The Physics of the World Cup: VAR, Smart Balls, and Soccer Aerodynamics (EP 45)

Hosted by Lester Nare and Krishna Choudhary, this episode is our World Cup special — a deep dive into the science, physics, engineering, and data behind the beautiful game. We start with the offside rule and the controversy around semi-automated VAR. How can a system decide whether a player is onside or offside by only a few inches? Krishna breaks the problem down like an experimental physicist: player speed, ball-contact time, camera frame rate, significant digits, and the error budget behind the line on screen. From there, we get into the actual technology: player tracking, digital twins, high-resolution cameras, and the connected match ball sensor that helps determine when the pass was played. Then we move from refereeing technology to the ball itself. Why does the 2026 World Cup ball look the way it does? How do Platonic solids, panel geometry, and surface seams affect the way a soccer ball flies? And why was the 2010 Jabulani ball so controversial? We go through drag, drag coefficients, wind tunnels, the drag crisis, golf ball dimples, and why the roughness of a ball can completely change its trajectory. Finally, we look at the hidden engineering of the World Cup pitch — real grass in NFL stadiums, LED grow lights, drainage systems, turfgrass science, and even 3D-printed cleat-foot testing devices — before ending with match momentum, possession value, hydration breaks, and the data science behind modern football analytics. Support the show Donate: FFPod.com/donate Follow: @FFPod on X / Instagram / TikTok / Facebook Show Notes Semi-automated offside technology and connected-ball systems Adidas Trionda — official 2026 World Cup match ball Aerodynamics of World Cup balls and the Jabulani drag-crisis controversy World Cup 2026 pitch engineering and turfgrass research Possession value and match momentum in football analytics

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Krishna Choudhary?

  If we take a look at that image, the ruling is extremely precise. That means that the VAR is able to discern down to just a few inches. How are you getting that precision? What they do is Hawkeye creates digital twins. The players get scanned head to toe, and you create a digital twin of their body scanned by a computer. The ball actually has an internal sensor. It's a 14 gram sensor, an inertial measurement unit. That thing takes data at 500 hertz, 500 data points per second, and it's measuring acceleration and things like that. So when you hit it, you'll know within 5 hundredths of a second when the ball was hit.

• 0:41Lester Nare?

  Hello, Internet. This is your captain speaking, Lester Nare, joined as always by my co-host and our resident PhD, Krishna Choudhary. This week, we are going to get into our World Cup special as we are all enjoying the world's beautiful game of football. And we're going to talk about some of the technology, physics, and science behind the beautiful game as we see it today. As always, we are going to talk about the science from the ground up today because this is From First Principles.

• 1:30Krishna Choudhary?

  So the World Cup means a lot to the both of us. We were just at the Iran versus Belgium game at Los Angeles Stadium.

• 1:39Lester Nare?

  Los Angeles Stadium.

• 1:40Krishna Choudhary?

  In Inglewood. The game ended in a 0-0 draw. It was still pretty sick. Nonetheless, the Iran goalie did an amazing job.

• 1:50Lester Nare?

  The stadium was crazy. The energy, there's a huge, I think the second, the largest Iranian population outside of Iran is in Los Angeles. There was a lot of, a lot of energy in the stadium.

• 2:00Krishna Choudhary?

  Yeah, yeah. And I mean, the World Cup means a lot because I grew up in India. And in India, like, or in any really developing nation. World Cup means you you stop what you're doing and you watch all the games. We used to root for either Argentina or Brazil, a lot of Brazil fans in India against whoever was playing. Argentina, because I think a lot of my parents' generation grew up with watching Maradona win in like eighty-six against England and everyone's like, yeah. So, so it's, you know, I grew up watching it and then to to actually see a game live, it was it was also unbelievable.

• 2:37Lester Nare?

  I mean, for me, my my family is a soccer family. I've played soccer my whole life.

• 2:41Krishna Choudhary?

  Right.

• 2:41Lester Nare?

  You know, I mean, the ninety-four World Cup, I was I was four, you know, I have those faint memories of like, you know, my dad's, you know, in his postdoc program, there was a bunch of Brazilians. And, you know, I played when I was young. My little brother plays professionally in the US currently. And so as someone who has, you know, been in the national team pool, I was in the Olympic Development Program when I was younger. I I wanted to play for the men's national team. I didn't make it. I wasn't good enough. But the idea that, you know, especially in this World Cup hosted at home, to see the progression of the US men's national team. Quick shout out to the US women's national teams, which is four-time World Cup winner. And so we we do have great football heritage in this country.

• 3:25Lester Nare?

  We've just not seen that translate into the the men's game yet. I mean, it's just such an emotional thing to see it finally get its just desserts and not being called a foot fairy anymore.

• 3:36Krishna Choudhary?

  Yeah, and we're doing quite well, you know, so far, so good. So far, I think we are topping our group.

• 3:41Lester Nare?

  Yes.

• 3:42Krishna Choudhary?

  Um, and, you know, we're gonna, I think we're gonna win it all, but, you know, we'll we'll see what happens.

• 3:47Lester Nare?

  We'll see, we'll see.

• 3:49Krishna Choudhary?

  So I've been watching a lot of the games and I'm gonna start with some, the first thing that actually got me going down this rabbit hole of technology behind the World Cup. I was watching the game with England versus Croatia in the group stage. And at like right before halftime, Croatia got an equalizer right before the half to make it two-two. Ivan Perisic delivered a perfectly weighted pass to Peter Musa. And from this perspective, it looks offside to me that Peter Musa's the blue shirt right outside the the bigger box, whatever that's called. And he he seems to be on this side of all the all the English defense. So.

• 4:31Krishna Choudhary?

  Then we can go into the the next photo, which shows the actual judgment, right?

• 4:37Krishna Choudhary?

  Looks offside to me.

• 4:40Lester Nare?

  So so this is this is the offside rule is is is been something that has been changed and complained about for a long time. And I think what's interesting about the offside rule that is is not as well understood is that the specific verbiage, because the idea is you have the usually the goalkeeper is the last defender before the goal. And then, you know, if you're in between, basically, if you're in between the the second to last defender as a forward, like you're offside, right? And the idea is you want to stop camping and all this stuff, just hanging around by the goal. In this case, people are asking, well, his arm is offside.

• 5:17Krishna Choudhary?

  Yeah.

• 5:17Lester Nare?

  So why is he not offside? And technically, the the definition for the offside rule is that it has to be a playable body part. And the way that's defined is that means the head, the torso, the legs and feet. So hands and arms do not count as as offside because you can't really play with those. So this is where this is where you're seeing players now lean. But the issue is the shoulder, you don't want your shoulder to get over there. But if the arm is over, technically, based on the current rules, it's not offside. And so like, again, there's sort of small details there.

• 5:58Krishna Choudhary?

  Right.

• 5:59Lester Nare?

  But this is the offside is very controversial. Some people have argued that we should, you know, the games would be more exciting and more goals if it's your full body.

• 6:08Krishna Choudhary?

  Yeah.

• 6:09Lester Nare?

  Not a part of your body.

• 6:12Lester Nare?

  If I were to choose, I'm kind of inclined to say, yeah, I think it should be full body.

• 6:15Krishna Choudhary?

  Yeah, more goals, baby.

• 6:16Lester Nare?

  Like, I don't like if I'm leaning just over the line, like.

• 6:19Krishna Choudhary?

  So here, so here's the deal, go back to go back to that image.

• 6:22Lester Nare?

  Yeah, yeah, yeah.

• 6:23Krishna Choudhary?

  This is this is, you know, I was watching this in the commentary, England was pissed. The British lady on Fox One was pissed. I was confused. And here's why I'm confused, okay? If we take a look at that image, the ruling is extremely precise. Okay, they're saying, oh, the arm is over the line, but the body is not, as you're saying, right? Um, but that means that the VAR, this video referee thingy.

