Will this toy engine work at full size? (yes)

[@SteveMould]

But what was that giant duck doing there? The sponsor is Jane Street. Fine out more about their internship programme here: www.janestreet.com/internships/?Steve+Mould+September

[@Ibemyselfnooneelse]

Is that the taskmaster season 16 ep1 duck?

[@migs7220]

The duck is to test for sharks.

[@triple7988]

Would it work better with a check valve system? One pipe forward pulling in and the other pushing?

[@Mr.Donahue]

The AI kinda makes you sound like a pubescent teen. LOL

[@Crayphor]

I wonder if the "curse of dimensionality" could have a similar intuitive explanation to the square-cube law. The curse of dimensionality is that as you increase the number of dimensions a volume inhabits its mass moves farther from the center and clumps at the edges of the volume. This effect has an impact on machine learning. As you increase the number of "features" in a sample of data, the more sparse the feature space becomes.

[@wolf1066]

Thought they really had built a life-size pop pop boat for Steve to ride but then I saw the rubber ducky for scale and realised they'd simply shrunk Steve down enough to fit in a toy boat...

[@felixmervamee7834]

That explains the high-pitched voice, too! We're onto you and your "AI", sir!

[@DanielFrost79]

😂😂

[@Eighty8Fitter]

He’s from the movie downsizing, so he’s 4” tall 😂

[@Unapersonaconunmicroscopio]

For those curious: 12:37

[@herauthon]

he has been Streveled

[@JTCF]

Yeah, square-cube law really defines the size of some things when it comes to engineering. You can't scale things up too much, and also can't scale things down too much. Some engineering solutions just work best at certain scales. And also various material properties come into play.

[@iskierka8399]

It can be misleading, however. Vehicles can often get *more* efficient at larger sizes, because they are *not* subject to the cube part - as vehicles are not solid bodies, they are generally "skins" defined by their structural requirements, and larger size (without thicker skins) in many cases means disproportionately greater strength. This is why larger aircraft have more range and capacity than smaller - the airframe and system weight scales up only with square law (sometimes less; you don't need more computer for a bigger plane), while the cargo and fuel volumes available scale with cube, giving them enormous capacity for both.

[@bluerendar2194]

@@iskierka8399 It's just square-cube in reverse, and the point still holds that "Some engineering solutions just work best at certain scales". Same is true for ships btw, which is why container shipping has gotten larger and larger as port facilities become able to accomodate them.

[@maxgood42]

@@bluerendar2194 Yes and no becouse as the plane / boat / truck gets bigger the speed vs mass changes... or does it? This is what E=MC2 is actualy about eg; if a single engine plane can do 200 miles per hour with 4 people 1 engine and 14 gallons of fuel then in upscalling to a plane with 4 engines and 16 people using less fuel per mile per person but does not brake the sound barrier and still makes the trip a bit quicker, also down scaling has it's problems, A car with 4 people can do about 100kmh and use about 7 lts but a motor bike that is 1/4 the size and weight uses about 4 lts to get the same distance in the same time So the big question here is what are the veriables, Fun Fact- We could reduce our carbon on the road by half by reducing the speed limit World Wide to 80kmh and limiting the acceleration rate accordingly. But then Cars wouldn't have so much ware and tare and need replacing or fixing and and and.......

[@communications23]

Makes me think, wouldn't fitting it with two or more smaller pop-pop engines make it more efficient / faster?

[@maxgood42]

@@communications23 Yes I think something like that may work , smaller pipes for faster reaction and such. Also maybe the POP bit is a flaw that sounds great as a toy but not effecient. Trains don't go pop to move and they are a steam engine ???

[@mrBDeye]

My Father and I crafted and sold handmade pop pop boats on a website 20 yrs ago. The boats were called “featherlite steam boats” because they were press formed from aluminum sheets and we included certificates with serial numbers for each one. These were the only pop pop boats with small rudder on the rear. Fun times ! Although my Father has passed away some time ago I still have the press forms to create the boat hull and top and all parts to braze the engine parts.

[@mrBDeye]

@beingsentient The boats we made to operate using olive oil and wick. Other boats that were made in India came with small candle. The flame created on either type would technically never reach melting point of lead/tin solder. Besides, the water/steam inside the pop engine would also prevent temperatures to reach melting point of lead/tin solder. This is why plumbers use maps gas torch (1000 degree) to desolder copper pipes that still have some water inside.

[@robertmencl9169]

@beingsentient tje boat is suposed to be in the water before you put the heater in it

[@EggplantHarmesan]

I found an older article about it by googling. That's neat!

[@copperstaterocketguy1640]

You should re-visit producing them... We need a simple toy nowadays

[@William-nameNface]

You should definitely bring it back, even if it’s just a few a year on the side

[@xxFreakifyxx]

I love the whole sequence in Ponyo when she enlarges the little pop pop boat and I’m so glad to know it would actually work for real!

[@nickyos8640]

All I could think of is ponyo

[@JoshW-b9o]

That's the first pop pop boat I had ever seen with Soske (not sure of the spelling on that) piloting the boat!

[@Kalpit147]

I was 11 when i saw ponyo. That was how i was introduced to pop pop boats. I kinda wished to witness the same speed and sound as that boat in the movie

[@r1konTheAutomator]

Right!! This is the only thing I'm thinking of the whole time lol

[@MrBrineplays_]

When I saw the thubnail, I was like "Hey that's ponyo!"

[@kowalityjesus]

There's a society somewhere in our galaxy where pop-pop boats are the most advanced form of propulsion

[@defenestrated23]

what is the Orion drive but a giant nuclear pop-pop boat?

[@newhek]

@@defenestrated23 the pop-pop drive

[@ThePixelated_kris]

Pop pop car

[@Splarkszter]

Actually... i think internal combustion engines are a kind of pop-pop boat system.

