Can water solve a maze?

Aug 15, 2023

Can water solve a maze?

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Here’s the original simulation by bergmanjoe: https://www.tiktok.com/@bergmanjoe/vi…
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Content

0.131 -> (upbeat music)

7.83 -> - So many people sent me this simulation

10.62 -> of water pouring through a maze by Bergman Joe.

13.26 -> And it makes sense that you sent it to me

14.58 -> 'cause this is the kind of thing that I would make for real.

17.64 -> So of course when I saw it, I had to make it for real.

21.21 -> I actually made four mazes in total,

23.85 -> a simpler one and a more complex one,

26.13 -> and I also made large versions of those two mazes.

28.98 -> Let's look at the small mazes first,

30.81 -> because when you see what happens with those,

33.06 -> it'll be obvious why I made the larger versions.

36 -> And by the way, this simulated version

38.49 -> does eventually fill up completely with water

41.43 -> and it's very satisfying.

42.78 -> But if you want to see that ending,

44.64 -> you'll have to go to Bergman Joe's profile,

47.46 -> link in the description.

48.54 -> Okay, so here's the simpler maze first.

50.61 -> And what we find brilliantly is that the water simply solves

54.27 -> the maze without taking any wrong turns at all.

58.02 -> And actually that makes sense

59.31 -> because every time the water comes up

61.44 -> against an incorrect path,

62.94 -> well, the air inside the path has nowhere to go.

66.09 -> So while the water is trying to push itself

68.04 -> into the incorrect path,

69.36 -> the air pressure inside that closed space is pushing back.

72.9 -> If I had to characterize this as a maze solving algorithm,

76.14 -> the algorithm would be something like,

77.73 -> try all paths simultaneously using air pressure,

81.81 -> which is cool.

82.643 -> When the tank runs out it's fun to watch

84.3 -> the air bubbles solve the maze as well.

86.79 -> And actually it's quite different

88.14 -> to Bergman Joe's simulation

90.06 -> where the water eventually tries every path,

93.18 -> even after it's found the solution.

94.89 -> What about the more complex maze?

96.63 -> Well, first one, I chose the maze where the solve path

99.6 -> takes the player all the way back up to the very top again.

105.75 -> Well, already something seems to be amiss,

108.96 -> like there shouldn't be any water here,

111.69 -> or at least not yet.

113.43 -> And there shouldn't be any water here either,

116.13 -> or at least there shouldn't be if this maze

117.93 -> is following the same rules as the previous maze.

121.32 -> So what's going on here?

122.94 -> Well, the explanation is quite simple.

124.77 -> I just didn't build a watertight maze.

127.53 -> The reason I didn't build a watertight maze

129.03 -> is because it's really difficult.

130.98 -> Like I've got three layers of laser cut acrylic here,

133.89 -> a black layer, that's the maze itself,

135.66 -> and two clear layers sandwiching the black layer.

138.06 -> And the best way to bond these layers together

140.28 -> is with solvent that literally dissolves the acrylic

143.01 -> on both sides so that they weld together

145.44 -> when the solvent evaporates.

147.03 -> That's easy enough when you're bonding the black layer

149.88 -> to the first clear layer.

151.62 -> The solvent simply seeps between the two bits of acrylic.

154.89 -> But then when you put the second clear layer on top,

157.53 -> well, how'd you get the solvent in there?

159.3 -> A fun side note.

160.133 -> One thing you realize very quickly

161.58 -> when you laser cut a maze is that mazes

164.07 -> are always made of two separate pieces.

166.17 -> I mean, it's obvious when you think about it,

168.15 -> but it's quite cool to see.

169.5 -> Actually a maze becomes very easy to solve

171.39 -> if you color the two parts separately.

173.49 -> But anyway, why did I build the larger mazes?

176.19 -> Well, look, I stated that the reason

178.14 -> water doesn't go in here is because there is air in the way.

182.01 -> But why doesn't the air just bubble out

184.08 -> so the water can get in?

185.82 -> Well, it's because of surface tension.

187.68 -> The air is unable to bubble past

189.72 -> to the surface tension of the water.

191.43 -> So if we make the maze bigger

193.5 -> until surface tension isn't significant anymore,

196.83 -> we should expect the maze to be solved in a different way.

200.28 -> We should expect the water to use

201.96 -> a different solving algorithm.

203.88 -> Maybe something closer to what Bergman Joe showed

206.67 -> in his simulation.

207.93 -> By the way, for the larger maze,

209.1 -> I had the genius idea of laser cutting thin channels

212.61 -> into the outer clear acrylic so I could squirt

215.82 -> the solvent in once the clear sheet was in place.

218.4 -> But anyway, here's the simple maze in action.

221.34 -> And you can see without the power of surface tension,

223.74 -> the water finds the lowest possible place it can go to.

227.19 -> Sometimes momentum plays a part

228.9 -> so it will fill certain paths before others as a result.

231.93 -> But broadly without surface tension,

234.12 -> the water tries more paths before finding the correct one.

237.66 -> If I had to describe it in terms of a solving algorithm,

240.42 -> it would be something like, always take the path

242.88 -> that takes you lower until you can't anymore,

246.18 -> and then take the next lowest path.

248.31 -> We'll get to the more complex maze in a second.

250.32 -> But first, let's compare this to Bergman Joe's simulation.

253.2 -> More of the maze becomes full of water,

255.18 -> but it doesn't fill up like it does in Bergman Joe's.

257.91 -> Like water can never get into this region,

260.43 -> or this region, or any of these regions.