• 6:50Lester Nare?

  Assistant review, yeah.

• 6:51Krishna Choudhary?

  Yeah, is able to discern down to just a few inches.

• 6:55Lester Nare?

  Yes.

• 6:56Krishna Choudhary?

  Okay?

• 6:57Lester Nare?

  Yes.

• 6:58Krishna Choudhary?

  That's where the judgment is happening. It's like if his body was a few inches this way or that way, it would have been offside or onside. Okay. That is where I started calling BS. Okay, because as any good experimental physicist, you are worried about those margins, okay? And what you're telling me is that the plus or minus, like in that judgment, is is within a few inches.

• 7:23Lester Nare?

  Yeah.

• 7:24Krishna Choudhary?

  Okay? How are you getting that precision?

• 7:27Lester Nare?

  I I think a lot of people would like to know.

• 7:29Krishna Choudhary?

  Right?

• 7:30Lester Nare?

  Because this is also something that's relatively newish, the semi automated technology.

• 7:34Krishna Choudhary?

  Yeah, yeah, and and it it like from just a mental perspective, it didn't really make sense to me. So I'm going to lay out the argument here, okay?

• 7:41Lester Nare?

  Yeah, yeah.

• 7:41Krishna Choudhary?

  So offside depends on two things, where the player is compared to the other players. So where the players are and also when the ball was kicked.

• 7:51Lester Nare?

  Yes.

• 7:51Krishna Choudhary?

  Right? Because it's the placement of the players when somebody made the pass. Okay?

• 7:55Lester Nare?

  Yep.

• 7:56Krishna Choudhary?

  So let's go into what the errors are in each of those measurements. Okay? The impact or the contact time when I'm like kicking a ball, the the passer's foot in the ball, that's going to be approximately a hundredth of a second. Okay, so 10 milliseconds. Now, a player that's making a run, let's say that's sprinting at his like peak velocity. In that case, it wasn't peak velocity, but let's just imagine, right? At its peak velocity, he's going to be going like 10 meters per second. Rough ball far, right? Roughly. Um, and so while the passer is making contact with the ball over that 10 milliseconds, the player will have moved 10 centimeters.

• 8:39Krishna Choudhary?

  That should be like, do you understand? So, so you're not, it's when the when part is ill-defined by 10 milliseconds, which means the where part should be, if you knew exactly where the player was, it would already be ill-defined by 10 centimeters, okay? But I don't even think that that's, that's, and, and this is, this is, this is hedging on the fact that I know exactly where the players are.

• 9:06Lester Nare?

  Right.

• 9:06Krishna Choudhary?

  That again, I don't understand because you've got, like, from my camera perspective, right? The, the error in the cameras should be another few inches. So that's only going to add to that error budget.

• 9:19Krishna Choudhary?

  But then I start thinking, okay, the passer's foot and the ball make contact in 10 milliseconds, right? But like, the camera that's doing this judgment is at like 30 frames per second.

• 9:29Lester Nare?

  Yeah.

• 9:29Krishna Choudhary?

  Which means that like, from one frame to the next is 30 milliseconds, right? 30 times, that's, that's your time resolution.

• 9:37Lester Nare?

  Right.

• 9:37Krishna Choudhary?

  So again, now you're going to a third of a meter. That's a foot. That's this big.

• 9:43Lester Nare?

  And it's the difference.

• 9:43Krishna Choudhary?

  Is the error.

• 9:44Lester Nare?

  Yeah.

• 9:44Krishna Choudhary?

  And, and that, the offside judgment there was like, they were like, oh, this is here. And the, the line is like cutting through his body. Didn't make sense to me.

• 9:55Lester Nare?

  I think a lot of people who are anti-VAR are gonna love this conversation.

• 9:58Krishna Choudhary?

  But, but so, so from a, from a fundamental physics perspective, right? When you're, and this is something that you learn in undergraduate physics very, very early. There's an importance in significant digits. When you don't like, you don't like, um, you know, when, when you're even like measuring the, the most simple experiment that you do, like the first week or two of undergraduate physics lab is you measure gravity. Okay? And in order to do that, you're not really measuring gra, like, that's not the important part. The important part is to measure the distance between two timing, like photogates, and then drop a ball. So that you measure the time difference between this and this and then this and the impact to the ground. And then you measure these two distances.

• 10:42Krishna Choudhary?

  And the real exercise there is to say, how precise do I know this distance and this distance? How precise do I know when the ball hit the ground? Right? And how many significant, like, is it .1 seconds, .01 seconds, so on and so forth? Is it within a centimeter? Like, is it nine centimeters? It could be 10 centimeters. No, it couldn't. But it could be 9.5 or 9.7, right? There's a plus or minus there in the deviation. And so from that, you can then calculate gravity. And you're not going to report it as 9.847265, right? Because you need a much more precise experiment to actually determine that level of precision of gravity.

• 11:24Lester Nare?

  As we talk about, you know, a variety of fundamental research papers, the instrumentation is a key thing we talk about. And the level of precision of that instrumentation matters quite a bit. It's why we have electron, you know, it's why we have very, very, very precise detection machines in order to reduce.

• 11:43Krishna Choudhary?

  Yeah, that error, that error budget. Okay? And so that's why, like, I was just doing these calculations while watching this going, this is nonsense. There's no way that this could possibly be happening. Because you need to bring down both the time of contact of the ball.

• 11:57Lester Nare?

  Yeah.

• 11:58Krishna Choudhary?

  Right? To within a very small time step of like, when did the player hit the ball? And then two, where the players are.

• 12:07Lester Nare?

  Yeah.

• 12:08Krishna Choudhary?

  Okay. They need to bring both of those errors down. Well, I looked into it and they have. Okay?

• 12:13Lester Nare?

  This is, they have. This is so interesting. Because a lot of people, I'm so excited. I'm so excited about this.

• 12:18Krishna Choudhary?

  Yeah. And so it turns out, they hired this company called Hawkeye. That's, what they do is Hawkeye creates digital twins. So on photo four, you'll see. The players get scanned head to toe and you create a digital twin of their body scanned by a computer. And then that digital twin of the athlete can be dropped into a virtual simulation of the game to determine their exact position. Based on 20, 16 different high resolution cameras. So in photo five, we've got the photos of the high resolution cameras. And one of the, one of the things that you learn in experimental science is like the error goes down by one over the square of N.

• 12:59Krishna Choudhary?

  So in this case, whatever, if you had just one camera and you, you were trying to track the position with 16, your error goes down by a fourth.

• 13:07Lester Nare?

  Yeah.

• 13:07Krishna Choudhary?

  Okay, four times smaller.

• 13:10Lester Nare?

  Yep, yep.

• 13:10Krishna Choudhary?

  Okay, that's quite good, but that's still not enough. The real magic here is the digital twins. Because it's something that we do a lot in science, which is we've got a model of our system and then we've got data. We fit the model to the data to get really high precision. We do this a lot with atmospheric. Transits of like exoplanets, right? Like the exoplanet goes through, we get some spectra. The spectra is noisy. But we try to fit models to that spectra to really understand what is going on. In this case, our model is the player's. 3D digital twin and we're fitting that model to the data from the 16 different sensors.

• 13:46Lester Nare?

  I, I think most people didn't even know that they got scanned into 3D for reasons other than to be put into the FIFA, oh, excuse me. Uh, FC 26, the game, because now FIFA no longer gives EA Sports the rights. So it's no longer FIFA insert year, it's now FC. But like, for most people, when they think about like, they think about motion capture and 3D scanning. That's the context.

• 14:07Krishna Choudhary?

  Yeah.

• 14:07Lester Nare?

