At a high temperature driven by coherent granule movement, a randomly generated cluster of granules causes a drop in pressure in their region, thus attracting more granules to the cluster? And coherent granule movement is some kind of resonance effect that occurs only at a certain frequency and its multiples of shaking? I'd like to learn more. How about a part two and explain things a bit more?
@peterc1 Actually the 'layers of atmosphere' are due to the Earth's gravity, pulling the gases to it. The denser gases accumulate close to the Earth, while the lighter ones are pushed upwards. The higher you go, the less dense the atmosphere it.
@Jebus495 That's what I was assuming he meant, but I was hoping for a clarification. It does make me wonder what effect changing the gain would hold, if any. Due to the natural limiting effect of the piston (because of the limited stroke) it would be akin to changing the feed signal from a sinusoidal wave to a square wave. Thanks.
@HotblackDesiat042@Jebus495, at the beginning he says that he is only changing the amplitude, not the frequency, because amplitude has a greater visual effect on the system, or something like that. So it's amplitude/gain, not frequency.
@thesourceofx Okay. So my question still remains concerning the natural limiting effect from the piston/solenoid in relation to the feed signal. At what amplitude does the piston's stroke max out and limiting begin? Next, what is the equivalent structure of the feed wave when the particles go from being chaotic to coherently driven?
@HotblackDesiat042 those are still great questions, and I don't have the answers :(. Just wanted to clarify on the amplitude vs. frequency problem. My thoughts on the limiting effect, however, and if I understood you correctly, I don't think there is a limiting effect, practically. The way he talks about higher amplitudes makes it seem like they've reached quite a large amplitude experimentally.
@thesourceofx Thanks for your input. Perhaps they are not amplifying it to the extent in which limiting occurs. I’m just curious to know if they are reaching, or passing that point in amplitude.
@HotblackDesiat042 When I speak of limiting I mean the point at which the amplitude of the drive signal is sufficient to extend the piston/solenoid to its farthest extent, thus reaching its maximum stroke. Any increase in amplitude beyond that point will be clipped as the piston cannot extend farther. When the amplitude is pushed beyond this point is would be akin to a square wave feed versus the sine wave feed, as that would be the motion the grains would feel.
If you have particles of many different sizes, could you use this to sort through the particles you want? Or do the different sizes interfere with this experiment?
@DemiImp Substantially different size particles may account for the behavior, therefore same sized particles that are clean are useful to rule out these issues.
tidy darts. I saw a video recently about Mercury when vibrated. So it works with liquids to? Could it work with solids? Intelligent materials? I wish i could vibrate my way out of being hammered.
I'm glad I found this because I have to admit I didn't quite understand what you meant when you explained this to me on the open day. I think I know what it's about now :)
Actually on their channel(sixtysymbols), there is a video explaining it with a different example.
Basically, the more closer together the beads get, the more they collide with each other...and thus waste their energy. Less energy..less movement, less movement, less temperature/pressure, less pressure, more particles.
@itchBob Brilliant how a desktop with a 480GB solid state capable of writing 1.2 Gigabytes per second costs $2500, 5 years ago a system capable of recording at that speed cost $30'000 and was the size of a refrigerator.
Too bad I don't know of any capture cards that go over 120 FPS... with a computer like that you could do 1000 FPS B&W or 300 FPS colour... 1000 FPS lossless... at that speed you'd probably have some very interesting observations over the longer periods of time 480GB would allow.
Have you tried redoing the experiment ona a tray with higher sides, so particles will essentially never hit the lid? What about a tray that is round? Or round and slightly conical?
I have a question; This might sound bizarre, but you know the law how these is an attraction (gravity) between two masses. For instance, if you have a cup of coffee, your foam always goes towards the sides (it is closer to the mass of the cup), maybe that is what is happening in your particles... They move towards one end because are there is a build up of particles there, they attract towards that force.
@frichikendz I'd guess at least part of the reason why that happens is because the liquid is most hot in the middle of the cup and cooler at the sides. Hot water (at least >4deg C) rises and cool water sinks, so small currents are formed which, at the surface, are moving toward the edge.
Perhaps you should try it in a cylindrical chamber, just for interest's sake to see where, if at all it would still clump. The pressure seems to be lower in the corners, is this true?
@murdakah The effects of the side walls are definitely something we're interested in. Typically In simulation we work with periodic boundary conditions, which is to say no side walls at all, but that's something we have been moving away from recently.
Chladni nodes. They propagate differently when the edge of the surface is clamped and has holes drilled in it, as opposed to a flat square plate with no holes.
It's not strange at all. The dimension of the box he's conducting the experiment creates a natural frequency where particles are pushed into one area. Its not some magic chaos effect.
