Bizarre Spinning Glue

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PVC cement (it's technically not glue) spins in water. It might be because the solvent is being expelled onto the surface of the water creating jets the propel the blobs around.
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[@SteveMould]

I never knew there was so much chemistry involved in plumbing. More research needed. The sponsor is NordVPN: Get 4 months free when you buy a 2 year plan: nordvpn.com/steve and use promo code "steve" at checkout.

[@Timothy.Hutama]

I think you overlooked surface tension too quickly. Very small gradients can make large marangoni flows and in this case the mixing is happening at a variable rate. I think what's likely happening is as the polymer is "drying" you have microvoid formatio based on phase separation determined by a three part system according to Flory-Huggins thermodynamics. When that happens you have nanoliters of solvent being expelled. This theory is explored in this paper doi.org/10.1021/acsmacrolett.8b00012. But self-propelling droplets are explored also in papers like doi.org/10.1063/1.4939212

[@choiceschoices5910]

YOUR CRUST IDEA IS CLOSE, EXCEPT THAT THE CRUST IS AIRTIGHT SO FOR MORE SOLVENT TO ESCAPE, IT NEEDS TO EVAPORATE & BURST OUT OF THE CRUST !!!! (NOT SHRINKING CAUSING CRACKS) THANK ME LATER ^_^

[@davemarm]

My guess is that there is a quick change of shape the moment it hits the water which causes propulsion in the form of a spin. Do you have a high speed camera to test this?

[@benmartin5346]

@@choiceschoices5910 do you know where the caps lock key is...

[@ikbintom]

@@Timothy.Hutama so then what causes the variable rate of the mixing?

[@keekedup]

"It's not glue, and that's an important difference" *puts glue in title*

[@realcygnus]

@Brady Prince brah

[@NandR]

They called my chemistry class “General Chemistry”. When really it was watered down lies about physics.

[@yixunnnn]

EXACTLY

[@skyboosm]

@@NandR sociology is just applied biology Biology is just applied chemistry Chemistry is just applied physics Physics is just applied mathematics Mathematics are just mathematics

[@SaraWolffs]

@@skyboosm Mathematics is applied logic Logic is applied philosophy Philosophy is applied psychology Psychology is applied biology and now we're stuck in a circle.

[@FlyByPC]

“The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka' but 'That's funny. '” - Isaac Asimov

[@waffleboy159]

Only then can you imagine the implications. Endless possibilities can stem from finding that anomalous crack in our knowledge. Probing that crack, we can find new caves, connections, etc.

[@thanksfernuthin]

That's great. It makes me think immediately of the technician working on a microwave dish and the chocolate bar in his shirt pocket melted. "That's funny." Soon we all had microwave ovens.

[@rhys11707]

Which one of his books is that quote from?

[@definesigint2823]

@@rhys11707 The earliest known reference appears to be from Usenet, 1987, in the Fortune program's source code. Ref: quoteinvestigator.com/2015/03/02/eureka-funny/ . This find looks like something that would take a lot of digging to improve upon.

[@Davidowalls19]

Means the same exact thing. Aha!

[@danielgrass9881]

“I tried to make a solvent, but had mixed results” Pretty good pun

[@wich1]

Actually, not a solvent, a solution

[@thomassynths]

Solvents can separate materials.

[@TheMrKeksLp]

@@thomassynths By mixing with the solvent ;)

[@finchisneat]

@@TheMrKeksLp that was implied ;)

[@tomgrime526]

The PVC cement is actually a suspension of low molecular weight PVC, these initiate furthrr polymerization on contact with water. This is how PVC is produced industrially. This process is extremely exothermic. I'm guessing the effect is caused by water forming PVC capsules, heating up the trapped solvent water mix until they break (as you speculated) and release a pressurised jet of hot liquid. Perhaps you could test with thermal imaging camera on cement in a small amount of water. Incidentally you weren't able to make your own cement because the PVC pipe is high molecular weight.

[@TheReligiousAtheists]

I hope he sees this

[@Nevir202]

Ah, that’s good to know.

[@dennyskerb4992]

Great comment

[@davefoc]

Could an infrared camera be used to confirm this theory?

[@mycosys]

This is kind of what i was suspecting myself. Theres also a bunch of big polymer 'springs' for want of a better word forming and flailing about in the polymerisation process.

[@SWebster10]

Why glue spins like crazy in water “It’s not glue, and we don’t know.” Thanks Steve!