  I think it's a very important detail that that's why when you see those little die, like the little example photo we just showed.

• 14:14Krishna Choudhary?

  Yeah, yeah. That's, that's the 3D model of the players.

• 14:17Lester Nare?

  The player itself.

• 14:18Krishna Choudhary?

  Of the player itself. They're using like computer vision to actually like fit the 3D model to the player. And this is something that like we do all the time, like even in neuroscience and behavior experiments, like when you have like a rat running around in a maze. You've got a camera that tracks the rat, right? And then there's, you can create a 3D model of like the rat's joints. To figure out his body position, correlate that to the neurons that are firing and so on and so. It's used a lot in behavior experiments. I'm sure like similar technology is being used to recreate the player positioning at every given moment.

• 14:46Lester Nare?

  So. Cause Ivan Perisic and Erling Haaland are very different players.

• 14:51Krishna Choudhary?

  Yes, exactly.

• 14:52Lester Nare?

  You know.

• 14:54Lester Nare?

  And so it matters.

• 14:55Krishna Choudhary?

  Yeah, and it is kind of cool that like they have that kind of granularity.

• 14:58Lester Nare?

  Yeah.

• 14:58Krishna Choudhary?

  So that's the where of where the players are. Now, what about the when? Right? Because I said the 30 frames per second is not going to do you any good. Even the 50 frames per second, if you have a high speed camera, it's not going to do you any good. Um, and by the, by the, judging by the size of that camera.

• 15:13Lester Nare?

  Yeah.

• 15:13Krishna Choudhary?

  Like, that's not like one of these like 100 frame per second.

• 15:16Lester Nare?

  100%.

• 15:16Krishna Choudhary?

  Cameras, right? So to get the, the timing down.

• 15:21Lester Nare?

  Of when the ball was.

• 15:21Krishna Choudhary?

  Of when the ball was hit, the ball actually has an internal sensor. It's a 14 gram sensor. An inertial measurement unit, an IMU, that's used in like gyroscopes and things like that for aerospace. In this case, they stuck it, it's inside the FIFA ball, like just beneath the surface. That thing takes data at 500 hertz, 500 data points per second. And it's measuring acceleration and things like that. So when you hit it, you'll know within 5 hundredths of a second. When the ball was hit. So now you can finally get the, the.

• 15:54Lester Nare?

  Like a level of resolution.

• 15:55Krishna Choudhary?

  A resolution down to that size. So now, when they show that line, that line has a thickness of about a centimeter or less. Otherwise, it should be a blurred out line.

• 16:05Lester Nare?

  Right, right.

• 16:06Krishna Choudhary?

  Right? Because I don't know where the, where the ball was, when the ball was hit.

• 16:10Lester Nare?

  Yes.

• 16:11Krishna Choudhary?

  Right? So that kind of made sense. And combined, this gives the comprehensive VAR system.

• 16:17Lester Nare?

  Yes.

• 16:17Krishna Choudhary?

  You've got the 500 hertz from the ball, you've got these 3D positions from the players, and that's where you get that line.

• 16:23Lester Nare?

  And, and so when people hear VAR, they think, and it did used to be this way where it was just some, some people in a room and they would draw lines manually.

• 16:32Krishna Choudhary?

  Yeah.

• 16:33Lester Nare?

  On, on the video.

• 16:34Krishna Choudhary?

  Based on a video.

• 16:35Lester Nare?

  With, at an angle that was not the correct angle. It was all these things.

• 16:38Krishna Choudhary?

  Yeah, all these things. And it's like, I, but now it kind of makes sense.

• 16:41Lester Nare?

  Now it's, it's.

• 16:42Krishna Choudhary?

  Right? With the amount of data that's going in, I can understand if the error budget is for like that thickness of the line.

• 16:48Lester Nare?

  It's reasonable.

• 16:49Krishna Choudhary?

  Yeah.

• 16:50Lester Nare?

  Now, now, again, in the World Cup, not in all leagues in the world, not club level, everyone's a little different. But specifically for the World Cup and their VAR system.

• 17:00Krishna Choudhary?

  Yeah, yeah. And so I wasn't done there because this got me thinking about other stuff. Okay, like, for example, you've got the sensor that's in the ball.

• 17:11Lester Nare?

  Yeah.

• 17:11Krishna Choudhary?

  How come the sensor is off like to the side just underneath? The ball surface.

• 17:17Lester Nare?

  Yeah.

• 17:17Krishna Choudhary?

  Um, and if you look at the 2022 World Cup, that also had a sensor, but it's at the center, it's suspended at the center. That kind of naively made sense to me, but off to the, just under the ball. Doesn't make sense to me because it's kind of lopsided now.

• 17:32Lester Nare?

  And, and so just for folks who may be listening, you know, the, the 2026 ball basically has like an AirPods size case, an AirPods case. Or like a wireless headphone case size, just nodule just below the surface on one particular spot in the ball. Versus in 2022, it was sort of looks like the structure of, um, we, we talk about, there's a center point in the center of the ball where the sensor is. And again, naively, it's like, yeah, the center point.

• 17:57Krishna Choudhary?

  Then you want to tell where the ball is.

• 17:59Lester Nare?

  Where balls on all sides. Why, if it's on one side, how would it know on the other side?

• 18:02Krishna Choudhary?

  Yeah, and it's like, and if it's on one side, wouldn't it be like lopsided? It would like affect the rotation, right? Um, so there's a reason why the sensor should be right underneath the surface. And this kind of also makes sense. I just thought it was, it was a bit weird that they didn't do it even in the beginning then, if this is the reason. And the reason is that you want higher linear speed. Like if, if you've got the sensor right at the center, right? And the ball is not moving and just spinning. The, the sensor is not going to register a lot of movement.

• 18:33Lester Nare?

  Yeah.

• 18:33Krishna Choudhary?

  And these things are accelerometers at the end of the day. And an accelerometer measures linear acceleration. It discerns spin based on linear acceleration and how like, oh, at one point there's a acceleration in the X direction. Then it's in the Y direction, then it's in the X direction, then it's in the Y direction. And the cycling is going to get you the spin rate. Well, if you're closer to the edge of the ball, then as the ball spins, you have higher linear acceleration. And so your signal noise effectively is like larger. Right. Right? Right, it makes sense. And so that makes sense why it would be over there. But that means that you have to balance it. Yes. And actually, I thought back to my classical mechanics days. And it's very easy to balance something and make it look like a sphere.

• 19:15Krishna Choudhary?

  Because all you have to do is if you have one thing over here and you know you want the center axis to be like that origin point, then you just make a similar weight on the other side. But that can't be enough because now you have a preferred axis. So you need two other on this end and on this end. And then what ends up happening is for those who are in undergraduate physics and have taken an advanced course in classical mechanics. What you're doing is making the inertia tensor diagonal. Yeah. In that like there's a matrix and everything else is a zero except the stuff in the diagonal. And all of the diagonal elements are the same because you have the same mass here, here and here. And so you can just factor out everything and it becomes the identity matrix. We have zeros everywhere and just 111 and it looks exactly like a sphere.

• 20:00Krishna Choudhary?

  And this is one of the coolest problems I remember homework problems in my classical mechanics was like proving that like a sphere spins the same way as a cube. In for all intents and purposes, which is kind of crazy to think about like a sphere literally looks the same from every side, right? In the sense that like, for example, I can take a sphere, like let's say a uniform sphere. And I can attach a string to it, to the, to the, to the ceiling. And then when I, when I like twist it, it's gonna oscillate like this. And the frequency of oscillation like this doesn't matter where I attach on the sphere. Because if I rotate the sphere this way and then try to, try to do it.

• 20:43Krishna Choudhary?