I don't think it's dull. I'm curious, though: does this say anything about the accuracy of this model being used to approximate the behavior of gases, or do gases do this, too? Is this massive (PUN) pressure increase in any way effected by gravity?
i got article not found when i tried looking for the paper itchbob said. "prl.aps.org/abstract/PRL/v107/i4/e048002" but theres only a 404 error there.
It looks a lot like the grains are just riding a standing wave set up inside the enclosure. Have you tried multiple frequencies at once to see if the bubble forms in the same way or if maybe multiple rings or bubbles of different sizes form. Very interesting physics here. Keep up the great work!
Am I understanding this correctly. The lower pressure area has a higher rate of collision. With the higher collision rate the probability that 2 or more particles will hit another at the same time increases thus transfering all that energy into a single particle which ends up pushed into the higher pressure area taking all that energy with it? In other words is the action similar to evaporation?
Could this be in any way connected with the Earth spin, it's motion through space, stronger gravity fields in a certain direction??? I cant understand why this should happen or why they group together in a certain place... is it always the same place or is it random grouping??
That is a really good question... I suspect that, although those forces are non-zero, they have a negligible effect in this. I am also pretty sure that the writers explored that path before publishing.
I think one way to tell would be to look at the accuracy of the physics engine that was used for the simulation, how detailed the factors are in use. If those forces are indeed taken into account, then they could be "turned off" and run again to see what happens.
Varying the amplitude changes the net energy into the system --wouldn't changing the frequency do the same? At what critical point does the pahse transition (chaos-->stocastic) happen? Is this a function of the phase space betweent that transition and the change "back"? How about higher energies? Do you get other phase changes at higher energies? Finally, just curious--what were you looking for when you found this phenomenum?
The boxes are manufactured in the university workshop. I'm hopeless at making stuff, but we're lucky to have a team of really talented engineers who can build just about any weird thing you ask them for, a big thank you to them for all their efforts on our behalf.
We clean and dry the beads to make sure they don't stick together.
We've done some brief experiments on mixtures of particles with different densities, and this phase-separation is extremely effective at separating the particles.
Those of you asking about chladni patterns, the apparatus is the same/similar, but the underlying physics is quite different.
Someone asked what happens if we do the same thing in a bigger box. It turns out to be quite hard to make a flat shaker that's mechanically stable over a large area, so instead we use smaller particles, which gives us a relatively larger box. Because the phase-separation is driven by fluctuations in the density, basically bubbles form everywhere, and grown together. It's awesome to watch - we're still finalising those measurements, I'll try to get a video of it online soon.
Do you think that these results have implications for stellar formation & distribution of matter in the Universe? I was considering that before I saw the experiment "batch" at 9:34. It kinda looks like many animations I have seen of gas clouds collapsing.
For a bigger box, have you looked into using other materials? It looks like you are using Aluminum, what about Titanium or composites? I would be very interested to see the results with a larger box and nano-fine particles.
To answer how the pressure goes down at higher concentrations is tricky. Essentially in low density regions the particles can more easily enter the resonant state, so if there is a random fluctuation leading to a momentary low density region, then it gets resonant and heats up. Imagine someone jumping up and down in a crowd, if they hit someone on the way down, they will push them sideways. That's exactly what we see, the resonant particles push out sideways, and form a bubble.
In the simulation we can do the experiment with and without gravity. The same results are obtained. To get a wee bit technical, this is related to the frequency independance of the results: Since gravity and frequency are the only experimental parameters to have a time dimension, if gravity is not relevant to the results, then by dimensional analysis frequency is out too.
For enough particles, basically they act as a liquid, then you're in the hydrodynamic limit, and the whole system can be described by Navier-Stokes equations, but the big surprise is how that behaviour emerges from the chaos dynamics of a single particle.
If you take a single particle, and place it between the plates, then at certain amplitudes it's found to resonant. Placing two or three particles in the system, they basically act as independant resonators. So the question is, if we keep increasing the number of particles, do they eventually stop resonanting and start acting as a gas? We find that the single particle resonance persists, and eventually becomes a shockwave traveling through the particles, it looks really cool.
PART 2: A few of you have asked about repeating the experiment in vacuum. This is a terrific question, since often granular dynamics are governed by air flow around the particles. We've done the experiment, it's immensely hard not to have all the particles sucked up into the pump. The phase-separation (bubble) is still there at very low pressures, so we conclude it's not an air driven phenomena.
PART 1: morning Everyone, James here. I'm going to try and address some of the questions that you've all been asking, I'll have to do it in small chunks, because of the character limit, so please see PART 2 ... 12?
Despite of it's simplicity, this may be one of the most amene and interesting sixtysymbols videos to watch. I agree with @Jan1515 that much of it is merit of the edition. Also because Dr. Tetris seems sounds like a lovable person. heh
I wonder if it could be possible to obtain a vacuum zone with this technique in an actual gas...