[@pedrovieira4227]

lmao

[@mikegLXIVMM]

"It not glue as we know it captain" - Spock.

[@MyNameIsXYlp]

I really want to quote Jesse Pinkman right now

[@polarknight5376]

​@@MyNameIsXYlp"This is my own private domicile and I will not be harassed, bitch!"?

[@evilotis01]

"He spent the rest of the day adding drops of PVC cement to the puddle" I RESPECT THIS MAN

[@ErsagunKuruca]

If he didn't, I wouldn't really trust him. Same with skipping stones on a frozen lake. If you hear that sound and not want to do it again and again, you are weird and not to be trusted.

[@kingcosworth2643]

Obviously an employee

[@justinhsu3253]

As a chemist in a adhesive maker who play with those cements everyday, I can tell that the main components of PVC cement is PVC, MEK, and cyclohexanone. (or tetrahydrofuran) Since MEK , cyclohexanone and tetrahydrofuran are all partially or full water soluble, some solvent would dissolve into water and make PVC solidify into a film covering the blob. And the osmosis difference building across the film pulls water into the blob and make the blob expand at the surface. (Therefore the films and wings form when wet blobs are dropped.) When the blob is firmer and the film is fixed by rigidity and cannot expand, osmosis difference just pull solvent out into water instead and create a propelling stream. Then with higher curvature of surface, the blob tail can gain more propulsion with more surface area, which makes blobs run, or spin if tail is warped. Maybe try mixing some color into PVC cement and we can find more data.

[@truestopguardatruestop164]

Thanks for sharing this information! We need more to read this comment so Steve can read it! Liked

[@scooterdon8365]

Perhaps plot motion vs time vs mass of drop to relate to reaction rate and then a scan through temps and digital video analysis a plot of motion would serve a bit like DSC to find peaks at specific temps

[@andrewmeeks6938]

Does MEK in solution with water appreciably depress the boiling point of water?

[@handack6764]

I would like to do the same experiment: do you have a brand name of PVC that spins!? The last glue I bought does not work...

[@NEMountainG]

I love how some of these videos don’t really give a satisfying answer. This is how real science works and it’s super interesting how much there still is to learn about the simplest things.

[@KJF87]

even when it is almost known, it is still so far from scientifically proven too. It is fascinating what we can hammer at until it gives up the answer!

[@thefekete]

"and he spent the rest of the day playing with drops of PVC cement in the puddle" Meanwhile the water was shut off in his house and his wife was furious.. small price to pay in the name of science😋

[@loz11968]

Also his boss what do you mean you need more PVC cement and why is that job taking so long lol

[@SupaDanteX]

Steve once abandoned groceries and his wife, to waste containers full of shampoo. These people are a menace to society.

[@null3736]

because its looks like free energy so he could have an idea

[@stevecoffman2559]

But you had fun!

[@mrsurdeo2michaelkennedy221]

Steve, I am a commercial diver. I watched this video and when you talked about dry ice it brought up a memory... when groceries are sent offshore in the gulf of mexico, they are sent with dry ice. There was one occasion where I was in the water on a decompression and they threw the dry ice overboard. Dry ice sinks. But it sunk to a certain point and it stopped sinking. Then it seemed to hover mid water. I watched this phenomena for several minutes. I cannot remember my depth but I want to say it was shallower than 100', well within scuba range. It was awesome. I watched it come down off gassing the whole way and then just stop and off gassed until there was nothing left, and then another chunk was thrown overboard and did the same thing. I just found out about your channel and I am impressed. Maybe you can do something with this.

[@Alalea17]

Probably the depth where the water is such high pressure That it has the Same weight as the dry ice. Water is liquid so ist gets compressed faster than a solid piece of ice

[@carlosandleon]

I guess it’s just neutrally buoyant at that depth

[@carlosandleon]

@@Alalea17water doesn’t compress

[@WalkingTrashcan]

@@carlosandleonwater does compress but under extreme pressures. 20000psi to compress by 5%

[@jamesamato1437]

Very interesting video. Perhaps you may have given up on the surface tension theory a bit prematurely. I found that one droplet of liquid dish soap causes the PVC cement globs to stop moving immediately. This argues against the "driving force" arising entirely from the momentum of jets being expelled from inside the globs. Perhaps small amounts of solvent leach out (as you suggested) and cause fluctuations in the local surface tension. These fluctuations in surface tension may lead to the chaotic movement. The dish soap would lower the surface tension uniformly, thus abolishing any heterogeneity. We'll have to do more tinkering to sort this one out.