[@thinkbolt]

Whoville

[@roygriffiths4399]

An anecdote from the UK. In 1946, I had a tinplate boat about the size of a slipper. In the centre was a small container into which one poured about 20ml of methylated spirits. Around the rim of the container were two layers of smallbore pipe. The two pipetails were soldered either side of the rudder, one being 10mm above the other. One lit the meths ,waited for a few minutes for the water to heat and expand in the top pipe before watching the boat cross the pond in silence. I still have it in my nostalgia box.

[@benjaminjones5029]

Was that your boat Pop Pops?

[@theiigotriangularround4880]

You were alive in 1946

[@mystifoxtech]

​@@theiigotriangularround4880 yes they were

[@theiigotriangularround4880]

@@mystifoxtech were or are

[@mystifoxtech]

@@theiigotriangularround4880 were because it's no longer 1946

[@uffle]

my childhood dreams after watching ponyo have been made real

[@TatsukiHashida]

My exact thoughts

[@atsurao]

Exactly what I was thinking!

[@prestonbyrd8443]

I watched ponyo in 2020, but I felt the same way.

[@gigglesseven]

PONYO WANTS HAM

[@QuiGonJoe]

just need a massive candle

[@PlaywithJunk]

Now I know why USS Enterprise has it's shape 🙂 It's an interstellar pop-pop boat!

[@patrickglaser1560]

I always thought the enterprise a looked funky

[@siggyretburns7523]

Thats what I thought too. But after loosing my eye brows lighting dylithium crystal with a Bic lighter, I kinda lost the enthusiasm to continue with the project.

[@PlaywithJunk]

You did not realize how that works. You need matter and antimatter that pops in a Dilithium chamber and makes a Warp field. Burning the Dilithium crystal is dangerous. You know how dangerous Lithium is... so imagine Dilithium. You may have lost an arm.

[@stampedetrail2003]

Ha beat me to it

[@crazyghost8379]

Said like a Legend

[@sidecarbod1441]

12:36 I like the fact that you have scaled up the duck so that it remains at the correct size for the full sized pop pop boat, great attention to detail!

[@MttGaming904]

whatt?

[@TristanCunhasprofile]

There's two ways to make a human sized put-out boat. I feel like this one is the "one horse sized duck" strategy. But I think I'd like to see the "100 duck sizes horses" strategy too

[@DarkestVampire92]

Yeah that'd be interesting to see- 100 pop pop boats trying to push a life-sized boat. While a normal sized duck watches.

[@alanherlan3429]

@@DarkestVampire92 I think pulling with the pop pop boats hitched up with ropes would work better it would be like a carriage except it travels on water and it is hitched up to non-living pulling things

[@tsm688]

I'm sure you could design a more optimal horse-duck. Without the popping diaphragm, better heat conduction At a certain point it would start resembling a steam engine. Eventually, it would just be a steam engine

[@dankline9162]

Well! They dont make giant batteries for electric cars either, so I think scaling up the boat with the appropriate amount of mini poppers would be worth doing. You could probably set them up to fill easy too.

[@neilfromclearwaterfl81]

@@tsm688 Wonder how using a valved pulse tube like in a drip coffee maker would work to improve things by eliminating the extra volume in the steam pot. Using a flow through design like that might improve outflow a bit and a header with backflow preventers using multiple pulse tubes could provide for even higher velocity output through a single final outlet. Probably would be highly inefficient though with higher water temperatures at the outlet. Wonder what Count Rumford would do... Best!

[@PeperazziTube]

In chemical engineering, there are concepts to overcome the square-cube law. Instead of a scale-up of a reactor (bigger tank), you can do scale-out (more reactors). In extremis, this results in chip-size reactors with lots of surface area. To bring this into the context of the video, just use 10,000 of the minisized pop pop boats :)

[@MachtPlays]

Thank youuuu. I had the same thought just from understanding automotive engines lol.

[@Tyche-Love]

😂 he could ask Boudreau for pointers... lousiana has had a pop pop river parade for over 80 years.

[@TimothyReeves]

Maybe a shell and tube type heat exchanger could be adapted to convey heat to the tubes with the water inside the tubes. A lot of hot air in the shell. I imagine it would have to be pretty hot and perhaps a blower in the shell to increase convection a lot.

[@snerttt]

I actually had the same thought, but I was thinking of creating chips of microscopic popping chambers.

[@tsm688]

@@snerttt too small and capillary effect will prevent them working. I don't think they can be made too much smaller than the small ones already are

[@Yukihuru]

This is a very interesting and fun experiment. In Japan, it is called a pom pom boat. It is fresh in my mind that it appeared in the anime "Ponyo". I thought it would not work with a scaled-up model, but was a bit surprised to find out that it could work with low efficiency. The biggest surprise, however, was their attempt at a full model. It's fantastic.👏👏👏

[@RandomBogey]

2:25 Honestly kind of surprised no one there put an RC rudder on the teddy bear boat. Or even a fixed/adjustable rudder to make it just go in circles and not straight out on the lake

[@mctripleA]

It probably goes tok slow for a rudder to make much of a difference The human sized boat steers by moving the motor rather than a rudder

[@neutronenstern.]

​@@mctripleAIt will make a difference no matter how slow it goes.

[@FPVREVIEWS]

because most of the time it does not go fast enough for the rudder to overcome the wind turning it.. so would only work a small portion of the time.

[@aritakalo8011]

@@neutronenstern. However they could do a nozzle jet deflector just like waterjet boats have. One probably could make one easily from one of the variants of semi rigid hose and couple actuators

[@ThisIsAitch]

Realistically it was a prototype to test the scaling ability of the engine, not the full functionality. Likely just not worth spending time on it when you can prove out the theory and move onto the full scale boat.

[@iansigman1651]

I wonder what the speed would APPEAR to be if you sped up the speed of a video of the full sized boat to the point where the frequency of the popper pan matched that of the toy's.

[@janmontkryf6783]

Let's try to answer this question with some dimensional analysis. What you're interested in is the ratio (speed of the boat)/(popping frequency). The dimension of this quantity will be speed divided by frequency or (m/s)/(/s) = m in SI units. So the quantity you're after has the dimension of length, and it's not unreasonable to guess therefore that it might scale linearly with the length of the boat. So, if you make the boat (engine and all) twice as large and then speed up the video to match the popping frequency, I'd guess that the boat would be twice as fast.

