Hello Steve! Wow, what a great video! 👏 I'm a researcher, and I'm coincidentally finishing my PhD in this research field. We used to call it Bulk Metallic Glasses (BMGs), or just metallic glasses, as you mentioned. In all these years that I've been studying this field, your way was one of the most interesting to present the public that I've ever watched. I'm so happy to see something I study being presented so well to so many people due to the high visibility of your channel! It made my day! You commented on the possibility of someone sending you spheres also made of metallic glass (and yes, you are correct, it would be the ideal way to maximize the bounce time). In the laboratory where I work, we usually produce several amorphous metal alloys, the biggest difficulty is only in the spherical shape, since to get an amorphous structure, as you said, we need a certain cooling rate, and that's why we suck our samples to a chilled mold. I am already in contact with my advisor, so that we can study the possibility of producing this type of spherical samples and send them to you! Hope this message reaches you! (Help me with a like guys!)
Good point! I wonder what a multidimensional graph of the results for each combination of variables ( air-resistance / ball-size / ball-material / surface-material / base-material ) would be like.
As a mechanic without an engineering degree, I'm curious if temperature would have an effect? Would heating or cooling either the materials of the bearing and the impact plate or the air within the glass column make a measurable change? Also as a mechanic who deals with bearings in the field and not a lab, would impurities (finger oils or dust) affect results? I've dealt with bearings that a dirty finger print would affect it's performance, although that is probably more a rotational force.
Running tests with the system at different temperatures would be interesting. A heated ball would have more energy to start with. But, the electrons in the balls metal could be more free to move around. If it's cooled, the electrons are more tightly held but over all the ball has lower energy. Or, heat transfer with the air would cancel out any temperature change. A cool line of inquiry no matter how it turns out.
I can say from personal experience that a steel screw dropped onto a tile floor has a coefficient of restitution of at least 1, and this coefficient value is proportional to the rarity and cost of the screw.
Tim is great. I can honestly say I've enjoyed every single show of his. I like how a lot of my subs know each other, and work together. They've even flown from the US to do a show with Steve.
Yes a great illusion. Thumbnail gave the illusion that a ball bearing could bounce on amorphous metal 259 times yet only it was only 45 times. Grand ! Amazing ! Warms my heart too ! Just loved it when I wasted 18 minutes to have the illusion shattered.
The brick was interesting. I 3D print and have seen people using stone tiles as a base to stand their printers on, then on a table. The stone slab either absorbs the vibrations or simply keeps them in the machine, more or less, which reduces vibrational noise during operation. I guess this video indirectly answered my curiosity how that even works :D
@@MrAlex3461 Not sure how good bricks are. Might work. A concrete or stone slab has some weight to it that reduces table wobble. But try the bricks, I'm curious if that works too
to count all but the audio rate bounces, you can use audacity’s sound finder feature (i think that’s what it’s called, and it’s in one of the last three menus). it creates labels which are numbered in a separate label track. you can also slow the audio down and then run the sound finder, to give it an easier time finding the bounces.
As an engineer we call the balls ball bearings and the assembly simply a bearing. As a bearing consists usually of an inner and outer bearing run with the bearings working between being ball bearings needle bearings tapered bearings ect.
@Steve_Mould The question at 11:30 actually depends on the phonon generation. An amorphous material has a poorly defined resonance structure for absorbing energy and generating phonons. Phonons are associated with heat and sound (heat is really just sound with randomized phases). With poorly defined resonances, the metallic glass is more likely to reflect the phonons generated back into the bearing. Crystalline structures generally are going to have sharper resonances, generating phonons at that frequency. Those phonons will scatter off defects in the lattice generating heat. All crystals have defects (mathematically the edge of a crystal is a defect). The impact of the bearing on the surface is going to have a spectrum associated with the deformation of the surface. Ideally you want to minimize the phonon resonances at peaks in the the deformation spectrum and those that occur, quickly reflect back into the bearing, before it leaves, and preferably in-phase. TLDR: exceptionally stiff, amorphous materials are best.
Love the bounciness! Would you be able to explain in another video why the balls tend to bounce back to the center of the trampoline? I have an idea, but after I lost our argument last time, I won't share it just in case!
I have no idea what im talking about but if i had to guess, i would say that it's because the trampoline deforms in such a way that is kinda slanted towards the center, as the closer you get to the center, the further you are from the supporting springs on the edge. Therefore, when an object impacts the trampoline the point of impact closest to the center is deformed the most since it has the least support, bouncing the object towards the center.
As a materials science and engineering student currently taking classes like "Structure and Characterization of Crystalline Materials" AND "Mechanical Behavior of Solids", this was a super cool video to watch! Thank you for sharing your knowledge and doing so in such an intuitive way, Steve!
Another one! See above to a fellow student studying exactly what's in the video! Good luck with your studies, I hope you get to do everything you want to achieve in life 😊👍
@@davetran2537 I am based on the U.S.'s east coast. That being said, MSE is a great area of study regardless of where you go. In the U.S. at least, most universities have similar curriculums
Steve, Little tip of advice from an audio engineer. If you ever find yourself needing to count the peaks of a audio waveform again. Save your time and eyes, Look up Dynamic Splitting. You essentially set a threshold above the noise floor and it will detect any transients (peaks) above your setting and then splits them all. Resulting in each transient being its own audio "file". Highlight all files and see how many you have selected, or a good Slicer will tell you how many transients are detected before actually splitting for you.
If it helps, the outer and inner parts of a ball bearing are called races. The reason they call it a ball bearing is to denote the type of bearing inside the races, as there are tapered bearings and rod bearings as examples of alternatives. Awesome video, thank you for sharing.
Perhaps someone else has mentioned this but I noticed that no where in the video did you mention the sound itself as an energy leak. When you created the vacuum test, the sound was quite apparent meaning that each bounce sent a compression wave through the metal disk, then the base metal cylinder, then the brick, then the metal plate, then the air gap, then the microphone. That has to be a major loss of energy, possibly more that any from air resistance.
You are correct sir. In terms of entropy the base is at a state of rest and the ball is at an energy level higher than it's resting state. Energy will go from higher to lower. So the impact energy transfer will be many times higher than the energy transferred to the air. The ball shaped also contributes to this.
I created a jig to test COR in university as a project. After testing a number of materials, was very surprised(as was the class when I demonstrated) that cast acrylic had an extremely high COR. I don't know why but everyone assumed it would dampen the bounce.
Yeah, you can get acrylic balls at TAP that bounce like really noisy superballs... they also don't really warm up as they bounce. Unless they crack or chip, they really don't stay deformed. PLA on the other hand... "sploot"
The 5mm balls used for 'bb gun' ammunition are very bouncy on a hard surface (floor tiling is best but also very bouncy on wood laminate flooring). I think they are also some sort of cast plastic. Used the property for a 'door trap' to make sure no-one was sneaking into a room of mine before - count the balls load them into a pot that is released if the door is openend; because they bounce all over the place it's hardly likely they would all be found and replaced so you know if the trap was sprung (count the balls in the trap without setting it off). Unfortunately I forgot I'd set it one time, and ended up with balls bouncing everywhere on entry. 🙄
it would be interesting to retest the smallest ball bearings you had in the vacuum chamber to see if there is a large gain with them as you had already selected for the ones that were least effected by air resistance
In a past job I had the fun of formulating, melting and casting new formulations of amorphous metal that did not contain Beryllium. Be is a very toxic element that is dangerous to work with so we were trying to find amorphous metals that didn’t require Be but still could be amorphous when chilled at achievable rates. The larger a piece of metal you can make amorphous, the more applications there are. Also this stuff melts really low so it can be made to work in metal injection molding. So cool to see Steve playing with it.
@@chem101studygroup4 Unfortunately no, for at least two reasons. First is what you alluded to, we were definitely under NDA’s for the work we were doing because my company was a vacuum melt shop just making the alloys, not the finished parts. We were doing R&D contract work for the amorphous metal company, basically. Second reason is, as Steve said in his video, there are a whole bunch of elements in the mix, so I don’t remember everything and all their percentages! But the elements he mentioned, Ti, Zr, Ni, were all in there along with several other uncommon metals. Interestingly the process to make the alloy amorphous took at least two steps. You couldn’t just melt from pure starting elements and cast and amorphous part, you had to go through a particular post alloying process to induce the amorphous structure.
@@michaelwerkov3438 not sure what the state of the art is today but I think the earliest applications were things like dental components (braces). I think the idea of a golf club head being made out of this material was someone’s dream. My company only made the alloy not the end product so I don’t any more about that than what you could find on google.
