The Unsolved Mystery of Impact Flashes - Smarter Every Day 307

I'm very excited about this video because it's something I've been wanting to learn for years. Have you ever noticed when you have two things flying very, very fast and they impact in slow motion, that little spot right there where they touch for the first time, there's often a little flash of light, and it looks different at different times, but it's there, and we don't really know what it is. So today's video is all about that. We're going to do experiments here in the garage. We're going to see things that we've done in the past. For example, years ago, some friends of mine and I, we built a supersonic baseball cannon, and we saw it then. No, no, no, am I seeing fire? There's fire!?! There's fire! That was unexpected That is seriously like striking a match. That doesn't compute. I kept the glove. What causes that? We have a leather glove and a leather baseball. Why is there a flame? Fire? What is that? Because this also happens when the baseball hits a plastic bucket of sprinkles. Two, one. So we've got another flash of fire/light, whatever it is. Just a couple of frames in the ultra high-speed video. But then we also see something like it when we fire a bullet versus a Prince Rupert's drop. So that's metal versus glass. Okay, look at this. Bullet versus bullet. Both of these are lead. [Explosion followed by glass shattering sounds] There's another time I've seen flashes when I hit things. In this garage, with that high-speed camera right over there, I'm going to show you in a minute, when you hit Wintergreen lifesavers with a hammer, you get sparks, and it's crazy. And then perhaps the most fun is when we shot a gallon of mayonnaise. That is amazing. So we made fire. We dieseled mayonnaise. Ken is on fire. This is the best advertisement for Ken's extra mayonnaise ever. Dude. And it's not just my stuff. Have you ever heard of How Ridiculous on YouTube? [Brett] We have 15 giant balloons all in a massive line. Oh, my goodness. Oh, wow. This is Brett with How Ridiculous. You guys do all kinds of crazy stuff, right? [B] Our channel is called How Ridiculous, and I think that accurately describes what we've done for many years. [D] I love it, dude. What were you doing when this thing happened? This light? [B] We had two glass spheres, probably, I don't know a bit smaller than a bowling ball, I would say. We don't know the exact speeds, but they were probably going at least 100 miles an hour. [D] And what happened? [B] Well, miraculously, we got them to collide at all. So the balls didn't fit perfectly in the canon. So we had basketballs put in first, then the glass balls. So then when we fired the glass balls out, in the slowmo, it was super strange. One glass ball comes out of the left side, and then the other side, a basketball comes out first, and one of the guys were with us like, did we forget to put the glass ball in the other canon? We're like, no. So what happened is the basketball must have been not that inflated or whatever. And the one on the right side has actually come out in front of the glass ball somehow. And then it's getting closer and closer to the barrel. And we're like, come on, we really need this to happen. And then the glass ball just emerges and we celebrate because we know, Oh

we're going to see a collision, which was one thing we didn't know if it even happened. And then as they collide, there's this flash of light and you see from the footage, we just were completely shocked, surprised. We celebrated. We just knew we'd captured something really, really epic and rare. [D] So you saw a flash of light when they hit? [B] Yeah, that's right. [D] Another channel you probably heard of, The Slo-Mo Guys, Gavin and Dan, fantastic guys, really good friends of mine. In fact, the reason there's paint on my ceiling right there is because they did that. We've worked together for many years. They have a ton of footage. I wanted to talk to Gavin about this. How are you, man? Good to see you. [G] [D] So you guys were trying to shoot a bullet through a bullet. [G] This one was as simple as I wanted to try and recreate the shot where one character gets shot through his own bullet, basically, by a different bullet. [D] What happened when they hit? [G] There was just a big flash on impact as one bullet went into the hollowed out area of the bigger bullet, and everything mulches together. It's so hard to film. Even at hundreds of thousands of frames a second, you see it for a few frames. [D] So we have flashes of light with leather versus leather, leather versus plastic, hammer made out of steel versus sugar. We've got metal versus metal, and we have glasses versus glass. We've got all these different things happening, and there are a few different explanations that could possibly describe these things. I think it's pretty obvious that one of these things is not like the others. When we hit the lifesavers with a hammer and we get