Dropping 100ft of ball chain off a 40ft tower (slow motion).

Ball chain is often used on ceiling fans and hanging lights for pull switches. This is 100 feet of ball chain dropping off a 40 foot tall tower. The chain gets pulled up out of the jar at the same speed the other end is falling. The upward momentum creates an interesting loop at the top.

[jeffbransky]

As the chain falls, a greater and greater amount of mass is accelerating as it falls to earth. The falling mass reaches terminal velocity and pulls the supply of chain at the same velocity. The low mass of supply is moving so fast it can’t make the U turn instantly at the speed the falling portion is pulling it. Inertia causes the low mass of supply chain, which again, is traveling at the same rate as the falling chain, to rise up. You might say the falling mass is whipping the links in a controlled manner.

[pamelatollett]

Very cool video! Thank you very much for sharing

[christophermaglio]

I'd love to hear an explanation of the physics, the fact that it pulls away from the edge is not what I would have expected. I don't know if Destin of "smarter every day" has done a similar video but that style of video explanation would be interesting to hear. The interaction between momentum of the chain and KE of the chain causing it to lift off the lip would be great to mathematically quantify i.e. how chain type, its mass per unit length, height of the tower, etc. affect how high the chain will lift off of the lip of the glass.

[atheistaetherist]

Steve & Co are mostly wrong.
The question(s) are not whether there is a reaction force, they are
(1) whether the reaction force is needed to create a fountain,
(2) whether the reaction force affects the height of the fountain.
The answers are No & No.
In relation to the horizontal fountain, the answers are Yes & Yes.
But, the original questions relate to a chain from a bucket/beaker/container/can -- not from a horizontal surface.
So, that was their first mistake.

Now to their second mistake.
The mere existence of a reaction force does not make the answers Yes & Yes.
The reaction force (at launch, in the bucket) borrows power from the falling chain.
So, it can't add to the height of fountain (at launch, from a bucket).

Links landing on the floor do add to the tension in the falling chain.
Hence they add to the height of a fountain.
But the lever action (kick) at launch in the bucket does not add to the height of the fountain.

There are (can be) two kinds of kick.
Kick 1. One is the simple lever kick (due to a say 90 deg bend in the chain).
The other is a similar kick that is due to the chain having a bend beyond 90 deg.
Kick 2. We sometimes see a bend of 180 deg, or more.
That large bend creates a slower & possibly greater kick.
But, both kinds of kick (at launch) borrow power from the chain, hence they don’t add to the height of the fountain.
Except in the case of launching horizontally from a horizontal surface, where there would be no vertical fountain were it not for these two kinds of kick.

Except that there is a third kind of kick that will give u an enormous vertical fountain offa horizontal surface.
Kick 3. And this kick can be created by laying the chain such that as it is being yanked horizontally it has to jump over itself.
It’s a jump-kick, & has zero to do with lever action.
Whereas the other two kinds depend on lever action.
Kick 1 & Kick 2 do not add to the height of a fountain, koz they borrow from the system.
Kick 3 also borrows from the system, hence at launch from a bucket it can't add to the height of a fountain.
But, from a horizontal surface, Kick 3 does add to the height of the fountain, koz, without it, the height would be zero.

Kick 4. However, Kick 1 & Kick 2 can give a small non-zero height from a horizontal surface, but this usually arises due to the chain clattering over the (usually) sharp edge at the end of the surface. This can be called Kick 4. It thrives koz its effect is cumulative (as are Kicks 1 & 2 & 3).

Steve & Co are wrong.

[atheistaetherist]

Ok, this youtube of a chain fountain proves that the lever-link-kick-reaction at launch in the bucket doesn't add to the height etc of the fountain.
U can see that many times the rising chain lifts a tangled mass of chain, & in no instance does this make a major difference to the fountain.
This is koz the power robbed from the system to lift the tangled mass gives back power later.
Similarly a lever-link-kick-reaction in the bucket robs power & gives it back.
A lever-link-kick-reaction doesn't add to the fountain.
It doesn't help to initiate the fountain.
Steve Mould is wrong.

[slimmmerman]

Where is the rest of your "40 foot tower"?  Unless you are telling me that you stand 14 ft tall... If you need help with that;  an average ladder's rungs are between 10 and 12 inches apart.  Now since your ladders each have 10 rungs... that'd make them each 10 ft tall!What else have you lied about? Let me guess... the chain is only 50 ft long...