[@Moz29]

If it’s built to scale and had same popper frequency wouldn’t it appear the same speed?

[@DougSalad]

​@@Moz29doesn't that depend on the mass of the boat?

[@amiwatchesyt]

Yeah, but in an steady state I think the calculations would be correct. An analysis of the energies would probably shoulw that mass doesn't matter if buoyancy remains constant. On the other hand the steady state speed definitely depends on the drag of the boat, that is proportional to the surface, supposing the same form factor. So my guess is you would have to square it

[@khajiithaswares4147]

​@@janmontkryf6783this sounds like it was made by chatGPT

[@cyootlabs]

It's cool that it works scaled up! At the sacrifice of 1:1 modeling after the source material, I bet this would get better performance in terms of speed if done in parallel with a specific size. If the reservoir size that provides the most propulsion that also has the least amount of weight / water can be worked out, I bet it might be able to go a lot faster. I'm no expert but a V8 pop-pop boat sounds pretty cool.

[@Attemptedburger]

a system of check valves to allow it to pull water from the front and expell out the back would probably be another improvement to the design.

[@NicolasBana]

I think you don't even need check valves, just a longer tube in the front with maybe a couple kinks to increase resistance so that water flows fast out the back and slowly fill back up from the front

[@ek8710]

Very much like a pulse jet engine

[@katelights]

@@NicolasBana tesla valve.

[@fishyerik]

@@NicolasBana How would the water "know" how to choose either path over the other? It's not like your'e going to get ramjet effects at those speeds. If you design the tubing to be direction biased it's considered a check valve, like the tesla valve.

[@NicolasBana]

Just by making the tube longer and/or smaller diameter it has more resistance to flow so when the bump happen it would expel more water from the shorter/larger pipe generating a net difference in force.@@fishyerik

[@miladdilmaghani]

To somewhat counteract the square cube law, we could use fins to increase the surface area of the water tank, maybe an idea for a future video?

[@mikerich32]

You would also need fins on the INSIDE of the water tank as well. It's not just heat transfer to the metal from the flame, but also the heat transfer from the metal to the water that is limiting it when scaling up.

[@hashbrown777]

Just use a bajillion smaller engines, heat pipes to the big burner You dont build a single giant piston if you want to scale up an ICE, you build a V8

[@fishyerik]

@@mikerich32 Heat transfer from metal to liquid water is many times more efficient than that of flame to metal. Unless you create and maintain an insulating layer of super heated steam between the liquid water and metal the water at the boiling point will absorb all the heat from the metal much faster than fins could transfer the heat further up. That's why copper heat pipes are much more efficient than solid copper rods. In fact, increasing the area of the metal by using corrugated metal would be much more efficient than metal fins for the same amount of flame to metal interface area.

[@adriansue8955]

Do like Train Steam Engines instead of one big tank, a series of pipes with the flame all around them.

[@Gusto20000]

Or use that gas and water to power a steam engine or a steam turbine

[@seneca983]

10:30 But one thing you're neglecting here is that the cross-section of the boat, and therefore the hydrodynamic drag it experiences, only goes up by the square.

[@MttGaming904]

6liks:D

[@AquaticBubble]

As an estonian, seeing such a big content creator visit the small country and seeing a physics youtuber go to ahhaa is really exciting :D

[@Meg_A_Byte]

I got excited too! Tom Scott was in Tartu many years ago and now Steve Mould, that's just great!

[@Valuiskihh]

My kids went to Tartu with grandma to ahhaa, they loved this keskus (centre) 😊

[@ZephyrysBaum]

@@Meg_A_Byte i remember him getting pulled over by the military there, right?

[@Meg_A_Byte]

@@ZephyrysBaum It wasn't in Tartu and it wasn't military but boarder patrol, but yeah, funny story nontheless.

[@minaDesuDesu]

I was taken by surprise when he suddenly mentioned Ahhaa. Glad to see our country represented.

[@legendarything4406]

when I watched the movie ponyo, I was fascinated with their pop boat. id never seen even a toy of one before the movie, and i wanted one so bad after seeing them driving around their city in one with just a candle powering it. incredible that this works at this scale. so cool

[@jpeg4113]

I was thinking the same. Ponyo got me obsessed with pop-pop boats.

[@gricogary5772]

When tou say ponyo Its equivalent of smile to me

[@williamparker9506]

I just watched it, and I'm here now 😂

[@11equalsfish]

It's so cool to see it for real!

[@dilligaf8349]

Had a bit of a fascination with these boats and this video was fun to watch with a great educational piece on how scaling up works, doesn't work. Brilliant work and great to see those guys where happy to have you come and test their boat.

[@matthewbartos2971]

Hence why cars have multiple cylinders, square cube law. If you tried to blow up a three liter bottle the explosion is way slower and takes more rotational mass to keep going as compared to six half liter bottles which explode faster and can keep each other moving. This can be applied to whatever engine size you have.

[@coolhand1983]

I was literally just thinking along these principles!

[@scottg3192]

V12 pop pop when?

[@lukelun]

damn this makes so much sense, thats insane. thanks

[@gs425]

Multiple cylinders is also preferred as it allows a faster revving engine than a single of same capacity. Power = torque x speed of course. However their is a limit on piston speed due to materials and lube etc, so using multiple cylinders overcomes this.

[@kallewirsch2263]

It is also the reason why kids (eg. in winter) cool down much faster then adults. Their volume, which stores the thermal energy, is in relation much smaller then the surface, which distributes the heat to the air.

[@ThatPawikBoy]

My grandfather made me all sorts of interesting inventions out of metal, wood and other materials (even lightbulbs with the dynamo) to play with, including pop-pop boat (not life-size, of course). I love him so much.