[@savannahamato148]

What a splendid theory! I’ll be sure to show theory to my father, he loves experiments like this.

[@ThomasGiles]

Me: "I moved the light round a bit and I could see better." Steve: "I used extreme lighting angles to take advantage of the differences in refractive index." ;P

[@heekyunglim7839]

I had to pause there and rewatch it about 10x's to get it. Lol

[@Alex-lc1bv]

5:40 Wow, that dry ice floating around is mesmerizing. Very cool.

[@pvic6959]

lol cool indeed

[@asdfxcy]

I worked at the Technorama for a while and yes, I loved watching those little pieces of ice! There's a lot of other great stuff there as well, including a fire tornado, levitating superconductors, a drawing pendulum, a cloud chamber and of course a chocolate workshop.

[@alexflowers0852]

Looks like microorganisms moving on the microscope

[@Jesse__H]

I thought the same

[@ericeaton2386]

That was my first thought too

[@1.4142]

journey into the microcosmos

[@FIRE_STORMFOX-3692]

@@1.4142 yeah!

[@Vicha57]

it looks like "cement"

[@melo.4489]

That happened with a dead insect recently with here. I was cleaning the house, it fell on a puddle and started spinning like crazy. I checked closely to see if it was still moving, but other than that spinning, it was completely still, and it started instantly spinning again after I stopped examining it. It's one of those insects that exhale a weird smell sometimes, so oils/aromatic components might have something to do with that effect, too.

[@TechyBen]

Could be oils. They also have tiny water phobic hairs. However, theoretically water phobic surfaces should not generate their own energy. So perhaps it's a mix of the water phobic effects with oil or solvents as the driving/fueling force?

[@LucasRodmo]

Both of you, best theory so far

[@hobbyhobbyhobbyhobby]

If the oil from the bug and water is causing spinning because they aren't mixing properly, it'd be interesting to test if a water/alcohol solution still produced spinning with the oily bug because water and alcohol should allow the oil to mix

[@macronencer]

"One of those insects that exhale a weird smell sometimes" - I'm genuinely intrigued. I have never heard of such a thing, and I don't remember ever having smelt an insect in my life. What fresh new horizon of science is this? :-O

[@LucasRodmo]

@@macronencer are you kidding? Many insects use smells as defense. The most known infamous is the nezara viridula.

[@hpekristiansen]

PVC cement is highly intelligent, but severely lacks arms to get out of a potential drowning situation.

[@Catastropheshe]

I chuckled 😄

[@Gedom666]

Outcome of the video: It's much harder selling a VPN since the Tom Scott video...

[@letsgocamping88]

However A password manager is well worth having.

[@Zveebo]

Tom Scott was a brave (possibly stupid) man making that video 😂

[@amansaxena5898]

Haha, he is jow giving a much more sane reasoning for why to use VPN, unlike the usual "It encrypts your data and keep you safe"

[@lettersnstuff]

@@barongerhardt skip the fbi watchlist and get a vpn xd

[@Eralen00]

@Mr. H This is why I've always been skeptical of password managers. They seem like the perfect target for hackers

[@keco185]

Does the same effect happen was put the cement in different fluids that might not react with water?

[@MonkeyJedi99]

Ooh! Good thought!

[@PrinceP1025]

Also when you put a drop of water on the glue to see how the water reacts to being put in the glue!

[@great__success]

I would definitely test oil....also changing temperature might be worth exploring

[@Catastropheshe]

@@great__success and alcohol

[@vjm3]

Hey I just want to say "thank you." This made me think about it, when for a few weeks now I haven't really thought all that deeply about something. I just kinda appreciate that. It's like a gift.

[@yschroder]

I remember an experiment from when I was a kid, where you would dip the end of a match in glue and it would move across a bowl of water when thrown into it. We used "UHU Kraft Alleskleber" (from Germany) for that experiment. And that one contains dissolved polyurethane which solidifies when the solvent dries up. The effect is similar so it probably is not related to the PVC but mostly the solvent.

[@keco185]

Now I’m just waiting for someone to do a master’s thesis on this

[@xpqr12345]

You might want to cut the waiting short, and pass a word to Thunderf00t, he and some other chemists published a paper some time ago (1-3 years) about why the alkali metals more or less explode in contact with water. He might be the right person to investigate this matter.