@@michaelwerkov3438 I guess rails for larger ones, and in general bearing surfaces which need to be stiff, also precision things, where plastic deformation would lead to problems over time.
I wanted to be a materials scientist when I was little, until I got a little older and realized that my days would be spent doing things like this all day long. It's much more enjoyable to watch you do it for us, lol.
I was in the middle of saying "The ruby is a bit sad" right when you said it was disappointing. I just got off a binge watching watch repair videos, and those ruby gems are usually SUPER accurate.
@@ashkebora7262 The problem with the ruby wasn't how high it bounced, it's that it didn't bounce straight so he had to keep the tube around it See 2:00
@@cogwheel42 Huh, I took it as more of a general performance gripe. I guess that's what I get for having it as largely background. Not surprising it'd be really hard to make a perfectly spherical ruby, though. Ball bearings are made while soft and _then_ hardened, but there's no way to soften a ruby! It probably takes quite a bit of effort just to get a visually nice sphere, let alone a 'perfect' sphere. Even the zirconium oxide bearings, which have a similar hardness, have much easier manufacturing processes than artificial rubies. A somewhat normal ceramic sintering process vs growing a crystal. One you can pretty much define the shape you want even if it's a bit nutty. The other, you have to rely on the crystal structure growing.
@@cogwheel42 About that: I'm wondering if this may not be entirely due to the ball not being sufficiently spherical, but rather that the internal oscillations not damping between bounces. So that apart from the first bounce, it was off-spherical for every subsequent hit, and thus likely impacting a point whose local tangent wasn't in-plane with the plate. Of course, once it rubs the tube it's going to lose energy and start rotating and it's game over from there.
I can't believe i found this through a nile red video. You both are amazing but this is what i would call excellence. Pacing is extraordinary. Intrigue phenomenal. Truly top tear content.
I'm a glass blower and I thought I was going to learn about a new type of glass I didn't know about, however I did learn as much as I usually do with your videos which is a LOT! Thanks again for making great informative videos
Plasticity changes a lot with the change in temperature. It would be great to see how frozen metals compare to room temperature metals in this test. Steve probably has liquid nitrogen next to his bed, so he could make a test and let us know how it worked.
Yes, i was totally expecting cooled and heated slabs too. Eg. how much more time/bounces would a reduction in temp of the block to -40°C yield. Nothing, a bit, much?
I dont think there will be a big difference. Plasticity in metals comes manly from the movement of dislocations. By cooling a metal the dislocation movement is decreased and therefore plasticity is decreased. Since this is already a glass the dislocation movement is already neglectable.
I wonder about sympathetic vibration. If you were to produce the same vibration (pitch) near the base, would that affect the bounce? And would a slightly off-pitch tone negatively affect it? There are so many interesting ways to modify this experiment!
A tip on the support: alternating layers of dense and light materials will make a low-pass filter, reflecting more power back up into the ball and keeping the supporting surface quieter. For example, resting the bouncer base on, well maybe just a somewhat wider plate to give it some stability (say a chunky steel plate), then supporting that on something soft like plastic or rubber, or hollow even, like a balloon, or foam (but, foam is also quite dissipative -- this would make more like an RC filter than an LC filter, in electronic analogy), or something flexible in general (like enough springs to support it stably). Then support that in turn with something heavy, and so on and so forth. This can't be done hastily, of course; you want similar masses throughout the stack, of the massive components that is, and likewise similar springiness of the light components. (In fact, the relative proportions of each (how much lighter or heavier a component is, relative to the [geometric] mean) gives the shape of frequency attenuation curve.) Just using similar amounts will be reasonable enough, and use enough mass and spring rate that the free-bounce rate of the stack is much slower than the bouncing of the ball. That is, the cutoff frequency is well below the excitation frequency. Using things like balloons is obviously a bit complicated if you want to test it in a vacuum, heh.
@@thomasgeorge1836 This. Resonance, being a feedback loop sending energy back into the system, could extend bounce time. A filter will not. All a filter will do is dissipate the energy loss as heat, not sound. Work is work.
From what I gather they were made as an Educational demo. So not available commercially in this format. The company (as a spin off) still manufactures items from this material and other similar ones.
When the frame rate makes the bearings appear to hover is so cool! Bouncing in and out of the plane of focus is really cool too. Well done. You look like a week off is in order.
MetGlass is indeed interesting. It's also the basis for those retail store theft prevention tags. Apparently, they've got some weird magnetic properties, and that's why the detectors only go off if you take a tag through.
You never heard because it's a lie. Metal which is also glass does not exist. There is metallic glass, and although it sounds almost the same, it is quite different. The title of this clip is clikbait. After all, amorphous structures are a very interesting topic and it's nice that someone is trying to say something. It's just a pity that it's presented this way
Thank you for this awesome channel :) I am nearly 40 years old, and still love watching stuff like this. Sometimes, being a child at heart means that you never stop learning and keeping things fresh in the mind.
Great video Steve, thanks for sharing. I did my graduate work years ago on amorphous carbon films. What's always stuck with me is just how *weird* amorphous materials are compared to their crystalline counterparts. They will behave in ways you totally don't expect and do things you didn't think were possible.
@@BillyBob-wh4sq The classic example is how some types of glass will *very* slowly flow over time under the pull of gravity. Really old glass windows are sometimes thicker at the bottom than the top. (Edit: It turns out that this particular fascinating property of amorphous solids is a myth. Whoops....) From my Master's work, amorphous carbon can behave like a semiconductor, and my work centered on using layers of the stuff as thin film solar cells. Et cetera.
@@bencushwa8902 Thicker bottom? Yeah, it's a nice legend. But in some cases, the upper part of the glass was thicker. Reversed gravity? No. A thousand years ago they produced glass plates with uneven thickness, and probably usually they put the plates into the windows with the thick part down. But not always. Considering the fact that glass melts at around 900°C (1200 K), the ambient temperature of 27°C (300 K) is not sufficient to allow any deformation. As a rule of thumb, temperature-induced phenomena inrease their rate twice, if temp. is increased by 10°C. But if a window glass is kept at, say, 300-400°C, deformation is likely after years. A steel kept at 300°C would maintain its shape. I haven't performed such experiment by myself, but working with metals and metallic glasses, I dare to expect such behaviour.
@@jarekferenc1149 I was just about to type out a reply about the properties of glass detailing the explanation one of my professors gave me in grad school, when I decided to do a bit of reading before hitting "enter". I'm glad I did. Turns out he was wrong, have had this incorrect notion about amorphous glass rolling around in my head for two decades, and now I have a few choice words for him. Thanks for pointing this out.
i think he meant even if you took away air resistance (and related air stuff), still the ball will stop because it will eventually get so close to the surface that molecular forces will start playing part
@@pvic6959 Even without molecular forces, the ball will eventually stop (assuming imperfect bounces). Since the ball bounces lower each time, it also bounces more often and you get a converging geometric series for the time between bounces. You can find more results online explaining this.
@@iteragami5078 it bounces lower each time yes, but without intermolecular forces it would keep bouncing just the height of each bounce would approach 0 but never actually reach it
@@bobstr6224 If it's converging, it reaches 0 at one point. I think that you might not be taking into account that the period also shortens. You want to walk 100 meters. You walk the 50 ms, and that takes you 1 minute. You walk the next 25, and that takes you 30 seconds. You walk the next 12,5 mts, and that takes you 15 seconds. If you continue like this infinitely, halving both the distance and the time, you finally walk the whole 100 meters in 2 minutes.
@@frechjo The example you said only true when the velocity is constant. But when the ball bouncing, its velocity decreasing due to lost of energy: E=1/2×m×v² -> since the mass doesn't change the velocity does. So if you doesn't take air resistance and molecular forces and anything into consideration and you write down the time-hight function of the ball, its limes will be 0 but only in the infinity, so it means in reality it never reaches 0. So in this case the only reason the distance will reach 0, because it will reach the planck length and the ball can't travel less distance than that. I hope I could help. Sorry if my english isnt the best, btw how bad is it?
This video answers the question I had some time ago. Also I love how in depth you go to explain things. As a mechanical engineering student am learning about some the things mentioned in the videos such as crystal structure, dislocations, plastic and elastic deformation, and material science. So cool! I also feel like your video helps me understand it much much better
Andrew, believe me or not, but I reckon that materials science is a wonderful intellectual experience allowing us to understand how this world is built, how it works and why it works. It doesn't matter if the materials are natural or man-made, because the physical and chemical principles (fundamental to materials science) are universal. In my country, there are several faculties at technical universities that do teaching and researching entirely in materials science.
