This Drill Powered Spool Proves Me Right

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This is my response to Mehdi's video on the chain fountain, aka The Mould Effect.
Check out Mehdi's channel ElectroBOOM here: / msadaghd
Check out Atomic Shrimp here: / atomicshrimp
Check out HowNOTtoHIGHLINE here: / @hownot2
Discuss this video on REDDIT: stvmld.com/pn26e3fz
Check out mine and Mehdi's original chain fountain videos here:
• World Record Chain Fou...
• Chain Fountain Dispute
Check out Atomic Shrimp's video on the chain fountain here:
• Investigating the 'Mou...
Interrogate the simulation source code here:
github.com/RichtersFinger/Cha...
www.maartenbaert.be/extremeph...
You can buy my books here:
stevemould.com/books
You can support me on Patreon here:
/ stevemould
just like these amazing people:
Glenn Watson
Peter Turner
Joël van der Loo
Matthew Cocke
Mark Brouwer
Deneb
Twitter: / moulds
Instagram: / stevemouldscience
Facebook: / stevemouldscience
Buy nerdy maths things: mathsgear.co.uk

[@SteveMould]

What do you think? Have I convinced you? You can also discuss this video on REDDIT: stvmld.com/8asj3e4u

[@sublivion5024]

Yes

[@Regularsshorts]

Quite,interesting but not convincing yet! Keep going

[@jackals1737]

@@Regularsshorts you havent even watched the video yet lol

[@notyou6674]

what if you drop the pot while it happens

[@akinor1414]

I dunno, but I think you ate spaghetti before shooting this video, just look on the corners of your mouth 😂

[@ElectroBOOM]

Damn it! I'm starting to get more convinced by your theory!! Is it the start of losing my 10000 cents?! We shall see! But this video was quite clear and understandable. Thanks!

[@billrupert7560]

Only one option left, you have to go into space and perform the experiment without influence of gravity or friction.

[@windows9x554]

Yes!

[@saltysoyman6908]

I believe in you, mehdi

[@maya20484]

That debate is simply so exciting to follow, thanks a lot for you both

[@ncialex4009]

Or in Zero-G plane, the closest thing we have on earth for no gravity.

[@TiagoTiagoT]

This feels like that stuff we read in history books about mathematicians, and scientists in general, throwing challenges at each other; it's awesome!

[@Unsensitive]

10,000 cents says you're wrong! Not just feels like. It's just like that, but with videos, not letters.

[@Dargonhuman]

@@Unsensitive Yea I was just thinking this is literally the same thing in a different format. Hell, we could be witnessing history being written right now as this ... feud(?) might be in the history books of the future (or ... if books are phased out, then whatever format history is taught in the future...)

[@elysiummaybe8574]

Man i love it when scientists and mathematicians throw duel at each other.

[@cjslime8847]

I know just like we did it for fun and Knowledge I am not saying knowledge isn’t fun

[@6lack5ushi]

Einstein Bohr debates!!!! I feel you!

[@PhilfreezeCH]

7:50 Not only can you see the fountain rising up on the left but you can actually see the pile being pushed down as well. So there is a clear force being applied there.

[@LifeInJambles]

Oh yeah good call, that's pretty pronounced.

[@fabiancoretti4237]

this comment fully proved the theory for me, i don’t see how it could be anything else besides the moving chain having it’s own “push” affect on the stationary one

[@jada90]

That's a really good point.

[@thomasrogers842]

I actually came down into the comment section to mention this, glad other people agree!

[@justc1re617]

This is literally spot on. Thank you

[@BlackSoap361]

I used to watch the anchor chain do this whenever we dropped anchor on boats, when I asked about it the experienced sailors told me it was my imagination or not to worry about it. Glad to see someone finally proved what I observed as a kid was actually real. It isn’t just bead chains, works with bigger chain too.

[@Kazokano]

I'm glad that someone other than myself used to find the properties of such stiff chains interesting as a child! I was quite fascinated by them... well, regular bead chains of various sizes, not anchor chains. :P If you tie them into certain knots in just the right way, you can get them to retain their shape, and thus produce neat little sculptures made out of chain loops. It's been too long for me to remember exactly how it's done though. ;_;

[@briggy4359]

Fascinating

[@tricksyhobbitses1695]

I was wondering just this now, thanks for sharing.

[@sergioh2015]

Thing about old-school mentality is that they don't care for deeper thinking, just that something works, and that's it. I will say though, that when you do run into those gems that are just as deep thinkers as others, because they have the wisdom of an old person, with the creative mind of a kid.

[@alexsawa2956]

I vaguely recall this phenomenon depicted in a Saturday morning cartoon...it might be better called the "Wile E. Coyote effect" ...or is that the act of running off a cliff and remaining suspended in the air until you realize you're in midair?

[@veritasium]

I’m convinced! Give the man 10,000 pennies.

[@BlueScapegoat]

Damn I love you folks

[@Prophet_of_Colour]

Where Neil and Bill cannot be, Derek can. Nice to see so much good and prolific scientific debate out for a general audience who are genuinely interested in the questions, the answers, and of course the methods.

[@dtibor5903]

But first, ask NileRed to cover them with gold kzbin.info/www/bejne/fpLJdmRtbMiJldE

[@morkovija]

KZbinrs testing weird things and discovering effects should be a thing, and I'm glad the trend has started x)

[@Prophet_of_Colour]

I saw this comment at 42 likes, as it should have been seen.

[@pbryan]

With videos like this by you and Mehdi, I find myself feeling just a little bit romantic about the scientific method. Devising new hypotheses, developing new experiments to disprove them, admitting and correcting mistakes, changing minds with friendly competition, all in the quest for understanding. Thank you both for advancing the field.

[@caenir]

Veritasium had a similar type of situation with two different explanations for an effect and a bet. Might want to check that out if you haven't already

[@storminmormin14]

I feel this same thing. Something, about the purity of science.

[@MarkLemanUK]

Seeing real debate and discussion with obvious respect for eachother is such a good example to anyone interested in science. It's also a massive contrast to those psudo science KZbinrs that promote things like flat earth and antivax.

[@chrissutton4708]

This 100%

[@puddingninja]

Ahh romantific

[@webx135]

This whole bit is easily one of my favorite internet moments. The simulation made a real difference to me. You ought to just put the beaker on a load cell and record the down-force directly. How long until we get a Medhi/Mould channel? Call it, like, "Mouldhi"

[@benfranklin5335]

Moldy

[@icebuildsrobots]

ElectroSTEVE

[@BraverSpider]

MouldyBOOM

[@asmoth360]

SteevoBOOM

[@RaphaelTreza]

Nice steve, maybe you could use cotton down the pot to cushion the chain and check if the fountain still happens.

[@thomasd1396]

that's a very good idea

[@brothertonwing4554]

I was thinking a layer of neoprene or rubber would be interesting

[@adnanchinisi7871]

But how much force can the cotton absorb?

[@blakeestes]

Wouldn't the chain itself negate the usefulness of putting something soft at the bottom? If the beads are metal wouldn't they be hitting off each other and still creating the effect? I guess it might dampen the initial fountain, but with a long chain I don't think it would change anything.

[@Ryukurai]

@@blakeestes Couldn't you in theory test different materials lining the bottom that would potentially provide a measurable difference if the kick-back is the force responsible for creating the fountain? (Even if the difference is small due to the beads hitting off each other, that'd be uniform among the test I think?)

[@IbakonFerba]

Man I love this new trend of science youtubers doing "live science" and trying to proof each other wrong! Always restores a bit of my faith in humanity ;)

[@roroflowazoro]

da this is some of my favorite Y.T. content

[@circle7motorsports]

Whats cool is this is how it's always been its just in journals and not in the public eye this is just peer reviewed science it is great to see tho.

