate your work so much Justin Kriske

[@bigl6322]

I’ve just retired from building and repairing CT and MRI scanners for 40 years…worked with everything from liquid helium and a variety of thermodynamics to high Tesla magnetic fields, High freq 150kv generators and a variety of radioactive isotopes. Only had 2 years of formal education, but I have always had a fascination with how shit works. I only discovered Steve here about 2 hrs ago on a chain fountain video, that took me to tensegrity, then to heron fountain and I’ve been thoroughly entertained and educated..Totally enjoying your explanations, theories, and demonstrations… thanks!! your kids are lucky to have a father like you, my dad is the one who provoked and nurtured my curiosity…. I liked and subscribed!! (And am making my friends watch your videos cause they are clueless..lol)

[@nicholas3435]

4:46 nice book you've got there

[@SteveMould]

Why thank you!

[@nayunis9289]

This was very interesting! Thank you!

[@987654321mnbv]

Shelf toilets were popular all the way from Netherlands to the Pacific coast of the USSR. They can still be found all over this enormous stretch of land in old buildings.

[@stephenrhea5677]

4:29 The bg music for that perfect peel 😆😂

[@-danR]

I want the outro music; dang I know it but can't remember the name or band.

[@wrongrabbit]

With all the "gas is less dense than air" quotes in the comments, before someone else points it out, at 8:37 he meant "half column of liquid, half column of *air* on the right"

[@guiorgy]

Well, I missed that one as my mind was still on the first mistake :p

[@Reth_Hard]

I don't think so!

[@lii1Il]

Cool! New subscriber. I've been looking for a clear explanation of these.

[@aoyuki1409]

the heron fountain looks like a good example of a potential energy battery. you pour liquid at the top, essentially adding mass with high potential energy and it pushes the fluid in the middle into the bottom reservoir. so the amount of potential energy u can store is whatever the amount is in the middle reservoir and the depth is the distance between the middle and bottom reservoir. i dont know how this will work out if upscaled due to friction, surface tension, bubbling etc but it feels like you can fill the middle reservoir as to fill up the system with potential energy, start it with a small amount of potential energy by filling up the top reservoir, and harness the flow of liquid coming from the middle reservoir to the top reservoir

[@tehklevster]

When I used to visit Amsterdam for work and asked about the "poo shelf" in the toilet bowl I was told that it was because folks from the Netherlands like to eat lots of pig based products. Pig based products can be susceptible to worms, and so the shelf allows the poo-er to inspect their delivery for parasites.

[@SpiderTNT.]

i doubt people here actually use it to look for worms specifically, but i do think its quite normal to have just a quick look while flushing to make sure nothing suspicious is going on.

[@therealteal620]

@@SpiderTNT. or to admire your own work ( ͡° ͜ʖ ͡°)

[@MissJilly0]

@@SpiderTNT. if you're regularly getting worms from your pork, you probably don't have a toilet to poop in

[@nara97]

I didnt knew this o.O i thought it is for, not beeing too loud when it "plops" xD xD 💩💩

[@XpVersusVista]

@@nara97 what this person said is incorrect, please stop believing everything you read on the internet. It's in part due to the splash back, and in other parts that the general quick view, that you get, helps with noticing grave medical issues. You will quickly see if you have blood in your stool, which can indicate cancer. Yet it doesn't hurt, so if you never see your poo you won't notice the blood. Which is in part the reason that the death rate by colon cancer is lower in europe than in america. Simply because people notice issues sooner and get checked out sooner, thus having a better therapy outcome.