this blue light that's happening, it seems to be coming from the fracture itself, not from the impact. In fact, later in this video on the second channel, we shot the lifesavers with a pellet, and we saw the blue flashes of light, but something interesting happened. We saw the flash of light on the impact surface, but we also saw it on the side opposite of the impact surface where the lifesaver was ripping apart. That tells me that this is happening because of the fracture or the cleaving of those crystalline structures. And in the video, we refer to this as triboluminescence, which has to do with the fracture of a crystalline structure. That's fascinating, and that differentiates it from these other impact flashes we're seeing. So what do you think it was? [B] Well, I think initially we had no idea. We were like, what is that? One of the guys that was with was a high school science teacher. And so he ended up having a bit of a look into it, and he thought it was this phenomenon called triboluminescence, which mysteriously, he's like, it's not fully understood, but what we've demonstrated is maybe one of the bigger versions of it that anyone's seen. Often that's really small things, but we've done it on such a big item that it was such a rare occurrence that he was like, I think we've seen something that's truly special today. [D] So when I first saw the two glass balls hit each other on Brett and How Ridiculous video, I thought, yeah, that looks like triboluminescence. But the more I started reading, the more I realized that triboluminescence, apparently, is something that happens on solids with crystalline structures. Glass is an amorphous solid. It's not a crystalline structure solid, to my understanding. I really appreciate the humility here. Brett's like, I think this is what it is because that's where I'm at. I thought that's what it was as but I don't know. There's these other things. There's another mechanism called fractoluminescence. When things fracture, they cause light. There's other things called mechanoluminescence, I think is what it's called. There's all these different possibilities that we have here. Another one is just straight up friction. We've got a baseball coming into a glove really, really hard. Is it creating enough friction that it causes light of some sort? There's a lot of really big words to describe when light is produced. It's almost like the term luminescence is used as a suffix for when we get light from something we don't understand. Sonaluminescence, fractoluminescence, triboluminescence, mechanicaluminescence. All these things seem to be rolled into the thing I did made light, and I don't know how. I've even thought about electrostatic discharge. When two things come close and they have dissimilar charges, they'll zap a little bolt of lightning across the gap there. There's a lot that this could be. I've even thought about the Kopp–Etchells effec. That's when you have helicopter blades rotating in a sandy environment, and when the sand hits the helicopter rotors, you get little flashes of light. There's a lot of things this could be, and I want to show you something that happened right here in this garage that makes me think I'm starting to understand this. Okay, so let me show you a paper over here. This is a paper written by a guy named GI Taylor, Sir Taylor, the same Taylor that did the ultra-laminar flow. Okay, this is a paper by GI Taylor, and what he did way back in 1947

is he developed a way using math to describe the strength of materials upon impact. So basically what he was trying to do is create a relationship between dynamic stress, yield stress and the velocity of a cylinder hitting a flat plate. This is called a Taylor impact test. So if you're a mechanical engineer and you're going to model something using finite element analysis, one of the first things you do is a Taylor impact test. Which is why we have this crazy device sitting right here in my garage. Okay, so this is a twelve gage shotgun, and it's bolted to the steel table here. And I've got this crazy box that I designed and had a friend help me make. So what happens is you shoot some cylinders into this thing and you strip off what's called a sabot. Now, this is what the projectile looks like. A sabot, what it means is you have a thing on the outside of the projectile that takes up the diameter between your projectile, which is that rod in the middle, and the side of the barrel of the gun. And you can see I designed this sabot so that the sabots would fall away. They would pedal away like that. And so what happens is this rod will be fired here, and it will go into this chamber, and then as it peddles out, the sabot will be stripped away by this plate, and then it'll go over to this plate and impact this surface. So the idea is to take a cylinder and impact this plate. Now, the velocity that you use or you generate with the gun, as you hit that at different velocities you should get