[@bramweinreder2346]

It is possible for reasonable people to disagree. And what do reasonable people do? They talk, and use facts and logic. The premise of all good science is 'I don't know'. So they try to demonstrate how they think it happens, and are open to scrutiny and demonstrations of more likely theories. It's not a shame to be proven wrong, if your theory is the reason that other people come up with different theories that may or may not be more valid. In fact, you just helped further your common field of interest. And that's the beauty of it.

[@mrchaehaeman]

Prove*

[@onradioactivewaves]

This is how science is supposed to be.

[@AtomicShrimp]

Nice, and I love the surgical empiricism here - dividing this problem up into pieces has not always been easy - I like what you did here - for me, the simulation where the bottom of the pot is removed is the killer moment I think (and that the simulation can provide force data). Nice work!

[@noizeuk]

I am sad Steve didn't use a wobble dog and settled for a drill :(

[@jacywilson]

I think the de-looping effect is also an important part that needs to be better understood. Why does it give an upward force when the loops are pulled straight?

[@ObjectsInMotion]

You should do a follow-up video in light of the new info! Some of the things in your video could use updating

[@mattieo2844]

Oo never thought I'd see you here shrimpy, love u

[@ObjectsInMotion]

@@fwiffo Did you not watch the video? There are at least 3 examples of falsifying in this video alone.

[@zredk9]

The rivalrous banter between you and your nemesis reminds me of a quote from the movie Heaven Can Wait… “The likelihood of one individual being right increases in direct proportion to the intensity with which others are trying to prove him wrong.”

[@Kazokano]

From the very beginning (when I started watching these videos, that is), I intuitively guessed that the lower flexibility of the bead chains was key to understanding the effect. As a child, I loved to play with such chains because of how interesting it was to twist them into different shapes. If you tie them into certain knots, you can actually get them to retain their shape in surprising ways.

[@emil0asp]

I LOVE this back and fourth feeling where I have been "pretty sure" both parties were right respectively after each video. The realisation that I was wrong is humbling.

[@helpabrothawithasubisaiah5316]

I had thought Steve was right the whole time, but I respected mehdi and could still see his side but was more inclined to Steve's

[@ignitionnight]

After the first video I was certain I was right that it was simply the chain construction that caused the rising fountain and no kickback force. After this video I feel partially correct, but got there by accident and sheer luck. The thought process that Steve and Medi followed was much more rigorous than my guess process. I appreciate the entire process they've gone through more than the end result of who is "right."

[@ElizabethSwims]

You have won back my vote of confidence. I think the real phenomenon is how each of us can have our minds and perception changed with a good argument and it's important to avoid a "one and done" approach to evidence and arguments. I am team Mould again... pending further evidence.

[@303elliott]

It's shocking how convinced I was Mehdi was right, and how convinced I am Steve is now. It really makes you question your confidence

[@truestopguardatruestop164]

@@303elliott wait until Medhi releases the video on a zero G plane

[@ElizabethSwims]

@@303elliott i know right! It really illustrates the importance of having an open mind and allowing change when new evidence is presented.

[@imignap]

Good observation...

[@noahway13]

Nice way of saying you were wrong.

[@frosty1433]

5:15 the beads have to be horizontally constrained and stacked vertically. He’s losing a ton of energy from the chain whiplash. The chain wants to move side to side but if it can’t it must go up. Unless the energy is great enough.

[@Marnige]

I agree. I wished he show the original ball chain and see if it would grow in height.

[@Version135]

Great job. Kickback maybe not the most intuitive word to describe it for me but this certainly makes sense. The inertia tries to bend the chain when it pulls away and the chain presses against the ground when it bends. Awesome video.

[@tim-timman8868]

You've changed my mind; was agreeing with Mehdi's explanation after your initial videos. Your new demonstrations are great. Good job! And kudos to Mehdi for not letting you throw in the towel, we need more of this!

[@aashsyed1277]

18 HOURS AGO? HOW?

[@timongutleb8940]

@@aashsyed1277 Patreon supporters have early access.

[@aashsyed1277]

@@timongutleb8940 ;0

[@adamkloc9518]

me too

[@andrewmack2280]

Chain-ged?

[@BRizZleDubstep]

I just want to say that I love this back and forth “KZbin science drama” and it would be awesome to see more creators challenge each other with different hypothesis. I suppose it might be hard to find a surplus of topics to argue, but if it’s possible I’d love to see more of this!

[@Loganxmusic9339]

The only kinda drama I care to watch!

[@nozzbean1709]

It doesn't deserve to be called drama

[@KOZMOuvBORG]

Debate, not Drama

[@oobanoobaisterrible]

KZbin drama but like not cringe

[@zaphodbeeblebrox2817]

As others have pointed out, at 7:00 with the horizontal chain, he says it "the fountain doesn't grow" when clearly it does grow from the point of acceleration to the arc (equivalent to vertical fountain height) at 7:40 he makes the same claim yet you clearly see it increasing. Also notice at 7:00 the chain rapidly spiraling at the point of acceleration. In almost all videos you see this spiraling yet no one makes mention of it. Think about a football(American) when spun on its side it will stand up and spin. kzbin.info/www/bejne/gqCWhJ-qoNmcnNE

[@jobansand]

7:56 this convinced me. Also, splitting into two parts and narrowing down what the Mould effect precisely is was a very good idea.

[@itsphil30]

Interesting points, I used to be industrial abseiler and found that I also had the Fountain effect when throwing my rope off tall builds. I used to have the rope tied in daisy chain and rope was 11mm thickness. I agree with your kick back resistance. Thanks for the video. All the best. Phil

[@MrLast98]

I love how this is the best """""drama""""" between two youtubers, but instead of insulting each other you're fighting hypothesis after hypothesis, admitting mistakes and challenging each other to disprove the other person better than last time. Yay for the scientific method!

[@du42bz]

Based comrade

[@nomadMik]

So it seems the antonym for a pissing contest is a chain fountain contest.

[@saltysoyman6908]

Thats why I love this so much

[@zaphodbeeblebrox2817]

They’re both wrong. In all the videos the chain or rope ALWAYS Spirals. A spiral has angular momentum kzbin.info/www/bejne/gqCWhJ-qoNmcnNE

[@bobbodaskank]

It's similar to Veritasium's recent wager with a physicist over the wind-propelled car that could exceed the speed of the wind. Very respectful, everyone learns more than when they started including the one who was right; good stuff.

[@seeteasea5497]

I’d love to see Steve’s Amazon account for the last few months, just loads and loads of chains

[@hesperhurt]

Warehouse picker thinking either; A. Seriously obsessed with 1970s style door obstructions. B. Prolific kidnapper. C. Just another day at the office.

[@AsbestosMuffins]

that or ali-express

[@pipebombmailer]

history: chains chains chains long chains long chains silly orangutan picture long chains

[@hesperhurt]

In all seriousness though... surprised he hasn't encountered supply"chain" issues with Brexit. . . . ... sorry😞

[@DarkFire32001]

@@hesperhurt as a former amazon worker, we've seen worse lol

[@black_jack_meghav]

this debate inspires me to study physics more precisely and get all the pieces together. i have a hand wavy understanding now. Thanks steve and mehdi!

[@CHLBUTTERWORTH]

We need the gods of KZbin physics to come in a finish this for once and all. I call upon Veritasium, MinutePhysics and Smarter Every Day to join in

[@mel_0642]

We do need the gods. But we have one! Veritasium joined

[@bufoalvarius2520]

Pbs space time

[@Bashfulvideos1]

Pretty sure one of them have released it already

[@TheCosmokramer1]

Cody’s Lab and ScienceAsylum joined the fray!

