It feels like a glitch in the matrix. The sponsor is KiwiCo: Get 50% off ANY crate kiwico.com/stevemould50

Ah! You should've tested the smaller ball bearings again in the vacuum tube, as they were most affected by air resistance.

That was really cool. This has made me want to try and make one of these... If I succeed, I'll send you one!

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.

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.

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!)

it took a lot of balls to make this video. well done!

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.

The sound during the vacuum test is a really good illustation of energy lost through the materials when it bounces

I love the bit where the bounces per second matches up with the frame rate and it looks like it’s floating.

Grand illusions is a real one for loaning you that

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.

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

Your videos are just amazing

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.

I've never been so sincerely interested in a bouncing ball before

If you assume a fixed coefficient of restitution (between 0 and 1) for a given ball and surface, even with perfect conditions (vacuum, etc), the time for each bounce is a fixed fraction of the time of the previous bounce. Thus the times of the bounces form a convergent geometric series, making a finite total time. Thus even if there were infinitely many bounces, the bouncing would stop after a finite time. (As you say, physical reality cuts it short in any case.)

Grand Illusions is such a gem, it warms my heart to see you guys team up in any way!

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!

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

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 love grand illusions! Tim's channel is so positive. It's always pleasant when things I follow collide

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.

I mess with crystallization quite a bit and I really like the way you illustrated the concept of amorphousness.

GrandIllusions is one of my favorite channels. Awesome to see their own atomic trampoline in your video Steve!

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.

Watching the metals change by weight making a normal distribution, very cool. Why are the amorphous metals suddenly harder to find?

This is insanely fun to watch. Great explanations.

@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.

0:35 "bearing balls" 😂

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.

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.

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.

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

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.

Very interesting video, loaded with information. To understand it all, I'll probably need to bounce back to it.

What an amount of work! So impressive!

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.

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.

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)

Awesome video! Maybe the smaller ball bearings would have a significant difference when placed in the vacuum? Earlier in the video you specifically chose the medium ball bearing because they were less affected by air resistance than the smaller ones.

0:43 thats a lotta balls

Wow. Your section on plasticity was ridiculously well explained. Fantastic job as always.

I love how these properties can be explained by the atomic structure. It's so fascinating. Something they rarely do in the university (focusing on formulas etc).

Very cool - I suspect you're right about matching the elasticity of the two surfaces, you're improving the impedance match between the two surfaces thus ensuring the most efficient energy transfer.

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

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!

Okay best video out there! Straight to the point and crisp video. Thank you so much! Life Saver!

The nerding out never ever ends in this one, I love it, very satisfying.

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

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.

So nice of Tim to lend you their very bouncy metal!

This guys videos are so amazing they spread like mould.

As usually, I find incredible how you managed to condense such monstrous amounts of information in human words in just a few minutes.

A collaboration between Steve Mould and Grand Illusions was not one I was ever expecting.

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.

The ruby bearing is especially wear resistant. These are used as the point [of contact] in performance tops that are designed to spin as long as possible.

This channel never ceases to impress me

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.

Great vid! Watching it made me think of a bounce test, with a steel ball bearing on perfectly flat anvil. The blacksmith in question was extememely impressed on how long the bearing bounced, as well as how much he could conserve in an arm swing with his hammer. It totally sits in line with the results in your vid. As we know, energy cannot be lost, but transferred into an alternative form - sound, heat, light, friction, deformation, etc. I would love to see the results with a hardened vehicle on a flattened, hardened surface (due to the atomic gaps being smaller) as well as on a hardened amorphous (if it is possible) material. Is it physically/atomically possible to revolutionise the ol' hammer? Food for thought!

Steve, this is just a wonderful video. I’m really enjoying the channel. Thank you

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 love the end of the run when there's that rapid ramp up in the frequency. Reminds me of black hole mergers.

LOL, it was great to relive the Liquidmetal infomercial. I'm pretty sure I have the Liqidmetal driver golf club laying around. I remember they made tennis rackets too!

Fascinating stuff. I'd love it if you would have explained how something like spring steel counters normal steel's plastic deformation properties.

You need to test a Newton's cradle with ball bearings from amorphous metal or Liquidmetal.

I'm always glad to see you collaborate in a way with Grand Illusions.

Nice video. Missed to mention that it is in fact the hardness property what we are looking for rather than stiffness

Interesting. I would also have liked to see the effect of different temperatures on the plate and ball. Wagering that a colder surface would have better elasticity.

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 😊

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.

Ayo grand illusions, that's my guy! What a neat channel man!

This channel is a treasure to humanity

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.

I 💜 how the final section of really tiny bounces starts to look weird as it briefly comes into phase with the camera frame rate!!

I'm with you! My first thought was of amorphous metal ball bearings. So curious how that might affect the bounce

You are a wonderful parent and I am so jelly. Love kittens too.

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 like the part where he said ball bearing

The tuning of the ball material to floor material reminds me of impedance matching for optimal power transfer.

I really like those top down shops of the ball falling in and out of focus

2:18 "the ruby in particular is disappointing because it cost a lot of money" *IT'S DOING ITS BEST OKAY?!*

00:02 "In the late noughties..." When was that?

somone should count how many times he said balls

It sounds very similar to gravitational wave coalescence, that ramp up of frequency as energy is dissipated from the system is very familiar

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.

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

As for the sound wave counting, I would have run a function on my DAW to Turn signals above a certain magnitude into MIDI notes, those are easier to count that individual peaks.

The thing that came to my mind when I was watching this was it similarity to Euler's Disks. I would look into the the technology and study behind those because they are just as dependent on material sciences and conservation of energy and you might find some useful information about this topic.

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 :)

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.

I feel absolutely certain that Grand Illusions would have been enthralled by your tests, observations and results. It takes a keen mind to take someone else's work and think 'what if?'

would be interesting to see a machined ball of the same amorphous metal on the same surface... since it could be cooled at 1K per second and it would still be amorphous...you can shape it while cooling. It would be bounciest combination ever!

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.

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.

I love this video because I only have a 10th grade understanding of physics from 10 years ago, and I barely had any problem understanding this video because it's so well explained.

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.

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.

I love the practical experimenting of this. I would be curious what would happen if you Cooled the glass and bering down. As this would rise the ridgidness of both surfaces. Also If you also had a layer of Metalic glass between the tube and the brick, or have multiple layers of metalic glass. Love the work

I think you might have stumbled upon the secret to the euler discs. The sound the ball makes when it's almost done is similar to the disks when they are almost done. Idk worth looking into though