[@PhilBoswell]

@@xpqr12345 it would give him something to do besides ranting at SJWs. If I'd seen his serious research first, I might have had much more respect for him…

[@xpqr12345]

@@PhilBoswell It's been quite a while since I heard him rant at SJWs, I would have to look up his channel to know how long ago it was. But his YT channel and ranting aside, he is a serious chemist, with a number of years in research chemistry. He has also started a second channel, Voice of Thunder, to separate his factual videos from his more opinion-based videos.

[@ikbintom]

I would if my uni were already doing something similar! This would make for a pretty nice master's research project indeed

[@shookings]

@@xpqr12345 except that would necessitate talking to thunderf00t, and he's a colossal cock.

[@themarblers4399]

You can build a schliren imaging system to detect the solvent bursts.

[@revenevan11]

That's exactly what I was thinking! It'd be really interesting to see all kinda of imaging methods applied to this system. It could really illuminate the inner workings of these spinny bois lol.

[@ikbintom]

Maybe even just food colouring in either the water or the cement would work?

[@TechyBen]

@@ikbintom Problem is you'd need something bonded *to* the solvent. As else it's measuring how well food colouring seeps out of the cement and might even cause undesired effects.

[@ikbintom]

@@TechyBen good point!

[@JakeBiddlecome]

I wonder if you could get schlieren videography to work crossing a water boundary. In either direction. I feel like you'd have to be in the same material (air or water) as the light source and subject for this to work.

[@georgebuzea6879]

2:53 the alcubierre drive in soap-water continuum my friends 😂😂😂

[@danielstephenson7558]

I'm always amazed with your videos, Steve for not only showing me something I have never seen before, but in demonstrating a theory on how that other thing might work, you show me something else I have never seen before to explain it. I loves it.

[@witerabid]

title: "Why Glue Spins Like Crazy In Water" Steve: "PVC cement isn't actually glue" smh...

[@eugenesesmaiii3278]

And we still don't know *why* it spins! 😅

[@CriticalRider]

But the French name on the tube he showed calls it "Colle", which means glue and not cement.

[@no-trick-pony]

"Glue" instead of "PVC cement" makes for a more.. not clickbaity.. but clickable title for a larger audience I guess (though in all fairness, this time around it kinda is clickbait, since we never got an explanation, just guesses)

[@Daniel-sm5vy]

@@no-trick-pony he should have titled it "why does cement spin like crazy in water"

[@DreamItCraftIt]

Cement is a type of glue I guess? There's a bonding happening

[@Muonium1]

At first I thought it had something to do with Marangoni effect and the surface tension mismatch between the solvent and water, but the pepper really does reveal discrete jets and now I think the surface crust fracturing thing periodically releasing pulses of MEK as the droplet contracts probably is what's going on. Dye the cement with something like fluorescin and inspect the interaction with a UV lamp to maybe see what's going on in more detail...

[@hamjudo]

Any dye that dissolves in that solvent will work if it can be mixed in uniformly.

[@AngDavies]

pubs.acs.org/doi/10.1021/la301437f I think the marangoni is right- here's a paper where they make a similar situation- plastic dissolved In solvent, added to water- moves in weird patterns. Different plastic, and Ethanol instead of mek, but they seem fairly confident it's due to the marangoni effect, and they can even predict it so as to control the motion, so I'm inclined to believe them

[@MarkTillotson]

@@AngDavies That looks just the same phenomenon

[@willdbeast1523]

On the dry ice on water (4:22 onwards) what is it in the jets we can actually see? Is the CO2 visible or does it cause water to condensate into a misty thing?

[@neur303]

Yeah, on Wikipedia it says that it stems from the bulk water so I imagine when sublimating there is always a small film of water in contact with the cold gas that interacts and interleaves with the gas molecules creating a fine mist. Would be interesting if that can be visualised. If what I say is true, there should be a frequency that is dependent on the temperature which should be measureable and fairly constant.

[@neur303]

I didn't find a full explanation but this blog entry has some empirical data chemedx.org/blog/dry-ice-five-different-liquids

[@nasonguy]

So glad you're posting this. A neighbor and I have spent a lot of time staring at drops of PVC cement scooting around puddles while we're fixing our busted ass well from the 80's. We use the blue stuff here in the U.S. and it acts identically... We always wonder why it does that but never get curious enough to figure it out, haha, now I know and I can flex on that old man next time we have to fix a leak. Darn, just finished the video and now all I get to tell him is "something about the solvent and the water"...