Hey,I'm not a scientist, but I heard him say that when they run it in the computer simulations they get the same effect, and in the computer the box is perfect, no bending.
Yes, It is by testing, flat and level but maybe they didn't test the flatness while vibrating at high oscillation. I would also like to know how they measured the level. eg Did they use digital instruments?
Extremely level for such a precise experiment as this. The level on one spot on earth varies throughout the day because of earth's rotational/ gravitational pull changing the shape of the globe. Use a little thought/imagination/creativity and you to can think more deeply (not just at the obvious).
Please keep this up. You are easily as good at explaining difficult concepts as any I've ever seen and your comfort and confidence on camera show. Well done.
Hi everyone, James here. Really impressed the insights in the comments and questions. Thank you, keep them coming. Those of you who are interested, the paper we published can be found here:
@itchBob Great video, one of the best from Sixty Symbols in a while! Although for some reason the above link doesn't work for me; this one did however, for anyone else who found the same. I guess you'll have to take the space out, as YouTube doesn't like it.
I have studied mechanical vibrations, using simmilar setups, using sand particles on vibrating plates as well.
Is the sand not just collectiong at one side, due to the the amplitude of a certain modeshape? Or that the rig is EVER so slightly tilted or certainly not perfectly plane?
I know very very little of physics and science but could this relate to the inner workings of a star? Possibly where the particles of elements are withing the star? Like maybe the core is the hottest so there are more particles on the outskirts of the star?
@Atveurf He said the denser areas were hotter so the pressure was lower causing other particles to collect there. If these related then the center of the star would be low pressure and have more particles, or the out side would be hotter with more partials, but less dense. Neither of these make any sense to me, but that is not my field.
I am doing a senior project and I am wanting to do something with physics (or cosmology) but they are wanting us to do something that can be argued. I was thinking quantum physics or string theory but I don't know where to go with that. Can someone help me, please?
Please explain the mechanism that causes the pressure to go DOWN at higher concentrations. This makes no sense. At what size grain does this effect kick in? Why does this effect come and go as you continue to raise the amplitude? It defies intuition. Why is it so different from say, air? If a particle is moving randomly, surely there is a lower probability of it staying in an area of higher particle concentration due to there being a greater chance of collision and hence bouncing out.
@Ichijojichan Theres another video from them where professor Bowley explains an effect very similar to this one. It's the "Bouncing Balls - Sixty Symbols" or "r - coefficient of restitution" from the website. Maybe it's related
@Ichijojichan I'm guessing the particles resonate between the top and bottom surfaces at a certain frequency and so they have a lot of kinetic energy, but if they get too crowded and start bumping into each other the resonance stops because the particles are hitting the top and bottom at random times during the up/down cycle.
At a high temperature driven by coherent granule movement, a randomly generated cluster of granules causes a drop in pressure in their region, thus attracting more granules to the cluster? And coherent granule movement is some kind of resonance effect that occurs only at a certain frequency and its multiples of shaking? I'd like to learn more. How about a part two and explain things a bit more?
andwhatfire 4 days ago
Have you ever tried putting in some coloured beads? It might help analyse the movement of individual "particles".
Ypthor 1 week ago
How come pressure decreases when particles clump together in this case?
cateattingmonster0 2 weeks ago
He loves boxes
MrTabamon 2 weeks ago 13
like a polaroid picture
legendaryswordsmith 3 weeks ago
ahah was eating a pizza with no anchovies while watching this, almost overcooked it too because the video was so interesting :P
jayxtreme6 3 weeks ago
@jayxtreme6 why is it notable what topping the pizza didnt have
zombierobopirate 5 days ago
right when it was geting good an error popped up :(
haflappy 3 weeks ago
So you're saying that if we shake our politicians hard enough they finally will start to make some sense?
BarneySaysHi 3 weeks ago in playlist Uploaded videos
When the grains concentrate, is they pattern they form random? When they all concentrated to one side of the apparatus, why that side?
falcoperegrinus82 3 weeks ago
When the sand collect into a corner, is that a corulation to how there are different "layers" of the athopshere?
peterc1 1 month ago
@peterc1 Actually the 'layers of atmosphere' are due to the Earth's gravity, pulling the gases to it. The denser gases accumulate close to the Earth, while the lighter ones are pushed upwards. The higher you go, the less dense the atmosphere it.
speckles298 4 weeks ago
I whas just gonna say it's a kind of resonance, an than you said it :p
MrMinimalSWN 1 month ago
Granular smiley face 9:37
suicidalkatt 1 month ago 17
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suicidalkatt 1 month ago
wouldnt the rotation of the earth make the experiment impossible?
Supacalaz 1 month ago
@Supacalaz why's that?
