Things are hotting up in Chain Fountain Hypothesis Land!
The ever-entertaining ElectroBOOM vs the soothingly British Steve Mould, talking about why chains rise up when they fall.
ElectroBOOM's First Chain Video: youtu.be/hx2LEqTQT4E
Steve’s First Video: youtu.be/qTLR7FwXUU4
Steve’s Second Video: youtu.be/bcsb1xAv7XA
Paper on Cascade of Hanging Chains: arxiv.org/ftp/arxiv/papers/18...
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Invisible Wizard - 13th Level Scrote, Wed 1 Sep 2021, 21:26,
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I’ve only watched Mould’s video so far.
Not sure what he means about an upward force from the container, particularly because the fountain effect still appears when there isn’t one.
It also works with rope, I think, so to my mind the main factors are going to be the stiffness of the chain, its density and maybe the minimum bend radius. Come to think of it, the ball chain doesn’t really have any stiffness beyond what results from simple inertia.
I’m going to watch more Mould videos; he doesn’t get on my wick the way Tom Scott does.
Ed: does it actually happen with rope or was I not paying close enough attention?
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jonbob loves you, Wed 1 Sep 2021, 21:52,
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No, go back and watch the videos
there's a lot more to it and he does talk about the stiffness of the chain, bend radius etc and has some links to people who show the effect with rope.
This is a saga and I'm really pleased to see a process of argument between two science communicators who use experiments and hypothesis to try to prove their hypotheses and disprove the other.
If people are watching this they are understanding how humanity is advancing and not watching flat earth / anti-vax shite.
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garold you're on mute I SAID YOU'RE ON MUTE, Thu 2 Sep 2021, 8:19,
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I’d already seen mehdi’s videos.
I’d love to see the experiment done with a very flexible bike chain, which can’t change length unlike other kinds. As well as that it’d be fascinating to see what happens if you could propel the chain up from the bottom to start it off, just for comparison.
I remain unconvinced about any lever effect making a difference, but I’ve really enjoyed thinking about the problem these past few days.
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jonbob loves you, Thu 2 Sep 2021, 17:15,
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He's saying that
because the chain can be thought of as a series of rigid poles, when you lift one end of each pole, it wants to rotate around the centre of mass which means the other end pushes against the surface, imparting an upwards force. These forces add up, being larger with the speed you pull the chain, leading to the chain leaping from the surface.
The rest of the effect is the natural tendency of a chain to follow the route taken by the previous sections.
This is why he says there has to be a minimum bend radius, so that the chain will act like a series of poles, not just a flexible tube.
Mould asserts that it should not happen with rope and some surface is required, technoboom is trying to show the effect is still there without a surface or minimum bend radius.
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My Name was saying these words inside your head on, Thu 2 Sep 2021, 10:53,
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Yeah, I noticed this when I was a kid, but never chased that branch of physics
I coulda bin a content provider!
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Invisible Wizard - 13th Level Scrote, Wed 1 Sep 2021, 22:12,
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It was explained back in 2014-5
royalsocietypublishing.org/doi/full/10.1098/rspa.2013.0689
Steve Mould demonstrated it back in 2014, so he's milking it again for views :-)
(, Thu 2 Sep 2021, 12:23, Reply)
It was demonstrated, but the explanation is in doubt.
So Mould is defending his position.
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Invisible Wizard - 13th Level Scrote, Thu 2 Sep 2021, 15:40,
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