About 08:55 _You can never have a coefficient of restitution of exactly one ..._ And you can literally hear it. The sound the bounces make is already energy loss.
One thing you did not state and may not have considered: The resonance frequency of the cylindrical platforms. The sound wave generated by the ball impacting the surface travels to the bottom before being reflected back to the top. Larger balls take longer to deform and bounce than smaller ones. The right-sized balls are probably better timed to be leaving the surface when the reflected sound wave (or multiple) gives it a resonant nudge.
Sound in metals travels at kilometres per second. In a millimetre-sized objects this means that the base frequency of standing wave would be of megahertz. How can this be matched to bouncing at 1-10 hertz, and bouncing frequency is variable?
@AndrewWithEase11 11 Let me be the advocatus diaboli. He's not necessarily a fool. Basically, the idea is correct: to match the resonance in the bottom platform to the bounces of the balls against the upper surface. The trick is in numbers. We all don't need to be physicists or any kind of experts, and know by heart the values of certain properties of materials.
The reflection of energy should be solely the job of the amorphous metal. The mass beneath it is merely a bandaid for energy that leaks below the surface. To that end, the sound that emanates below the mass is the remainder of the leakage. Having a sympathetic resonance might half the leakage but the best bandaid would be the hardest possible mass. A mass made of tungsten or cobalt would allow the amorphous metal to absorb and reflect almost all of the energy itself.
Very cool! I posted a link to this video in my materials class and challenged the students to identify all the concepts you cover that were in my lectures. Dang is that bouncy! If you really wanted to see how far you could push this in terms of number of bounces try looking at what blacksmiths do to their anvils; they are trying to maximize the amount of bounce when the hammer strikes in order to reduce fatigue.
I LOVE how Steve approaches these problems with the scientific method. He is a true scientist. Making small changes analysing the results and seeing how to continue
one of the best bounces i witnessed was an old style computer mouse wheel, unlike the solid rubber balls, it has a dense metal core and the peripheral rubber doesn't get to deform much. just roll one of those towards a ceramic tile skirting board and you'll be amazed at the speed it'll return back to you
Someone call the Slow-mo guys, right? But seriously, it would be really cool to compare the deformations of the various balls and the plate as they touch.
4:15 Sorry, I'm going to interject here with a minor correction! The time that the ball is in the air after each bounce is proportional to the speed at which it left the ground. If the speed decreases by a constant proportion after each bounce, then the total time can be represented by a geometric series, which will converge to a finite value. Therefore the ball does eventually stop bouncing, even in an ideal scenario.
Yes, I agree. "It would never stop bouncing" is very misleading here. In the mathematical ideal world, while it would bounce infinitely often, it still does so in a finite amount of time.
Incredible video as always! I love your videos but it's not often that they are in an area of my expertise (materials science)! I was blown away by how well you communicated and animated some really central concepts! Your animation of the rapid cooling of atoms being represented by suddenly applying gravity was really beautiful and intuitive and not something I had seen in my entire PhD program in materials science! As I was watching the video, I wanted to comment about rubberbands and why they are my favorite materials science demo. When you elastically deform a spring made of metal, you are storing energy in the lattice by straining the bonds between the atoms for all of the reasons that you very well covered in the video. In a polymer, there is not such an analogous lattice structure (there are crystalline regions in polymers but this is a different and vast and fascinating other topic). The long, flexible chains are pretty easily able to move around one another and rotate about their bonds when the material is deformed and so any given bond is not particularly strained. When undeformed, the polymer chains are randomly arranged among one another, like spaghetti. When the material is deformed, the chains elongate in the direction of the deformation and (this is the really interesting bit) the conformational entropy of the chains is reduced as the chains become more ordered, like dry spaghetti in a box. A restoring force is created (by what? the chains? the bulk material? the universe?) in order to increase the conformational entropy of the chains. If a metal spring can be thought of as an energy spring, a rubber band can be thought of as an "entropy spring"! It is a way for us to feel and experience entropy which can be a very abstract and slippery concept for many. Honestly, I think that polymer material science (which was my focus) has so many topics (entropy springs, polymer crystallization and spherulites, polymer single crystal growth, conductive polymers, biodegradable polymers,...) that I think you would find interesting and be right up your wheelhouse! Great video as always! Can't wait for the next one! Also, I may (very small chance) have a way to track down a metallic glass ball bearing. I'll keep you posted :)
Yes! When I learned that about rubber I was so excited! And if you do get a lead drop me an email (I don't get to read every comment) steve@stevemould.com
This comment by Nina M is among those that make UA-cam so worthwhile. Though certainly YT comment streams can get choked with rubbish, it's also a place where we sometimes have the opportunity to hear from people with special and interesting contributions to make. Thanks Nina M!
When you put a stretched rubber band in the freezer it stays elongated until it reaches a certain temperature. When rubber bands get stretched they get warmer. When rubber bands contract they get cold. That points towards temperature above a certain threshold being responsible for the force rubber exerts to regain it's original shape. Are there any polymers that act like rubber but can be polymerized in an stretched state?
We've bumped the hell out of it. Its currently top comment. Please contact him. Just in case he cant find this. Actually im gonna repost your email to his comment thread.
One think you should look into for further improvement is to place the rig on an anvil or some other very large hardened steel thing. fun fact, blacksmith anvils are commonly tested for their quality by bouncing a ball bearing and seeing how high it bounces the ball back up. The higher the bounce, the better it will be to forge on.
@@gregoryford2532 i imagine its also to assist the blacksmith. from what i've seen, blacksmiths use the bounce of their hammer a lot to reduce the amount of effort needed to forge something
I could only wish that you mentioned that the ability to record the bounce sound in vacuum is an example of one type of energy loss. But just fantastic content as usual.
"a much larger, heavier metal slab" - Anvil! The word you are looking for here is 'anvil' :D You can feel a huge difference between the plastic deformation of hitting hot, malleable metal with a hammer versus when you miss and hit the anvil face directly.
Excellent video. When you pressed your thumb on the artist's eraser around 10 min in it triggered an olfactory memory and I could smell the eraser from my childhood. Fascinating.
I too missed my chance to buy one of those years ago. Apple bought the patent and we never heard about it again. Two things you should have tried: 1. Actual glass flat plate instead of the "metallic glass" 2. Zirconium Oxide plate Also, I wonder if the brick offered an impedance mismatch with the metal block causing it to pass less sound energy to the base. And one more thing... You could have calculated the coefficient of restitution from the audio recording using the time between strikes.
I suspect if you have the base on something like your driveway or the garage floor (this is probably the best option) it might give you a better result. As Garage floors are pretty much the heaviest thing you can easily get access to and they are well supported and dense.
Seriously probably the best channel I've stumbled upon (from a recommendation after ElectroBOOM videos) - educational content, well explained, well visualized always. I love the way your brain works, because I also like looking at random things and wondering how they work, or why something gave a different outcome than usual.
I think the ZrO2 ball bearing is a good approximation to an amorphous metal ball bearing. ZrO2 is a tough ceramic material that resist to falling impact (did not dissipate energy forming microcracks) and did not suffer plastic deformation. The fracture toughness of ZrO2 used in ball bearing are almost 2X higher than other technical ceramics like Al2O3 (or ruby) and are more than 10X higher than glass.
Zirconium Oxide is a fascinating material. It's used in knife bearings, and I've cranked down the pivots intentionally trying to crush the balls, but have never been able to. Also, they will cut channels in 66HRC steel with 23% Vanadium Carbide content (VC content, NOT V content!) after only a few dozen open/close cycles. Totally different animal, but Elastic Ceramic is another really interesting material. I'd love to see it featured on this channel.
You could put a hidden planar speaker under the platform and have it make the same sound as the bouncing ball but out of phase with it. By varying the amplitude of the sound of the speaker I think you would see some interesting results.
Awesome video! Those were some very impressive bounce times! You mentioned that if every next bounce was some fraction of the height of the last, then this height would never reach zero, so the ball would bounce forever. However, the time between bounces also would reduce exponentially, so you end up with a geometric series that converges. You actually end up with a beautifully simple formula for the bounce time using idealized physics (so no air resistance or deformation just instantaneous bounces with a constant coefficient of restitution), total_bounce_time = sqrt(2*initial_drop_height/gravitational_acceleration)*(1 + coefficient_of_restitution)/(1 - coefficient_of_restitution). Of course, the real world is a good deal more complicated, but in this view, the ball bounces infinitely many times in a finite amount of time. Anyways, great video! :)
By the way, if you graph the logarithm of the delay times between bounces you get a decreasing line, whose slope it's just the coefficient of restitution. Any departure from the linear behaviour is due a failure in the simplistic assumptions.