[@nikiTricoteuse]

Love this and love the transparent version too. It's great to see a visual of how it actually works. When my daughter was little, we were SO poor that l had lied to her and told her that takeaways (she heard people talking about them) were things you cooked at home and took away to eat. I used to make homemade hamburgers, pack a picnic and the putt-putt boat and we'd walk to a nearby park that had a tiny shallow creek. (She was so young and we were so broke that l'd even save the middle ⅓ of her hamurger bun to make breadcrumbs with 😊). We'd eat our picnic and sail the boat in the creek using a stick to steer it. We even made our own fuel for the boat using part of a wad of cotton wool and cooking oil. By the time she started school things had got a little easier and we could afford actual takeaways occasionally so, her classmates never got to tease her about it but, our takeaways and afternoons with the putt-putt boat are actually a happy memory. It was more than 20 years ago now and l found the wee bottle of spare oil and the cotton wool tucked into a pocket of the picnic basket a while ago, and had to grin at the memory. Of course l've still got the boat too, I never knew the front lifted off though. 😊

[@donmelbouchard]

Sweet memories

[@b_ks]

Okay, what's an actual take-away?

[@liquidblake]

@@b_ks it's what the English call takeout

[@susanbrearley437]

​@@b_ksMcDonalds,kebabs,kfc etc etc

[@robertschnobert9090]

Man, I wish I could afford a burger. I'm on a pasta with ketchup diet hahaha 🌈

[@coffeeshangarworkshop8051]

I wonder if making a Multi-motor pop pop would work better. With more smaller motors you would get faster cycles and hopefully scale that speed up.

[@lukasdolezal8245]

I think the speed would still not change. each motor would push same amount of water each cycle, so each would push the same distance. I guess the only difference is more power, ie ability to push heavier boat but still the same speed.

[@antonliakhovitch8306]

​@@lukasdolezal8245Think of it in terms of Newton's laws - for every action, there is an equal and opposite reaction. Pushing one liter of water out the back of the boat requires significantly more force than pushing one milliliter, and as such will also apply more forward force to the boat. As for "pushing a heavier boat but at the same speed" - in this case, "speed" and "pushing power" are the same thing. They're related by F=MA -- so for a constant force, a lighter boat will accelerate faster.

[@antonliakhovitch8306]

​@@lukasdolezal8245(I think your logic begins to work *if* the boat is travelling as quickly as the water coming out of the engine, but in this case it's a small mass of fast-moving water pushing a heavy boat slowly. However, this might set an upper limit to the speed you can gain by adding more engines)

[@MarmaLloyd]

If timed properly this could be cool. Like a cross between a cam and pop

[@LanceThumping]

If he's right about only needing a single pipe then why use a tank at all. Take a bunch of regular pipes, cap the ends, bundle them together and run a burner against them. Then it should work like your idea.

[@covenantor663]

I noticed quite a few comments regarding stiffening the top of the boiler to gain better efficiency. When I was young I got a pop-pop boat for Christmas. An el-cheapo from Hong Kong or Japan, but surprisingly well made. I remember the boiler being reasonably rigid and was quite a fast little boat.

[@benjaminchung991]

Could you improve the boat with a regenerative heat exchanger and running the burners through effectively a fire-tube boiler inside of the chamber? That way you can recover energy that's lost to the water, and can increase the heated surface area.

[@mattymerr701]

Steam train, but boat

[@oraziovescovi1922]

I bet this engine could be massively improved with a bit of thermodynamic engineering and a solid build and I want to see it so bad

[@JohnDBlue]

I was just thinking what if you heat it from the inside of the tank without specifics because I don't really know how any of this works 😅

[@fireskorpion396]

​@@oraziovescovi1922i was also thinking that heat fins would make a huge difference probably

[@gcewing]

At which point it's starting to sound something like a Stirling engine with a water piston.

[@jorge8596]

I want a full pop-pop boat engine optimization series. I'm interested in seeing what can be achieved with them

[@ricdavid]

Seconded. This is the real science we need our top minds working on.

[@ColinDaviesNZ]

I wonder if pop pop boat races would be a good way to solve some of the issues.

[@leoneventicinque6731]

I call the support of @Integza!

[@thewesty101]

This made me think about using it like a ram pump. Move some water up a hill for the cost of a fire. With it sitting in the sun it would get started faster too

[@tsm688]

After a certain point it would just be an ordinary steam engine

[@Naro_Rivers]

I worked out the square-cube law, at least in part, as a teenager, but never heard the name for it until well after college. My best friend couldn’t wrap his head around it when I tried to explain it shortly after discovering it.

[@MttGaming904]

ok

[@madeintexas3d442]

I made a regular one of these as a project for school. It was all woden and brass and looked very good for someone in middle school. I still have it sitting on a shelf .

[@MachtPlays]

Fire it up!

[@flamesofhellstudio]

Holy shit, you've managed to explain to me the square cube law better than any other video I've seen on it. And now I know why it's called the square cube law, one thing scales on the square and the other on the cube.

[@dp909rev6]

If you made the tank rigid, instead of letting it flex up and down, a lot of your energy would go into thrust behind instead of into the air above the boiler. It wouldn’t make the pop pop sound, but it might be more efficient.

[@ApolloVIIIYouAreGoForTLI]

In the summer here in Australia you wouldn't need to run these off gas, the solar heat would probably be enough :D

[@azrobbins01]

He would probably get better propulsion if he just vented the gas directly into the water to push the boat.

[@MartinTowell]

Change Summer to Winter. In the Summer, here, you're likely blow the thing up with too much heat.

[@sihamhamda47]

Yeah, use a big convex lens to concentrate solar light in small area

[@samuelpierce2.088]

I realize that it’s not at all practical, but your comment gave me an idea: What if they replaced the propane and burners with solar panels and coils of wire, and then shrunk the size of the metal pop-pop plate into a more rigid capsule-shaped canister? Theoretically, you could then run a pop-pop boat for as long as there was water in the tank, and as long as the solar panel continues to provides electrical-to-thermal energy to the water in the tank, which could be for a really long time.

