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u/Carbon-Base 1d ago
One of the ways this is explained - the metronomes transfer energy to the board, which in turn transfers energy back to the metronomes. The metronomes are not precisely identical to one another, even if they are set to the same bpm they will eventually be out of sync without the rollers underneath the board. When you add the rollers, the board can then facilitate energy transfer back into the oscillations. Oscillations that are higher in frequency will have energy taken away, and oscillations that are lower in frequency will have energy added. This goes on until you reach phase lock, or equilibrium.
This wouldn't be possible without a light support (foam board) that can help couple the motion of the metronomes. It also wouldn't work if you changed the orientation of the metronomes (angle, direction, spacing).
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u/pulithi_mavan 1d ago
Can someone explain why this happens?
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u/gigaishtar 1d ago
Newton's Third Law. The metronomes are on a platform with rollers underneath. As each metronome swings, it exerts a small sideways movement causing the platform to shift which in turn affects all the other metronomes, subtly changing their timing causing them to eventually synchronize.
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u/Z_Overman 1d ago
is this why soldiers etc shouldn’t march in step on bridges? is that a thing?
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u/KuullWarrior 1d ago
Resonating frequency, similar phenomenon, yes
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u/Ryeballs 9h ago
The dynamic load on the bridge gets really funky as well.
Let’s assume 1000 people at ~75 kgs/ea. An average walking step will multiply the force by ~2.5. The impact force on the bridge becomes 187.5 metric tonnes of force every step when synchronized (1000x75x2.5).
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u/robot_allbotross 1d ago
I believe it’s because it’s on a surface which rolls slightly? Or maybe tilts, idk.
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u/pulithi_mavan 1d ago
I see that now.. thanks
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u/AdFancy1249 1d ago
Even if the table weren't on rollers, it would happen eventually, unless the surface were very solid. As explained, the vibrations cause movements in the base (even a solid table moves enough). That small movement affects the others.
As more metronomes line up, the remaining ones will synchronize faster.
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u/Valuchian 1d ago
They are all on the same surface. This means that as the metronome's arm swings, whatever the majority of the metronomes are doing at that time will be how the surface is pulling.
think Newton ~ Equal and Opposite reaction. If the metronome swings one way, the table has to push equally the otherEvery cycle the majority's swinging slows down or speeds up the metronomes not in sync till evenetually they are all swinging at the same time.
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u/WaldenFont 1d ago
And if you do this with a bunch of mechanical looms in a factory building, the building will collapse.
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u/roastedmarshmellows 1d ago
I’m guessing we discovered this the hard way, eh?
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u/WaldenFont 17h ago
Oh did we ever.
Curiously, the wiki makes no mention of the looms synchronizing, but the docents at the NE textile museum in Lowell explain that this was the trigger.4
u/wakallll 1d ago
"The surprising secret of synchronization" by veritasium on youtube at 5:00. He goes into detail and has graphics for it
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u/ohwhatfollyisman 1d ago
there's a veritasium video which goes into detail on this phenomenon--one which was shot before its enshittified takeover.
am not linking it here because i don't want the new money-grabbing owners of the channel to profit off clicks on it.
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u/Background_Honey9141 1d ago
Did the channel actually changed owner?! I just thought maybe Derek wanted to do something else and hired new people. The new videos are a lot less engaging that’s for sure.
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u/zdm_ 23h ago
not really... in my opinion, the channel still uses the same formula as before.I still learn a lot and frankly I dont see the "private equity" or "owner change" bsd people are just saying it because of that one vid from another channel. the same effort is still being exerted by the same production team Derek had. yeah theres that one video they split into parts then so??? I know corporations=bad but Derek wouldnt be handing it over to someone without good intentions and afaik he still plays a large part on the backend production. I still love Veritasium.
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u/geoff1036 27m ago edited 21m ago
I know others have answered but I'd like to try my hand lol:
All the metronomes are on one rolling platform, basically all connected to the same set of wheels. This means that all the momentum of every swing is felt by every metronome, because each swing rolls the base in the direction it was swinging, and if you add up all the left and right swings at a given time you get the net force imparted on the whole "cart" at once.
Of all the pendulums, at any given time, most of them are going to be swinging one way, and the rest the other. The majority is going to be decided by which metronomes are most synced at the beginning, as they are already closer and thus take less time to sync, and thus create a bigger wave. The majority swinging one way creates a major force in that direction, and the minor force the rest create gets cancelled out and overcome, meaning that every pendulum that was going the other way gets pushed or pulled harder than it would if it was standing still or moving with the majority. This causes the minority pendulums to take one or two swings at a slightly differing speed, and the laws of energy conservation and equal and opposite reaction do their thing to average out all the forces which is what eventually syncs them all up. Each one is slowed or sped up each swing by a fraction of the specific amount it needs to be to sync, probably in some sort of observable pattern, but I digress.
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u/senorbozz 1d ago
Whoever decided to end the video where we only get 3 seconds of sync is a criminal
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u/3rr0r-403 1d ago
Me watching the metronomes come in sync.
https://giphy.com/gifs/fVcAmX5QAR9lgysWcY
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u/Jello5678 1d ago
This is a real thing that actually happens, but this video of it looks AI generated.
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u/michaelswallace 18h ago
The AI giveaway to me is the title and snappy one liner with an arrow. No real people talk like that for general uses, it's only AI imitating marketing material verbiage
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u/Iain_McNugget 1d ago
Now do the same thing with 100 of those waving golden cat things. Much more unnerving!
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u/QueenOfTonga 1d ago
They must all be set to the same tempo, surely, just started at different times.
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u/igotshadowbaned 6h ago
The video cut before they all synced. 6th column 2nd from the back was still off
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u/stereoscopic_ 1d ago
But what happens when the ground doesn’t move?
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u/aNeverNude666 9h ago
It would be like when you see a line of cars with their blinkers on.. they’ll fall in and out of sync randomly
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u/BLAKDIEN0MITE 1d ago
I've noticed this with turn signals while sitting at red lights since I was a kid
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u/Individual-Schemes 1d ago
The only problem I see with this video is that it doesn't go on long enough.