3:15 Watching the various sizes of balls bouncing side by side, it almost looks like a distribution curve that you could use to guess the optimum size to be somewhere between 6 and 7 mm. Except the 5mm ball isn’t having any of it. :)
I'm imagining someone who could supply the ideal amorphous ball, but they're a staunch "it's a bearing ball, not a ball bearing, so I can't help because I only have bearing balls, not ball bearings!"
Penn State University did a thing on properties of super cooled steel more than a decade or so ago. Nice to finally see a semi detailed & more entertaining show on it.
Your kitten is absolutely adorable! I love it! Also great video; I wonder how much better a diamond ball on a diamond plate would be (and how much more expensive XD)
All I can say as far as getting your hands on similar ball bearing is that several years ago, and I couldn't even tell you what year, I read an article about a specific iron alloy metallic glass which exhibited exceptional bounce. If you can find that scholarly article I'm sure he'd be able to contact one of the participants in the experiment and see where they source their material heck you might even be able to lay your hands on the original Ball bearing in the experiment.
There's a term used in numismatics called plastically deformed die error. It occurs because the die or dies being used are not hardened sufficiently enough to maintain it's designed shape. The alloy of the die "warps" over time getting more and more pronounced. That deformation is transferred to the planchet being struck. A cool error for collectors and good example of physics at work.
I've always loved the sound of a beat increasing in frequency until it becomes a tone. I don't know why, I just find it hypnotic. Of course, the best such sound is a coin as it finishes its spin. The moment the frequency modulation of the sound starts becoming its own audible frequency is just incredibly satisfying to me. Now I find myself wondering if that effect would last appreciably longer on an amorphous metal surface. I'm weird, I know.
Have you ever tried lowering a plate towards a ping pong ball bouncing? It is very satisfying :-) And incidentally a great model for molecules in a pneumatic piston where the gas heats up when compressed.
If you are testing number of bounces again, samplers like the one in Logic Pro x can easily tell you by loading in the audio file and using transients/peaks as the metric that decides chops/divisions. then it will may tell you how many it was able to locate (dependent on the software it should show up pretty apparently, I know logic’s quick sampler does)
Reaper does it too. Many ways to do this. Remove silence by playing with the threshold will chop the file into several pieces, select them and it will say how many... Also slice by transient.
@@ci8001 I love it. It even handles video well. Interface is great and send recieve setups are extra good. Gets frequent updates, is a tiny install no bloat, doesn't crash much, and allows recording to ogg or mp3 so that projects don't take up alot of space, and has a huge community so lots has already been done with scripts etc and get questions answered quick. Comes with good built in vst as well. And if price is a thing, you can use it free forever. It was made by the creator of Winamp back in the day so it's nostalgic for me. But it's missing some of the big boy features, for ex Cubase has cool pitch correction and tempo correction suite only available in Cubase, and you get no vsti or sample packs.
Would you be interested in using some of the sound files and measurements to calculate the gravitational constant? Not only could it be a relatively cheap way to calculate g, I am curious if it could measure the gravity gradient by performing the bounce tests at various heights.
You're going to have to assume that the collision time (the time the ball bearing spends in contact with the surface) is constant, which might introduce some error. A second source of error will be due to the sampling frequency of the audio stream. You could probably get a pretty nice value out though.
@slowmoguys @SteveMould @nilered I'd like to see a sheet or disc of bouncy metal shot at in slow mo. Would it deflect or ricoshade the bullets and bounce back or go straight through? Armor made of bouncy metal. Could the bouncy metal deflect a bullet?
That was genuinely fascinating. I found myself dying to see it tried in a vacuum, until you hit that very subject. XD I think you would have gotten a more dramatic difference with the smaller balls in a vacuum if, as you said, air resistance was the main factor limiting them. I went looking for the Caltech paper to see what the final alloy was and found the simulations they ran to find the best conditions fascinating as well, and slow-cooling molten alloys in a centrifuge at 60,000 g kind of broke me for a second.
It feels like a glitch in the matrix.
The sponsor is KiwiCo: Get 50% off ANY crate kiwico.com/stevemould50
cool
Does the Royal Institution lend vacuum chambers to just anyone?
Do the KiwiCo subscriptions come with kitties?
What if the ball was also covered with a-metal?
What determines where on the surface the ball settles in to bounce? It looks like is always off center. Is there a sweet spot or maybe a sweet ring?
That was really cool. This has made me want to try and make one of these... If I succeed, I'll send you one!
Cant wait for the video in 3 years😀
@@alexhu5117 😂😆😂
Maybe Nile Green will make it first?
@@dove3853 You'll have to believe it as there's no actual evidence.
I miss you :(
Hello Steve!
Wow, what a great video! 👏
I'm a researcher, and I'm coincidentally finishing my PhD in this research field. We used to call it Bulk Metallic Glasses (BMGs), or just metallic glasses, as you mentioned.
In all these years that I've been studying this field, your way was one of the most interesting to present the public that I've ever watched. I'm so happy to see something I study being presented so well to so many people due to the high visibility of your channel! It made my day!
You commented on the possibility of someone sending you spheres also made of metallic glass (and yes, you are correct, it would be the ideal way to maximize the bounce time). In the laboratory where I work, we usually produce several amorphous metal alloys, the biggest difficulty is only in the spherical shape, since to get an amorphous structure, as you said, we need a certain cooling rate, and that's why we suck our samples to a chilled mold.
I am already in contact with my advisor, so that we can study the possibility of producing this type of spherical samples and send them to you!
Hope this message reaches you! (Help me with a like guys!)
+
Bump for visibility
Bump
To the top with you! 🚀
Bump
Ah! You should've tested the smaller ball bearings again in the vacuum tube, as they were most affected by air resistance.
Good point! I wonder what a multidimensional graph of the results for each combination of variables ( air-resistance / ball-size / ball-material / surface-material / base-material ) would be like.
I was hoping he would as well :(
Given how little it seemed to change his tests, I imagine the square cube law has a much greater affect on the end result
@@ittixen that would be a radar chart
Agreed, it's the first thing I thought about.
As a mechanic without an engineering degree, I'm curious if temperature would have an effect? Would heating or cooling either the materials of the bearing and the impact plate or the air within the glass column make a measurable change? Also as a mechanic who deals with bearings in the field and not a lab, would impurities (finger oils or dust) affect results? I've dealt with bearings that a dirty finger print would affect it's performance, although that is probably more a rotational force.
Running tests with the system at different temperatures would be interesting.
A heated ball would have more energy to start with. But, the electrons in the balls metal could be more free to move around. If it's cooled, the electrons are more tightly held but over all the ball has lower energy. Or, heat transfer with the air would cancel out any temperature change.
A cool line of inquiry no matter how it turns out.
I can say from personal experience that a steel screw dropped onto a tile floor has a coefficient of restitution of at least 1, and this coefficient value is proportional to the rarity and cost of the screw.
True. Also, the propensity of the screw to be lost upon dropping rises in direct proportion with the rarity/cost of said screw.
XD
What about shag carpet?
They don't bounce. They just teleport to another dimension.
@@rigidmenace3333 They go to the same place as the missing socks.
it took a lot of balls to make this video. well done!
You could even say it took BALLS OF STEEL
bearing balls.
NOT. BALL. BEARINGS.
@@zat-svi-ua he bore balls alright
@@zat-svi-ua Ball bearing balls. Sorted.
@@forced-to-have-a-handle-fck-g ball bearing ball bearings, my bad
I love the bit where the bounces per second matches up with the frame rate and it looks like it’s floating.
Me too
Who came here after Nilered video!?
Me!
here. insane dedication from him as always.
@@alphaclusters4537 yeah😂 he love doing rpg quest.
👋🏻 I never knew he was doing this until now. Lol
Me
Grand Illusions is such a gem, it warms my heart to see you guys team up in any way!
Tim is great. I can honestly say I've enjoyed every single show of his. I like how a lot of my subs know each other, and work together. They've even flown from the US to do a show with Steve.
Yes a great illusion. Thumbnail gave the illusion that a ball bearing could bounce on amorphous metal 259 times yet only it was only 45 times. Grand ! Amazing ! Warms my heart too ! Just loved it when I wasted 18 minutes to have the illusion shattered.
oof
I love grand illusions! Tim's channel is so positive. It's always pleasant when things I follow collide
And then bounce back with a high coefficient of restitution
@@fluffysheap or break apart, RIP glass tube
Awww, sir tim is such a sweetheart, that's awesome for him to loan you this. Anyone that watches his stuff can tell how precious every piece is to him
The brick was interesting. I 3D print and have seen people using stone tiles as a base to stand their printers on, then on a table. The stone slab either absorbs the vibrations or simply keeps them in the machine, more or less, which reduces vibrational noise during operation. I guess this video indirectly answered my curiosity how that even works :D
I've been using four foam mounts to try and achieve some sound deadening. Thanks to your insight I'll replace those foam pieces with bricks.