  The torsion pendulum is going to be exactly the same. Okay, the frequency of oscillation. For a cube, naively, you would think, oh, if I, if I, if I attach the string on the. On the flat part, or if I attached it to the corner, the frequency of oscillation should be different. But no, because the inertia tensor is identical in the sphere and the cube, or even one orientation, no matter how you rotate it, those things like don't change the inertia tensor. It's what's called a unitary transformation. I just remember this from like, it was like an undergrad problem at Princeton. The class was called death mech.

• 21:25Krishna Choudhary?

  And this was one of the problems that they to like prove that like this, this is the case. But yeah, it turns out it's like super easy to do now. So now you've got a sphere, you just make the balancing and everything works out. Okay.

• 21:37Lester Nare?

  And so part of that point there is that it's not just that there's one sensor on one point of the ball and that one hole like in the edge. They've now internally.

• 21:43Krishna Choudhary?

  Yeah, like they just offset the mass on, on all the three axes.

• 21:47Lester Nare?

  Yeah.

• 21:47Krishna Choudhary?

  And as long as they're perfectly perpendicular, you're good to go.

• 21:50Lester Nare?

  Which is why the manufacturing process also does matter quite a bit here. Because, you know, making it perfectly perpendicular is not.

• 21:57Krishna Choudhary?

  Yeah, and you do have to make it perfectly because otherwise I think these players at the top level are gonna know.

• 22:01Lester Nare?

  They're gonna know the difference.

• 22:01Krishna Choudhary?

  Yeah, and, and the other thing that, that brings me to like Adidas is like making new balls every World Cup.

• 22:08Lester Nare?

  Yes.

• 22:08Krishna Choudhary?

  I didn't know that. I thought it was the same ball. But no, it's like different balls.

• 22:11Lester Nare?

  So if you go to the FIFA store, or if you go to a game, what you'll see in one of the stores is they have the mini soccer ball collection. These like size one balls, they'll have every World Cup ball, right?

• 22:22Krishna Choudhary?

  Oh, wow.

• 22:22Lester Nare?

  As a box set, right? Because that's their whole shtick. That's their whole thing.

• 22:27Krishna Choudhary?

  Yeah, and, and we're going to talk more about these, the history of those balls coming up. But before we do that.

• 22:32Lester Nare?

  Some housekeeping, as you can see, and for me, I'm loving this. Talking about my favorite game in the world on the pod is incredible. But from a science-based perspective, and if you love this show and want to continue to support us, sharing it with a family member, a friend, a colleague, throwing it in the group chat, shooting the DM, you can always watch all of our episodes on YouTube and Spotify. That's where we have all our full episodes as well as directly on the website at ffpod.com. FFP pod, excuse me, dot com. We also include our research papers where that when they are there. And we have some special new, interesting, uh, interactive explorers that we're going to be putting

• 23:16Lester Nare?

  out over the next couple of weeks, which I'll only tease that much, but we have a birthday coming up. So that may be related. Uh, if you like our clips, you're scrolling on Instagram, you're scrolling on Tik Tok on X. We always put clips out for each episode. It makes it super easy to share. If you want to support the pod directly, you can donate at FFP pod.com backslash donate. Any amount helps the two of us continue to talk about the amazing science that not only FIFA apparently is doing, but particularly fundamental science research, which is really what we talk about very often. And again, we will continue to take book suggestions for the new bookshelf

• 23:55Lester Nare?

  that will go somewhere in between the two of us back here in the studio. We are about to receive our new neon signs, which I'm super excited about, as long as they are not too big. But I'm so excited about this episode. I want to get back talking about the new ball.

• 24:11Krishna Choudhary?

  Yes. And also one more thing about housekeeping. In the comments, please comment on our YouTube or on Spotify. Who do you support winning this World Cup? And it better be America. But anyways.

• 24:22Lester Nare?

  That's a good one. It's coming home. It's coming home. I love how they play, um, uh, uh, West Virginia after the.

• 24:29Krishna Choudhary?

  Oh, take me home country.

• 24:30Lester Nare?

  Yeah, take me home. It's talking about the World Cup.

• 24:33Krishna Choudhary?

  Yeah.

• 24:33Lester Nare?

  We're taking the World Cup home.

• 24:34Krishna Choudhary?

  Home.

• 24:34Lester Nare?

  Home here.

• 24:35Krishna Choudhary?

  Yeah.

• 24:35Lester Nare?

  To the US.

• 24:36Krishna Choudhary?

  Yeah. The tour of the 50 states, baby.

• 24:38Lester Nare?

  Exactly. It's going to be basically a tour of the world in our own country.

• 24:41Krishna Choudhary?

  Yeah. All right. So let's talk about this new ball.

• 24:44Lester Nare?

  Yes.

• 24:44Krishna Choudhary?

  So this year it's called the trionda. It was officially unveiled on October 2025 by Adidas, the official match ball. Who was that guy?

• 24:55Lester Nare?

  Yeah. Jude Bellingham, the, uh, as sometimes the darling of English football, sometimes the, uh, the villain of English football. Uh, the number 10, uh, really the, uh, his, his celebration when he scores a goal, he puts his hands out like he's the Jesus statue in Brazil.

• 25:11Krishna Choudhary?

  Oh, hilarious.

• 25:11Lester Nare?

  Um, great player. He used to play at Dortmund, made the jump to Real Madrid. Um, you know, I, I think, uh, he.

• 25:18Krishna Choudhary?

  Is he playing now for England?

• 25:20Lester Nare?

  He is playing now. Yeah. And at first, you know, he has a little bit of beef with. Part of it was media driven, part of it was real. So the English manager-

• 25:27Krishna Choudhary?

  Dude, the English media is crazy.

• 25:28Lester Nare?

  They're crazy about, they're crazy on this.

• 25:31Krishna Choudhary?

  And they're talking, I'm sorry, but they're talking a lot of shit about America. I hate it.

• 25:35Lester Nare?

  I'm not a fan of that.

• 25:36Krishna Choudhary?

  I'm not a fan of that.

• 25:37Lester Nare?

  I'm not a fan of that. Look, some of us, we watch the Premier League, we have nothing negative to say, just relax, okay? You don't have to point it at us. The small Jude thing that's funny is, the current English manager is Thomas Tuchel. He's a German. The English, we're not happy about that because they thought it was sabotage.

• 25:55Krishna Choudhary?

  Oh, kinda like how their royal family is German. But they don't have a problem with that, so. What's going on there, boys?

• 26:05Krishna Choudhary?

  Anyways.

• 26:07Lester Nare?

  So Thomas, so Thomas Tuchel, former Chelsea manager by the way, is now the English manager, and him and Jude have had some personal beef. Thomas Tuchel runs a really tight shop. He doesn't like ego, it's a team. And at first, the media was like, is Jude gonna play? Is he not gonna play? But he started and he's played. He scored a goal, he's done well. He's a key part of their team. However, he's also an Adidas athlete. And so he's always in a lot of the Adidas commercials.

• 26:33Krishna Choudhary?

  Okay.

• 26:34Lester Nare?

  Because he's obviously a big player in the world. I will also love to hear people's thoughts about each World Cup, Nike and Adidas both put out these like huge commercials with all of their stars. Adidas had one version, Nike had another, very different creative directions. I have my thoughts, but I'm curious to see how people, what people thought about the World Cup commercials, the full ones, not the clips, the full thing from both. Have you seen either of them?

• 27:03Krishna Choudhary?

  So the Adidas one is the Timothy Chalamet one?

• 27:05Lester Nare?

  Yes.

• 27:06Krishna Choudhary?

  Right?

• 27:06Lester Nare?

  Yes.

• 27:07Krishna Choudhary?

  And the Nike one is the one where Cristiano Ronaldo comes out of the fire, right? And it reminds me of like V for Vendetta.