263.01 -> And you can see why.

264.09 -> Again, it's air pressure.

265.86 -> Except it's not surface tension

267.6 -> that's holding the water back,

269.37 -> it's just the geometry of the thing.

271.26 -> Like air would have to go down

273 -> before it could go up in this scenario.

275.25 -> So it simply doesn't because air is less dense than water.

278.58 -> So my hunch is that what's going on

280.5 -> in Bergman Joe's simulation

282.54 -> is that there is no air in his simulation.

285.42 -> It'd be very difficult for me to recreate

287.19 -> that with my setup.

288.36 -> Like even if I could do this in a vacuum,

291.39 -> well, in a vacuum the water would just boil.

294.12 -> Maybe I could try it with a liquid that doesn't boil

297.87 -> in a vacuum.

298.86 -> That sounds hard.

300.18 -> Here's the more complex maze.

301.62 -> There is a slight leak here,

303.39 -> but it's water leaking from the tank to the outside world.

306.75 -> I don't think there's any significant leaks happening

308.94 -> within the maze itself, which is a huge relief.

311.67 -> And just like with the simpler maze,

313.23 -> the water goes to all the lowest parts it can do

316.41 -> before it's locked out by the geometry.

319.56 -> They say that if you are ever stuck in a maze,

321.87 -> just put one hand on the wall and keep walking forwards

326.28 -> and you'll eventually get out the maze.

328.26 -> Though, I suppose if there are two possible paths

332.22 -> through the maze, then the maze will necessarily be made

335.85 -> of three parts instead of the two parts of acrylic

339.03 -> that I showed you before.

340.56 -> And if you happen to put your hand on the middle part

343.47 -> then you'll just be walking around forever.

345.39 -> But anyway, one thing I really wasn't expecting

347.94 -> with this water maze was that the whole thing

350.85 -> grinds to a halt when there's still water left in the tank.

354.75 -> And I think that's because there are lots

356.25 -> of little bits of surface tension all around the maze

359.04 -> that need to be overcome.

360.69 -> But together, those little bits of surface tension

362.88 -> add up to enough resistance so that the pressure of water

366.15 -> from the tank just isn't enough to force everything through.

368.88 -> Like there's a little bit of surface tension here

371.31 -> that's preventing the water coming over this lip.

373.95 -> Another bit of surface tension here, here, here, here, here.

377.46 -> They're all resisting the flow of water slightly,

379.95 -> but together they present a significant amount

381.66 -> of resistance.

382.493 -> It's a bit like those coin games.

383.85 -> You know, you roll your coin in,

385.56 -> it gets pushed off the first shelf,

387.48 -> but then nothing happens on the second shelf.

389.76 -> Or maybe something does fall off the second shelf,

392.34 -> but there's no way anything's happening on the third shelf.

395.34 -> The final thing I want to show you is what happens

397.74 -> if I change the color of the water once the maze is solved.

402.36 -> It's fun, isn't it?

403.23 -> You can see that the red dye solves the maze

407.4 -> and slowly starts to creep into those stagnant areas.

411.78 -> So there you go, water can solve a maze.

414.33 -> It doesn't look anything like Bergman Joe's simulation,

417.6 -> not that Bergman Joe's simulation is wrong,

419.73 -> it's just simulating something that I couldn't recreate

422.88 -> here in my studio.

424.26 -> When I was given careers advice at school,

426.54 -> I can tell you for sure that making science videos

429.81 -> on YouTube was not one of the suggestions that they made,

433.17 -> mainly because YouTube didn't exist back then.

435.45 -> But also I feel like they probably weren't asking

437.52 -> the right questions.

438.42 -> So how do you find good careers advice?

440.76 -> Well, for people that are interested in finding

443.22 -> a fulfilling career that makes a difference in the world,

446.52 -> then I strongly recommend checking out

448.35 -> the sponsor of this video 80,000 Hours.

450.87 -> And I'll say at the top

451.8 -> that what they offer is absolutely free.

454.08 -> They're a nonprofit organization that focuses

457.23 -> on helping people find careers that solve

460.56 -> the world's biggest problems.

462.27 -> And there are two things that I really like about it.

464.22 -> The first is that it's evidence-based.

466.38 -> Their insights come from 10 years of research

468.6 -> alongside academics at Oxford University.

470.94 -> The second thing I like is just the sheer breadth

473.58 -> of different tools available on their website.

476.91 -> You could start by looking at their problem profiles,

479.46 -> for example.

480.293 -> Those are the things in the world that need fixing.

483.15 -> Or you could start with their decision-making tools

485.67 -> that help you to find a career based on what you are like.

489.72 -> Or you can dive straight into looking at specific careers.

492.63 -> There's even a podcast if you enjoy learning that way.

495.87 -> And then there's the job board,

497.85 -> which they have curated based on what their research

501.03 -> says are high-impact careers.

503.52 -> The best way to get started is to go

505.47 -> to 80,000 dollars.org/steve to be sent a free copy

510.06 -> of their in-depth career guide in which you can learn

512.91 -> about what makes a high-impact career,

515.46 -> get new ideas for impactful paths,

517.59 -> make a new plan based on what you've learned,

519.78 -> and put it into action.

521.1 -> The link is also in the description

522.66 -> so check out 80,000 Hours today.

524.88 -> I hope you enjoyed this video.

525.87 -> If you did, don't forget to hit subscribe,

527.79 -> And the algorithm thinks you'll enjoy this video next.

531.375 -> (upbeat music)

Source: https://www.youtube.com/watch?v=81ebWToAnvA