@@MrAlex3461 Not sure how good bricks are. Might work. A concrete or stone slab has some weight to it that reduces table wobble. But try the bricks, I'm curious if that works too
to count all but the audio rate bounces, you can use audacity’s sound finder feature (i think that’s what it’s called, and it’s in one of the last three menus). it creates labels which are numbered in a separate label track. you can also slow the audio down and then run the sound finder, to give it an easier time finding the bounces.
I think it's called Beat Finder - haven't used it for a while, so..?
I've not used it since 2003, i think it's called 'mute'?
Grand illusions is a real one for loaning you that
He's the best
Agreed ❤
Grand Illusions is just a real one. Lending it or otherwise.
Tim the icon and Hendrik the legend
Also an illusory one
As an engineer we call the balls ball bearings and the assembly simply a bearing. As a bearing consists usually of an inner and outer bearing run with the bearings working between being ball bearings needle bearings tapered bearings ect.
Interesting, I've only ever referred to them as xmm balls.
Correct
I know the whole assembly - which contains ball bearings - as a ball race.
As a rancher we call the balls eggs
@@Henry-Kuren xiao mei mei
@Steve_Mould The question at 11:30 actually depends on the phonon generation. An amorphous material has a poorly defined resonance structure for absorbing energy and generating phonons. Phonons are associated with heat and sound (heat is really just sound with randomized phases). With poorly defined resonances, the metallic glass is more likely to reflect the phonons generated back into the bearing. Crystalline structures generally are going to have sharper resonances, generating phonons at that frequency. Those phonons will scatter off defects in the lattice generating heat. All crystals have defects (mathematically the edge of a crystal is a defect). The impact of the bearing on the surface is going to have a spectrum associated with the deformation of the surface. Ideally you want to minimize the phonon resonances at peaks in the the deformation spectrum and those that occur, quickly reflect back into the bearing, before it leaves, and preferably in-phase.
TLDR: exceptionally stiff, amorphous materials are best.
Love the bounciness! Would you be able to explain in another video why the balls tend to bounce back to the center of the trampoline? I have an idea, but after I lost our argument last time, I won't share it just in case!
I would love to hear your theory even if it is wrong.
hey funny eletricicty man
ok
I have no idea what im talking about but if i had to guess, i would say that it's because the trampoline deforms in such a way that is kinda slanted towards the center, as the closer you get to the center, the further you are from the supporting springs on the edge. Therefore, when an object impacts the trampoline the point of impact closest to the center is deformed the most since it has the least support, bouncing the object towards the center.
I think the surface must be slightly dished or concave. Each time it bounces off center, it gets steered back toward the middle.
As a materials science and engineering student currently taking classes like "Structure and Characterization of Crystalline Materials" AND "Mechanical Behavior of Solids", this was a super cool video to watch! Thank you for sharing your knowledge and doing so in such an intuitive way, Steve!
Another one! See above to a fellow student studying exactly what's in the video! Good luck with your studies, I hope you get to do everything you want to achieve in life 😊👍
neat so you're learning about piezoelectric crystals and things like that?
Hey man, are you based in the UK? I applied for mat sci at a load of places and just sent my applications, and wanted to know how your experience is!
@@jimbothegymbro7086 That's actually a class I will be taking next term!
@@davetran2537 I am based on the U.S.'s east coast. That being said, MSE is a great area of study regardless of where you go. In the U.S. at least, most universities have similar curriculums
Steve, Little tip of advice from an audio engineer.
If you ever find yourself needing to count the peaks of a audio waveform again. Save your time and eyes, Look up Dynamic Splitting. You essentially set a threshold above the noise floor and it will detect any transients (peaks) above your setting and then splits them all. Resulting in each transient being its own audio "file". Highlight all files and see how many you have selected, or a good Slicer will tell you how many transients are detected before actually splitting for you.
If it helps, the outer and inner parts of a ball bearing are called races. The reason they call it a ball bearing is to denote the type of bearing inside the races, as there are tapered bearings and rod bearings as examples of alternatives. Awesome video, thank you for sharing.
agreed, i wonder why no one seems to know this? i'm an old man (!) but i would have thought the name would have stuck.
Your videos are just amazing
Bien
Very good
Good
Nice
Nice ☺️
Wow. Your section on plasticity was ridiculously well explained. Fantastic job as always.
Perhaps someone else has mentioned this but I noticed that no where in the video did you mention the sound itself as an energy leak. When you created the vacuum test, the sound was quite apparent meaning that each bounce sent a compression wave through the metal disk, then the base metal cylinder, then the brick, then the metal plate, then the air gap, then the microphone. That has to be a major loss of energy, possibly more that any from air resistance.
While he didn't specifically point out the sound as energy loss, he did reference the different energy losses based on the base that it is on.
You are correct sir. In terms of entropy the base is at a state of rest and the ball is at an energy level higher than it's resting state. Energy will go from higher to lower. So the impact energy transfer will be many times higher than the energy transferred to the air. The ball shaped also contributes to this.
It seemed that the higher energy content of the higher frequency bounce helped it run out of energy almost immediately.
@@douggale5962 It loses a percent of energy with every bounce. The more bounces per second, the more energy loss events per second.
I remember in kinematics we used to neglect sound energy loss since its insignificant compared to friction/drag and impact losses
I feel like I learn more and tire less, watching Steve than anyone I have ever listened to. Supremely fascinating! Kudos to Mehdi as well!
I created a jig to test COR in university as a project. After testing a number of materials, was very surprised(as was the class when I demonstrated) that cast acrylic had an extremely high COR. I don't know why but everyone assumed it would dampen the bounce.
Yeah, you can get acrylic balls at TAP that bounce like really noisy superballs... they also don't really warm up as they bounce. Unless they crack or chip, they really don't stay deformed. PLA on the other hand... "sploot"
The 5mm balls used for 'bb gun' ammunition are very bouncy on a hard surface (floor tiling is best but also very bouncy on wood laminate flooring). I think they are also some sort of cast plastic. Used the property for a 'door trap' to make sure no-one was sneaking into a room of mine before - count the balls load them into a pot that is released if the door is openend; because they bounce all over the place it's hardly likely they would all be found and replaced so you know if the trap was sprung (count the balls in the trap without setting it off). Unfortunately I forgot I'd set it one time, and ended up with balls bouncing everywhere on entry. 🙄
it would be interesting to retest the smallest ball bearings you had in the vacuum chamber to see if there is a large gain with them as you had already selected for the ones that were least effected by air resistance
Excellent point
ok
seems like it would make for a good revisit as it is just retesting in the vacuum chamber so i have me fingers crossed there will be part 2
In a past job I had the fun of formulating, melting and casting new formulations of amorphous metal that did not contain Beryllium. Be is a very toxic element that is dangerous to work with so we were trying to find amorphous metals that didn’t require Be but still could be amorphous when chilled at achievable rates. The larger a piece of metal you can make amorphous, the more applications there are. Also this stuff melts really low so it can be made to work in metal injection molding. So cool to see Steve playing with it.
Are there any non protected formulas you can share?
What are the applications?
@@chem101studygroup4 Unfortunately no, for at least two reasons. First is what you alluded to, we were definitely under NDA’s for the work we were doing because my company was a vacuum melt shop just making the alloys, not the finished parts. We were doing R&D contract work for the amorphous metal company, basically. Second reason is, as Steve said in his video, there are a whole bunch of elements in the mix, so I don’t remember everything and all their percentages! But the elements he mentioned, Ti, Zr, Ni, were all in there along with several other uncommon metals. Interestingly the process to make the alloy amorphous took at least two steps. You couldn’t just melt from pure starting elements and cast and amorphous part, you had to go through a particular post alloying process to induce the amorphous structure.
@@michaelwerkov3438 not sure what the state of the art is today but I think the earliest applications were things like dental components (braces). I think the idea of a golf club head being made out of this material was someone’s dream. My company only made the alloy not the end product so I don’t any more about that than what you could find on google.
@@michaelwerkov3438 I guess rails for larger ones, and in general bearing surfaces which need to be stiff, also precision things, where plastic deformation would lead to problems over time.