different amount of yielding, like mushrooming. Taylor came up with the original relationships between yield stress, and he showed that it was different with dynamic stuff. So this was an analytical model, meaning he used math. But then he got some friends. He's got Carrington here. Carrington actually did some of the test, and he mushroomed some projectiles, and they took microscopy of the results. And he had another guy here named Wiffon, and Wiffon did the same thing. And so they were able to come up with a relationship between the strength of material, the velocity of the cylinder, and how much it squished. So let me explain what I was doing when what I'm about to show you happened. So I was doing some initial tailor impact tests, and I had different cylinders that I had created with different photopolymers. There's a company called Formlabs, and they have these different plastics that you can 3D print. So I made some cylinders, and I was testing the cure time. I would cure it for 15 minutes in the oven. I'd cure it for 30 minutes. 45 minutes, and I started getting really different results with impacts. But one of the things I wanted to do is I wanted to test polycarbonate, and I wanted to do it really, really fast. So David, who was helping me that day, and we made a hot load on the shotgun shell, so I can change the velocity by how much powder I put in this thing. So we made a really, really fast load, and we shot a rod of polycarbonate against that flat piece of stainless steel, and something amazing happened. Two, one, fire. [Bang] See what happened. Ha ha ha ha. Oh, man. That's nuts. Dude, look at this. We stripped the Sabot. It just turned bright. Look at that. Flash big time, didn't it? That's crazy. What on Earth? What the heck? What is even happening? And then it splattered like crazy. Okay, so that flash was crazy, right? I mean, it looks like a little bitty bomb going off on one side of the impact surface is there. But one thing that made it so undeniably different from everything else we've seen, glove versus baseball and all this stuff, is that it seemed to have a direction to it. So when it hit, it almost farted out the side of the impact surface, like poof, and it made this little cloud of fire over to one side. You see that? It clearly has a direction, and that direction seems to somehow be related to the obliquity of the cylinder as it impacts the surface. Okay, let me try to explain what I'm talking about here. I've got a little bitty booger of clay here, right? And I've got my rod that I'm going to shoot against the surface. If the rod comes along and it hits this thing perfectly straight

it's going to squash out the gas that's in between the rod and the surface. We're going to get a flat, like a flat, squish, okay? But if I don't hit at an orthogonal direction, I have a little bit of obliquity to it, meaning I'm tilted like this. As it hits, what's going to happen is it's going to roll that gas out to one side, and you're going to get this little poof out in one direction. There's going to be some directionality to it. When I told a friend about this, his name is Louis, I said, Man, look at this. He's like, Oh, man, look, the little gas. I was like, Yeah, I know, right? He sent me this paper, Using mechanoluminescence as a low-cost Non-destructive Diagnostic Method for Transient Polymer Impact Processes. Now, when I looked at this paper, what's interesting is the researchers basically built a little thing. They said, Look, when we hit plastics versus something. We're getting this really big flash. And they actually created a device to measure where that flash starts and where it moves to. And they use that as a way to measure the obliquity of impact. And they have this really super cool graph here that I think is really neat. So basically, you can see the impacts in the middle there, and then it starts pushing out to the side. And they use that as a way to measure impact obliquity, which I think is really cool. So these researchers, Gwo and Chin, in Indiana somewhere, they... Oh, at Purdue. Indiana somewhere, Purdue. Okay, so Chin and Gwo at Purdue, they say it's a meccanoluminescence. They say it's the breaking of polymer bonds that create this light. I don't know that I agree. I think it's the gas. So I showed this video to the smartest person I know, Don Pettit. Don is a genius. He's really good at surface chemistry. And Don said, Oh, this is interesting. Destin, what if you fill the box with a different gas and see if you get a different effect? He says, Argon is known to flash very brightly when it's activated, so maybe you could do that. And so I started looking up some stuff. There's this thing called shock ignition. And so I don't know how that works because noble gasses, we're told, don't burn. They're noble. They don't oxidize. So the idea of burning argon or igniting argon is interesting. It will flash before some of the other gasses will. So that's what we're going