[@enzochoi923]

great build! I'd love to see a racing league of these (where people compete optimizing them for more 'horsepower')

[@turgsh01]

Sounds like a liability issue. Not everyone is smart enough to do things safely. To elaborate since no one here seems to figure out the risks involved... Propane tanks can very easily explode like a grenade if the hoses and whatnot aren't set up correctly. That "grenade" can injure surrounding participants, judges and audience members who had nothing to do with it. While I agree that idiots shouldn't be protected from themselves because we definitely have far too many in the world and protecting them is only making it worse, I do believe we should protect the innocent ppl surrounding the idiots.

[@jcKobeh]

"hose power"

[@Sam97979]

@@turgsh01 racing REAL cars and boats is wayyyy more complicated and dangerous, and we let any idiot do that worldwide. people die. We still allow it. A pop pop league would be fine as far as safety is concerned.

[@BillAnt]

I remember building a similar model boat back in the late 1970's as a kid (may have been Popular Mechanics magazine). Instead of a pop-up boiler, I used a thin copper pipe coil heated with some alcohol inside the boat, and the two pipes out through the back under water. It was basically creating a water jet powered by the copper coil heat exchanger, and the water didn't run out like in this boiler, it only stopped once the fuel ran out. Surprisingly it was traveling pretty fast without making any popping sounds. Long before the internet, simple things got us kids amused. hehe

[@thecrazyfarmboy]

​@turgsh01 the more we idiot-proof the world, the more idiots we end up with. The more idiots we have in society, the more ways they'll find to do things dangerously. In other words, so what if someone might get hurt in a life size pop pop boat race. Nobody makes it out of life alive anyways

[@DanYHKim2]

Aside from the cube-square problem, there also the fact that the viscosity of water does not "scale up" at all. It is possible for water to escape from the tubes, since they are so much larger than the tiny tubes in a toy boat.

[@reanimationxp]

I really appreciate your explanation of the square cube law and how it pertains to the scaling up of the boat in different ways. Some of this was intuitive to me like the mass being the ultimate reason it goes slower rather than the same relational speed, but other parts like the surface area and diameter of propulsion tubes was not. Like you, I'm equally fascinated by how they're the same speed when it all shakes out. Anyway your description was very succinctly put and I learned something. You've demonstrated not only a great understanding of the physics but also a talent for explaining things in an easy to understand manner. I strive to do the same thing for people about my areas of expertise so I love and appreciate videos like this.. thank you!

[@tsbrownie]

I've made several of these and one trick is to keep too much water from entering the chamber on each cycle. One way is to better match the chamber with the pipe sizes. And as mentioned in the video, the water input can not exceed the heat that can transfer through the chamber per cycle to flash the water to steam. I'd guess that if they made this chamber more rigid, decreased the internal volume, increased the heat transfer, and limited the water intake (the rigidity and volume will help) it would work better. How much water could this setup flash? Maybe a cup? Probably less.

[@trif55]

I'd really love to see someone try and optimise a pop-pop boat a bit like that guy who optimised a trebuchet to shoot supersonic!

[@Eyes0penNoFear]

​​@@trif55I'm off to try and find that trebuchet, any suggestions? Edit: a simple search for supersonic trebuchet did the trick. Who'd have thought? 😅

[@nzbeeman]

I was thinking along the same lines. Wen I was a kid we made one with just a copper coil. It didn't make the pop-pop sound anywhere as much as the toy in Steve's first video. Much more like the glass version.

[@blandhoke]

Thanks for finding advertisers that aren't earphones. Aaand your content is on point/ awe inspiring. Well done.

[@odesseus]

"We're very much on the cutting edge of life-sized pop-pop boat technology." I totally guffawed at that.

[@craigwall9536]

Dunning-Kruger writ large...

[@jamesfunk7614]

The demonstration with the cubes reminded me about tiny critters, such as ants, being able to lift something that is many times their mass, while we have difficulty lifting something that has about the same mass as us: The mass of a muscle increases proportionally with the cube of its linear size. But, the strength is limited by the cross sectional area, which increases proportionally with square of its linear size.

[@leonerduk]

The square-cube also relates to ants in that an ant can fall out of a tree and land on the ground without a problem. Terminal velocity for an ant is no big issue.

[@ireallyreallyhategoogle]

It's also why truly gigantic ants are not possible.

[@bunderlemu7802]

Thanks to their size, humans can withstand weather and other hazards much better than ants. A human can destroy a colony of ants, if he/she wants to. Luckily for ants, most they do now is staring idly into a shiny rectangle thingie.

[@lcfflc3887]

mass doesn't always equals weight.

[@WagonLoads]

@SteveMould I have a challenge for you.... Design human powered bicycle (with or without 2 wheel tilt steering front end) Where when you go around a bend(turn the bike), you harness the centripetal forces of the turn into a mechanical feedback loop, that keeps the bike self balanced. Objective is to use centripetal force of the turn to keep the bike tilted at the correct angle so that the center downward mass is parallel to the bike frame... You are allowed to think outside the box when it comes to conventional designs.. Like cams, pivots, swinging seats, etc.... Human power: no servos, gyros, motors... Balance: completely done by the bike, not the human... Is that possible?

[@praveenb9048]

Next up: Tom Scott crosses the Channel in a pop-pop boat.

[@MttGaming904]

Oh no.

[@ChrisParrett-qo4sx]

Interesting, Steve… A point missed by yourself and the others is that a pulsating water engine (PWE) or 'pop pop', 'Tok Tok' etc., doesn't have to have the flat plate. Toy ones only had a flat diaphragm to make an engine noise. A simple coil of tubing over the flame works better as the flash boiler, and was used in larger model boats like the beautiful, pressed aluminium 'Miss England' by Victory Industries, sold just after WW2, as well as in many kit and scratch built models. The PWE engine works by rapidly boiling the water in the flash boiler, which turns to steam and forces the water in the tail pipes out quickly. As the steam hits the cold pipes, it condenses, while the exiting water providing the thrust carries on moving down the long tail pipes under its own inertia (some small toy 'pop pops' only had a single tail pipe). The moving slug of water's inertia then creates a vacuum after the pressure of the steam bubble disappears, which eventually pulls in water, increasing the cooling of the condensing steam and refilling the tube, and 'boiler' section, with liquid. The coil (or chamber/boiler) over the heat source gets rapidly boiled again to send another pulse of steam down the system as it overcomes the back pressure from the now condensed previous bubble of steam and the drawn in water, which is pushed out to provide thrust (but not a lot). A 'full size' PWE powered boat was actually built before WW2, though only a dinghy in size and very slow, it was virtually silent and used to stalk and net waterfowl on a calm pond. My late father had a huge collection of old steam powered toys, including a lot of PWEs. Most of the PWEs were small candle or spirit heated 'pop pops', but some commercially sold ones, usually methylated spirit fired, were as big as half a metre long or more.