POV: You are Nile Red watching this at 3 am in comlete aaaaweee
I wanted to be a materials scientist when I was little, until I got a little older and realized that my days would be spent doing things like this all day long. It's much more enjoyable to watch you do it for us, lol.
sometimes boring and well paid job is better
@@bettertelevision968 Sometimes indeed.
So, I have a question for you. What happens if the ball is made of Alon? That is transparent aluminum. :) Would the ball bounce differently?
@@thatguyalex2835 probably
@@bettertelevision968 well that is definitely possible
The sound during the vacuum test is a really good illustation of energy lost through the materials when it bounces
I was in the middle of saying "The ruby is a bit sad" right when you said it was disappointing. I just got off a binge watching watch repair videos, and those ruby gems are usually SUPER accurate.
It wasn't so much an accuracy thing as it was a poor coefficient of restitution given its hardness.
@@ashkebora7262 The problem with the ruby wasn't how high it bounced, it's that it didn't bounce straight so he had to keep the tube around it
See 2:00
@@cogwheel42 Huh, I took it as more of a general performance gripe. I guess that's what I get for having it as largely background. Not surprising it'd be really hard to make a perfectly spherical ruby, though. Ball bearings are made while soft and _then_ hardened, but there's no way to soften a ruby! It probably takes quite a bit of effort just to get a visually nice sphere, let alone a 'perfect' sphere.
Even the zirconium oxide bearings, which have a similar hardness, have much easier manufacturing processes than artificial rubies. A somewhat normal ceramic sintering process vs growing a crystal. One you can pretty much define the shape you want even if it's a bit nutty. The other, you have to rely on the crystal structure growing.
@@cogwheel42 About that: I'm wondering if this may not be entirely due to the ball not being sufficiently spherical, but rather that the internal oscillations not damping between bounces. So that apart from the first bounce, it was off-spherical for every subsequent hit, and thus likely impacting a point whose local tangent wasn't in-plane with the plate. Of course, once it rubs the tube it's going to lose energy and start rotating and it's game over from there.
I can't believe i found this through a nile red video. You both are amazing but this is what i would call excellence. Pacing is extraordinary. Intrigue phenomenal. Truly top tear content.
I'm a glass blower and I thought I was going to learn about a new type of glass I didn't know about, however I did learn as much as I usually do with your videos which is a LOT! Thanks again for making great informative videos
Plasticity changes a lot with the change in temperature. It would be great to see how frozen metals compare to room temperature metals in this test. Steve probably has liquid nitrogen next to his bed, so he could make a test and let us know how it worked.
he's too cool not to have liquid nitrogen lying around
Yes, i was totally expecting cooled and heated slabs too. Eg. how much more time/bounces would a reduction in temp of the block to -40°C yield. Nothing, a bit, much?
I dont think there will be a big difference. Plasticity in metals comes manly from the movement of dislocations. By cooling a metal the dislocation movement is decreased and therefore plasticity is decreased. Since this is already a glass the dislocation movement is already neglectable.
Would love to have seen temperature taken into consideration. Even if the changes are almost unnoticeable, it would be cool to see just how much.
I wonder about sympathetic vibration. If you were to produce the same vibration (pitch) near the base, would that affect the bounce? And would a slightly off-pitch tone negatively affect it?
There are so many interesting ways to modify this experiment!
A tip on the support: alternating layers of dense and light materials will make a low-pass filter, reflecting more power back up into the ball and keeping the supporting surface quieter. For example, resting the bouncer base on, well maybe just a somewhat wider plate to give it some stability (say a chunky steel plate), then supporting that on something soft like plastic or rubber, or hollow even, like a balloon, or foam (but, foam is also quite dissipative -- this would make more like an RC filter than an LC filter, in electronic analogy), or something flexible in general (like enough springs to support it stably). Then support that in turn with something heavy, and so on and so forth.
This can't be done hastily, of course; you want similar masses throughout the stack, of the massive components that is, and likewise similar springiness of the light components. (In fact, the relative proportions of each (how much lighter or heavier a component is, relative to the [geometric] mean) gives the shape of frequency attenuation curve.) Just using similar amounts will be reasonable enough, and use enough mass and spring rate that the free-bounce rate of the stack is much slower than the bouncing of the ball. That is, the cutoff frequency is well below the excitation frequency.
Using things like balloons is obviously a bit complicated if you want to test it in a vacuum, heh.
Took the thought right out of my mind. Resonance might be the key to longer bounce times with less energy lost.
@@thomasgeorge1836 This. Resonance, being a feedback loop sending energy back into the system, could extend bounce time. A filter will not. All a filter will do is dissipate the energy loss as heat, not sound. Work is work.
Y'all thinking too hard, I love it
I've never been so sincerely interested in a bouncing ball before
It would be even more exciting to watch paint dry... on the molecular scale... timelapsed
I actually have..., but it was part of a recurring nightmare i have when i get the flu. lol.
This whole thread is pretty relatable.
Watching the metals change by weight making a normal distribution, very cool.
Why are the amorphous metals suddenly harder to find?
From what I gather they were made as an Educational demo. So not available commercially in this format. The company (as a spin off) still manufactures items from this material and other similar ones.
When the frame rate makes the bearings appear to hover is so cool! Bouncing in and out of the plane of focus is really cool too. Well done. You look like a week off is in order.
MetGlass is indeed interesting. It's also the basis for those retail store theft prevention tags. Apparently, they've got some weird magnetic properties, and that's why the detectors only go off if you take a tag through.
I mess with crystallization quite a bit and I really like the way you illustrated the concept of amorphousness.
I'm always glad to see you collaborate in a way with Grand Illusions.
This is actually so cool! I’ve never heard of this but truly quite interesting. I love how much research you put into this experiments 😊
You never heard because it's a lie. Metal which is also glass does not exist. There is metallic glass, and although it sounds almost the same, it is quite different. The title of this clip is clikbait. After all, amorphous structures are a very interesting topic and it's nice that someone is trying to say something. It's just a pity that it's presented this way
As usually, I find incredible how you managed to condense such monstrous amounts of information in human words in just a few minutes.
@Erico Watts finally!! 😂 Get outta here man
Yep. When they made Steve, they broke the Mould.
4:50 The fact that this is the best material to make a bouncing ball bearing out of is consequential enough to slip me into a trance.
do you like how i roll, i got zirconium balls
Thank you for this awesome channel :) I am nearly 40 years old, and still love watching stuff like this. Sometimes, being a child at heart means that you never stop learning and keeping things fresh in the mind.
A collaboration between Steve Mould and Grand Illusions was not one I was ever expecting.
It has happened before!
2 great people
Great video Steve, thanks for sharing.
I did my graduate work years ago on amorphous carbon films. What's always stuck with me is just how *weird* amorphous materials are compared to their crystalline counterparts. They will behave in ways you totally don't expect and do things you didn't think were possible.
That sounds really cool! Do you have any examples?
@@BillyBob-wh4sq The classic example is how some types of glass will *very* slowly flow over time under the pull of gravity. Really old glass windows are sometimes thicker at the bottom than the top. (Edit: It turns out that this particular fascinating property of amorphous solids is a myth. Whoops....)
From my Master's work, amorphous carbon can behave like a semiconductor, and my work centered on using layers of the stuff as thin film solar cells.
Et cetera.
@@bencushwa8902 Thicker bottom? Yeah, it's a nice legend. But in some cases, the upper part of the glass was thicker. Reversed gravity? No. A thousand years ago they produced glass plates with uneven thickness, and probably usually they put the plates into the windows with the thick part down. But not always.
Considering the fact that glass melts at around 900°C (1200 K), the ambient temperature of 27°C (300 K) is not sufficient to allow any deformation. As a rule of thumb, temperature-induced phenomena inrease their rate twice, if temp. is increased by 10°C. But if a window glass is kept at, say, 300-400°C, deformation is likely after years. A steel kept at 300°C would maintain its shape. I haven't performed such experiment by myself, but working with metals and metallic glasses, I dare to expect such behaviour.
@@jarekferenc1149 I was just about to type out a reply about the properties of glass detailing the explanation one of my professors gave me in grad school, when I decided to do a bit of reading before hitting "enter".
I'm glad I did. Turns out he was wrong, have had this incorrect notion about amorphous glass rolling around in my head for two decades, and now I have a few choice words for him.
Thanks for pointing this out.
It took a lot of balls to make this video Steve.
This channel never ceases to impress me
your originality is just as extraordinary
Same!
I suspect the reason for the small ones coming to a stop is more about air turbulance between ball and surface than molecular forces.
i think he meant even if you took away air resistance (and related air stuff), still the ball will stop because it will eventually get so close to the surface that molecular forces will start playing part
@@pvic6959 Even without molecular forces, the ball will eventually stop (assuming imperfect bounces). Since the ball bounces lower each time, it also bounces more often and you get a converging geometric series for the time between bounces. You can find more results online explaining this.