[@superman-fb4ye]

@@TheCosmokramer1 what about V SAUCE everyone forgot about it

[@whitk034]

I have to admit that I was convinced when I saw the horizontal demonstration. After you reframed it and explained it I realised how two very different things can have the same perceived effect

[@jahrazzjahrazz8858]

Wasnt that hard to see if you looked carefully, people called that out already in the comments on Mehdis original video, but if you just watch it on the side you get swayed by eloquence more than reason

[@swampypolitics9574]

Perception is everything. You see two things and think they are completely different even though the are not. But if you only ever saw one view you'd think that view is correct by default and think the other view is wrong even though the are the same. This is true for almost all of life. Example. Someone says if a dog barks at nothing there's a ghost.. well they are perceiving that the dogs barking at nothing. Because the dogs senses are magnitudes more sensitive than a person's.. they might have senses something. You as a person go and look and see nothing and think the dogs barking at nothing. If you had the perception of the dog as well that might not be the case. In both cases your seeing the dog bark. They are both the same. But you don't see the other information and there for say it doesn't exist and there's no explanation. Life is chaotic. Another one example is high tensity situations. You can have 3 people in an area witness the same event but have completely different explanations because of their perception. News media uses this as a deception tool for profits. They lie by ommission. If they only wrote " there's nothing there the dog was barking at nothing this proves it" and that's all they focus on the consumer only does as well. They leave out " dogs have highten senses and might have senses something like a mouse or another animal next door or outside the window you can't see or didn't notice". If that's included the consumer now isn't set that the first point is the only truth. Now there nuance. Or they leave out information from an event for whatever reasons. So the perception of the viewer is X happened.. the perception of the people involved say " no all this happened too so maybe it was this" the news viewer perceive the outlet as authoritative so they disregard the witness statement that they sent report as false or un verified. Even though the outlet never verified what they stated. Perception is everything. Example. You see a dude haul off and shoot someone in the head. Immediately you think evil person murdered this guy. Later on it's revealed the person he shot raped and tortured his daughter and got off. Now if you only witnessed it and never got any information your perception is this person just blasted this guy for no reason and you spread that as facts when it's wrong

[@revimfadli4666]

Or, you know, both can contribute to the same effect, be it additively, multiplicatively, etc. Doesn't have to be just one. The validity of one cause doesn't necessarily invalidate another

[@saltysoyman6908]

Could be wrong, but what if the chain isn’t rising because it doesn’t have to go up to start. Medhi’s hypothesis was that the momentum of the chain going up was creating a force that made the chain rise, but if there is no rising to begin with, how will it rise at all. All the momentum is going horizontally.

[@zaphodbeeblebrox2817]

@@saltysoyman6908 In all the videos the chain or rope Always Spirals. A spiral has angular momentum kzbin.info/www/bejne/gqCWhJ-qoNmcnNE

[@adityachk2002]

The simulators did a great job tbh, they deserve the credit

[@InvincibleExtremes]

That's incredible. I love that you both go after this very seriously.

[@whatdoahknow3173]

I absolutely loved this video! It feels so real, you guys are haveing an actual public debate, to test your theories and continue to learn. One thing that annoys me is when the modern scientist show "it works in the computer model!" But no real debates or tests.

[@lovisericachii4503]

Or how claimed experiments can't be replicated.

[@backwashjoe7864]

Are they testing theories or hypotheses?

[@chunye215]

This is getting out of hands, I see a global chain shortage emerging

[@starwarized]

you could say they caused a chain reaction

[@johnharris6589]

Reminds me of an old joke the punch line was "where is all the chain coming from"

[@1.4142]

Someone will have to start a chain store to sell these.

[@danieleliahushapiro4280]

You had me in the first half of your comment , not gonna lie...

[@Nimelennar]

They're going to have to improve the supply chain.

[@RichtersFinger]

Thank you for featuring my simulations.

[@krampusz]

I found your channel when the yt algorithm recommended your bead chain fountain video to me. I stayed there for the other simulations as well, they are really interesting!

[@RichtersFinger]

@@krampusz Thanks!

[@seattledanr5363]

Ok Steve, you've won me back. I did not notice the falling arc in Mehdi's 2D experiment, or how dramatically he imparted the arc in his beaded fishing line. Both valid points. Your 2D comparison of the ball chain spaced out versus bunched together specifically shows the need for the kick-off effect to increase the height of the arc. I'm convinced...again. Are we done yet?

[@iCuMlOuD]

There's an easy explanation as to why it decreases (5:20 mark). The chain used up around the end is further back than the fountain origin. As such, gravity + friction cause the lag to a much greater degree than at the start. More force is required to maintain the shape but more force is not being applied to do so. Check the equation and see that the force required increases in a linear fashion.

[@simplyydream]

In the pot there is also a distance change though

[@NiceAstronaut-]

Seeing the chain try to kick through the bottom of the pot when you removed the floor in the simulation was what really convinced me

[@OwenWalker]

This explained the theory of the kickback force for me as well. After that it all clicked into place exactly how this appears to be caused. The wave generated during the stiffer chain unraveling creates a downwards force which flings the chain upwards due to it rebounding off the bottom of the jar, or in the horizontal case rebounding off the pile.

[@DinoDiniProductions]

Oh come on, 1) The amount of movement is nothing compared to the motion required to yank the thing out of the pot 2) Once it gets yanked it wants to keep on going, so there has to be some kind of bulge, otherwise there would be an infinite acceleration involved 3) You can't just assume gravity has nothing to do with it.

[@Caelinus]

@@DinoDiniProductions The simulation removed the downward force of gravity in the pot, so what you are seeing is probably a wave of force that would normally push against the rigid surface beneath it. After it leaves the pot gravity is in effect again, and is what is causing the chain to pull out from the pot. So it is not being ignored, and it's effect on acceleration is maintained. The only difference is that the simulation was an attempt to remove any forces originating inside the pot to show that the chain fountain came from those.

[@DinoDiniProductions]

@@Caelinus Oh OK, but in any case those small forces are insignificant compared to the huge force that keeps being overlooked: the force applied by the chain vertically, which is automatically present and unavoidable due to the fact that the container has depth.

[@hanvyj2]

@@DinoDiniProductions which keeps the chain following through its path - like Medi showed, that force is enough to fight gravity (decaying slightly due to friction). That's "the first half" Steve is talking about. The tiny kickback forces just need to be a tiny bit greater than friction, that causes the "wave" to decay - that slight force pushes it up. Not much, the culmination of all the kickback force, minus the friction forces, only slowly "grows" the fountain. It's not much force - but it's acting on a system near equilibrium. The equilibrium is caused by the much greater force you are talking about - but that's well understood.

[@Sneder]

14:11 "Having this disagreement has been fairly enjoyable" This is what I love about science and more specifically science on KZbin. Its so great to see people completely disagree on things and enjoy themselves while doing it. Just like Veritasium's recent video's on the vehicle that travels into the wind. Keep up the good work!

[@Alkis05]

Yeah, this video was much better than the first and convinced me you are right. The only thing in medhi's video that had me going was the spaced chain part, but the way it was addressed here cleared it out. The chain don't rise, it only keeps the shape it had.

[@SeraphOfTheNine]

just my 2 cents: amazing channel and I've made a point to try and watch one a day so I can retain what I learn. Thank you for your hard work in delivering these concepts in easy ways to understand :)

[@aykincakaloz]

I just watched the previous video like 5 minutes ago. KZbin recommendations are now so advanced that relevant videos are not only recommended but made when I would watch them

[@redyau_]

Perhaps youtube knew when this was set to release, so it recommended the previous one to watch first quickly before this one ;)

[@Tomapon]

If you hold the Motorized Spool™ on a higher level than the beaker, thus pulling the chain up rather than down, will there be a peak/fountain that rises above the spool too?