• 27:13Lester Nare?

  It's, yes, yes. Very, very different. There's a huge legacy to these. Like they've each, like they've had, like, you know, there's the Jogo Bonito era with Nike and, but-

• 27:22Krishna Choudhary?

  I was more just like impressed at how many big names were in each of them.

• 27:26Lester Nare?

  Yeah.

• 27:27Krishna Choudhary?

  Right? It was like crazy.

• 27:29Lester Nare?

  A lot of money.

• 27:29Krishna Choudhary?

  Yeah.

• 27:30Lester Nare?

  A lot, a lot of money. I'm not a huge fan of the non-football players being in these commercials.

• 27:35Krishna Choudhary?

  Oh, yeah, yeah.

• 27:36Lester Nare?

  I don't know if I'm into that. I, if they're celebrities, if they're just like normal background actors who played, like, that's fine.

• 27:44Krishna Choudhary?

  Oh, yeah, but like LeBron LeBron was in the Adidas one.

• 27:47Lester Nare?

  You know, the the the uh the Nike one.

• 27:51Krishna Choudhary?

  Oh, yeah, that was the Nike one.

• 27:52Lester Nare?

  The Nike one.

• 27:53Krishna Choudhary?

  Don't sue us.

• 27:54Lester Nare?

  I get it. I get it. You have, you know, cross sport.

• 27:57Krishna Choudhary?

  Yeah.

• 27:57Lester Nare?

  Branding, but LeBron has his own commercials.

• 28:00Krishna Choudhary?

  Yeah.

• 28:00Lester Nare?

  He doesn't need to be there. Travis Scott. I don't know that you need to be in. I don't know that you need to be there. I don't know.

• 28:06Krishna Choudhary?

  Yeah, I mean, just like, I don't know if you need to be in the Odyssey. But, okay.

• 28:12Lester Nare?

  Moving on, moving on.

• 28:15Krishna Choudhary?

  All right, okay, this this episode, as you can, it's it's it's casual.

• 28:18Lester Nare?

  It's World Cup fever.

• 28:19Krishna Choudhary?

  It's a World Cup. It's World Cup, baby. All right, so um the tri-onda, right? It consists of three countries that are hosting.

• 28:25Lester Nare?

  Yes.

• 28:25Krishna Choudhary?

  Um, so you've got the the Mexican, like, I guess the the the Talon thingy, then the Maple Leaf, and then um America has the stars in the in the blue. Okay. Now, the challenge is the following. You want to make an artsy ball, but you got to play with the number three, right? And three is kind of a weird number because it's not, it's odd. It's like not symmetric about a sphere type stuff. You got to like fit three somehow. Okay, now. Now, to understand this challenge, let's begin with the inaugural cup in 1930. Okay, in the 1930 finals, they had this volleyball looking thing.

• 29:05Krishna Choudhary?

  Both Argentina and Uruguay had actually different preferred balls. And Argentina used theirs in the first half. Uruguay used theirs in the second half, so they had different balls for the two halves of the World Cup. And um Argentina was leading at halftime with their ball, and then Uruguay won the match, which is kind of hilarious to think about, right? Um, so that was in the 1930s. And then Buckminster Fuller.

• 29:30Lester Nare?

  Bucky.

• 29:31Krishna Choudhary?

  Yeah, he's an American architect. And he changed the ball in the 1970 World Cup. And it was the first time that Adidas actually manufactured the official ball. Adidas has made the official balls ever since. What he did was use geometric shapes. He was a big fan of using like, you know, the Epcot like ball.

• 29:53Lester Nare?

  Yep.

• 29:53Krishna Choudhary?

  That Epcot center, that that's it looks a lot like that. So the Fuller's ball, that Buckminster Fullerine.

• 30:02Krishna Choudhary?

  It's the classic ball that we know from the Pele 1970 World Cup. This pattern is now so iconic, right? It's got the black pentagons, and I think that's photo 13. Black pentagons, white hexagons, 20 white hexagons for 12 black pentagons. Now, this is like the soccer ball.

• 30:19Lester Nare?

  Yeah. If you grew up playing at any point in time prior to like the modern era, this is everything you played with.

• 30:25Krishna Choudhary?

  Yeah, and because it's got so many panels, what you're trying to do is create a shape from fabric that is a sphere, right? That's the challenge. And now, this ball is so spherical that now players can start curving their kicks intentionally. They can allow the shape to have a predictable path through the air. How does that soccer ball actually work, though? Okay, well, it's actually derived from a platonic solid, which is our emblem here, our part of our logo. You start with an icosahedron, which is a bunch of triangles. And then you take the points and you just squish them.

• 31:08Krishna Choudhary?

  Okay, so an icosahedron is a bunch of equilateral triangles put together. And you take all of the pointy edges and you start squishing them. So here's the icosahedron, starts out. You start squishing them until you get a regular hexagon. A regular hexagon, meaning the pink part, all of the edges are the same size. That's when you get the soccer ball shape. Okay? Very, very nice, very, very beautiful. This year's ball is also derived from a platonic solid, but actually from the simplest one, from the tetrahedron, not from the icosahedron. And this is where the genius of like starting to use three, because you still want to use triangles, because triangles have that three. So what you do is you take the triangle, the equilateral triangle in your tetrahedron,

• 31:50Krishna Choudhary?

  you start shifting the shape such that the points become these flaps. Those flaps then have the patterns for the three countries. And then you put that together, just as the tetrahedron was, but now in terms of a sphere. Okay?

• 32:04Lester Nare?

  And so we're just basically sort of like taking the core shape of the triangle and just taking the stat surface area and making it a blob.

• 32:12Krishna Choudhary?

  Yeah.

• 32:12Lester Nare?

  That can then be patched.

• 32:14Krishna Choudhary?

  That can then be patched together, right? Now, the problem is... Compared to the Bucky Ball, this has fewer seams, right?

• 32:21Lester Nare?

  Yes.

• 32:22Krishna Choudhary?

  And if it's got fewer seams, there are fewer grooves within the ball.

• 32:27Lester Nare?

  Right.

• 32:28Krishna Choudhary?

  Right? The Bucky Ball has 20 hexagons, 12 pentagons, so a lot of these edges.

• 32:34Lester Nare?

  Yes.

• 32:34Krishna Choudhary?

  And so there's a little roughness there.

• 32:36Lester Nare?

  Yes.

• 32:36Krishna Choudhary?

  With this one, there's fewer seams, so there's fewer grooves. The ball is gonna be a little bit smooth. So you have to counteract for that.

• 32:43Lester Nare?

  Yes.

• 32:43Krishna Choudhary?

  And this is especially bad in South Africa with the Jubalani.

• 32:47Lester Nare?

  Yes.

• 32:47Krishna Choudhary?

  Ball that apparently everyone hated.

• 32:49Lester Nare?

  Yes, and this was 2010.

• 32:51Krishna Choudhary?

  Yeah.

• 32:52Lester Nare?

  The Jabulani Ball.

• 32:53Krishna Choudhary?

  Jabulani.

• 32:54Lester Nare?

  Was famous. We were sophomores?

• 32:58Krishna Choudhary?

  Yeah, I was, I was just graduating. So I had just graduated.

• 33:02Lester Nare?

  Ah, yes, yes, yes.

• 33:03Krishna Choudhary?

  I just, I remember, I just graduated high school and we were in India for like-

• 33:08Lester Nare?

  For the World, for the World Cup.

• 33:09Krishna Choudhary?

  For the World Cup, yeah.

• 33:09Lester Nare?

  This is so, and you know, at the time, it was so funny because I remember, you know, you don't always, because you play in, in both high school and college and club, you usually, you play with select, or sometimes you'll play with some of these Adidas or Nike balls.