[@jvtaxi3766]

Absolute nonsense.

[@TheManOfMyriad]

Very cool, I had wondered if there was a more efficient way to make this work! Cool history, I doubt there's many people who'll know of this these days

[@StuartChignell]

​@@TheManOfMyriadby inclosing the heart source you would also increase efficiency.

[@EMLtheViewer]

@@jvtaxi3766Care to explain?

[@jvtaxi3766]

@@EMLtheViewer Try study the subject a little more ,then see if you really want to ask me to explain.

[@OliviaSNava]

So in other words, regarding your square-cube law theory of speed, if we want to get a life-size pop pop boat, we need 8,000 small ones acting together since it's 20x as big.

[@idrlc2123]

Man, this reminds me of Ponyo.

[@eagleloid]

That must have had some inspiration to this project.

[@monkey_man70-1]

Absolutely wonderful explanation using the harmonic motion of a spring attached to a mass. I now have an incredibly intuitive model for how the pop-pop boat works thanks to this video. I am very very glad you exist and make videos like this. Thank you Mr. Mould!

[@disqorddoge1101]

We made one once at home using half a water bottle, a tea light candle and some thin metal tubing. My dad created a single loop out of the tubing to act as the heating chamber instead of the typical metal tank. Filled the tube until water came out the other side and placed the flame of the candle either in the middle of the loop or under the front side of it. It worked. I think it might have worked better if we didn’t need to run a slightly smaller metal wire through the tube to ensure it didn’t collapse when bending it into the loop.

[@DocTinfoil]

Your wooden cubes are a PERFECT description of reality!♥ Thank you, Steve!♥

[@thinkinsidetheboxsquarecir3303]

💯🎯And he proves NASA’s full of it! Rocket science have the same Dilemma!

[@dfriedbauer]

I have been dreaming about this since 2009, when I watched Ponyo for the first time.

[@MttGaming904]

me to but not 2009

[@TCAPChrisHandsome]

I learned about the square cube thing when I wondered why elephants have such massive ears. Big animals have more insides that need to be cooled down, small animals have less insides that need to cool down. Elephants have massive ears full of blood vessels, so they can dissipate body heat

[@helenault7452]

Suggestion: Use a single propulsion pipe with a pair of check valves that allow water to flow in through the front of the pipe and out through the rear. I suspect that it's best to make the inlet slightly larger than the outlet. I'd go with the type of swinging-gate check valves often used in wells because they lack a spring that could interfere with flow at the very low pressures involved.

[@treborobotacon]

Except a pop pop boat works by pulsing water in and out not by expelling water.

[@TlalocTemporal]

If we're moving to a flow through design, we might as well full commit. Use a drip coffee maker heater for the heating mechanism, basically make the whole system a steam jet engine.

[@helenault7452]

@@TlalocTemporal No need for full flow-through on the entire system. In fact, that wastes the heat in the water of the pulse-generation section of the plumbing. But using separate inlet and exhaust orifices in the jet segment means that inflow can have a larger orifice than exhaust, providing the opportunity to increase exhaust velocity without reducing return flow as well, which ought to improve performance. We're talking about a very weak pulse as currently configured; this could make a measurable difference. I very much doubt that the system can be made effective enough to be truly practical, but it might be possible to lift it to the level of entertaining curiosity at full size.

[@liam3284]

When I was young, made one using a copper coil rather than a diaphragm.

[@corbeaudejugement]

​@@treborobotaconthe end goal is to eject water out of the exhaust to move the boat.

[@procrastinatingnerd]

I wonder if it could get more propulsion with some check valves directing the propulsion through some smaller output, but suck the water back in through a larger input.

[@MrAlbinocreeper]

yes, but a pop pop boat is supposed to need no moving parts

[@Meatball2022]

@@MrAlbinocreepercan use Tesla valves. No moving parts. Put an intake valve on the front and the output on the back. Double the propulsion with no moving parts.

[@chrisdofman7878]

Volume and surface area is only part of the problem, pipe run is very important. You have vertical pipes with 90 degree bends, that will significantly reduce flow, the heat wasn't really scaled up either. You need to bring the plate closer to the water to reduce static head, increase the heat and make the flow of water as smooth as possible by straightening the pipe as much as possible, Pipe diameter is also important. Friction loss is irrelevant due to the short distance but you will need to understand the volumes of water flowing in and out of the engine to calculate the pipe diameter required, the pipe needs to be small enough to only just allow the required flow, valving and other forms of throttling won't work.

[@jacobe2995]

I have always wanted to see a full-size boat with hundreds of smaller popop engines along the bottom.

[@Pants4096]

This is the pop-pop boat version of the horse-sized duck vs 100 duck sized horses debate... ◡̈

[@natebell4764]

This is my thought after the suare cube law segment.

[@aanchaallllllll]

0:14: 🚤 The video showcases the process of building a life-sized pop-pop boat. 3:03: 🚤 The video discusses the features and operation of a pop-pop boat. 6:50: 🚤 The video shows a pop-pop boat in action and explains how it works. 10:09: 📐 The video discusses the square cube law and its relevance to the pop-pop boat. 12:50: 🚢 The video discusses the movement of a tanker in water and suggests a potential improvement in its design. Recap by Tammy AI

[@ambition112]

Thanks for saving time! Amazing summary tool with lovely time stamps!~ where u download this Tammy AI?