Riou2294 1 month ago
@Riou2294 the position of the grains
Supacalaz 1 month ago
1:46 That was a good one. XD
TheCaphits 1 month ago
Was the sine wave at 4:44 just a coincidence?
stanek 1 month ago
this stuff is so interesting
lemonlimelukey 1 month ago in playlist More videos from sixtysymbols
When he says "as we shake it harder" is he increasing the amplitude/gain or the frequency on the piston?
HotblackDesiat042 1 month ago
@HotblackDesiat042 Looks like the frequency of the piston.
Jebus495 1 month ago
@Jebus495 That's what I was assuming he meant, but I was hoping for a clarification. It does make me wonder what effect changing the gain would hold, if any. Due to the natural limiting effect of the piston (because of the limited stroke) it would be akin to changing the feed signal from a sinusoidal wave to a square wave. Thanks.
HotblackDesiat042 1 month ago
@HotblackDesiat042 @Jebus495, at the beginning he says that he is only changing the amplitude, not the frequency, because amplitude has a greater visual effect on the system, or something like that. So it's amplitude/gain, not frequency.
thesourceofx 1 month ago
@thesourceofx Okay. So my question still remains concerning the natural limiting effect from the piston/solenoid in relation to the feed signal. At what amplitude does the piston's stroke max out and limiting begin? Next, what is the equivalent structure of the feed wave when the particles go from being chaotic to coherently driven?
HotblackDesiat042 1 month ago
@HotblackDesiat042 those are still great questions, and I don't have the answers :(. Just wanted to clarify on the amplitude vs. frequency problem. My thoughts on the limiting effect, however, and if I understood you correctly, I don't think there is a limiting effect, practically. The way he talks about higher amplitudes makes it seem like they've reached quite a large amplitude experimentally.
thesourceofx 1 month ago
@thesourceofx Thanks for your input. Perhaps they are not amplifying it to the extent in which limiting occurs. I’m just curious to know if they are reaching, or passing that point in amplitude.
HotblackDesiat042 1 month ago
@HotblackDesiat042 When I speak of limiting I mean the point at which the amplitude of the drive signal is sufficient to extend the piston/solenoid to its farthest extent, thus reaching its maximum stroke. Any increase in amplitude beyond that point will be clipped as the piston cannot extend farther. When the amplitude is pushed beyond this point is would be akin to a square wave feed versus the sine wave feed, as that would be the motion the grains would feel.
HotblackDesiat042 1 month ago
Just to clarify: they don't really know why this happens, correct?
GFxLiquidHandcuffsX 1 month ago
@GFxLiquidHandcuffsX that's what it seems like, yes. He says it's a new field of study, so they are probably just trying to figure it out now.
thesourceofx 1 month ago
congrats sixtysymbols, you have succeeded in what all scientist must do, confusing the majority of their audience. round of applause!
legorex630 1 month ago
If I had funded this research, I'd ask for my money back.
LV07TSK 2 months ago
wow, isn't this the same guy here?? (top tetris player)
watch?v=v0QQtxwta38
Premed1981 3 months ago
Does this explain why galaxies form in clumps? Bubbles?
cjhess 3 months ago
Isn't this very similar to the other sixty symbols video with some orange beads jumping from side to side? Can't remember what its called though.
fritspas 4 months ago
9:38 it's a smiley ace
GypsyCrusher 4 months ago 2
If you have particles of many different sizes, could you use this to sort through the particles you want? Or do the different sizes interfere with this experiment?
DemiImp 4 months ago
@DemiImp Substantially different size particles may account for the behavior, therefore same sized particles that are clean are useful to rule out these issues.
keystothebox 1 month ago
Would you agree that this is the amplitudinal analog of cymatics?
Perhaps much can be learned from cross referencing the results from these two disciplines...
dev0n1va 5 months ago
"you just squeeze a gas, it gets hotter"
HCLivess 5 months ago
@HCLivess Yes and if you decompress a gas it gets cold. Play with some air dusters and you will notice this phenomenon.
keystothebox 1 month ago
tidy darts. I saw a video recently about Mercury when vibrated. So it works with liquids to? Could it work with solids? Intelligent materials? I wish i could vibrate my way out of being hammered.
starsndspiders 5 months ago
I'm glad I found this because I have to admit I didn't quite understand what you meant when you explained this to me on the open day. I think I know what it's about now :)
mothercromby 5 months ago
@EveryoneIsBoring
Actually on their channel(sixtysymbols), there is a video explaining it with a different example.
Basically, the more closer together the beads get, the more they collide with each other...and thus waste their energy. Less energy..less movement, less movement, less temperature/pressure, less pressure, more particles.
UninstallingWindows 5 months ago
@itchBob Brilliant how a desktop with a 480GB solid state capable of writing 1.2 Gigabytes per second costs $2500, 5 years ago a system capable of recording at that speed cost $30'000 and was the size of a refrigerator.
