We need to jiggle the balls around
August 30, 2019 4:17 PM   Subscribe

Two minutes of balls settling into a lattice [YouTube]

This is actually a follow-on to Steve Mould's [YouTube] earlier video on self-organizing balls as a model for heat treatment of metals [YouTube], itself a follow-up to a video on using 3,000 steel ball bearings to model crystal defects [YouTube].
posted by noneuclidean (25 comments total) 26 users marked this as a favorite
 
Great stuff; thanks! Granular media have so many amazing properties. Some of this stuff is cutting edge but important parts have been worked out by industrial engineers long ago, to shuffle coal into hopers and such. I don’t have any cool videos of that at hand but I’ll try to find some :)
posted by SaltySalticid at 4:22 PM on August 30, 2019 [1 favorite]


Did I miss an announcement that August is Balls Month on the blue? There are four ballin’ stories on the front page right now.
posted by migurski at 5:06 PM on August 30, 2019 [9 favorites]


Ooh, here’s a good short science teaser from the NSF, skip to 1:45 for the action.
posted by SaltySalticid at 5:32 PM on August 30, 2019


Happens with atoms too. Watch the top layer. A dislocation (linear defect) forms at 0:10 and disappears at 2:08.
posted by dephlogisticated at 5:51 PM on August 30, 2019 [1 favorite]


Happens with atoms too.

I have no particular knowledge of this kind of stuff, but it did remind me of a crystal lattice forming.
posted by Ickster at 6:41 PM on August 30, 2019 [1 favorite]


Isolated holes don't move around nearly as much as those courses I took about semiconductor theory would have me believe.
posted by ckape at 8:15 PM on August 30, 2019 [4 favorites]


Speaking as a metallurgist - yes, that's what atoms do in crystals and a great model for how metals anneal.

This is only 2D and the only close packed arrangement is hexagonal, but all models are wrong and some are useful, ok? There's grain boundaries, vacancies, grain growth, and movement of lattice defects.

(ckape - holes in semiconductors are defects to do with electrons and other charge carriers. These defects here are atomic, so less mobile.)
posted by happyinmotion at 8:58 PM on August 30, 2019 [4 favorites]


Speaking as a metallurgist - yes, that's what atoms do in crystals and a great model for how metals anneal.

I have tried to do hammer annealing of metal and it's fucking witchcraft. Metal is so strange to work with, esp like silver, gold, some others... like you can bang it around, you can use a hammer to mix it together, you can stretch it (gold is the champion), you can flatten it (gold is again the champion)... like, with very simple tools and a bit of heat you can do a LOT to a lot of precious metals. Platinum is a bastard.

Alloying is also really peculiar, as you always "lose a little to the gods" (weight of casting comes out as less than weight cast), and with gold, you mix this and that and you get different colors of gold. Each of those colors have their own peculiarity for being worked with for final finishing, and it often comes down to individual castings because of how the mix was done in the furnace.

Anyway, crystals, and metal, and working with metal... I don't know blacksmithing, but gold and silver and diamonds and etc and I are old friends, even if we haven't hung out in a long while.
posted by hippybear at 9:05 PM on August 30, 2019 [6 favorites]


Crystals are weird, yo. It's pretty amazing how the turbine blades in many modern engines are cast in such a way as to grow only one single crystal grain. This is to minimize creep under heating and stress, but also helps in prolonging the life of the blade. The bigger gain is from efficiency, though. The increased dimensional stability allows the clearance between the tips of the blades and the seal to be much smaller, allowing less gas to pass by uselessly.

The ability to grow very large single crystals is also a necessary component of the modern internet, since long distance fiber would be basically impossible otherwise. More generally, such a high degree of control over material properties is a prerequisite of a ridiculous amount of the stuff we have come to take for granted over the past 40-50 years. It touches nearly everything we do in some way or another.

Worryingly, the vast majority of our success in this respect would not have been possible without the progress in basic physics that itself has only been possible with the help of the sort of "big science" projects that are becoming increasingly questioned by large segments of society on both ends of the political spectrum.
posted by wierdo at 9:40 PM on August 30, 2019 [4 favorites]


Thanks, Mould is one of the things in my feed that I always have to not post because they're mostly awesome and I want to post all of them. He repeatably goes from "duh, obvious" but end up "damn, that's some fine explaining".