[@ruaine83]

Yes, just like it did in the video, it's due to the rotational forces and inertia. There is much more mass coming from the original container to the spool than is pulling on the spool itself, since the spool is rotating, thereby imparting an angular acceleration on the chain, the conservation of momentum will sling the chain out from the axis of the spool.

[@Tomapon]

@@ruaine83 Might be, I wish to see it though. I'm guessing it might depend on the diameter of the spool too, if it's too wide it might not be "bendy" enough for the chain to peak upwards.

[@thundernuts8308]

@@Tomapon its anomalous to the shapes sizes and material used. There is a proper diameter and speed that will nullify backlash, but the equation eludes me . E=mc2 but the speed of light being replaced by the relative gravity to its most predominant magnetic or gravitational influence .. here would be what we deem gravity.

[@thundernuts8308]

And what proves this is it would not happen if the little spheres were magnetic because it would dampen or cancel out the K energy build up in the chain.

[@Tomapon]

@@thundernuts8308 Perhaps the fountain might move to be near the Motorized Spool™ instead of the beaker :o

[@nilsmargott7015]

Great video! I might have another interesting idea: The falling end of the chain speeds up because it is nearly performing a free-fall accelleration. As we've seen, a chain wants to maintain its shape, so every part of the chain also wants to keep up with the increasing speed. At the beginning, the rising part of the chain inside the glass is so short that gravity forces and inertia only have a small effect. So what if we look at the top of the fountain as being a half circle? Objects moving along a circular path are pulled outwards by the (imaginary) centrifugal force. Because the lower half of the circle is missing, the sum of all centrifugal forces points straight upwards. I think this might be the reason why the top of the fountain is rising. The centrifugal force at the top of the fountain is pulling the rising part of the chain higher out of the glass. The fountain is growing until the gravity force of the rising part (which becomes longer and heavier as the fountain rises) matches the pulling force of the fountains top. Having reached that "point of equal forces", the fountain will remain a stable hight until the end of the chain. Does that make sense?

[@elderfrost9892]

thats another way to explain it, the same forces are still present just in a different order, it shows somewhat how a chain preserves its weight. However, I dont think the centripetal force alone would be stronger than gravity in this scenario, partly because gravity is what powers it in the first place, and partly because the experiment on a flat surface doesn't show this behavior. I think its closer that the tension and centripetal forces are canceling each other, and gravity is still uncountered, hence the sinking without the kickback. great idea though!

[@davesmith3289]

"The centrifugal force at the top of the fountain is pulling the rising part of the chain higher out of the glass" Centrifugal force is fictional, it does not exist and therefore has no effect. If you want to know why the chain jumps into the air just watch a video of a skateboarder doing an ollie.

[@deemon710]

Ok Mould. You've convinced me that the height is due to both the resistance to bending and the fact there's a base to push off of. Well demonstrated. The simulation was what pushed me over the fence when it depicted the spike in downward force right before the bead came up.

[@MrSkypelessons]

I've been an admirer of both of your channels for a long time, and I must say, you both have a wonderfully pedagogical approach. I really appreciate your content and your commitment to the scientific method.

[@CaptainSpock1701]

Dude, you said exactly what I was going to say, you just said it better, so I'll just agree! Ditto.

[@samsamson391]

Pedagogical. I never knew this word. I had to double check to see if it even existed. I give myself one week to use it in everyday life. Thx! 😂

[@MrSkypelessons]

@The mRNA jab Is the mark of the beast As soon as your Bitcoin payment hits my wallet, the lesson will start.

[@vigilantcosmicpenguin8721]

The scientific method, and also entertainment. That's all you need.

[@1stGruhn]

Oh man, that howNotToHighLine plug! As a rock climber myself, that guy is seriously helpful in showing what gear can handle.

[@Bretttwarwick]

I'm glad I pointed it out to him in his last video. I had been binge watching a lot of those videos a few hours before Steve's last video on this topic came out so the scene was fresh in my mind. HNTH is such a great resource for climbers.

[@aspuzling]

How not to highline is amazing. Don't know how they can afford to break so much stuff!

[@iain_nakada]

Yep, excellent channel. Really useful, and pretty fun to watch too. Someone compared it to watching that hydraulic press channel...

[@AlexCFaulkner]

Coming back after Mhedi released another video!

[@XllxSilentxllX]

I think you have the best simulation so far at this point. I have to side with you and believe that there is another force behind the chain in creating the fountain. Incredible detail, I think you have it my friend.

[@americankid7782]

I love KZbin scientists making the new modern “drama” videos debating science.

[@saqibsultantemuri2437]

Mould-Effect surely caused a very pleasant "Chain-reaction". Love to watch your guys intellectual discussions.

[@DeXoDeD]

Under-rated comment. I wish I could award you like on reddit.

[@vigilantcosmicpenguin8721]

That's a good one.

[@MichiruYami]

Never doubted you dude! Good work!

[@Jimmytrue0512]

Bravo Steve. This is excellent. I am now convinced by your explanation, where previously I found mehdi’s video more convincing

[@dejantot542]

My favorite part is how you selectively break the rules of physics in the simulation to reaffirm your hypothesis in an intuitive & visual way, amazing work!

[@MegaBrokenstar]

@SaltyBrains this was my first reaction to the use of simulations as well, that they are probably not the best for unknown physics problems because they were by definition programmed without an understanding of the mechanics at hand, but in combination with the other evidence I do find it convincing in this case.

[@zaphodbeeblebrox2817]

LOL so true. As others have pointed out, at 7:00 with the horizontal chain, he says it "the fountain doesn't grow" when clearly it does grow from the point of acceleration to the arc (equivalent to vertical fountain height) at 7:40 he makes the same claim yet you clearly see it increasing. Also notice at 7:00 the chain rapidly spiraling at the point of acceleration. In almost all videos you see this spiraling yet no one makes mention of it. Think about a football(American) when spun on its side it will stand up and spin. kzbin.info/www/bejne/gqCWhJ-qoNmcnNE (read description)

[@ScottRathbone]

I think the interesting point is at 9:49 when the gravity is removed in the simulation. The chain line being pulled out drops below the level of the base line, without gravity this can only mean it was pushed down. If the bottom was still there then that push would result in a reactive force from the bottom of the pot, proving Steve correct in saying there is a "kick" from the pot.

[@felipeghirello5314]

That also happens at 8:01 in the horizontal dirll pull

[@zaphodbeeblebrox2817]

Gravity always plays a part. In all the videos the chain or rope Always Spirals. A spiral has angular momentum kzbin.info/www/bejne/gqCWhJ-qoNmcnNE

[@HenryLoenwind]

@@zaphodbeeblebrox2817 Gravity also plays a part when it's switched off...?

[@zaphodbeeblebrox2817]

@@HenryLoenwind it’s impossible to switch off gravity

[@sealdraws1984]

@@zaphodbeeblebrox2817 wdym? it is possible, either in a well made simulation or more realistically in space where its almost negligible

[@dicerson9976]

It looks to me like the reason the stiffness of the chain imparts force on the bottom of the bot is because the chain's resistance to being bent means that when one bead in the chain moves upward the next bead at rest is "pushed" into the pot slightly as it at first resists bending. If you think of the beads as being connected by tiny teetertotters or seesaws, it becomes alot easier to understand what appears to be happening. When the first bead is lifted, it's partner bead gets pushed down into the bottom of the pot due to the stiffness of whatever happens to be connecting the beads together which is in addition to the pull of the chain itself in the other direction. Pull one bead up, and the other gets pushed down. Furthermore, the bit of wobble in the actual position of the chain is explained by this as well. If you were to take a slightly flexible piece of wood and then bend only one end while holding the other in place, then let go the other end will suddenly flick as the entire piece of wood attempts to return to its original shape and chances are it'll so do quite violently. So as the beads in a chain continue to be pulled and are finally lifted from the bottom of the bot (or from the other beads farther down the chain they are resting on top of) the chain's stiffness again causes them to flick back into place and wobble- hence the very chaotic movements of the fountain.