[@kaisle8412]

"Why Something That Isn't Glue Might Spin Like Crazy in Water"

[@temkin9298]

It looks like a bad quality videogame collision box interferance

[@jeffpkamp]

It's like a pvc world with solvent "hot spots" that work their way up to the surface making volcanic eruptions of solvent into the water.

[@Laralinda]

I thought of lava, too, as watching the blobs.

[@Redrield]

The bit about the two models for movement is really interesting, reminds me of an experiment from a couple of years ago I did in chem class. We were synthesizing various esters given the reagents on hand, and one of the samples that my partner and I made danced around in a way somewhat similar to the cement here after it was placed on a petri dish with some water. I can't remember what ester we had created but it was quite weird to watch in the moment. It really did look alive

[@DriftKingNL]

3:44 Me in the club trying to get a girl.

[@riuphane]

I'm incredibly surprised (and pleasantly so) about how much a learned from this video. This was beyond fascinating and exactly why I've been an avid subscriber. Thank you so much for sharing!

[@oliverb104]

great video as always mr Mould! Whilst the pepper worked perfectly well, mica powder used in make up creates a rheoshopic fluid which would show all those cool water vortices really well!

[@suprvideo]

Intriguing, fascinating, beautifully filmed, and so clearly explained. As usual. Great video!

[@griffinbeaumont7049]

"PVC cement isný actually glue" The french label: "PVC glue"

[@wpyoga]

Where I live, it's also called PVC glue (translated).

[@bl4cksp1d3r]

Technically, it isn't. It can applied just like glue for pvc, but it actually "welds" the pvc together, like Steve said

[@unpairedelectron2886]

A bit of extra information: The key ingredient in most PVC cement is actually tetrahydrofuran, or THF. THF is an ether.

[@K-Riz314]

I'm guessing that's not as easily obtained as MEK, which can be procured from most hardware stores.

[@DebenValleyLightRail]

Great video - I'm just finishing my PhD about the behaviour of wood floating in hot fluidised particles. The wood emits jets of gas which interact with the fluid in a way not all together dissimilar to the dry ice on water demonstration. Indeed, I've used the dry ice/ water system was a quick way of explaining my research.

[@patrickcompton1483]

Your inference ability is a great contribution to science, steve, and I believe your videos should have way more viewers than they get. Great job m8, keep it up.

[@kevinpotts123]

1:06 saying "jerk around the bowl" while showing what looks to be jizz in a bowl is peak KZbin content for me.

[@magnusshrugged]

STELLAR!

[@ThomasGiles]

Steve from an alternate reality: "...And this is how soap-propelled yachts work in the grand ocean rallies."

[@TechyBen]

Would give a whole new meaning to the words "Green Peace" ;)

[@crow2989]

That dry ice scene probably looks so stunning in person

[@Colbasaurus23]

This is one of the best videos you have put out Steve - thankyou this was excellent!

[@BlameItOnGreg]

Definitely one of those “hmm, well that’s interesting” moments.

[@saims.2402]

Damn, plumber turned scientist has got to be one of the best career stories.

[@thzzzt]

A good plumber certainly makes enough to have his own lab.

[@MarkTillotson]

I refer you to Colin Furze, plumber turned crazy inventor :)

[@ThexxCODxxFATHER]

The waves in the clouds at 6:00 remind me of those videos of black holes orbiting and shedding gravitational waves

[@Mikeyman6488]

At the explanation of floating dry ice, my mind immediately went to Monty Python: "Very small rocks!"

[@blazbohinc4964]

I was JUST watching the "I hacked into my own car" as it went offline, removed by you, Steve. What happened? Somebody called? Now I want to know more!!!

[@adamlahaie723]

Another comment said there was an audio bug and he will reupload it

[@ConnorMezza]

glue normally: sticc glue in water: speen

[@redyau_]

It always takes great willpower to click on your videos, as I know it will be "mentally demanding" to watch. But it's always so worth it!