Too bad I don't know of any capture cards that go over 120 FPS... with a computer like that you could do 1000 FPS B&W or 300 FPS colour... 1000 FPS lossless... at that speed you'd probably have some very interesting observations over the longer periods of time 480GB would allow.
HWGuyEG 5 months ago
Comment removed
HWGuyEG 5 months ago
Can any of this be applied to population dynamics/chaos theory?
currymakersuperfly 5 months ago
This needs a "box" remix.
19Tranc3r92 5 months ago
Have you tried redoing the experiment ona a tray with higher sides, so particles will essentially never hit the lid? What about a tray that is round? Or round and slightly conical?
Gameboygenius 5 months ago
I have a question; This might sound bizarre, but you know the law how these is an attraction (gravity) between two masses. For instance, if you have a cup of coffee, your foam always goes towards the sides (it is closer to the mass of the cup), maybe that is what is happening in your particles... They move towards one end because are there is a build up of particles there, they attract towards that force.
frichikendz 5 months ago
@frichikendz I'd guess at least part of the reason why that happens is because the liquid is most hot in the middle of the cup and cooler at the sides. Hot water (at least >4deg C) rises and cool water sinks, so small currents are formed which, at the surface, are moving toward the edge.
Gameboygenius 5 months ago
This is an extermally imature thing for me to say, but i'm going to say it anyway. This video is a big "thats what she said"
FAB12UCB 5 months ago
Can you please inform us what you know of Neutrinos
skooldayz 5 months ago
@bl4ck0p I can't give out the code we're using, but I can point you at this fabulous paper from Stefan Luding, which fleshes out the basic concepts.
www2.msm.ctw.utwente.nl/sluding/PAPERS/coll2p.pdf
itchBob 5 months ago
@itchBob Any chance of making the simulation software available to download?
bl4ck0p 5 months ago
thumbs up if you saw the smily face at 9:37
wazscience 5 months ago
interesting
TheCaprecorn 5 months ago
Perhaps you should try it in a cylindrical chamber, just for interest's sake to see where, if at all it would still clump. The pressure seems to be lower in the corners, is this true?
murdakah 5 months ago
@murdakah The effects of the side walls are definitely something we're interested in. Typically In simulation we work with periodic boundary conditions, which is to say no side walls at all, but that's something we have been moving away from recently.
itchBob 5 months ago
shit
MJapan555 5 months ago
i want to see it done without the lid on!
MegaPronk 5 months ago 2
Chladni nodes. They propagate differently when the edge of the surface is clamped and has holes drilled in it, as opposed to a flat square plate with no holes.
1isaacmusic 5 months ago
"Now If I shake it even harder"... hahaha
drummeratsix 5 months ago
Comment removed
pudgey952 5 months ago
Very interesting video :)
TheeImmortalPhoenix 5 months ago
Comment removed
TheeImmortalPhoenix 5 months ago
Great one! This guy's really good :)
WhitnosFilms 6 months ago
what happend to his head?
Streety101101 6 months ago
@Streety101101 Nothing has happened to my head!
itchBob 5 months ago
@itchBob :P
Streety101101 5 months ago
@Streety101101 It's packed with intelligence!
garyprein 5 months ago
Really enjoyed this one. Made me think of all sorts of possiblities! Thanks
lllakeside 6 months ago
Comment removed
nicpetnic 6 months ago
I don't understand half of what this channel is talking about but it's fascinating. I love learning about these complex sciences.
UDubFootballFan 6 months ago in playlist Videos from sixtysymbols
when it hits that certain amplitude, is it like hitting a certain critical point that a bifurcation is created?
greasy220 6 months ago
9:39 God is laughing at your experiment. Rejoice! In the glory of Jehesus.
playadominical 6 months ago
It's not strange at all. The dimension of the box he's conducting the experiment creates a natural frequency where particles are pushed into one area. Its not some magic chaos effect.
525047 6 months ago
Does it work the same for stars or planets formation? Gas into ¨solid¨ state?
ralaneu 6 months ago
This is one of the, if not, THE best video on sixtysymbols, thank you very much Brady!
Acid113377 6 months ago
You must put some some sand and gold grains in there and see if they separate!
fettfettmerafett 6 months ago
I don't think it's dull. I'm curious, though: does this say anything about the accuracy of this model being used to approximate the behavior of gases, or do gases do this, too? Is this massive (PUN) pressure increase in any way effected by gravity?