[scottrobinson]

Why they take thinge off youtube like this same effect can be used to power any thing turn and alternator that chain will keep running when its set in motion

[atheistaetherist]

(1) The Cambridge explanation is rubbish. There is never a bonus-kick at the container/jar/beaker.
There is indeed a bonus-kick when a falling chain-link hits (collides with) the floor of the laboratory, & this adds to the downward pull of a chain, & increases the height of the fountain etc (by say 1% in practise they say)(by potentially no limit in theory).
But that extra (bonus) force is initiated by the falling/colliding link itself.
Meanwhile, back in the jar, during launch, a rising/yanked link will indeed get a mini-kick from the floor of the jar (or from the links supporting that link), but, that kick is not initiated by the rising link, it is initiated by the preceding link.
The preceding link has a limited amount of impulse to give.
The kick from the jar results in a similar (but opposite) kick being given to the preceding link.
But the kick from the jar is not a bonus-kick.
The initiating impulse from the preceding link is not added-to by the kick from the jar.
The impulse of the kick experienced by the rising/yanked link has been borrowed from the preceding link.
In reality, borrowed from the full/whole chain.
Hence, at the jar, links or beads, it makes no difference.
In summary. Yes there is some kick-effect at launch (even in a bead chain), but, these kicks are not bonus-kicks. They borrow from the overall power of the chain system, they don’t add to the fountain.

(2) In reality, at launch, there is no rising/yanked link. Duznt happen.
What i mean is, we mostly have a wide rising/yanked arc, made of many links (beads here).
In slow-mo u can see that there is mostly a long arc of moving beads.
And the movings usually involve being dragged horizontally for a time, & gradually upish.
There is no sudden up-kick -- it is gradual – very gradual.

(3) Look in slow-mo at a bead-chain fountain in the launch zone.
There are say 4 adjacent beads acting as pseudo-links being yanked/jerked up.
(a) Firstly, these pseudo-links are not rigid, they have a lot of give, & loss of force.
(b) And, the pseudo-link & the trailing say 5 or even 10 beads can be seen to be mostly moving horizontally (mostly sideways) & have daylite under them.
(c) They almost never have a solid floor to kick (down) against.
(d) And, on the rare occasion that the last bead in the pseudo-link does enjoy an upwards (very very weak) kick, this kick is mostly sideways, off a slippery & loose bead or two. Beads do not provide anything like a solid surface to kick offa.
Sheeeesh! Stone the crows! Milo give me strength! Are we blind!

(4) The fountain (ie the arch)(the half circle) is simply due to the inertia/mass of a chain.
If a stationary chain hangs over the top of a wall, it forms a sharp V-bend.
If the chain is pulled down on one end, then it will rattle up & over the wall, with speed.
If the speed is sufficient, the sharp V-bend will become a U-bend, due to centrifugal/centripetal forces opening up the V.
If speed increases, the U-bend opens further.
At hi speed the rising chain leaps up clear of the wall, & stays clear, & the U-bend opens more.
And we have our fountain.
The height of the crest/fountain depends on speed.
The radius of the U-bend of a fountain duznt depend on the speed or height (they say).

(5) Steve Mould shows how a horizontal tight pattern of rows of chain (beads) gradually pushes away to the west (due to the kick-effect) when the end of the chain is pulled east.
Yes, there is some kick effect.
But, the greater part of the effect is due to a chain's inclination to retain a pattern.
Here, we see that at each end of each row Steve's chain forms a loop, looping around & back throo say 220 deg, such that the rows sit hard up to each other.
As the chain is drawn east, the loops move across & back & across & back etc.
Now, Steve knows that a chain has a memory, ie it tends to retain a pattern. Here, that pattern is a 220 deg loop.
And, as the loop or loops traverse across & back etc, the loops slowly push the rows west.
That westwards slow pattern-push is a different animal to the quick jerk of a link-kick.

(6) It is virtually impossible to load/store a chain in a jar without having loops. And loops result in jumps.
If u have a close look (in slow-mo) u can see that chains have a lot of horizontal movement before exiting vertically, & the chain sometimes suffers little jumps in the jar, as each leg of each loop jumps (while moving horizontally) over its mate.
Jumps magnify the fountain, kicks dont. OOPS. No, i am wrong. These little jumps are not bonus-jumps, just like the kicks are not bonus-kicks. Any vertical impulse gained by a jump must have been borrowed from preceding links.

(7) Also, the horizontal movements seen in the container/jar/beaker are a waste, they rob power.

(8) But, in any case, we don’t need bonus-jumps nor bonus-kicks to achieve a growing fountain, & to achieve a high fountain.
All we need is lots of speed. The bead-chain will crest at any height, depending on speed. There is no limit (the strength of the chain is a limit)
The idea that something special (like a bonus-kick) is needed (if the chain is to rise above the edge of the jar) is silly.

(9) One thing that everyone has missed, in every youtube re the chain fountain (that i have seen), is that vertical jump effects & vertical kick effects (etc) are cumulative, and lasting (tautology alert).
Or at least partially cumulative & lasting. Air friction, & link friction see to that.
Anyhow, cumulative/lasting effects are the reason for some of the slightly weird gyrations/waves.
For example, it (lasting accumulation) is why we eventually get a persevering, vertical component of arc (a mini fountain) when the test is strictly in the horizontal.
In fact, the lasting/cumulative effect is a major cause for a standard vertical chain fountain.
There needs to be an initial vertical rise out of the jar.
A horizontal initial exit wont do the trick.

[Observer]

OH MAN!  TIy go to all that trouble of buying the chain and climbing up the tower, then let the chain hit the railing messing up the experiment!  Do it over correctly, please.
Cheers...

[sturgeindustriesltd]

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