[@DaBlondDude]

I like that you also showed your thinking, approach and how you tested it, complete with explanations. =)

[@JamesWeetman]

Why does silicone squeezed from a tube straight into water seem to set immediately? If you press out a string of it right into water you get silicone noodles

[@nicholasevans1781]

Wooooow

[@roquesales_]

Yeah

[@roquesales_]

I think super glue too

[@damiangames1204]

Well I know that superglue polymerises on contact with hydroxide ions, usually in air - it also polymerises/sets very quickly in water. Maybe a similar reaction that is started by hydroxide. I can't remember the exact process but I learned about it in chem at one point

[@poptartmcjelly7054]

because silicone works by hydrolysis, you can imagine it as a two component epoxy where silicone is one part and water is the other.

[@yura2424]

4:25 Be careful with dry ice. In Russia several people have died from suffocation when a lot of dry ice was added to a swimming pool in a closed room for a cool 'jacuzzi` effect.

[@neur303]

You probably also shouldn't eat it as you probably would get internal frostbite.

[@dennyskerb4992]

Furthermore, don’t put it on your pecker.

[@MatthiasYReich]

Omg, Technorama! So many childhood memories... I should go there again

[@HappyQuailsLC]

I really liked your theory regarding the cracks and the fact that you attached a glob to the side of the container and held some on a tool, which anchored it from above along with the very interesting insight by your scientist friend all made for an especially insightful and estate examination of this topic. Thank you for doing it.

[@gadlen2]

Love your brain: don't put your fingers in methyl ethyl ketone! Fabricators say, "Methyl ethyl ketone, not even once!"

[@iluapJ]

What does it do??

[@dennyskerb4992]

Linoleum factory’s used MEK like water for years.

[@moumous87]

Do more research on this and it will become “The Second Mould Effect” !!!

[@girlsinredtrenchcoat1169]

I love the adhd "explanatory dead end" he's just like "hmm what else does wierd stuff on water? Soap! Is it the same? Nope let's talk about it"

[@magnusshrugged]

Your Tag is PRICELESS!! 😂

[@maidbloke]

You are exceptionally good at explaining things. Thank you.

[@MKRLN]

I like your "crust" theory. It's simple, elegant.

[@joaomanoellima5947]

Now the "Mould Effect" will get a chemical definition

[@davejacob5208]

that last point about our perception of what objects are animate or inanimate was really interesting for me in the context of free will: if the first "intuition" of children is to simply base the perception of it (i take being an animate object to mean having some sort of more or less free will) on unpredictable/hard to predict movement, then that fits into the very common incompatibilist view of free will being about not being determined by any causes or rules.

[@earlye]

7:14 - a blob drops in, and binds to two other blobs. Slightly above frame-center. For some reason, I found that kinda neat.

[@pietro93vit]

Steve Mould is currently editing his last video on an audio bug, dont worry he'll back soon !

[@blazbohinc4964]

okay, good. Thanks for the info

[@jordanwhitecar1982]

"It will jerk around the bowl." -steve mould 2020.

[@solarnaut]

1:07 "jerk around the bowl" as various sized globs of viscous "fluid" sputter down into the bowl :-/ hmmmmm. . . as the joke goes about the psychiatric patient who sees all the dirty images in the rorschach ink blots: "i'm perverted ? ! ? . . . You are the one showing me all these dirty pictures ! " Haaaaaa.

[@samp-w7439]

Circle jerking diva

[@vedritmathias9193]

8:40 I think you're on the right track. Here's my idea: As the solvent evaporates (faster in air than in water), the blob contracts, putting pressure on the solvent within, which will randomly break through to release some pressure, causing the jet, until the crust contracts further and the jet is cut off.

[@BLeeWitzig]

This would be fun to put in the end of a straw to create a controlled jet of water. Cut a half inch piece of straw and seal off one end and put a drop of glue inside so it directs all the jets in one direction

[@colevano]

smh, he didn’t do the pepper and the polystyrene boat :(

[@mycosys]

Wouldnt there be a polymerisation reaction going on that would account for quite a bit of energy, weird springs, changing hydrophobia and a bunch of other stuff?