TomatoBreadOrgasm 6 months ago
What would happen if you tried doing this in a vacuum? Any different?
norblits2 6 months ago 2
thought provoking as always
7JFS7 6 months ago
i got article not found when i tried looking for the paper itchbob said. "prl.aps.org/abstract/PRL/v107/i4/e048002" but theres only a 404 error there.
knivesron 6 months ago
It looks a lot like the grains are just riding a standing wave set up inside the enclosure. Have you tried multiple frequencies at once to see if the bubble forms in the same way or if maybe multiple rings or bubbles of different sizes form. Very interesting physics here. Keep up the great work!
josh2utube 6 months ago
Am I understanding this correctly. The lower pressure area has a higher rate of collision. With the higher collision rate the probability that 2 or more particles will hit another at the same time increases thus transfering all that energy into a single particle which ends up pushed into the higher pressure area taking all that energy with it? In other words is the action similar to evaporation?
solace1369 6 months ago
Who is the effect going to be named after? The James effect? :)
wearetomfoolery 6 months ago
i love how he got so happy with the boxes, awesome!
cheeseontoast14 6 months ago 2
Could this be in any way connected with the Earth spin, it's motion through space, stronger gravity fields in a certain direction??? I cant understand why this should happen or why they group together in a certain place... is it always the same place or is it random grouping??
takkischitt 6 months ago 2
@takkischitt
That is a really good question... I suspect that, although those forces are non-zero, they have a negligible effect in this. I am also pretty sure that the writers explored that path before publishing.
I think one way to tell would be to look at the accuracy of the physics engine that was used for the simulation, how detailed the factors are in use. If those forces are indeed taken into account, then they could be "turned off" and run again to see what happens.
jasmith101 6 months ago
Do a video about absolute zero.
1337x1337x 6 months ago in playlist More videos from sixtysymbols
why couldn't our physics lab have been this cool?! or cool at all...
PopeosVideos 6 months ago 11
One of the best channels anywhere on the Internet. Consistently jaw-dropping, accessible science.
bjjolley 6 months ago 2
This man knows his boxes :/
lalagaga333 6 months ago 23
Varying the amplitude changes the net energy into the system --wouldn't changing the frequency do the same? At what critical point does the pahse transition (chaos-->stocastic) happen? Is this a function of the phase space betweent that transition and the change "back"? How about higher energies? Do you get other phase changes at higher energies? Finally, just curious--what were you looking for when you found this phenomenum?
pgm3 6 months ago
what i don't understand is why the pressure of an area goes down when there are more beads in that area. could you please clarify why this is? thanks
steveg12345678910 6 months ago
4:06
ArtTheRussian 6 months ago
All the gas in my bedroom did this yesterday, and I passed out! ;)
cuntylishus 6 months ago 2
i was lost at SIXTY SECONDS.. but whats the point in all this anyway..?
not nocking your work. but i just dont get the point of it.. looks good though..
MrProjectdjim007 6 months ago
It's a black hole, a lot of mass collectiong more mass. ;)
rousp1 6 months ago
Thank you very very much |:)
TemporalOnline 6 months ago
9:39 - lol, the face! :D
BrotherBloat 6 months ago 3
This comment has received too many negative votes show
Boring.
TheBoyofnothing 6 months ago
PART 7:
The boxes are manufactured in the university workshop. I'm hopeless at making stuff, but we're lucky to have a team of really talented engineers who can build just about any weird thing you ask them for, a big thank you to them for all their efforts on our behalf.
We clean and dry the beads to make sure they don't stick together.
itchBob 6 months ago 5
PART 6:
We've done some brief experiments on mixtures of particles with different densities, and this phase-separation is extremely effective at separating the particles.
Those of you asking about chladni patterns, the apparatus is the same/similar, but the underlying physics is quite different.
itchBob 6 months ago 4
PART 5:
Someone asked what happens if we do the same thing in a bigger box. It turns out to be quite hard to make a flat shaker that's mechanically stable over a large area, so instead we use smaller particles, which gives us a relatively larger box. Because the phase-separation is driven by fluctuations in the density, basically bubbles form everywhere, and grown together. It's awesome to watch - we're still finalising those measurements, I'll try to get a video of it online soon.
itchBob 6 months ago 3
@itchBob (Part #5)
Do you think that these results have implications for stellar formation & distribution of matter in the Universe? I was considering that before I saw the experiment "batch" at 9:34. It kinda looks like many animations I have seen of gas clouds collapsing.