/me waits for the machine learning folks to come in about simulated annealing.
posted by zengargoyle at 9:42 PM on August 30, 2019 [1 favorite]


using 3,000 steel ball bearings to model crystal defects

Funny that they do Estimation Time! at the end of this video. Matt Parker estimates 3,000 balls between the lattice and the beaker of spares and is off by quite a bit: the package came with 10,000 balls. I wonder why the bad estimate made it into the video title?
posted by carsonb at 11:25 PM on August 30, 2019


the package came with 10,000 balls

Ack...I hadn't watched that whole video in a couple years and forgot about that part.
posted by noneuclidean at 4:42 AM on August 31, 2019


I'm fascinated by how some of the gaps behave like bubbles in liquid as the balls settle themselves into shape.
posted by EmpressCallipygos at 5:01 AM on August 31, 2019


Reacting at a visceral level, watching this is both frustrating and mesmerizing. It *hurts* somehow when the gaps continue to not close, but I must keep watching.
posted by mrgoldenbrown at 8:02 AM on August 31, 2019 [1 favorite]


AAAAAAAAAAAAHHHH

Do people find this relaxing because I was about to break my screen in order to give the dang thing a jiggle, Jesus.
posted by MiraK at 9:32 AM on August 31, 2019


I have seen the desk toy called Atomix that these videos are based on... it really is fascinating to "anneal" the tiny ball bearings.

Worryingly, the vast majority of our success in this respect would not have been possible without the progress in basic physics that itself has only been possible with the help of the sort of "big science" projects that are becoming increasingly questioned by large segments of society on both ends of the political spectrum.
I do wonder, knowing what we have learned in the last 60 years, whether we could re-build the SR-71 so that it could fly faster or higher.
posted by Multicellular Exothermic at 10:06 AM on August 31, 2019 [1 favorite]


We call the higher and faster SR-71s rockets and satellites and space planes.
posted by zengargoyle at 10:17 AM on August 31, 2019 [1 favorite]


Ack...

No, no! It's actually in the title of the video on youtube, so your transcription/link is correct in that sense. Just weird.

Do people find this relaxing because I was about to break my screen in order to give the dang thing a jiggle, Jesus.
Yah I definitely port some anxiety onto those fault lines. But watching the other videos, there are excellent illustrations of why that happens which helped me cope a lot better.
posted by carsonb at 11:48 AM on August 31, 2019


One surprising thing to me was that the self-reproducing defects seemed to move faster the closer to the upper edge they got.

A rectangular parallelogram shape looked fastest.

Game of Life -like.
posted by jamjam at 12:20 PM on August 31, 2019


Some people have ASMR, I have this.
posted by SakuraK at 1:12 PM on August 31, 2019


BBSMR
posted by moonmilk at 1:45 PM on August 31, 2019


jamjam, gravity. The balls have no appreciable interactive forces alone (magnetic or sharing electrons, etc. They're spherical cows). The balls are confined to a space and a XY plane. The shaking is mostly random. The major force that effects the balls is gravity. This little demonstration wouldn't work in space (in orbit) because no gravitational potential field.

Non Spherical Cow, atoms have some forces between them besides gravity. You jiggle them apart with a strong shaking and slowly reduce the shaking to let them attract each other until they settle into the lowest energy place. Every atom is happy.

There are flaws in this process. The amount of shaking and how you change the shaking influences the flaws (on purpose mostly). If the result is every atom in perfect place, a change results in fracture, something breaks and goes snap. If the result is sorta imperfect the change just flexes or slides and things rearrange.

If this square piece of plastic holding the balls was exactly the right size and you shook from hard to soft slowly enough you would end up with a perfect crystal structure. Gravity, the only force in play in this Spherical Cow will ensure that high energy states move upwards.
posted by zengargoyle at 3:43 PM on August 31, 2019


Is a spherical cow the source of those balls of butter you get at restaurants for your pancakes?
posted by hippybear at 3:48 PM on August 31, 2019 [1 favorite]


There's at least one, and she's probably really really tired.
posted by zengargoyle at 4:01 PM on August 31, 2019


............so
..........soot
.....................thing.............all the..........
....................little..........balls..................................sorting................
.......................................................themselves.................................into......


......................perfect uni...................................ty.
posted by Lipstick Thespian at 6:06 PM on August 31, 2019


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