[@ikbintom]

I guess if the solvent depolymerizes the pvc, then it repolymerizes once the solvent evaporates. Don't quote me on anything chemistry-related though. The physicist's approach would be: rather than guessing at the influence/presence of the things you name, just measure the speed of the particles and calculate the kinetic energy, and try to calculate the chemical energy associated with the solvent's evaporation and see if they're about the same magnitude. That would indicate that indeed evaporation jets cause the particle to self-propel. Edit: I tried to get an idea of this, but I don't know how to properly estimate the amount of solvent per burst.. I have an eyeballed kinetic energy of ½mv² = 0.5* (4/3 * pi * (3 mm)^3*0.9kg/L) * (5cm/s)^2, which is around 0.1 µJ. That's with a radius of 3mm, a density of 0.9kg/L and a velocity of 5 cm/s, all of which are just guesses. I'm just hoping I get the magnitude right-ish ;) For the other energy, if I assume that the solvent is cyclohexanone, then the heat/enthalpy of vaporization is about 450 kJ/kg (I'm not sure if that's the right quantity though), and a shot in the dark for the amount of solvent per burst is a factor 100-1000 smaller (in radius) than the whole blob? No idea if that makes any sense. But it does result in the same magnitude: 450 kJ/kg * (4/3 * pi * (0.003 mm)^3) * 0.9 kg/L = 0.05 µJ and 450 kJ/kg * (4/3 * pi * (0.03 mm)^3) * 0.9 kg/L = 46 µJ. Sadly, the unknown-est variable is cubed, so I'm not that much wiser now..

[@BLUYES422]

That description at the end is a good one, I've seen that weird crust occur with ink from a bic ballpoint pen, if you put it in water it coats the surface in what appears to be a rigid film

[@alexz7914]

He explained the effect/possible answers to its strange behaviour very well. Altough the explanation/sponsorship announcement was very good. Because he said at least research it and decide for yourself. But I can highly recommend it.

[@DustyKorpse]

The concrete thing we can take from this is ‘Martins’ like to drop thing’s in puddles. Do you know a ‘Martin’, continue the research see if they like dropping things in puddles. 😉👍🏻

[@jurjenbos228]

How about Martin Polyakoff?

[@paultreadwell8612]

Maybe try a little boat filled with MEK and a pinhole in it.

[@neur303]

Wheeeeeeeee :D

[@ZSchrink]

I'm going to need you to hurry up and post enough content that I can show my future child one of these videos every single day for life! 😅 I am new to your channel and absolutely love the way you explain complex ideas in easy to understand ways. Thank you!

[@majorglitchstudios5362]

The rapid, jerky movement and the formation of “fins” really reminds me of pen-ink on water. I wonder if they have similar causes? If not, the ink reaction would still be a neat topic for a video.

[@LuckySlevin7]

Why didn’t you pour the pvc cement out of a beaker? This is OF BRAND!

[@LadyEmilyNyx]

"It's not glue, it's cement, and that's a very important difference" Looks at title... Why GLUE spins like crazy in water. Guess it wasn't that important a difference after all.

[@Cameron1411]

Hey Steve!, I've noticed when using a garden hose you can cause it to hold itself up from the thrust it generates, BUT, when you submerge the end in to water it drops like it suddenly generates less thrust?? Any idea why? Could be an interesting video. You need to hold the hose about 1m back from the end depending on water pressure for best results. Cheers!

[@SeanBZA]

To make PVC weld you need the MEK solvent and a carrier, which for most PVC cements is actually styrene monomer. You dissolve polystyrene into the MEK and, once the bubbles are finished dissolving, you have the cement. You do not use PVC tube because it has a lot of filler in it to get it rigid, and this is non soluble, as it is mostly calcium carbonate powder.

[@ashishrai6544]

We should do a detergent boat race.??

[@AttilaAsztalos]

Hint: the direction of the boats can be stabilized by also sticking a small magnet on them, therefore making them floating compasses. Courtesy of a "DIY polystyrene miniboats" toy set I got as a kid many decades ago...

[@ThomasGiles]

Steve: "PVC Cement is not glue." Me: glances nervously at the title.

[@neoclod3112]

Some of these Dry Ices we see look like little galaxies spinning. 4:47 The little two galaxies there look cool. Also the little explosion each emits is pretty cool!

[@bradhayes8294]

PVC cement is actually not cement. It's a solvent (usually MEK or "safety solvent"). You can get it either doped with or without PVC resin. I believe you can get it with several different percentages of added PVC resin. The addition of PVC to the solvent is intended for use on larger diameter joints and when the dry fitted joint, for whatever reason, is sloppy or loose. The added PVC resin fills in any gaps, nicks, or scratches existing between the two parts. After applied to both surfaces then joined together it melts the surfaces of both PVC/CPVC parts being joined. The liquified PVC mixes together upon assembly. And then, as you said, it evaporates leaving the common wetted surfaces "welded" together. That's why it's referred to as solvent welding in the industry. Manufacturers recommend roughing, cleaning, priming, and applying solvent to both surfaces to be joined. They also recommend giving the parts being joined a 1/8-1/4 turn twist during/after full insertion. This is to provide shear mixing of the two liquified surfaces, perpendicular to the direction of flow, prior to resolidification, reducing the likelihood of a leak.