to do today. We're going to put argon over in that box, and we're going to see if we can get a different effect. I think that's really cool. So What I've got here is I've got this LC 320s high-speed camera. We're going to get an overall view of what's going on, not a high frame rate. And then we're going to use the V2511 here. A little loud, but we're going to set it up and we're going to try to get a really high frame rate of what's going on. But before I do that, I want to try to recreate the compression of a gas to make fire. I've purchased a couple of little science toys here. This is a thing called a fire syringe. It's literally a syringe, and we're going to compress the gasses. Now, if we look at this paper that I found, using the ideal gas law, if you compress, there's a really cool example here. If you compress a gas, depending on the value of Gamma, then you can go, let's say we compress it seven times. So we go from one atmosphere to seven atmospheres. The temperature goes really, really high. So just by compressing a gas, and if you do it fast enough, you don't lose temperature to a conduction and stuff, that's called adiabatic compression. That's what a fire syringe does. This is just a piston, and it's got an O-ring at the end, two O-ring, and this is just a cylinder. So the instructions say I'm supposed to put a little cotton fluff in there, and I think the cotton fluff is what's going to catch on fire. Let me shove that down in there. Okay, Good. Okay, so let's just put this. Okay, so the syringe is in there, and this cylinder is charged with just normal room air, and we're going to slap this thing and see if we can make fire. All right, here we Three, two, one. Yeah. Let's go look at that in high speed. We compressed the gas inside this cylinder. And once we did that, because of ideal gas law, the temperature goes really high till it exceeds the, I don't know, the flame temperature of cotton. I guess that's what it is. I think because of Rade Bradbury, I know that paper burns Fahrenheit 451.

So I bet cotton somewhere around there. So it got really hot in there. But I don't think that was the actual gas is burning. That was the cotton burning. It looks pretty cool, though. This is what's known as adiabatic compression. Basically, adiabatic is a fancy word that means heat doesn't enter or exit the system. And in this case, the system is the tube. And because it happens so fast, heat doesn't have time to leave the system by being absorbed through the side walls of the fire syringe. So this is adiabatic compression. It looks like it almost squishes everything completely, and then you see a little bitty ignition on the cotton just in one little spot. Okay, let's put more oxygen in that cylinder and see what happens. So I've got two bottles over here. I've got nitrogen and I've got oxygen. Let's put oxygen in that cylinder. Yeah, it's oxygen. We'll see if it burns better. 100% oxygen. Okay, so we should have more oxygen in there now. I think this is going to work brilliantly. Yeah, that worked. Absolutely! Yes, sir! It looks like the spark starts at the moment of most compression, and then it's like that is the spark that starts the flame. And then when we expand the fire piston, so it's burning all over. So we must have got a really, really flammable mixture there. Man, it's even lightened my hand up. That's so beautiful. I love that. My hand looks really weird from this angle. That's odd. Okay, cool. Well, let's move on to else. I still don't know if this is what we're seeing, but that's pretty bright. That's very bright. Let's see if we can do Argon and oxygen and see if Argon makes a brighter flame. Argon, oxygen. Science! [Destin Laughs] Three, two, one. Okay, that felt brighter. That did feel brighter. It also hurt my hand. Oh, dude, it got so bright so fast. My sensor's messed up, but I'm going to call that brighter. Interesting. Looking back on this, I think I wanted it to be brighter. I don't know that it was. Maybe I hit it harder with my hand, but I don't think this is great data. Let's just move on. Just to double-check because it's a noble gas. Let's do just Argon, and I expect no burning. Just flood the area with Argon. Oh, I did get a smoke, though. It's interesting that it vaporizes when you release. You can see vapor in there, but I don't think... I don't know, maybe it got really hot and some moisture on the cotton itself vaporized or something. I have no idea. I started trying to figure out the way to explain the sponsor for this video, and I drew up a Venn diagram of all the things about the product that I like, but I realized a lot of it has to do with the people. First of all, this is a Canadian company. I like Canadians. In fact, the thumbnail for this video you're watching, probably made by a guy named Jeff from Canada. Really tight with Canadians, but the product that they are doing is cool, and it ticks all the Destin boxes. Number one, machining. I have been