• 33:24Krishna Choudhary?

  Yeah.

• 33:25Lester Nare?

  They became a little bit more popular later on. But you wouldn't really play with the World Cup ball, you know, in practice or whatever. But when the Jabulani came out, one of the things people love, i- i- it had this weird knuckle. So like, this is when like, you know, Cristiano Ronaldo's making these 40-yard free kicks in the Premier League and the, the people, goalkeepers hated it especially. A lot of players hated it too, but people who are like goal scorers or people wanting free kicks, they liked it because they would move around weird.

• 33:53Krishna Choudhary?

  Okay.

• 33:53Lester Nare?

  And so there's like, this is great for me because I'm gonna score.

• 33:57Krishna Choudhary?

  Yeah.

• 33:57Lester Nare?

  The keeper doesn't know where it's going. And I don't really, like, I think, I remember at the time, one of the things that would struck me about it was, and I didn't necessarily think about it, is the surface was so smooth.

• 34:10Krishna Choudhary?

  In part because it didn't have all the seams that you just talked about. Um, but it was extremely, uh, extremely controversial alongside the vuvuzelas. Yeah, the vuvuzelas is also very controversial. Yeah, and that's exactly what, right, you were saying that, you know, it moved weird. It moved so weird. And goalkeepers hated it. Hated it. Right, there is a nice fundamental physics reason for why it moves weird, and that's what we're gonna cover here. Okay. Okay, the physics of soccer ball flight and how the texture of the ball affects that. Cause the shape of the ball is just, it's, it's a sphere, right? But the, the roughness is really where the magic lies, okay?

• 34:50Krishna Choudhary?

  So, um, when you have a new ball, you gotta make sure it's not the Jabulani or whatever, right? You gotta make sure it's not that bad. And so Adidas actually did a bunch of tests, 300 lab tests. Those aren't published, but a group of scientists did independent tests. Um, this is from the University of Puget Sound in Washington. And then there's also some universities in Japan that landed their wind tunnel to do some of this testing. And it's really cool because they published a paper in Applied Sciences out of the MDPI Publishing Hub. Trionda enhanced surface roughness relative to the previous World Cup soccer balls. And they compared the physics between this soccer ball and all the previous ones. And it's actually really, really cool. I love that.

• 35:35Krishna Choudhary?

  The main thing that they care about here is drag. And that's the thing that, you know, most anyone cares about when it comes to aerodynamics. So drag is, you know, the resistance of the air to your motion, okay? And it's always proportional to the velocity squared. That kinda makes sense because the faster you go, the harder you're hitting the particles and the more particles you're hitting. So there's a double factor of the velocity, right? There's like, you're moving through this, so you're hitting the air molecules at a faster speed. So you're transferring momentum faster. And also there's more stuff that you're hitting the faster you go. So that's why you got a V squared. It's also proportional to the area because the larger the cross-sectional area. Yes. The, the more air particles you're gonna be hitting.

• 36:19Krishna Choudhary?

  It's proportional to the density of the air, obviously, because like, you know, the denser the air, the more the drag is gonna be. Yep. The, the denser the fluid, right? And then there's, um, something called the drag coefficient, which in this case is the C D. That's the coefficient of drag. And that's like the number that gives you the drag force.

• 36:37Lester Nare?

  Yep.

• 36:38Krishna Choudhary?

  Okay, there's like all of those factors, plus something having to do with the surface of the ball and the shape. The surface of the object and the shape, I should say. Okay? Now, with real objects like balls, there is something called the drag crisis. And that's what happens when you calculate the drag coefficient, the drag force, um, for different speeds. Naively, you would think that the drag coefficient is a constant. It does, it shouldn't depend on how fast I'm going. The, the, the effect of velocity is already in that equation.

• 37:12Lester Nare?

  Right.

• 37:13Krishna Choudhary?

  But there is a nonlinear effect on the coefficient itself that doesn't have to do with this physics argument. Okay?

• 37:18Lester Nare?

  That's interesting.

• 37:19Krishna Choudhary?

  There's something else that's going on. And actually, it turns out, the drag coefficient drops suddenly when there's higher speed. That's weird.

• 37:28Lester Nare?

  That's weird.

• 37:28Krishna Choudhary?

  At higher speed, it's easier to go through. So you can see in the wind tunnel tests why this is happening. So this is at NASA Ames Research Center. NASA loves aerodynamically testing these balls. So here you've got a soccer ball in a wind tunnel. The air is coming in from the left. And as you're spinning, what's happening is your laminar flow of the really nice air is getting broken up at the surface of the ball and it's creating turbulent flow behind it. Right? That has a very weird effect on the drag. Okay, here's what's gonna happen. The wake behind that ball is gonna create a region of low pressure. You can imagine, like here, the ball is stationary and the wind is going through, right?

• 38:12Krishna Choudhary?

  But in real soccer play, the ball is gonna be moving through like in, towards the right.

• 38:17Lester Nare?

  Yes.

• 38:17Krishna Choudhary?

  In this direction.

• 38:18Lester Nare?

  Yes.

• 38:18Krishna Choudhary?

  Right? Now, on the right hand side, the, the ball is hitting the air particles. So there's high pressure, right? Because it's like a piston, it's like sort of compressing air. And on the, behind it, there's gonna be low pressure. So there's gonna be a force backwards that is not just the particles hitting, but there's like a pressure difference.

• 38:38Lester Nare?

  Yeah, yeah, yeah.

• 38:39Krishna Choudhary?

  And that's gonna cause some weird stuff.

• 38:40Lester Nare?

  Okay, okay.

• 38:41Krishna Choudhary?

  Okay?

• 38:41Lester Nare?

  Yep.

• 38:42Krishna Choudhary?

  And it turns out.

• 38:45Krishna Choudhary?

  That the faster you move, that that low pressure effect becomes less and less.

• 38:51Lester Nare?

  Interesting.

• 38:52Krishna Choudhary?

  Which is a little bit non trivial. So let's go to the next photo, which is photo number 20. Yeah, here's what we're doing. The ball is moving to the right hand side.

• 38:59Lester Nare?

  Yeah.

• 38:59Krishna Choudhary?

  Okay, on the left panel, the ball is not moving that fast. When the ball is not moving that fast, the wake is actually a lot bigger. So the region of low pressure is a lot more, which means that pressure difference is bigger. And if the pressure difference is bigger, the drag force is going to be bigger. There's going to be a bigger contribution due to that pressure difference. On the right hand side, now you've got the ball moving faster. When you go faster, the laminar flow disconnects from the ball faster. And when that happens, you can actually like flow through the ball. Like you can, you can follow the curve of the ball more, which is a little bit non intuitive. Like the faster you move, the more the laminar flow hugs the ball.

• 39:44Krishna Choudhary?

  And so your low pressure region is actually smaller, meaning that the pressure difference is not that much, which means your drag has actually gone down. The faster you move, the drag actually goes down.

• 39:55Lester Nare?

  This makes me think of all the science to F1 cars, which deal with a variety of these concepts very heavily, but.

• 40:02Krishna Choudhary?

  That, uh, this is a big part of it. You wanna, you wanna make that low pressure region behind you not that big so that you have like a lot.

• 40:09Lester Nare?

  Which is why the cars are designed the way that they are.

• 40:11Krishna Choudhary?

  Yeah. And so the weight can be different at different speeds, right? And if you go to, um, the photo number 21, this is the curve that you're going to be looking at. On the X axis is the speed of the ball. On the Y axis is the drag coefficient. At low speeds, you've got a laminar boundary. And so the ball is going to hug, I mean, sorry, the laminar flow is going to hug the ball, but then it's going to disconnect very quickly. And you're gonna get a massive low pressure region, that's gonna cause a lot of drag.