[@matthewziemba7526]

I was more convinced by Medhi's explanation compared to your first video, but this video was very convincing, especially the sideways experiment on the floor where you made an object act as the lip of a container, as well as how the height of the fountain was different between the spaced out chain and the piled together chain.

[@zaphodbeeblebrox2817]

I'm not at all convinced kzbin.info/www/bejne/nmbFiWaXp6yhnJo

[@TheElectricCaveman]

I would be interested to see some experiments on a surface that would absorb some of the peaks in the normal force (foam, rubber, a pillow?) instead of reacting with a kickback force, and see how it makes a difference vs a hard surface.

[@martinshoosterman]

It would be interesting to use hollow chains that would float on water and try it.

[@haphazard1342]

Shouldn't be too hard to do a quick test on some memory foam.

[@facugaich]

@@martinshoosterman I think they would have to be neutrally buoyant

[@zunuf]

That would eliminate kickback from the jar. Normally there's also kick back from the chain stacked on top of each other. I wonder how much the foam would dampen that. You could try to space things carefully so the chain doesn't stack. I'd be interested in seeing this because I think the spring effect of the turning radius provides more of the force than the "lever" force of the beads.

[@moczikgabor]

@@zunuf Cover the chain itself with something. But all of these change other properties also, not just the kickback force. Like rigidity, friction, etc

[@KafshakTashtak]

Wait, we need Destin from Smarter Every Day as a judge as well.

[@rickvandam3238]

Yes that

[@PongoDaMan]

72

[@zaphodbeeblebrox2817]

Absolutely. we need a lot more judges. a high speed camera to prove/disprove my theory. kzbin.info/www/bejne/gqCWhJ-qoNmcnNE (you have to read the descriptions in the videos)

[@PongoDaMan]

@@zaphodbeeblebrox2817 oh banter! I love it!

[@zaphodbeeblebrox2817]

@@PongoDaMan but is it really banter if only you and I hear it? While thousands are convinced by this "Proof". I know Atomic Shrimp saw it, but he prefers Steve's "Proof" video because of the rigorous scientific methods he used (hand held drill, denying that it rises at 7:00, rock solid simulations) confirmation bias is a bitch these days. This is not science!

[@death4hiro]

Probably pretty late to this discussion, but I actually think that the demo at 5:46 disproves Mehdi's theory on the upward force being a reactive force to the downward falling chain. Before this, I thought that it could be a combination of both theories. Using Mehdi's theory, the height of the peak is dependent on the speed of the falling chain - I interpreted this as the acceleration of the chain leaving the pile needs to match the acceleration at the equal point in the falling chain. This would give rise to the force required for the chain to rise when leaving the pile, and thus leading to the kickback force (dependent on the chain rigidity). However, the 5:46 demo shows no matching upward velocity, regardless of how fast the chain moves downwards. Thus, currently siding with the need for the initial upward velocity, followed by the kickback force to raise this peak above the lip. And as the upward velocity increase, so does the kickback force, raising the peak.

[@blacky_Ninja]

Very nice demonstration 👍 Good thing you added that paper roll, otherwise you wouldn‘t really have seen how high above the ‚starting point‘ of the chain it currently is because of the extra way it had to travel. But i guess the simulation is a good way to prove it too. Anyway i‘d definitely say you have a goot point there. 😊

[@Real28]

Crowdsourcing science - freaking love it. You have 2 guys debating and others essentially peer reviewing. This is how you get to answers _really_ fast. Love it, love it, love it!! This is brilliant.

[@jathenmoors1]

What's more, through youtube and patreon, it's effectively being funded by the interest of the peers.

[@trouty7947]

It brings together the people that have the energy to try out any experiments and ideas, with the people that can find genuine flaws or weaknesses in just about anything. So you can rapidly get to the strongest possible answers.

[@PafiTheOne]

Between Mehdi and Lewin a similar approach led to destroying the correct lession and made an old teacher/scientist apologize for something that he never made just to escape alive from the emotional trap Mahdi have set.

[@MattsAwesomeStuff]

I first watched yours, and I was convinced. Then I watched Medhi's, and I thought yours was debunked and I was convinced of his. Now I see your rebuttal, and I think his is debunked and am convinced of yours again. What this teaches me is that I almost always believe the last person I talked to, and I should just shut up and wait for the community consensus to establish.

[@nathanb011]

Personally I was never convinced by Medhi for the reasons shown in this video: he never actually showed the Mould Effect with loose chain.

[@LaGuerre19]

You're a hero, Matt, and I applaud you 👏. Well, at least until someone comes up with a better reply lol

[@kindlin]

@@nathanb011 I was more convinced by everybody else being convinced, but I was still skeptical. I also laughed at Medhi when he said "see? no mould effect!" while it's actively producing the mould effect....

[@MsHojat]

This is truer than it seems for everyone learning about nearly anything. It's why it's important to be skeptical and have critical thinking. To have an open mind, but not so open that your head-jelly falls out.

[@tinybabybread]

It's good to recognize that you tend to believe the last person's argument, but you must realize that the community consensus must not convince you as easily all the same

[@doc_ineeda_win5834]

Love to see you break down the math in a mathematical problem and how you can do that part that gives you the idea on-how to test

[@niek9242]

Here is the thing. If the chain has any "stiffness" at all, the bottom of the chain thats leaving the pot can be seen as a part of the chain (of arbitrary lenght) that feels a force (being pulled up by the 'previous' part of chain) on only one of its sides. Since that part of the chain has non-zero stiffness/rigidity it will start turning around its centre of mass. But its either on top of other chain, or the bottom of the pot. So it will be 'pushing' (levering around its center of mass) on the bottom of the pot. Since the pot isnt moving down, it must be excerting an equal force up. That is the kick that the bottom of the pot gives the bottom of the chain. Or how the bottom of the chain pushes itself off and 'jumps' after itself. It would be really interesting to see how friction (like, chain to chain friction) would affect the height or stability of the 'jump curve'. Im thinking the levers might work even better if they cant slide across one-another as easily This is still such a rich topic for utterly pointless but nevertheless interesting research. How would weight, shape, etc etc of both pot and chain affect things? Would the jump be higher or lower on mars?

[@SISSYPUSS]

If there is a lever action effect created by the tiny balls, it could be measured by a calibrated scale / along with an accumulator to get a mass effect. I doubt there's a fraction of a gram produced, and even if so, the overall effect would be negligible. There's not much going on when 'next ball' is yanked from it's stationary position, that change of state is practically instantaneous.

[@sethamoto9061]

9:46 I had an aha moment. That simulation really helped me understand your view on the kickback force and why the rigidity is so crucial to the kick back happening in the first place.

[@craigfjay]

My moment was at 8:00, you can see the stack of beads being pushed downwards

[@drawapretzel6003]

@@craigfjay yep, i made a comment that its backwards wave propagation, essentially the force of the bead chain falling sends small waves backwards along the chain, which without a pot sends the beads below the level of the loops of chain, but with a pot, they cant travel any further down, so the pot exerts a force upwards, giving that wave a bit of energy back into the chain. Ultimately, the force is technically from gravity. Gravity on the chain, gravity on the pot, resistance to gravity, resistance to the backwards wave propagation. The simulations did for me something that a million beads in jars couldnt do, they showed a simplified version that performed according to obvious parameter. i could never actually tell where the force was being introduced before those simulations were shown.

