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

Published 2023-09-24
Visit www.janestreet.com/internships/?utm_source=youtube… to find out more about Jane Street's 2024 summer internship programme.

Pop pop boats, or putt putt boats are great little toys. But could a life sized one actually work?

Here's a video about the square cube law (sort of):    • What Happens If We Throw an Elephant ...  

Check out the AHHAA science centre here: ahhaa.ee/

You can buy my books here:

You can support me on Patreon and get access to the exclusive Discord:

just like these amazing people:

Alex Hackman
Glenn Sugden
Tj Steyn
Pavel Dubov
Lizzy and Jack
Jeremy Cole
Brendan Williams
Frank Hereford
Lukas Biewald
Damien Szerszinski
Marshall Fitzpatrick
Heather Liu
Grant Hay
John Zelinka
Paul Warelis
Matthew Cocke
Nathan Blubaugh

Twitter: twitter.com/moulds
Instagram: www.instagram.com/stevemouldscience/
Facebook: www.facebook.com/stevemouldscience/
Buy nerdy maths things: mathsgear.co.uk/

All Comments (21)
  • @kowalityjesus
    There's a society somewhere in our galaxy where pop-pop boats are the most advanced form of propulsion
  • @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...
  • @PlaywithJunk
    Now I know why USS Enterprise has it's shape 🙂 It'a an interstellar pop-pop boat!
  • 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
  • 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.
  • @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.
  • 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
  • @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.
  • @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
  • @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.
  • @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!
  • @todayonthebench
    Several smaller pipes seems like a logical improvement.
    Another thing would be a bit more bracing over the main tank, that likely also don't have to be that dish shape, perhaps something more sturdy could be more efficient.

    I would have gone for a section of pipe with added support rings on its outside. Then added some sheet metal outside it to funnel the flame up around the whole tank, as to provide more efficient heating of the whole thing. And of course clad the outside of the sheet metal in some degree of thermal insulation, as to waste less heat. Then perhaps it could even become a bit more fuel efficient.
  • @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.
  • I would think the simplest thing would be having rows of standard toy motors with a common burner. Lots of small high frequency engines that are already tuned.

    P.S. after your first video I bought these in bulk for Christmas presents (1 for me 😁) they were the most played toy by all, my friends spa-bath had a Navy 🤣
  • @owenmorong3150
    I wonder if the "pop pop" action would oscillate faster if you were in cooler water? Could be cool to try in the winter!
  • @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.
  • @odesseus
    "We're very much on the cutting edge of life-sized pop-pop boat technology." I totally guffawed at that.
  • The spring and weight model was such an elegant way to visualize a complex concept. Thank you for such wonderful videos.
  • @uffle
    my childhood dreams after watching ponyo have been made real