• 40:40Lester Nare?

  Oh, actually, this makes sense.

• 40:41Krishna Choudhary?

  As I, as I increase the speed of the ball, the, the laminar flow is gonna hug the ball and there's not gonna be that much low pressure, which means that the ball is just gonna be fine. That, at least that effect is, is gone. And so your drag coefficient, there's, there's a period where the drag crisis happens. That's the drag crisis regime, right? It should be, it should be flat, but it's not. There's a part that goes down.

• 41:04Lester Nare?

  It's, it's almost like the, if you give the, the, the flow more time, it will dissipate outwards, but basically the faster it's moving, you don't give it enough time almost to get out of the, that sort of contour of moving around the object that's coming through it.

• 41:19Krishna Choudhary?

  Exactly.

• 41:19Lester Nare?

  And so that's where you get the lower.

• 41:21Krishna Choudhary?

  Exactly. And this is why, this is why golf balls are not perfectly spherical. They have those divots. Actually, if you go to the next one, photo number 22, this is a golf ball in a aerodynamic simulation. The left is a ping pong ball. There you can see the, the laminar flow leaves basically at the equator here.

• 41:40Lester Nare?

  Yeah, yeah, yeah, yeah.

• 41:41Krishna Choudhary?

  From pole to pole. And you have a massive low pressure region.

• 41:44Lester Nare?

  Yeah.

• 41:45Krishna Choudhary?

  And so the ping pong ball is going to experience a lot of drag and it's gonna do like weird stuff. And that's by design, because you want the ping pong ball to be light and to be able to sort of stop within the distance of a ping pong table. The golf ball, on the other hand, has these divots and that creates turbulence. The turbulence is by design to make that low pressure less of an effect, so that it goes farther.

• 42:07Lester Nare?

  Farther away.

• 42:08Krishna Choudhary?

  Right?

• 42:08Lester Nare?

  Yeah.

• 42:09Krishna Choudhary?

  And that's the whole point of roughness on a soccer ball.

• 42:13Lester Nare?

  Yeah, that makes, and this now gets to the idea of why the Jabulani was so different, because again, we'd had this sort of classic style for such a long period of time.

• 42:24Krishna Choudhary?

  Yeah, we had the Bucky ball with all of those seams and all of that roughness. That's kind of like the golf ball's divots, right?

• 42:30Lester Nare?

  And we tried to get all fancy.

• 42:31Krishna Choudhary?

  Yeah.

• 42:32Lester Nare?

  You know?

• 42:32Krishna Choudhary?

  And why specifically, right? So if the ball is too smooth, what that's gonna do is there's gonna be a transition, as you saw in those curves, right? There's a transition from low speed to high turbulent speed. And what I want is to tune that transition, where that transition is happening. Now, if the transition... Happens too far up, right?

• 42:53Lester Nare?

  Yeah, yeah, yeah.

• 42:54Krishna Choudhary?

  Yeah, let's, let's stay on this one. So if the transition happens too far up, what's that? What is that gonna do? That means that it's in the typical range of free kicks, corner kicks and all of those things, right? The long passes. And when this occurs, the ball is kicked at high speed. But as it slows down, it's gonna be in that transition point. And it's gonna go into a spot with, from low drag coefficient to high drag coefficient. And it's gonna start doing weird things.

• 43:19Lester Nare?

  Right.

• 43:19Krishna Choudhary?

  What you want is most of the ball's trajectory to be in that low drag coefficient spot.

• 43:24Lester Nare?

  This is why with the Jabulani, it would start going really fast. And then in the last minute.

• 43:28Krishna Choudhary?

  Yeah, last, because, because it's transit, it slowed down into the high regime. This is exactly what the scientists saw in the wind tunnel measurements.

• 43:36Lester Nare?

  That's so interesting.

• 43:37Krishna Choudhary?

  So on the, on the X axis is the drag coefficient.

• 43:39Lester Nare?

  Yeah, yeah, yeah.

• 43:39Krishna Choudhary?

  On the Y axis is your velocity.

• 43:41Lester Nare?

  Yeah, yeah.

• 43:42Krishna Choudhary?

  All of the other balls, the Alriela.

• 43:44Lester Nare?

  On the, on the X axis.

• 43:45Krishna Choudhary?

  On the X axis is the velocity.

• 43:47Lester Nare?

  On the Y.

• 43:47Krishna Choudhary?

  On the Y axis is the drag coefficient. The main thing to see is that all of the other balls, the Trionda is in red. All of the other balls are in the other colors from all the different other FIFA World Cups. The, the Jabulani is in the yellow.

• 43:59Lester Nare?

  Yeah.

• 44:00Krishna Choudhary?

  It's the only one where the drag crisis is happening at a higher speed.

• 44:04Lester Nare?

  Yeah, yeah, yeah. Which, and, and that, I mean, this correlates to exactly what people saw.

• 44:08Krishna Choudhary?

  Exactly, yeah.

• 44:10Lester Nare?

  That's fascinating.

• 44:10Krishna Choudhary?

  So, so, but this is like now quantitatively, you can see that Jabulani is the outlier.

• 44:14Lester Nare?

  Yeah, yeah.

• 44:15Krishna Choudhary?

  Right?

• 44:15Lester Nare?

  And every other one effectively trends across the, similar profile.

• 44:19Krishna Choudhary?

  And what you want is whenever you make a new ball, you want it to basically do the same thing that the others did.

• 44:23Lester Nare?

  Right.

• 44:23Krishna Choudhary?

  You want, don't want it to do new things.

• 44:25Lester Nare?

  You can make it look pretty, but make it work the same.

• 44:27Krishna Choudhary?

  Yeah, make it work the same so that like, whatever the players trained with, that's what they're playing with, right?

• 44:32Lester Nare?

  Yeah, and I, I think just as someone who's played, like the way the ball work, like it is, it is, it is good. Like from a playing.

• 44:39Krishna Choudhary?

  Yeah.

• 44:39Lester Nare?

  Perspective, like I would not want, I can't really think of how I would want it to operate differently. Like there's, there's, you know, Futsal is an indoor soccer game where the ball is weighted totally differently. Because it's not supposed to go in the air.

• 44:50Krishna Choudhary?

  Yeah.

• 44:51Lester Nare?

  And it's very, very, very different. And I don't like it. I don't, but I get it, like I get.

• 44:56Krishna Choudhary?

  It's a different game.

• 44:57Lester Nare?

  It's just a different, it's a different game.

• 44:58Krishna Choudhary?

  Yeah, and they also. Calculated the trajectory, so they they took all of their drag coefficient data. And they said, okay, let's simulate a trajectory. The Y axis isn't important, it's a kind of like. What percent of deviation was the trajectory different? Based on like something that was purely a a flat drag coefficient. And the X axis shows the velocity, but again, the main thing to see is. The Jabulani in the yellow is the outlier. It's doing this weird.

• 45:25Lester Nare?

  It's almost the.

• 45:26Krishna Choudhary?

  Everything else is following the similar trajectory.

• 45:28Lester Nare?

  Yeah.

• 45:28Krishna Choudhary?

  Right of like how? How the data looks.

• 45:32Lester Nare?

  Yeah.

• 45:32Krishna Choudhary?

  But in all of their graphs, then they have multiple sort of plots. Showing the behavior of all the different balls. And in every single one, Jabulani is just showing something completely different.

• 45:42Lester Nare?

  I can't believe they got away with this.

• 45:43Krishna Choudhary?

  Yeah.

• 45:44Lester Nare?

  This is, this is actually, it's it's also, you know, I think. The fact that the science is backing up the visual observations.

• 45:52Krishna Choudhary?

  Yeah, it's kind of cool.

• 45:53Lester Nare?

  And the player observations are the player experiences that folks had is is kind of nice.