[@kindlin]

@@craigfjay 8:00 was my initial moment as well, for the overall explanation to fit, but it wasn't until 9:46 that the local mechanics of the phenomenon became apparent.

[@Znatnhos]

Dang, Steve, I'm really glad you made this follow up. I was one of those that felt there were a lot of unanswered questions. In a perfect display of the scientific method, you've strengthened your arguments substantially. As you say, it's not about winning, but about finding the truth and adjusting our positions based on new stronger evidence.

[@Nerdious_Maximus]

The lever effect Steve mentioned was close but it would happen even if you don't have something to support the chain. Because most of the mass of the chain is located in lumps and those lumps are connected by stiff rods any moving bend in the chain causes a repeated lever action where the inertia of the lump resists the pull of the accelerating side. This creates a lever that pulls on the other side of the bend, accelerating it a little. For the peak of the chain experiment this has little to no bearing because the energy to do this comes from the side accelerating down, meaning that the total forces don't change. The bend is different at the base, however. Instead of the forces opposing each other and negating each other one is thrown essentially away from the system, causing the other to act in a measurable way. In this case that means that when the lever action occurs where an upright chain pulls on an either horizontal or parallel chain the lever thrusts one end downwards below the original bottom line as the chain attempts to maintain its shape. This creates an upward force on the chain at the expense of the chain's elevation, and when measuring the forces in a situation where the chain is resting on a surface this looks like the chain is pushing against the floor even though no pushing is necessary to achieve the upwards force, as the force downwards would give the upwards boost anyways.

[@tropingreenhorn]

My intuition would be, it has to do with the concervation of momentum of the chain initially being pulled up into the air, and then having to redirect and fall downward due to gravity. If you have the chain in a beaker initially, you can see that the chain will on its own impart an upward monentum as the chain in the beaker starts out being lower and lower than the lip of the beaker.

[@familyguy0398]

This video finally made me understand the Mould effect. In order for the chain to be pulled up from the base, it needs to change the angle of the connecting rod between the two beads which has just enough resistance to push the bead into the base harder, causing it to have a higher kinetic reaction.

[@kdub3890]

The simulation was crucial for my understanding. Once I could see the loop first dipping downward when the bottom of the container was removed, I immediately grasped what you were saying about a "kickback force". Really well done all around.

[@Florian-ps1qv]

yes

[@adamozmin8970]

Yeah I thought when he was holding the pot he would absorb the kick back.

[@helpabrothawithasubisaiah5316]

I love a kickback, force

[@abcaabca6364]

I'm impressed. I had only considered this a nuisance when working with Christmas tree beads. Now, it is something to look forward to trying. Thanks.

[@smartbuildengineering]

This is the first I've heard of this phenomena, but my immediate intuition was: it's due to lag in the chain at rest rotating into alignment with the direction of the chain pull. In the case of a traditional link chain this would be from a combination of angular inertia and friction between links. If the chain is travelling faster than the time it takes for the 'picked up' chain link to rotate into alignment, the non-aligned link rises up, I.e. a 'kink' travels up the chain. If the same happens with the next link behind and so on, it results in a series of kinks that, if they don't straighten in time, create a rising wave. The misalignment might be small between each link, but combined they form a curve. It would be interesting to do duplicate drops with a link chain, first dry, then lubed, to see if there is a difference in wave height. I suspect the lubed one would create a lower wave, despite the potentially reduced friction over jar lip allowing a faster initial chain speed. I also suspect the layout of chain in a pot might effect things. I.e. I wonder if a chain laid out circles around radially around the circumference of a pot would create a different /more consistent height standing wave than one lapped back and forth into a pot, due the different angular change their links experience from at rest vs. direction of pull. I'll caveat all this by saying dynamics is not my area!

[@zaphodbeeblebrox2817]

Maybe more like this? kzbin.info/www/bejne/gqCWhJ-qoNmcnNE You have to read the descriptions I don't make good videos but check other vids of fountains too

[@crazyasspsychokilla]

My money's always been with you steve! In all seriousness though, these youtube "arguments" that are solved through experimental/empirical methods are great, super cool to see science resolve disputes in real time.

[@ZTenski]

The horizontal experiment with the drill, where the beads were spaced out versus not, was quite convincing. Nice video.

[@iamdave84]

Yes, around the 8:00 mark you see the stacked beads being pushed down. That convinced me.

[@Kvadraten376]

@@iamdave84 that part was indeed very convincing. Though I would have loved to see the experiment with the pile at the “bottom”, closer to the spool.

[@ZTenski]

@Timothy Lim it's not just the spaced out pile, it's that in combination with the pile that's *not* spaced out right next to it that makes it convincing. Specifically the part at 7:52

[@infi2723]

PLEASE READ: Using the spaced beads in that way is wrong in my opinion. if you just let the beads off the edge of the board, there is no upwards force acting upon the chain. its only being pulled to the side and down. But in a beaker/cup. the chain is forced to move UP out of the cup. therefore it initially creates and upwards force that then increases as the momentum of the falling side increases.

[@gdxd7956]

What's also not shown in that test, of the chain going off the edge sideways, is a camera recording the chain from the side. I am more than certain the chain makes a sideways loop, away from the board, that grows in lateral distance, as the chain falls and gains speed. Very bad example, not showing all the angles of the test. That's hiding information.

[@infi2723]

@@gdxd7956 yes i was thinking that too but didnt mention it. I believe if you showed another angle. You would see the same effect but sideways

[@shotguntornado]

7:51

[@infi2723]

@@shotguntornado I think the reason why the effect is not happening is because the length of one side gets longer and longer. and the drill is stationary. The reason it works on the left is because one side is always longer than the other, therefore more momentum. Another reason this could be happening is the drill is exceeding the force of gravity if it was vertical. The effect works vertically because the only main forces in play are gravity and momentum. if the side inside the cup took longer to get over the lip, then the effect would be smaller or nonexistent. I still believe the effect happens because the momentum of the falling side exceeds the threshold for the other side to slow down and start to fall.

[@tuomasrannikko4702]

I think the experiment with the chain bunched up on a surface shows the bunched up chain moving downwards, especially at the end. This would indicate the "kick down" effect. It's most apparent in this video where you're comparing the bunched up chain with lip together with the chain more loosely laid out on the other side about 8 minutes into the video. I think you describe the effect as the recoil on the stationary chain. Mehdi makes a similar experiment with a similar effect his second video at about 9 minutes in, but it seems the chain being pulled hits the "pile" so it's not as clear cut on that video, but I think I see the pile moving there as well. I think you're correct about the kick back. Love both of your channels. This is good.

[@bobvogel9916]

Trying to find the 'right' answer, vs. just 'winning'. What a concept. :-)

[@zaphodbeeblebrox2817]

But they ignore the obvious. In ALL the videos the chain or rope ALWAYS Spirals. A spiral has angular momentum kzbin.info/www/bejne/gqCWhJ-qoNmcnNE

[@isaacjackiw9711]

These were exactly my thoughts on Medhi's video, with regards to his experiments not actually showing the Mould effect. Glad to see them addressed, and with a proper explanation of the wave dynamics!

[@hanvyj2]

Yes I was nearly convinced then I noticed the "fountain" always decayed, (the floor one never goes "up", and he imparted the chain one with his initial movements). The hoover hose was interesting though.

[@noahway13]

Really? Sounds lame. No pics--it didn't happen.

[@isaacjackiw9711]

@@noahway13 you can go see my comment on Medhi's video if you don't believe me lol

[@noahway13]

@@isaacjackiw9711 Didn't check, but I believe you. Your reply was to nice to troll you.