[@cosmicjenny4508]

@@ambition112GO AWAY, BOTS

[@TheZoltanChronicles]

I'm impressed that the thing works at all. Life-sized pop-pop boat races should be a thing!

[@LegendaryKenneth]

Would be interesting to see if it would be more effective to use a large number of much smaller engines, instead of one big one.

[@PitchBlackCat]

I think the AI voice thing did a wonderful job, you are very legible and the background noise is very palatable, even with earphones. I think it's a keeper! The only 'weird' thing that stood out to me is that it changes your voice in such a way that you sound like a different person with the same intonation/speech pattern. Other than that i didnt notice anything unnatural about it. Hats off to whoever created that! 👏

[@jamesgabb9352]

It makes him sound like Rowan Atkinson to me lmao

[@C.I...]

I really would rather hear the noisy audio with subtitles. It's so weird and uncanny to me, quite creepy actually.

[@fkmobile1]

Which AI tool was it?

[@anonymousejr]

​@fareedakhan just commenting to get notified...

[@Quarterpounderspatch]

​@@anonymousejrsame

[@timlee4204]

I don't know where I got the idea but as a teenager I wound a coil of brass pipe, (about 2 turns) the coil was about 1 inch diameter and the pipe was small about 1/8". Mounted on the back of a sardine tin, metho was the fuel but it worked. The water in the pipe turned to steam, blasting out of the pipes, then when there was no more steam, the pressure collapsed and water got drawn back into the hot pipe which would immediately burst into steam, so the cycle repeats. Ted from down under.

[@PsiVolt]

it is a bit strange at parts, but it is incredibly how the audio while on the boat would have been unusable and probably require a voiceover even just a year ago but now we can noise-cancel and reconstruct dialogue pretty well given how I imagine the original audio is

[@aserta]

There's a drip coffee pump version of this (well, used to be one, back in the 90's) in France. Made into an actual wooden row boat. If memory serves me right, it had a glass lathe's burner oriented towards a 3~4 cm ID copper pipe, u-shaped, with check valves at the end. The intake pipe was bent forward in to a hook, which used to cause the pilot a head ache once in a while because it kept catching stuff from the lake it was tested on. There's that saying "once on the internet, always on the internet" but it's not true at all, can't find that forum for the life of me.

[@sceptic2061]

You can use that plate for cooking too. Amazing!

[@TheUnknownCatWarrior]

The pop-pop boat in ponyo except it abides by the laws of physics

[@evan7795]

I would love to see a pop pop boat with many many smaller engines. Like your eight cubes separately, the surface area would scale with the volume. But maybe the medium engine, so you wouldn’t need 1 million of the mini ones.

[@gankthis]

A lot of great theory here. I'm wondering about multiple tanks feeding to single or dual outlook with check valves. Honestly my mind is running wild with multiple ideas. Thanks for the content!

[@turgsh01]

This seems very interesting and might be worth looking further into. For example, would it be more efficient to have several smaller pop tanks or whatever, or a dozen even smaller ones? And what about automatic pressure release valves for better control of the release. Maybe have it release when it reaches a much higher pressure and have it cycle through the tanks like an engine cylinder.

[@Jimmeh_B]

That was my immediate thought too. One way valves. Two out at a set pressure and one in.

[@bobedwards8896]

the amount of fuel they are using is insane, better off using probably any other tech. even something like a pulse jet

[@Validole]

Problem is, you build up too much pressure, you'll empty out the exhaust pipes, meaning you're now pulling in fully cold water on the intake stroke, instead of condensing steam in the boiler end of the exhaust tubes.

[@VoltisArt]

@@bobedwards8896 making a _good_ boat was really not the point of the exercise. It's not even the point of the toy.

[@Mad_Catter_]

Time to make me an "eight cylinder" pop pop!

[@Lampe2020]

1:55 The teddy-bear-sized boat isn't a pop-pop boat, it's a clang-clang boat XD

[@VaalkinTheOnly]

Another way to think about the cube bits is that you're measuring the surface area by only 2 directions and the volume by 3, so you multiply by another of whatever number you were multiplying by

[@lewismassie]

I think this might be a fun propulsion thing for maker youtubers to try their hand at like pulse jets, ionic thrusters and air-powered engines

[@noturfather1106]

Look up Robert Maddox

[@piergaay]

What we see here is a good explaination why certain techniques do work in one scale, but not so much in another scale. Food for thought for many alternative energy ideas. Nice video, and not only for that!

[@georget.6357]

Oh, I have an idea! Make several pop pop motors of various diameters, run them sequentially and you could have an (obnoxiously loud) percussion instrument. I didn't say it was a good idea.

[@notanimposter]

This is literally a childhood dream come true! I always wondered if this could be possible, and I was beginning to wonder if I'd have to make one myself to find out!

[@AdamsWorlds]

Yes! Finally. This has been keeping me up at night every now and then. Always wondered what a life size one would act like, seemed like a no brainer to make if i had the funds lol.

[@chatlau8444]

Thank you for investing to make this clip. At least now I know I'm not the only one wondering if it's possible to create a full-sized, functional toy.

[@jacapig]

Ponyo confirmed completely scientifically accurate.

[@PushyPawn]

I like how efficient that pop pop boat is. Only needed one gas bottle.

[@PsRohrbaugh]

Candle, gas bottle, nuclear reactor...

[@jimstartup2729]

I actually did my mechanical engineering final year project on attempting to model the process on how they work. I also made transparent poppop engines, and rigged up several prototypes with thermocouples to map heat difference and so forth. I didn't get very far other than a ton load of data that was hard to interpret. I guess the problem is scaleability. A toy poppop boat only needs a little thrust ti get going but a flame provides a massive amount of energy for the scale of energy transfer in the expansion chamber. To provide the same ratio of energy transfer you need a heat source much more potent.. but material properties dont upscale so you cant heat a larger chamber the same way with all the pressure and energy required to produce the same reactional emotive power

[@jimstartup2729]

Unfortunately you can't just scale everything down or up. The size of molecules doesn't change when you shift the structure. There will always be an optimal size for certain things.