learning how to CNC machine for a really, really long time now, and I just get really excited by the smell of cutting fluid. And this product is machined out of aluminum, which is really, really cool. The company name is Henson. They make a razor for shaving, and it's just really cool. You open it up, no plastic. Isn't that interesting? You don't see that very much anymore. Nowadays, when I see a part, I try to figure out how it's made. And I can see under the head here on the razor, you can see the CNC tool path. So I can see that, and I know that part was CNC, shade, but this profile here that holds the razor down in a very precise way, that appears to be ground. I'm not sure about that. It might just be many passes on the CNC at a very fine step over, but it's pretty cool. With all that, you can see why precision is on my Venn diagram. The fact that this curve is held to such a tight tolerance all the way across means it supports the blade. This makes it great for shaving. On my Venn diagram, I've got price. The thing about Henson Razors is the only thing you're replacing are the little bitty blades that go in the razor itself. It's cheap.

You can buy a whole razor blade for less than a dime. It's a very smart way to think long term about how you are using a product in your house. The last reason I'm excited to use this product is because of nostalgia. But this is how my grandfather used to shave. He had a razor like this. I'm excited to use something like this for the same reason I like using film cameras and stuff like that. There's something that connects me to the past about using a real safety razor. I grew my beard out so I could shoot this ad, and I did not realize that a normal safety razor like this is better for once your beard is longer like this. I hate that I'm telling you this in an ad because it feels like you're not going to believe it, but it's true. All right, if you want to try a Henson razor, you can do that. Go into hensonshaving. com/smarter. Get a razor like your grandfather used. If you use the promo code smarter at checkout, you get 100 blades, which is basically two years of shaving for free. I like the Venn diagram that makes the Henson Shaving lineup with Smarter Every Day. Hinsonshaving. com/smarter. Give it a shot. Okay, so let's go back and see if we can repeat the thing that happened when David and I were shooting in the garage. So let's get the gun back out and let's see if we can make that flash of light again, just for repeatability purposes. And I got 12 grains of powder in this shotgun shell. I'm going to reconfigure the box So I'm going to make it where I can see through this and see through this front side here. That's dirty, isn't it? And then I've got this shield thing where I can contain it on the back side here. All right. So we've got an armored side, and we have a see through side. So I guess now we can just turn the light on here. Then that's It's not really bright for normal cameras, but we should be able to see it with high speed. We'll give it a shot and see if we can make a flash in there. That's our goal, right? I want to show you how I'm aiming this thing. I 3D printed a little laser adapter here, and I I'm going to get the laser in the barrel. And then over here, if I turn this thing on, I can see the laser on my hand there, right? Which means I got to make sure that the projectile goes through It goes through that and the sabot strip off. So it looks like we're aimed pretty well, but I always like to just look down the barrel because why not? It looks pretty good. It looks like it's pretty aligned. I don't know if you can see that at all, but yeah, it looks pretty good. Drop that plastic in there. Don't want it to be too exciting for us. Okay, so for a real Taylor impact test, what we want to do is we want to measure the length of the projectile. This is polycarbonate 75. 25 millimeters. Should be a 50 cal here. You got 12. 71 millimeters. How much does she weigh? 11. 4 grams. Okay, so we can use that information and we can back out, squish stuff if we had the high speed in the correct position, which we don't. But let's build this projectile here with my 3D printed, sabot. One, two, three. Okay. All right, that works good. All So that is a 12 gauge shotgun shell right there. I'm going to go over here, grab this bad boy like this. All right, we're on there. Okay, ready to go. Camera trigger right here. I'm going to take you off my head for a second. No, just ride this out of my head. Here we go. All right, here we go. Three, two, one. That's exciting. All right, we'll let the smoke settle there. Let's go look at what we got. We did. We got a flash. Right there, the whole thing. And then you can see it dies out right there. That is bizarre. We have to go much faster. It looks like there was a bunch of rust in the barrel. Hadn't shot it in a while. It's absolutely what that was. There's some flashes right there. The sabot hitting the steel.