@@iteragami5078 it bounces lower each time yes, but without intermolecular forces it would keep bouncing just the height of each bounce would approach 0 but never actually reach it
@@bobstr6224 If it's converging, it reaches 0 at one point. I think that you might not be taking into account that the period also shortens.
You want to walk 100 meters. You walk the 50 ms, and that takes you 1 minute. You walk the next 25, and that takes you 30 seconds. You walk the next 12,5 mts, and that takes you 15 seconds.
If you continue like this infinitely, halving both the distance and the time, you finally walk the whole 100 meters in 2 minutes.
@@frechjo The example you said only true when the velocity is constant. But when the ball bouncing, its velocity decreasing due to lost of energy: E=1/2×m×v² -> since the mass doesn't change the velocity does. So if you doesn't take air resistance and molecular forces and anything into consideration and you write down the time-hight function of the ball, its limes will be 0 but only in the infinity, so it means in reality it never reaches 0. So in this case the only reason the distance will reach 0, because it will reach the planck length and the ball can't travel less distance than that.
I hope I could help.
Sorry if my english isnt the best,
btw how bad is it?
This video answers the question I had some time ago. Also I love how in depth you go to explain things. As a mechanical engineering student am learning about some the things mentioned in the videos such as crystal structure, dislocations, plastic and elastic deformation, and material science. So cool! I also feel like your video helps me understand it much much better
Andrew, believe me or not, but I reckon that materials science is a wonderful intellectual experience allowing us to understand how this world is built, how it works and why it works. It doesn't matter if the materials are natural or man-made, because the physical and chemical principles (fundamental to materials science) are universal. In my country, there are several faculties at technical universities that do teaching and researching entirely in materials science.
About 08:55
_You can never have a coefficient of restitution of exactly one ..._
And you can literally hear it. The sound the bounces make is already energy loss.
I love the end of the run when there's that rapid ramp up in the frequency. Reminds me of black hole mergers.
I was thinking the exact same thing!
The similarity (also Newton's cradle and others) is no accident, on a basic enough level anyway!
0:43 thats a lotta balls
One thing you did not state and may not have considered: The resonance frequency of the cylindrical platforms. The sound wave generated by the ball impacting the surface travels to the bottom before being reflected back to the top. Larger balls take longer to deform and bounce than smaller ones. The right-sized balls are probably better timed to be leaving the surface when the reflected sound wave (or multiple) gives it a resonant nudge.
Absolute neek
Sound in metals travels at kilometres per second. In a millimetre-sized objects this means that the base frequency of standing wave would be of megahertz. How can this be matched to bouncing at 1-10 hertz, and bouncing frequency is variable?
@AndrewWithEase11 11 Let me be the advocatus diaboli. He's not necessarily a fool. Basically, the idea is correct: to match the resonance in the bottom platform to the bounces of the balls against the upper surface. The trick is in numbers. We all don't need to be physicists or any kind of experts, and know by heart the values of certain properties of materials.
The reflection of energy should be solely the job of the amorphous metal. The mass beneath it is merely a bandaid for energy that leaks below the surface. To that end, the sound that emanates below the mass is the remainder of the leakage. Having a sympathetic resonance might half the leakage but the best bandaid would be the hardest possible mass. A mass made of tungsten or cobalt would allow the amorphous metal to absorb and reflect almost all of the energy itself.
@@matthewvincent8971 am I the only one thinking to also make the ball of amorphous metal?
1:49 omg satisfaction kicking in! WHOOP! BOUNCE!
Very cool! I posted a link to this video in my materials class and challenged the students to identify all the concepts you cover that were in my lectures. Dang is that bouncy!
If you really wanted to see how far you could push this in terms of number of bounces try looking at what blacksmiths do to their anvils; they are trying to maximize the amount of bounce when the hammer strikes in order to reduce fatigue.
2:18 "the ruby in particular is disappointing because it cost a lot of money"
*IT'S DOING ITS BEST OKAY?!*
I LOVE how Steve approaches these problems with the scientific method. He is a true scientist. Making small changes analysing the results and seeing how to continue
You need to test a Newton's cradle with ball bearings from amorphous metal or Liquidmetal.
one of the best bounces i witnessed was an old style computer mouse wheel, unlike the solid rubber balls, it has a dense metal core and the peripheral rubber doesn't get to deform much. just roll one of those towards a ceramic tile skirting board and you'll be amazed at the speed it'll return back to you
I 💜 how the final section of really tiny bounces starts to look weird as it briefly comes into phase with the camera frame rate!!
Someone call the Slow-mo guys, right? But seriously, it would be really cool to compare the deformations of the various balls and the plate as they touch.
2:25 From this part I started laughing. All the other ball bearing are just sitting there watching the lil guy going like "man are you ok? stahp."
00:02
"In the late noughties..."
When was that?
I think he ment the 2000s?
Or he just weirdly said 90s
@@theiris10021900s.
4:15
Sorry, I'm going to interject here with a minor correction! The time that the ball is in the air after each bounce is proportional to the speed at which it left the ground. If the speed decreases by a constant proportion after each bounce, then the total time can be represented by a geometric series, which will converge to a finite value. Therefore the ball does eventually stop bouncing, even in an ideal scenario.
Yes, I agree. "It would never stop bouncing" is very misleading here. In the mathematical ideal world, while it would bounce infinitely often, it still does so in a finite amount of time.
_Achilles turtle flashbacks_
Incredible video as always! I love your videos but it's not often that they are in an area of my expertise (materials science)! I was blown away by how well you communicated and animated some really central concepts! Your animation of the rapid cooling of atoms being represented by suddenly applying gravity was really beautiful and intuitive and not something I had seen in my entire PhD program in materials science!
As I was watching the video, I wanted to comment about rubberbands and why they are my favorite materials science demo. When you elastically deform a spring made of metal, you are storing energy in the lattice by straining the bonds between the atoms for all of the reasons that you very well covered in the video. In a polymer, there is not such an analogous lattice structure (there are crystalline regions in polymers but this is a different and vast and fascinating other topic). The long, flexible chains are pretty easily able to move around one another and rotate about their bonds when the material is deformed and so any given bond is not particularly strained. When undeformed, the polymer chains are randomly arranged among one another, like spaghetti. When the material is deformed, the chains elongate in the direction of the deformation and (this is the really interesting bit) the conformational entropy of the chains is reduced as the chains become more ordered, like dry spaghetti in a box. A restoring force is created (by what? the chains? the bulk material? the universe?) in order to increase the conformational entropy of the chains. If a metal spring can be thought of as an energy spring, a rubber band can be thought of as an "entropy spring"! It is a way for us to feel and experience entropy which can be a very abstract and slippery concept for many.
Honestly, I think that polymer material science (which was my focus) has so many topics (entropy springs, polymer crystallization and spherulites, polymer single crystal growth, conductive polymers, biodegradable polymers,...) that I think you would find interesting and be right up your wheelhouse!
Great video as always! Can't wait for the next one! Also, I may (very small chance) have a way to track down a metallic glass ball bearing. I'll keep you posted :)
Yes! When I learned that about rubber I was so excited! And if you do get a lead drop me an email (I don't get to read every comment) steve@stevemould.com
@@SteveMould
Hey Steve! There's a researcher in these comments who can likely get you metal glass balls! Look for "Filipe Henrique Santa Maria".
This comment by Nina M is among those that make UA-cam so worthwhile. Though certainly YT comment streams can get choked with rubbish, it's also a place where we sometimes have the opportunity to hear from people with special and interesting contributions to make. Thanks Nina M!
When you put a stretched rubber band in the freezer it stays elongated until it reaches a certain temperature. When rubber bands get stretched they get warmer. When rubber bands contract they get cold.
That points towards temperature above a certain threshold being responsible for the force rubber exerts to regain it's original shape.
Are there any polymers that act like rubber but can be polymerized in an stretched state?
We've bumped the hell out of it. Its currently top comment. Please contact him. Just in case he cant find this.
Actually im gonna repost your email to his comment thread.
Köszönjük!
One think you should look into for further improvement is to place the rig on an anvil or some other very large hardened steel thing. fun fact, blacksmith anvils are commonly tested for their quality by bouncing a ball bearing and seeing how high it bounces the ball back up. The higher the bounce, the better it will be to forge on.
@@gregoryford2532 i imagine its also to assist the blacksmith. from what i've seen, blacksmiths use the bounce of their hammer a lot to reduce the amount of effort needed to forge something
I could only wish that you mentioned that the ability to record the bounce sound in vacuum is an example of one type of energy loss. But just fantastic content as usual.