[@hansisbrucker813]

It would be cool if you used those motion amplification cameras you covered in another video to show how the parts moved 🤔

[@peppersiegel7636]

AI Steve sounds like Steve is being possessed by a Smurf

[@fugithegreat]

My favorite part of the film Ponyo was when they grew one of these boats to kid size and went sailing over the flooded town. What a magical moment!

[@valentine7455]

lmao, the ai made him say fwequwency 7:00

[@osterberg87]

Can you make a permanent magnet motor with a diamegnetic material like bismuth. I know it will be x1000 worse but would it work as a generator? A little?

[@Validole]

It could theoretically work as a motor, but backwards compared to a normal induction motor. But diamagnetics don't have their own permanent field, so working as a generator is a no-go.

[@VoltisArt]

Making a permanent magnet out of something diamagnetic sounds...diascientific. I don't think it works that way at all, like trying to magnetize water or your body. No magnet, no motor or generator. Not 1000 times worse, infinite.

[@Shino_666]

if that steel slap pop-pop like the pop-pop boat, that'll sound like a thunderstorm.. XD

[@kchorman]

Great video, as always!

[@BLenz-114]

My intuition tells me that part of the problem with the large boat is that the metal on the top of the motor has NOT been scaled up correctly. It should be considerably thicker so you’d get a faster cycle.

[@SLO-Ride]

Unless it has already been mentioned (3798 comments at this time), the flexing bellow of the steam chamber should have a much higher tensile strength, in order for the water to be pushed harder, and to vacuum the replacing water. The normal pop-pop has a very stiff membrane, which gives it the loud pop as it flexes. The scaled up engine, must also have a very stiff bellow in order to snap up and down, rather than loosely balloon up and softly collapse. This would also require much more fire beneath. Again, look at the toy, which dimensionally uses a massive flame for the size of the engine.

[@fixitfox7869]

I wonder if you can make a life sized glass engine... sounds dangerous but it would be fantastic to see it happening at such a large scale, plus the glass wouldn't flex as much but I imagine that's what makes it so much more dangerous.

[@OmateYayami]

I doubt it, unless you used some special glass. I believe, the glass tank would need to be thicker to withstand the pressure, and glass is pretty heavy... and poor heat conductor. Plus as you say, imagine pressurised glass tank failing... although that's probably just a cherry on the top of problems with scaling glass.

[@eDoc2020]

A giant glass pop-pop boat you mean? I've seen videos of gasoline engines which have enough clear parts to see everything which is going on inside.

[@TheComedyButchers]

Shame that they didn’t make it look like the ponyo boat

[@stick3915]

So, as per your explanation about the square cube law with the blocks, where there are surface area missing after it goes inside the bigger cube: Does that mean that if the big human boat (or even the teddy bear boat) is propelled by 20 or 50 small pop pop boat engine, the boat will run faster? (theoretically, we will have 8 small cubes without the surface area diminished caused by the combination into a bigger cube).

[@dingo4530]

I'm only watching to find out WTF a pop pop boat is and what size they usually are

[@ashj_2088]

Had as a kid in the 90sgot it in Bali and on one had seen them in Australia

[@tonytubini6399]

A sad childhood, I can't imagine growing up never seeing the wonders of a pop pop boat. Up until I was about 10yrs old it held the prime place in my toy box I had a proper steam engine that ran a dynamo but I could easily understand how that worked but I didn't fully understand the workings of my little pop pop, it didn't compute😮

[@RachelWilde-p5t]

You should never take advice from someone who thinks red paint dries quicker than blue paint.

[@borium]

Very cool video Steve ,thanks for sharing .If you make the openings of the pipes smaller ,this will give you more thrust.

[@Alexander.0671]

So would increasing the surface area increase the frequency of the engine? If so, I'd assume you could make one using something similar to the fins in an Automotive radiator to help achieve faster speeds.

[@Tiaintherain]

Those propane powered portable showers are prefect

[@AnonymousAnarchist2]

Well heres a thought for you. I dont know your age, this is ment to be honest advice and not to talk down to you, but accessable to all ages. Heat capacity, how much heat energy any object can hold and carry to raise its tempurature by 1 degree. For air and aluminum, and steel, and copper, it all has a much lower capacity then water. So given that, what side do you think needs more surface area? What would be better, having more heated air from the flame pass over the same amount of water, or trapping more air for the same volume of water? You could have many smaller heating tubes with the same burner, and that would dramaticly increase the surface area (touching the air) to water ratio, or maybe make a bigger wider, thinner pop chamber if you did not want to spend months making one, would that work better then wjat youve propsed?

[@TheHuskyFamily]

wouldnt it make sense to build much more but smaller engines? why build one big one that takes long to heat up? make alot of small ones that are very quick to heat up? you increase the engine 100x times but increase the flame/heat 10x times? ofcourse its not going to work the same? and im no engineer, just logic..

[@stephenlee4369]

I used to play with this pop-up boat when I was 8 years old. This is genius ECO friendly technology.

[@baileescott401]

I want the water reservoir to be a cylinder, the structural integrity of a cylinder would allow higher pressures with less deformation

[@2testtest2]

This is essentially a cylinder already, just with a height of 0, and a slightly curved bottom XD. If the top was slightly curved as well (upward) that alone would make the reservoir much more rigid, even more so with an internal post in the center. I think the flat-ish shape is kind of necessary for the heat transfer to be efficient.

[@neogoo123]

So the video is great, but now I can't help but be curious about the AI you used to improve your voice while on the boat. Would it be possible to get information on it(Or make a video on it!)? I'm lay in the area of AI audio improvement.

[@Eagles_Eye]

the surface area / volume thing is also why Tesla developed the 4680 cell ( more battery, less metal casing ) it's also why its cheaper to buy 1: 2 liter milk package compared to 2: 1 liter milk packages, you got more packagings to pay for .

[@BashoftheMonth]

7:17 Whoops, let the demon slip out.