For a bigger box, have you looked into using other materials? It looks like you are using Aluminum, what about Titanium or composites? I would be very interested to see the results with a larger box and nano-fine particles.
jasmith101 6 months ago
PART 5:
To answer how the pressure goes down at higher concentrations is tricky. Essentially in low density regions the particles can more easily enter the resonant state, so if there is a random fluctuation leading to a momentary low density region, then it gets resonant and heats up. Imagine someone jumping up and down in a crowd, if they hit someone on the way down, they will push them sideways. That's exactly what we see, the resonant particles push out sideways, and form a bubble.
itchBob 6 months ago 4
PART 5:
In the simulation we can do the experiment with and without gravity. The same results are obtained. To get a wee bit technical, this is related to the frequency independance of the results: Since gravity and frequency are the only experimental parameters to have a time dimension, if gravity is not relevant to the results, then by dimensional analysis frequency is out too.
itchBob 6 months ago 4
PART 4:
For enough particles, basically they act as a liquid, then you're in the hydrodynamic limit, and the whole system can be described by Navier-Stokes equations, but the big surprise is how that behaviour emerges from the chaos dynamics of a single particle.
itchBob 6 months ago 4
PART 3:
If you take a single particle, and place it between the plates, then at certain amplitudes it's found to resonant. Placing two or three particles in the system, they basically act as independant resonators. So the question is, if we keep increasing the number of particles, do they eventually stop resonanting and start acting as a gas? We find that the single particle resonance persists, and eventually becomes a shockwave traveling through the particles, it looks really cool.
itchBob 6 months ago 4
PART 2: A few of you have asked about repeating the experiment in vacuum. This is a terrific question, since often granular dynamics are governed by air flow around the particles. We've done the experiment, it's immensely hard not to have all the particles sucked up into the pump. The phase-separation (bubble) is still there at very low pressures, so we conclude it's not an air driven phenomena.
itchBob 6 months ago 4
PART 1: morning Everyone, James here. I'm going to try and address some of the questions that you've all been asking, I'll have to do it in small chunks, because of the character limit, so please see PART 2 ... 12?
itchBob 6 months ago 7
This has been flagged as spam show
@itchBob
Is this clumping pretty much the same effect as found in the sixty symbols video, "Bouncing Balls"?(watch id "SRGf0Mq2Zwg")
Kargoneth 5 months ago
Another great video with another great speaker. Love these, they are a great way to communicate the fascination of (and need for) science.
eseurg 6 months ago
Related to resonance by any chance?
AntiProtonBoy 6 months ago
Amazing!!!!
orazdow 6 months ago
Despite of it's simplicity, this may be one of the most amene and interesting sixtysymbols videos to watch. I agree with @Jan1515 that much of it is merit of the edition. Also because Dr. Tetris seems sounds like a lovable person. heh
I wonder if it could be possible to obtain a vacuum zone with this technique in an actual gas...
damianpaz 6 months ago
Hmmm, is this technique of manufacturing?
clearmenser 6 months ago
I like Dr.Tetris :)
LogInfinity 6 months ago
cool video, but a Homer Genius distribution?
Masterplan79th 6 months ago
Cool :D
DPMH4 6 months ago
Is it know why the particles disperses again with the high amplitude shaking?
jaryH3 6 months ago
Awesome job brady
drosprey 6 months ago
Can anybody explain to me ??
06osteventon 6 months ago
Hey,I'm not a scientist, but I heard him say that when they run it in the computer simulations they get the same effect, and in the computer the box is perfect, no bending.
alasimorph 6 months ago
Maybe the box slightly bends when vibrating violently. The misshapen box therefore encouraging the granules to migrate towards locations of concavity.
Thumbs up to get the scientist to answer this post!!!
boldger13 6 months ago
@boldger13 You can know that the simulation is perfectly flat because you tell it, so I don't think they would've missed that so easily.
eltotoX 6 months ago
@eltotoX
Yes, It is by testing, flat and level but maybe they didn't test the flatness while vibrating at high oscillation. I would also like to know how they measured the level. eg Did they use digital instruments?
boldger13 6 months ago
@boldger13 how level can you possibly get it........?
azmanabdula 6 months ago
@azmanabdula
Extremely level for such a precise experiment as this. The level on one spot on earth varies throughout the day because of earth's rotational/ gravitational pull changing the shape of the globe. Use a little thought/imagination/creativity and you to can think more deeply (not just at the obvious).
boldger13 6 months ago
@boldger13 i mean how could the slightest change in level effect this?
azmanabdula 6 months ago
@azmanabdula
If it is un-level or warped while vibrating, the grain will migrate towards the lower elevations and expose the higher elevations.
boldger13 6 months ago
@boldger13 so even while it doing its "clump up" movement.....it is effected by our gravity?
thats weird......so it is not so random......plus does the whole plate move up and down in one movement....one piston
or does one side go up and the other down....and vise versa......like 2 pistons not in sync......?
azmanabdula 6 months ago
anyone counted the word "box" in this video? :)
2szymi 6 months ago
This is sooo counterintuitive!
RoGeorgeRoGeorge 6 months ago
But why is there a pressure drop?