Barely cleared the hole. Shaved a little bit, actually. Still attitude up a little bit. Yeah, same thing. Weird. Oh, we got a flash there when that hit, too. Well, we were able to repeat the flash. That's good. Okay, so we didn't have a high enough frame rate to see exactly what happened. But if you look, if we just go through frame by frame, you can see that it's rolling to one side. It starts when the bottom contacts, but the last bit of light we see is on the top. And that would fit into the little narrative we had earlier with the little booger of clay. Remember when it hits and it rolls to one side? So that could be a thing. I think what we should do now is we should tighten the camera up and go a lot faster. So I'll take this resolution and I'll just make it a lot smaller, and then I'll up the frame rate, and we'll see if we can see something again even faster. Maybe more powder, too, just because. Okay, we're going to do 15 this time. All right. Fifteen grains of powder. It's just a little hot, so I'm going to stay further back. Two, one. That was hot. Goodness, that is so fast. There's a lot of chaos. I love it. It lit up. Oh, man. Yes, a burst. Oh, it maxed it out. Definitely saw the gas. It was so bright, the sensor didn't know what to do with it. Nice. And we had these little secondary flashes as it goes through. That really feels like gas. And that's the booger theory that I have. You see it's lit up on this corner down here, and then it rolls out And then it shoots, and then it confuses the sensor. Okay, this time I'm going to use an opaque plastic. This is PETG, and we've been shooting polycarbonate, so the question is, will we also get the little flame pooting out the side. This is not the same plastic, so it might shatter and not contain the gas, but I don't know. But this should tell us if we're seeing a triboluminescent thing or if we're compressing a gas in shock, igniting it, maybe. 74. 56, 13. 5 grams. It's a 16-gram shot. Three, two, one. I think something weird happened. I think the Sabot's came out before the projectile. Sabot's. Very slow rod. So we sheared. So my delivery method did not work. I would be very surprised if we see any fire on this because it's going so slow. We did. It made fire. Even though it was going slow and it did the... That's the booger technique. I'm convinced at this point that a lot of times it's gas. I did see it in that bullet versus bullet video, like you've seen. We did a video a little bit before that. It might have even been the same day, but we've got to record. But we were just shooting straight into steel targets around 800,000 frames a second. That gave a little bit more freedom to see the flash because it wasn't being squished into a tiny little area of a bullet. It was being allowed to spread out more onto this steel plate. What's your theory on what that flash is? My theory based on what I've read, and I feel like, thankfully, I have really smart people in the comments of my videos, a lot of people were saying it was just gasses in the air being compressed to the point where They're physically lighting up, like they're getting that hot briefly. Because I was seeing it get squished between all the gaps where the hollow point little petals meet around the bullet. It was getting fired out of every available space. Now, the question is, what gas? Is it burning? Is something oxidizing? Or I've read about this thing called shock ignition of gasses. I've read about that. I think it's possible that we might be doing that because it's trying to move that gas so fast because it's 90 degrees out of phase from the... Or line from the flight axis when it hits, it's sending that gas out at an incredibly fast speed. Okay, so it created the little puff of fire with PETG, which is a plastic still. What happens with wood? This is like an insulator. It's not going to be triboluminescence. If we get fire with wood, then that would be amazing.