"a much larger, heavier metal slab" - Anvil! The word you are looking for here is 'anvil' :D You can feel a huge difference between the plastic deformation of hitting hot, malleable metal with a hammer versus when you miss and hit the anvil face directly.
Excellent video. When you pressed your thumb on the artist's eraser around 10 min in it triggered an olfactory memory and I could smell the eraser from my childhood. Fascinating.
I too missed my chance to buy one of those years ago. Apple bought the patent and we never heard about it again.
Two things you should have tried:
1. Actual glass flat plate instead of the "metallic glass"
2. Zirconium Oxide plate
Also, I wonder if the brick offered an impedance mismatch with the metal block causing it to pass less sound energy to the base.
And one more thing... You could have calculated the coefficient of restitution from the audio recording using the time between strikes.
God I hate patent law for enabling the kind of thing where you buy a technology and then just sit on it forever. OLED screens too.
It looks like the patents expired in 2017
@@falxonPSN Do you have a reference for that??
I suspect if you have the base on something like your driveway or the garage floor (this is probably the best option) it might give you a better result. As Garage floors are pretty much the heaviest thing you can easily get access to and they are well supported and dense.
Seriously probably the best channel I've stumbled upon (from a recommendation after ElectroBOOM videos) - educational content, well explained, well visualized always.
I love the way your brain works, because I also like looking at random things and wondering how they work, or why something gave a different outcome than usual.
The bit at the end when ur kids were all excited was so wholesome
I think the ZrO2 ball bearing is a good approximation to an amorphous metal ball bearing. ZrO2 is a tough ceramic material that resist to falling impact (did not dissipate energy forming microcracks) and did not suffer plastic deformation. The fracture toughness of ZrO2 used in ball bearing are almost 2X higher than other technical ceramics like Al2O3 (or ruby) and are more than 10X higher than glass.
Zirconium Oxide is a fascinating material.
It's used in knife bearings, and I've cranked down the pivots intentionally trying to crush the balls, but have never been able to. Also, they will cut channels in 66HRC steel with 23% Vanadium Carbide content (VC content, NOT V content!) after only a few dozen open/close cycles.
Totally different animal, but Elastic Ceramic is another really interesting material. I'd love to see it featured on this channel.
You could put a hidden planar speaker under the platform and have it make the same sound as the bouncing ball but out of phase with it. By varying the amplitude of the sound of the speaker I think you would see some interesting results.
0:35 "bearing balls" 😂
This is insanely fun to watch. Great explanations.
When I woke up today, I measured all my cheerios to make sure I was only eating the ones with the correct size and weight for optimal taste
If you need someone to "dispose of" the ones you scrapped, I'm always available
Awesome video! Those were some very impressive bounce times! You mentioned that if every next bounce was some fraction of the height of the last, then this height would never reach zero, so the ball would bounce forever. However, the time between bounces also would reduce exponentially, so you end up with a geometric series that converges. You actually end up with a beautifully simple formula for the bounce time using idealized physics (so no air resistance or deformation just instantaneous bounces with a constant coefficient of restitution), total_bounce_time = sqrt(2*initial_drop_height/gravitational_acceleration)*(1 + coefficient_of_restitution)/(1 - coefficient_of_restitution). Of course, the real world is a good deal more complicated, but in this view, the ball bounces infinitely many times in a finite amount of time. Anyways, great video! :)
By the way, if you graph the logarithm of the delay times between bounces you get a decreasing line, whose slope it's just the coefficient of restitution. Any departure from the linear behaviour is due a failure in the simplistic assumptions.
@@vincenzomartorana2625 to paraphrase your last sentence: If the data doesn't match the model, the model is wrong. 😆
@@jimbrookhyser and in this case testing the model is as easy as tracing a line through the experimental points 😏
3:15 Watching the various sizes of balls bouncing side by side, it almost looks like a distribution curve that you could use to guess the optimum size to be somewhere between 6 and 7 mm.
Except the 5mm ball isn’t having any of it. :)
The "We should expect smaller balls to stop bouncing sooner" had me dying 🤣
I'm imagining someone who could supply the ideal amorphous ball, but they're a staunch "it's a bearing ball, not a ball bearing, so I can't help because I only have bearing balls, not ball bearings!"
Penn State University did a thing on properties of super cooled steel more than a decade or so ago. Nice to finally see a semi detailed & more entertaining show on it.
Your kitten is absolutely adorable! I love it! Also great video; I wonder how much better a diamond ball on a diamond plate would be (and how much more expensive XD)
*kittens!
@@RCP-1136 I didn't watch all the way to the end; they're both adorable!
Did they come from Kiwico? But yes, very cute
Now I want to see Kiwico FOR cats! Make the world domination thing work faster
only channel where sponsored segments i enjoy as much as main subject.
All I can say as far as getting your hands on similar ball bearing is that several years ago, and I couldn't even tell you what year, I read an article about a specific iron alloy metallic glass which exhibited exceptional bounce. If you can find that scholarly article I'm sure he'd be able to contact one of the participants in the experiment and see where they source their material heck you might even be able to lay your hands on the original Ball bearing in the experiment.
As a student studying metallurgical engineering I absolutely loved this!
👀 Wonderful Video!
Fellow metallic ball enjoyer
There's a term used in numismatics called plastically deformed die error. It occurs because the die or dies being used are not hardened sufficiently enough to maintain it's designed shape. The alloy of the die "warps" over time getting more and more pronounced. That deformation is transferred to the planchet being struck. A cool error for collectors and good example of physics at work.
I've always loved the sound of a beat increasing in frequency until it becomes a tone. I don't know why, I just find it hypnotic. Of course, the best such sound is a coin as it finishes its spin. The moment the frequency modulation of the sound starts becoming its own audible frequency is just incredibly satisfying to me. Now I find myself wondering if that effect would last appreciably longer on an amorphous metal surface. I'm weird, I know.
oh man, I wonder how long one of those Eulers disks would spin on an amorphous metal surface
Have you ever tried lowering a plate towards a ping pong ball bouncing?
It is very satisfying :-)
And incidentally a great model for molecules in a pneumatic piston where the gas heats up when compressed.
If you are testing number of bounces again, samplers like the one in Logic Pro x can easily tell you by loading in the audio file and using transients/peaks as the metric that decides chops/divisions. then it will may tell you how many it was able to locate (dependent on the software it should show up pretty apparently, I know logic’s quick sampler does)
same with fl
Reaper does it too. Many ways to do this. Remove silence by playing with the threshold will chop the file into several pieces, select them and it will say how many... Also slice by transient.
@@capoman1 do you like reaper how's the UI
@@ci8001 I love it. It even handles video well. Interface is great and send recieve setups are extra good. Gets frequent updates, is a tiny install no bloat, doesn't crash much, and allows recording to ogg or mp3 so that projects don't take up alot of space, and has a huge community so lots has already been done with scripts etc and get questions answered quick. Comes with good built in vst as well. And if price is a thing, you can use it free forever.
It was made by the creator of Winamp back in the day so it's nostalgic for me. But it's missing some of the big boy features, for ex Cubase has cool pitch correction and tempo correction suite only available in Cubase, and you get no vsti or sample packs.
Would you be interested in using some of the sound files and measurements to calculate the gravitational constant? Not only could it be a relatively cheap way to calculate g, I am curious if it could measure the gravity gradient by performing the bounce tests at various heights.
You're going to have to assume that the collision time (the time the ball bearing spends in contact with the surface) is constant, which might introduce some error.
A second source of error will be due to the sampling frequency of the audio stream.
You could probably get a pretty nice value out though.
@slowmoguys @SteveMould @nilered I'd like to see a sheet or disc of bouncy metal shot at in slow mo. Would it deflect or ricoshade the bullets and bounce back or go straight through?
Armor made of bouncy metal.
Could the bouncy metal deflect a bullet?
i like the part where he said ball bearing
I don't recall saying that
That was genuinely fascinating. I found myself dying to see it tried in a vacuum, until you hit that very subject. XD I think you would have gotten a more dramatic difference with the smaller balls in a vacuum if, as you said, air resistance was the main factor limiting them.
I went looking for the Caltech paper to see what the final alloy was and found the simulations they ran to find the best conditions fascinating as well, and slow-cooling molten alloys in a centrifuge at 60,000 g kind of broke me for a second.
Could you release the audio file of the bounce? There are some interesting calculatios I want to perform (time between bounces, sound power, etc.)
So nice of Tim to lend you their very bouncy metal!