[@bibsp3556]

I love that you and Medhi do these things

[@MrSheymie]

Curvature of coils in pot constitutes a latent wave which imparts an additional along-chain torsional force (a coiled bead-chain will rotate along its length in order to lie in coils). The force of weight of chain falling to floor outside the pot transforms these latent waves (remember the bead-chain is not absolutely flexible, so it cannot bend at 180 degrees) and the slight torsional twist in the chain into a vertical one. In other words, the sudden subtraction of nascent wave energy and torsional twist energy in the chain get converted into along-chain energy. The released nascent energy is greater than the force of gravity acting on the descending end of the chain. Therefore, the chain ascends until the nascent coiled and torsional energy have been 'uncoiled' to the point at which they lose out to gravity.

[@jmacd8817]

One thing about the horizontal simulation, is that the movement “down” isn’t immaterial. You would need to compare that to a a chain actually falling down, but lower the beaker as you do it.

[@kriscpg]

there is one problem with that. as you lower the beaker, you wouldn't only be removing the bottom of the pot, but also "pulling" the chain down.

[@scares009]

That's what I was thinking as well. In the spaced-out example, the top of the beads is going down much faster than it is in the clumped example (or in the actual pot), so you'd need to account for that

[@meateaw]

@@kriscpg You could perhaps design a cup that rests the chain on a poorly supported paper floor. Something that would not provide a strong restoring force to any "kicks", but that would otherwise hold the chain if it is stationary. I think with a "soft" floor like that you could simulate the lack of beaker floor, but still support the chain for the experiment without imparting any additional velocity to the chain.

[@rylandavis2976]

@@meateaw even better. Calculate out how much force is being imparted to raise the chain on the floor and build the support just to support the weight. Then if there is the kickback force it should break through the paper. Although this would actually probably pretty hard to engineer accounting for all factors

[@matthieurobion5996]

So, from your theory, should you place a soft bottom to the pot (like a sponge), the chain shouldn't raise as much? I would be interested to see it ^^

[@FanaticTentacle]

This is very interesting. Indeed I agree, it should be tested with an energy absorbing bottom layer in the container (elastic vs. non-elastic deformation). I too think that this should have an impact if Mould is correct

[@PBMS123]

@@FanaticTentacle so plastic?

[@FanaticTentacle]

@@PBMS123 more like cotton balls

[@lewismillward2202]

No see the better solution would be a preassure pad at the base of the jar, if the preassure increases steve is correct but i doubt he is

[@carvalhorosolen]

@@SkELAo7 Usually the way the science proves something is right is by proving the other teories are wrong, isn't it?

[@rastamike8063]

I've watched all the videos and was on the fence until this one. You have convinced me that your hypnosis is most probable, Mr. Mould. Thanks for the discussion and brain excercise.

[@scaridaghostly]

When I was a kid I had a metal bead chain necklace that I loved to play around with, and I "discovered" for myself the chain fountain, it's different maximum curvature when slack and when taut, and it following a given pattern, so I am very invested in this debate

[@seth7745]

"Seeing as to how this thing is already made, I might as well try to simulate a gory chainsaw accident"

[@victoriaeads6126]

This entire chain of videos-pun entirely intentional-makes me think of how scientists of previous, pre-KZbin times would hash out such disputes, often to the benefit of science. Now we ALL get to be a part of it! I love this!

[@theRealWebmarc]

I suspect the fountain results from 0) initial state with a lip that causes a 180° change in direction from up to down, 1) acceleration of the chain as it initially falls, 2) as the chain accelerates, the impulse imparted to each ball also increases, requiring a longer period for gravity to counteract it... which means the fountain will grow until terminal velocity/equilibrium of the moving section of chain is reached.

[@Dr_Rocks]

This explanation really made me see how in Medhi's video every time there was an initial wave imparted, but no fountain grown from no arc

[@3mileshi]

Just seeing this, and have only recently encountered Mr Mould. I'm beginning huge fan. 2 thoughts stand out. 1. Adding the video with the figure 8 knots in a row, the Mould Effect reminds me of Knot Theory, in that there are probably some but not infinite number of variations in the wave form. And 2., Mr Mould doesn't just construct some wonderful science, watch his eyes. He's not reading off of a card, he's looking right at us. His entire argument/ lesson unspools carefully, in perfect order, never one missed word, until he's done. Amazing!

[@cobrasteve427]

Its the mass and inertia passing on through the linked chain that causes the fountain. The speed the balls are instantly accelerated to propelled in the initial direction due to their mass until the change in direction, be it force or gravity takes over. Because they are individually attached by string, the effect is translated to each ball consecutively. Nothing happens if pulled straight.

[@anonymoususer3561]

You should put the bead container on a weight measurer to confirm the kickback force

[@DrSuperKamiGuru]

He explained in a previous video that doing that is very difficult because the mass of the chain in the pot is constantly changing.

[@TamedRome]

@@DrSuperKamiGuru can we setup differential equations?

[@iaexo]

@@TamedRome This problem has already been solved, the solution is in a paper linked in Steve's first video on this "dispute"

[@KP3droflxp]

@Jun Yan Yap just because it’s a paper doesn’t mean it’s correct.

[@iaexo]

@@KP3droflxp Yes, but in my humble opinion what’s published there, or at least their key conclusions, are correct.

[@jamesross1003]

Start a fountain from a high place, then after it starts to fountain drop the pot into freefall. If the pot then accelerates faster than a dropped pot with no fountain then there is a kickback. The said kickback would push on the fountain forcing the pot downward faster. This would also exaggerate the fountain length as well. Might answer some of the questions to try this experiment.

[@haydenhagemeier4458]

However by having a fountain, mass would be leaving the pot, thus slowing it down, which would have a more pronounced effect than the kick back described. Right?

[@donalbaine]

@@haydenhagemeier4458 the mass leaving the pot should have no effect, I think, as the object will accelerate downwards the same regardless of the weight. If it falls faster than 9.8m/s², it will be due to the additional downward force created by the tension in the chain. What will likely happen though is that once the pot is dropped, the whole assembly will almost immediately be in freefall, which is indistinguishable from a weightless state. It will all fall together and appear motionless relative to each other (chain versus fountain versus pot). Interesting question, and I'd like to see the results of trying it out..

[@haydenhagemeier4458]

@@donalbaine awesome thanks for explaining👍

[@ameunier41]

The fountain would collapse rapidly as the pot accelerate, but I think with a high speed camera we could measure the initial acceleration of the pot. That is a tremendous idea, I was thinking about using scales, but the bead leaving the pot really complicated thing. With your idea the mass of the beads in the pot is irrelevant, since they are free falling and are not applying force on their own.

[@jamesross1003]

@@donalbaine Yes it would require a high speed camera and the important information we are looking for would be in the initial second or two. The idea was to remove as many variables as possible such that we are left with the usable data we need to answer the question.

[@oeliku3033]

I think ElectroBoom was with his approach to the reason for this being inertia of mass. As you know you can split every velocity in 2 vectors perpendicular to another. Since this is a chain, you can split the links up and look at them seperately. Now assume a coordinate system and make one axis follow the direction of the chain link and the other perpendicular to the chains direction. If you now drag the chain along on the ground, the velocity vector will always be 100% of the total velocity long (obviously). Now do the chain drop experiment: there are 3 stages (straight upwards, straight downwards and changing). We know how the velocities look during the upwards and downwards phase. But in the "changing" phase it is different. Because one: the chain link already starts this phase with an upwards velocity that is equal to the total velocity of the chain and two: it will experience a constant force in the chains direction - so along the arc. So as long as the chain is accelerating the speed vector of the chain link perpendicular to the direction of the chain is getting bigger (since the chain link is getting forced along a curved line). A bit like a vector of centripetal force would look like. This changing outwards velocity is the reason the arcs radious to get bigger. I think the hight in which the arc starts is also determined by the velocity, since then upwards component of the chain link traveling upwards is bigger with higher velocity and therefor it takes more time to cancel that upwards component of movement. When the speed is constant in an optimal scenario the hight should not change. And for 4:47 - the lengh the chain travels to the edge of the board gets longer and that changes the direction the individual chain link goes during the first phase - lowering the upwards component of the velocity. sorry for the bad english

[@JazzmatazzSSM]

I just discovered your channel and I love it!