Plus, this is way lighter weight, and we can make it go way faster. This feels like bass wood. This is going to be nothing. 4 grams, so it's like 25% of the mass. I wonder if we even come up to enough chamber pressure just on the shot in terms of ballistics. I'm worried about that. I don't know what's going to happen here. 3, 2, 1. I want to see. [Destin Laughs] Splinters everywhere. Oh, man, that's so good. Look at that. It's just like total carnage. Oh, man, if we see a fireball on this, this is going to be nuts. What are we even doing? This is so fun. Okay, so which one we look at first? Let's look at the big one first. Okay, yeah, we have a lot of unburned powder. A ton of unburned powder because we don't get enough chamber pressure to actually burn all the powder inside the barrel. Man, that is moving. Can wood make fire on steel? It did it. That's nuts. It's gas. It's got to be gas. Yeah, you can see the flame where it contacts first, and then it rolls it forward and it looks like it got hotter. Not unlike the fire piston, right? But it goes out pretty quickly. It extinguishes it much quicker. We don't see the rolling poof. That makes me wonder if the rolling poof has something to do with the material. I really want to do Argon, and I don't want to asphyxiate myself or suffocate myself. So Argon is heavier than air, I'm told. So what we're going to do is we're going to open the garage here to get some fresh air in, and more importantly, let Argon roll out. I don't think I'm going to use that much Argon. But what I'm going to do is I want to flood this box with Argon now to see if we can get a flash, because I have a Wikipedia article over here. It's on something called Argon Flash. Now, apparently, fancy-pant scientists in real labs, not garages, like my garage, they use... Check this out. Typical Argon flash devices consist of an Argon-filled cardboard or plastic tube with a transparent window on one end and an explosive charge on the other end. Many explosives can be used, PETN, COMP B, RDX. Basically, they put argon in a tube, and then they drive it with an explosive It's really impressive. Somehow, that makes a big flash. Now, what actually happens to make that flash? I don't know. I don't think it's the argon burning, but it's the shock ignition somehow of the argon. It requires a detonation in a supersonic shockwave in the argon. But I don't know if it's the other gasses in the tube that are making the flash or the argon itself that's making the flash. I don't know. But what I do want to know is if we fire polycarbonate, which gave us the most impressive flash, into a box that's flooded with argon, what happens? I think the way I want to do that is I've got this tube right here. This is an argon tank. I want to run a tube into the box like this. Basically, what I want to do is I want to take that hose and I want to pump it in there like that. So we're going to put argon in this side over here. I'm going to get some tape. I'm going to tape the box up so that we don't get leakage around all this, and we can just fill the box up over here with argon and let it flood over into this box. And then right before I fire, I'll pull that hose out and then fire and trigger the high-speed camera all at one time. I'm going to seal up all the Argon leak holes. Very scientific. Okay, let's turn it up. Flooding the box now. Gun is ready. Come on, pull the hose out. Here we go. Hose is out. Ready to trigger. Three, two, one. Our gun is off. Oh, it looks like it didn't make it through cleanly. There was a bright flash for sure. There's other things flashing as they hit, and those are pieces of the Sabo, are they not? It doesn't seem to be any brighter. Interesting. I think it's safe to say that we didn't see very big flashes there for whatever

reason, maybe because Argon is a noble gas. But what I do know is that I'm starting to feel like the gaseous environment that the impact occurs in dictates how big the flash is, which means we need to fill the box up with oxygen. We're going to make an oxygen-rich environment. Welders everywhere. They're I'm mad right now. All right, there we go. Yeah, there's a lot of oxygen in there, that's for sure. Polycarbonate. Put on the sabot. Three, two, one. That felt bigger. I don't know why. Okay. All right, cut off the oxygen. That did. That felt bigger. Whoa. It's white, and it kept flashing. It also hit more orthogonal than normal. So I wonder if that's another stuff that hit kept flashing. That's pretty big. That's a pretty big