[@krzysztofbroda5376]

tag me when someone comes up with a good explanation

[@ratclit]

i watched the whole video before posting this

[@brennonbrunet6330]

In regards to the "jerky motion of the blobs" I have a hypothesis: It's due to an uneven mixing of the cement. I believe that you have pockets of solvent suspended in the cement, which is working it's way out, possibly through cracks in the thin crust of pvc that you described. One way I can think of to test this would be to run the same experiment with samples of cement at varying degrees of mixed-up-edness and see if that changes the intensity or frequency of the jets.

[@jordant5107]

I've seen weird stuff like this going on in the lubrication cup of an air assisted airless paint sprayer. I have no idea what the makeup of the lubricant is, but at some point in time we put lacquer thinner in the cup to clean out lacquer that's gotten in there. Globs of lacquer or the lubricant or the thinner start moving around, almost like they move to the middle of the cup, down to the bottom, back out to the outside and up across the top to repeat the whole trip again. Pretty weird, makes me think they shouldn't be in the same space together.

[@tgmtf5963]

I am fist

[@KaRmaTheSchemer]

I am feet

[@ChaseHukill]

The fact that he didn't even use a coupling to join the two halves together is freaking me out, as I grew up in a family of plumbers

[@nikoacker9029]

I feel like this is one of the best VPN sponsorships I've seen so far, keeping it interesting by explaining what it actually does while not using maybe overexaggerated marekting phrases you heard a thousand times before

[@zungruitelbitladnaternoche7305]

As a kid, we used to make self propelled toy boats by taking a stick and put Pine Resin on one end and put the stick in pond water. The resin would expell something that made the stick move forward. It usually turned in circles but the game was to make one that goes straight and far. It left a rainbow wake behind in the water.

[@katephillips1342]

For a fleeting moment, that dry-ice video brought my mind to galaxies and the big bang. It's so beautiful

[@DreamsCatcher101]

The power of observation. Cant learn about something until you see it. Good job on the plumber for seeing it in the first place.

[@urbannanni5864]

When you were describing how children start determining animate vs inanimate, my daughter had a novel and dangerous method. She would wait for an opportunity, then quickly poke the eyes. If it didn't respond, like a doll, then it wasn't "alive". However, when that finger started moving towards grandma's face, it got a reaction. Ergo, alive. She survived this stage. She's 45 now and hasn't poked anyone in the eye lately. At least that I've heard.

[@arjovenzia]

I love those moments of 'huh, thats odd..." and the inevitable, "what happens if I...?" can defiantly relate to "spent the rest of the day playing with puddles/whatever got your attention"

[@DerekKerton]

Animate/In-animate discussion at 9:10 goes a long way to explaining how people think "UFO" is synonymous with "alien life". When specific motions are observed in the sky that trigger our "animate" interpretation, we feel like there must be intent. And since we think of flight as a difficult technological accomplishment, ergo complex flight appears to be from some technologically advanced entity with specific intent. Meanwhile it could just be some random physics taking place (or observer error, of course.)

[@ninjakille316]

"While we can rationalize that these blobs of pvc cement are inanimate, the way they move squarely falls into that model in our brain that tells us that thing has intent." What an incredible statement! This explanation makes me proud about the state of understanding today. We may no longer be at the height of scientific discovery, but we are building and strengthening some great bridges between scientific thinking and self-awareness.

[@nelsonlarson1476]

I used to do hardwood floors. If you were to put a top coat of floor finish on before the bottom coat had finish drying, then bubble would form from the continuing out gassing of the bottom layer. The explanation given around 8:30 is supported by this. The inside of the blob is still out gassing as the outside of the cement cures.

[@user-tr8ve8wt8r]

This really reminds me of something I would do when on hikes as a kid! The sap of the Balsam Fir tree behaves really similarly to the PVC cement in this video! Though it also left a rainbow coloured residue on the surface, so probably a different process causing the motion.