Gerardoe52 6 months ago
Please keep this up. You are easily as good at explaining difficult concepts as any I've ever seen and your comfort and confidence on camera show. Well done.
hagbardpork 6 months ago
The more I learn - the less I know. :(
shagster1970 6 months ago
is it like a bose condensate?
sk8hack 6 months ago
Hi everyone, James here. Really impressed the insights in the comments and questions. Thank you, keep them coming. Those of you who are interested, the paper we published can be found here:
prl.aps.org/abstract/PRL/v107/i4/e048002
itchBob 6 months ago 49
@itchBob Great video, one of the best from Sixty Symbols in a while! Although for some reason the above link doesn't work for me; this one did however, for anyone else who found the same. I guess you'll have to take the space out, as YouTube doesn't like it.
link. aps. org /doi/10.1103/PhysRevLett.107.048002
BradHProductions 6 months ago
@itchBob getting an 'Article Not Found' message at that link?
takkischitt 6 months ago
to ragiohead - surely you meant Concentricity?
alasimorph 6 months ago
I like this guys head. it's bald.
also this was a good video
Glickstick 6 months ago
I wish I could thumb up these videos at least a thousand times each!
anrade86 6 months ago
pretty cool.!
TeamVacaville 6 months ago
I have studied mechanical vibrations, using simmilar setups, using sand particles on vibrating plates as well.
Is the sand not just collectiong at one side, due to the the amplitude of a certain modeshape? Or that the rig is EVER so slightly tilted or certainly not perfectly plane?
I have to see that paper.... :D
thelemur 6 months ago
@thelemur
watched it a few times now... think i get it now. i would REALY like to read that paper :) Though my statistical mechanics is a bit rusty :s
thelemur 6 months ago
I know very very little of physics and science but could this relate to the inner workings of a star? Possibly where the particles of elements are withing the star? Like maybe the core is the hottest so there are more particles on the outskirts of the star?
Atveurf 6 months ago
@Atveurf He said the denser areas were hotter so the pressure was lower causing other particles to collect there. If these related then the center of the star would be low pressure and have more particles, or the out side would be hotter with more partials, but less dense. Neither of these make any sense to me, but that is not my field.
Psychodegu 6 months ago
Wow, that's actually quite amazing. Just makes me think about what else is out there that we haven't even tapped in to yet.
Superminyme 6 months ago
This series continues to blow my tiny mind! Thank you for making them.
I think I'll bring up granular dynamics in my job interview today.
Mojosbigstick 6 months ago
to me the layman, the result of this video just looks like ordinary standing waves, like this:
watch?v=GtiSCBXbHAg
:-/
roidroid 6 months ago
Did he say high school maths? Does that mean in The UK science is sciences, english is englishes and history is histories?
KmanWho88 6 months ago
@KmanWho88 Uh no. Calling it "math" is incorrect it is maths. (I'm Canadian and always say math but its maths).
jnigim 6 months ago
Its behaving like a gas, but not really. Physics in a nutshell for me :D
30LayersOfKevlar 6 months ago
Sixty symbols is bad ass.
SoulShepherd84 6 months ago
Isn't this pretty much the same effect as found in the sixty symbols video, "Bouncing Balls"?(watch id "SRGf0Mq2Zwg")
Kargoneth 6 months ago
@Kargoneth
Guess I'm not the only one to notice this.
Kargoneth 6 months ago
I am doing a senior project and I am wanting to do something with physics (or cosmology) but they are wanting us to do something that can be argued. I was thinking quantum physics or string theory but I don't know where to go with that. Can someone help me, please?
ravenheart93 6 months ago
This can be done at home too :)
BasherCoon 6 months ago
i thought this was common knowledge
-.-'
labobo 6 months ago
decrease in entropy = increase in temperature and decrease in pressure.... wtf...
nelson1tom 6 months ago
Please explain the mechanism that causes the pressure to go DOWN at higher concentrations. This makes no sense. At what size grain does this effect kick in? Why does this effect come and go as you continue to raise the amplitude? It defies intuition. Why is it so different from say, air? If a particle is moving randomly, surely there is a lower probability of it staying in an area of higher particle concentration due to there being a greater chance of collision and hence bouncing out.
Ichijojichan 6 months ago
@Ichijojichan Theres another video from them where professor Bowley explains an effect very similar to this one. It's the "Bouncing Balls - Sixty Symbols" or "r - coefficient of restitution" from the website. Maybe it's related
ricardjorg 6 months ago
@Ichijojichan I'm guessing the particles resonate between the top and bottom surfaces at a certain frequency and so they have a lot of kinetic energy, but if they get too crowded and start bumping into each other the resonance stops because the particles are hitting the top and bottom at random times during the up/down cycle.
njimko23 6 months ago
Wow... This is actually really interesting, and, as I think you said, counterintuitive!
Chirigami 6 months ago
5 people are antigranular
culwin 6 months ago
Whoever does the video editing is playing a great role in making sixtysymbols' videos as great as they are.
Keep up the great work :)
Jan1515 6 months ago 56