flash. I'd say it was bigger. Yeah. I feel like the flashes that we're seeing might not be triboluminescence. Or mechanoluminescence. I think sometimes they are, but I feel like this might be adiabatic compression or something like it. So we're compressing gas. And I think the beautiful thing about that shot is it was done at a 90-degree angle. It was very orthogonal to the impact surface. And I think that makes the gas have to rush out from the front of the impact surface faster because If you think about it, if you have a string and it's got some slack in it and you pull the string really tight, if you do the math, if you pull here, it takes an infinite amount of force on that string to keep it from moving in that direction. I guess what I'm saying is tangent is coming into play. So the velocity of that gas running out from under the impact surface is a function of how orthogonal you hit, which makes me interested in the glass balls hitting, because no matter where the glass balls hit, there's always going to be a 90-degree point because they're two tangents on spheres. There's always going to be one little spot where you're perfectly tangent. This is interesting. We have learned things today, and I want to shoot a marble now. I'm going to shoot a marble. Would you say the light was blue or the light was orange? I thought it was like a white, like whitey blue. When I first saw yours, I thought that it cracked the whole sphere, and then the light from around, like the light from the sun was illuminating the balls. And then I looked again, I was like, I don't think that's what that is. It looks different because it goes away. It does. Yeah, it does go away very soon. Oh, wait. Yeah. I'm about to I'm watching it right here. I'm watching it. No, it is quite yellow. It's yellow. Definitely. And there's nothing yellow around, as in it was snowing actively. Oh, that's a good point. So it was yellow. I'm toying with the idea that this is gas. This is the nitrogen in the air igniting between the balls. And then it's illuminating the glass like a fiber optic. It's like a lens, which is what the balls are. They're a big lens. But see, it could also be like I'm looking at the Wikipedia page on mechanoluminescence and triboluminescence, and there's a special one called fractoluminescence. So I think it's possible yours is that weird thing, too. So I don't know. Okay, I want to shoot a marble against the plate now, so I have to take the Sabo stripper plate out. So let's do that. So the idea is to fire the marbles directly through here with, I don't know, I guess we'll use some felt or something, and just impact directly. I've got some marbles shoved in shotgun shells here, and we're going to see if we can make it do it with glass. All right, here we go. Oxygen, and lots of it. All right, so there's oxygen going in the tank. Two marbles. Kind of an attempt at making it work there. Oxygen in the tank. Marbles in the tank. Box full of oxygen.

Three, two, one. There's a little flash right there. Oh, man, that's crazy. So gunpowder was still burning right there. Definitely a flash. And then the marble hitting the marble behind it flashed as well. There's so many things I need to do. I need to do a better job of putting the gasses in the box. I need to do some research and figure this out. But anyway, this was a good exploratory thing. So the question is, is it triboluminescence or is it adeabatic compression or is it fractoluminescence? What is going on? I think it has to do with oxygen for sure. The question is, when the plastics hit, are they particulating and then burning instantly? I really think it has a lot to do with the gasses. The question that's remaining for me is, are those gasses burning? I don't know. I'm leaning away from triboluminescence right now, and I'm leaning towards gasses. I need to do it in a vacuum. I need to fire that in a vacuum. That's what I need to do. Okay, anyway. I hope you enjoyed this episode of Smarter Every Day. We're just playing and learning, and I would love to hear what you think about all this in the comments below. You know how on the internet, sometimes people say, Well, actually, I would love to hear your well, actuallys down in the comments below. So please leave those. I'd be grateful. Big thanks to everybody that supports Smarter Every Day on Patreon at Patreon. com/smartereveryday. I am grateful. I'm going to keep working on this and more to come. Thank you so much. I'm Destin. You're getting Smarter Every Day. Have a good one. Bye.