[@oafkad]

As a kid the "wave whip" with ropes and the like always blew my mind. I would do it with bigger and bigger ropes to see how far it could go.

[@Tactcat]

I want to see waves in an extra dimension in space - you only get a Y wave on earth but imagine the wave going on the X as well, like a spiral! And yes, the "pull rope and observe feedback" is delicious, even more so as a child. MAGICAL

[@BingusFodder]

I loved it too, my friends and I would have battles where you each hold one side of the rope and take turns sending waves at each other. Because sending waves at the same time just cancelled each other.

[@sebastianpohlman9906]

And then you discover the mechanics of a whip, with decreasing thickness

[@markp8295]

Have you seen the chain whips they use as tourist attractions in China. There are videos on KZbin une of them. They get the chain to break the speed of sound using simple conservation of momentum.

[@kalkhasse]

It’s very interesting and fun to see the increasing precision and detail in the descriptions of the phenomenon under study. You can really tell that both Steve and Mehdi are learning and gaining more understanding as this goes on. Good work, both of you!

[@frankvl]

Watched all the videos, and I agree with Mehdi. The energy to lift the chain is not comimg from the pot, or any other surface, it's coming from the chain itself. As the Cambridge people explain, if 'link 1' is pulled in a certain direction, it forces 'link 2' to rotate around its center of mass. As a result, 'link 3' is pushed in the opposite direction of 'link 1'. Because of the law of inertia, 'link 3' does not yield so easilly, and therefore serves as a base for 'link 2' to push off from. The push on 'link 3' will cause it to rotate as well, but in the opposite direction of 'link 2'. A moment later, when 'link 3' is starting to get pulled in the direction of 'link 1', 'link 3' is forced to reverse its rotation given earlier. Due to the conservation of momentum, this requires a relatively large amount of energy, and this extra energy makes the effect on 'link 4' bigger. This extra energy that it takes to 'whip' (yes, this is a similar but reversed effect as that in a whip) the chains into the right direction will serve as a counter force to the force of gravity, thereby explaining why the chain has its critical speed less than expected. So, this effect causes a momentum in the links, and due to the conservation of momentum, it will form an arc in the chain. The radius of this arc will depend on the mass and 'stiffness' of the chain, just like the bend radius of rivers is depending on the width / depth. Note though, that the behaviour and bend radius of the ball-chain is different when the links are compressed or pulled apart! And the fact that in Steve's video the 'stack' of chain on the ground is finally pushed 'down', is a result of the down curve of the chain making room for itself, not a result of the chain pushing off from the 'ground'.

[@gsusfrq]

Medhi had me convinced with his last video, but you’ve redeemed your argument. Your simulations and physical experiments in this video, along with your detailed explanations, have me convinced on your side now.

[@amarug]

As a mechanical engineer, this debate has been a real treat. Shows how difficult classical mechanics can get. Medhis did an awesome job, but I'd declare Steve the winner. Simulations always have to be analysed carefully, however I think in this case the core of whats going on mechanically is represented and the consequences we learn from them unlock the physicis of whats going on.

[@VeteranVandal]

The thing is that there were 2 things going on, and the simulations and slightly different experiments show them: 1) wave propagation in a chain; 2) force of a pile over the links of a chain falling. Of course the force applied is not that big all the time or consistent all the time, but that doesn't matter for the effect since we just need the chain speed to increase in 1 side relative to the other. You can probably suppress the effect in many ways, some shown here too.

[@zaphodbeeblebrox2817]

Yes, they over simplify it. In all the videos the chain or rope Always Spirals. A spiral has angular momentum kzbin.info/www/bejne/gqCWhJ-qoNmcnNE

[@trouty7947]

Like the veritasium video on moving faster than the wind. It all comes down to forces at the end of the day, and it was very deceptive in working out how they balanced.

[@salamiboi1346]

Can me take a moment to admire the faces these two do when they are in a slow-mo.

[@dbongoloid9541]

I cant stop watching the faces now.

[@TheYear-dm9op]

Very epic indeed.

[@ABRARKHAN-wp4xy]

Your name should be Salmon boi

[@SawdustAndNoise42]

I think there are two effects occurring concurrently that is causing the chain fountain. The first effect is the acceleration of the semi rigid chain. To get out of the pot / pile the chain must accelerate upwards to match the speed of the falling chain V(up) = V(down). As the chain has little to "no" stretch this must be the case. To transition from up to down the chain must turn. With a supple chain there is "no" resistance to changing direction as there is no mechanical limit to how the chain can bend. 180 degrees is not an issue (yes this implies instantaneous acceleration from up to down but as it is passing as an arc over the lip of the pot the acceleration is slightly less than instantaneous as it is accelerating around a curve not a point). This is the effect observed in a string or the chain with the spaced out beads. The second effect is inertia. As the upward traveling semi-rigid chain is accelerated downwards it cannot change direction as sharply as a more supple chain can. As the chain moves faster and faster it reaches a limit as to how sharply it can accelerate around the edge of the pot with the inertia and the resistance to bending resulting in the lifting of the transition area from the edge of the pot and it reaching the highest point when the chain reaches terminal velocity. TMMV

[@SISSYPUSS]

There are three sections to this, a falling chain, a pulled chain, and the curved (top) chain. The curvature begins on either side of the curve at a point where it loses verticality, but snip the curved section off, temporarily. The rising and falling lengths are now the only working parts. Velocity of the chain moving upward is a function of the velocity of the falling chain pulled toward earth, by gravity minus the startup energy required for the non-moving links in the pot. The snap to yank the next ball from dead zero into motion has an energy cost, I'm not calculating that. Curvature is maintained when equilibrium is attained between a force pushing the chain inward against it's curve, and another one pushing it outward. A loss of this equilibrium would cause the half-circle to collapse or expand until it loses it's well defined shape. This self-balancing between the centrifugal and centripetal forces maintaining a spherical top is a good demonstration of a natural effect. Ready, startup! When the chain is tossed up and over, the links in the pot are engaged all that remains to shape the curve and maintain it, is acceleration. Objects in motion tend to stay in motion unless it's acted on by an external force, Newton's First Law of Motion. The curve will obtain a somewhat fixed height according to the properties of the chain, flexibility, the flexibility of the connecting length between chains elements, and without adding much more, the increasing velocity of the pulling (falling) chain. Maximum curve (fountain) height is attained when the velocity of the falling chain is met, at or near terminal velocity, roughly 1.61 meters per second for a small chain falling in air. For my chain, not your chain, I don't know the size of your chain. For those who tend to think in impossibilities, yes ten tons of chain will probably spin a paddlewheel to rotate a generator...whatever thing. Then there are ten tons of chain on the ground that have to be picked up and taken UP to the roof for a net gain of nothing. So forget it perpetual motion is impossible. Steve you almost convinced me, this demonstration comes around in some forum about every three years. Good presentation! 😂😂😂

[@HaloWolf102]

This is the KZbin drama I'm actually interested in. I get to learn along with it.