• 45:56Krishna Choudhary?

  Yeah, I think that's pretty cool. So this this particular tri on the ball, this is the most tested ball in history. It also went up in the NASA ISS. They were doing center of mass and balance. In microgravity experiments, which I I'm gonna be honest, I really don't. Understand, like what, like we're gonna be playing enders game football? In like zero G or something like what what is the need? But I also, I mean, it reminds me of that one show with Steve Carell about. Space Force where he's asked like. Why are you sending an orange to space for $10,000? And he's like, you know what, sometimes these astronauts that are up there for a year. Need to remember, because they're like eating airline food. They need to remember what an orange tastes like. And so sometimes maybe they're just playing football.

• 46:41Lester Nare?

  Yeah.

• 46:41Krishna Choudhary?

  But then just say that, don't be like, oh, microgravity. Why? No. I don't want, I don't care how the how the FIFA ball does in microgravity.

• 46:52Lester Nare?

  That's I, that's so, you know, hey, shout out to Adidas.

• 46:56Krishna Choudhary?

  Shout out to Adidas, shout out to NASA.

• 46:58Lester Nare?

  First football.

• 46:58Krishna Choudhary?

  Great photo.

• 46:59Lester Nare?

  Yeah, great photo.

• 47:00Krishna Choudhary?

  Yeah. Okay, so that's not everything, right? Because the ball. So the ball is moving in the air, but it's also got to interact with the turf. The turf is actually pretty cool. It's non-trivial to make the turf because we've got a lot of different stadiums across an entire continent, which means different climates. Some, um, some of them are in a covered stadium. Some of them are in the scorching heat. Some of them are in like Seattle and Vancouver. And this is a living, breathing entity, right? FIFA says that you have to have like living grass.

• 47:32Lester Nare?

  Yeah, the pitch is great. I want to be careful because people associate turf with artificial.

• 47:37Krishna Choudhary?

  Oh, yeah, that's what I mean by, yeah.

• 47:39Lester Nare?

  But, but the pitch, the field.

• 47:41Krishna Choudhary?

  The pitch, the field, yeah, has to be grass, living grass.

• 47:44Lester Nare?

  Not the NFL's turf.

• 47:46Krishna Choudhary?

  No.

• 47:46Lester Nare?

  They're very upset about that we've taken over all these NFL stadiums. We've put in real grass.

• 47:52Krishna Choudhary?

  Oh.

• 47:52Lester Nare?

  And they're like, why can't we get, because especially for football and like, I can't believe they don't do real grass, but it can be done.

• 47:58Krishna Choudhary?

  Yeah, I mean, like, real grass is also a big thing in the Wimbledon, right? It's like their, their courts have to be like really precise grass. And so, and once the grass is installed, you got to keep it alive.

• 48:09Lester Nare?

  Yes.

• 48:09Krishna Choudhary?

  For several weeks. And that's a difficult task. So FIFA has assembled a crack team of turfologists. Yeah, led by John Sorechan of the University of Tennessee and John Rogers of Michigan State University. They're kind of managing this whole thing.

• 48:25Lester Nare?

  The two Johns, we got the two Johns, we got the two Johns.

• 48:29Krishna Choudhary?

  And, and they, they do research on turf grass conditions.

• 48:34Krishna Choudhary?

  Like this, this next photo, this is from the University of Tennessee. They've got an indoor turf research building that is showing how like LED lights can be used to grow grass, like the purple light is something that is the chlorophyll centers of the grass are sensitive to. That's going to cause the grass to grow more. It's kind of crazy that like so much is going into it. Sorechan's team actually invented something called Flex, which is a portable device that's outfitted with a 3D printed foot with soccer cleats. And this thing is, this thing is like, it's, it's, it, it puts down. How a normal foot would go on the grass to measure the responsiveness of the grass and to sort of calibrate all of the grass to be the same across all of the stadiums.

• 49:20Krishna Choudhary?

  Like the amount of, the amount of stuff that people are inventing to, to keep this beautiful game going. I think that's kind of cool.

• 49:26Lester Nare?

  This is, this is, this is really sick and I'm going to make a brief plug. I'm, I'm, I'm pretty sure it's the, the, the Bernabeu, the new Real Madrid stadium. They have like multiple, so where the pitch is. It's, it's, it's literally, they will lower it down several stories and there's multiple, there's like multiple pitches stacked vertically on top of each other. So it drops down and then it slides and so they can literally replace the pitch. So it's like, imagine, imagine you have like an oven, a pizza oven with multiple racks.

• 50:01Krishna Choudhary?

  Wow.

• 50:02Lester Nare?

  Right? And so they literally will swap out pitches, bring them into the, the underground facility to mess up with it, but they can just basically, it's like this multi-level, multi-pitch. It is an unbelievable system.

• 50:15Krishna Choudhary?

  That's crazy.

• 50:16Lester Nare?

  We may want to do a follow-up on that because it is one of the coolest things I have ever seen and they spent a lot of money for it. But it's also the cathedral of football because they're the biggest, most winningest team ever, although, you know, I won't comment as a, as a Chelsea boy. Up the Chels. But you know, there is, I think the point just being like, there is a lot of work.

• 50:40Krishna Choudhary?

  Yeah.

• 50:40Lester Nare?

  That gets put into this. When this World Cup started, the, the pre-World Cup matches were not done in FIFA World Cup stadiums. Everyone's like, the Americans don't know what they're doing with the pitches. Relax.

• 50:52Krishna Choudhary?

  Relax. I mean, look at this next video that we're going to show of the 2026 World Cup and how SoFi Stadium, sorry, Los Angeles Stadium prepped for it.

• 51:00Lester Nare?

  Yes.

• 51:00Krishna Choudhary?

  Okay. Here, they're, they're showing, they put the sand, they're, they're putting like, um, black tarp down. Then they're putting sand on top because the sand is sort of where the water is going to go and then get drained out. And on top of that, they're putting the turf. Then they've got these LED lights that have, that go in every single night to, to make the grass grow. It's an incredible engineering feat and all of this turf, sorry, all of this grass is coming from like Colorado or something, you know?

• 51:28Lester Nare?

  Right, so they gotta ship it in.

• 51:29Krishna Choudhary?

  Yeah, they gotta like, this is incredible endeavor.

• 51:32Lester Nare?

  Yeah.

• 51:32Krishna Choudhary?

  For a stadium that as big as Los Angeles.

• 51:36Lester Nare?

  Yeah, which is a massive, and the grounds which we were there at.

• 51:39Krishna Choudhary?

  Yeah.

• 51:40Lester Nare?

  Are great and again, obviously the actual event, the actual match stadiums, we're gonna have the best.

• 51:47Krishna Choudhary?

  Yeah, yeah, and like they've got a drainage system to get the water out because the grass has to be wet, they've got fans to blow air across to stave off fungi, like, it's dope.

• 51:59Lester Nare?

  When it comes to entertainment in the US.

• 52:02Krishna Choudhary?

  Yeah.

• 52:02Lester Nare?

  We spare no expense.

• 52:03Krishna Choudhary?

  Yeah, exactly. The last thing that I wanted to touch on was as I was watching these games, I noticed something called match momentum.

• 52:10Lester Nare?

  Momentum.

• 52:11Krishna Choudhary?

  And I love data visualization and data analytics, so I got interested in this thing because I was like, how does, how does that work? Like, how do you know? Because it tracked to me visually when I was like, oh, like this team is doing well, the momentum for them was up. But as an analytics guy, you start asking like, okay, how do you actually calculate that? Because there's some, there's some, there's not some guy being like, oh, I judge the momentum to be this now. There's some automated algorithm that is doing it, right? And so what is that algorithm? I couldn't find much on it, but I found a few things. First thing what they do is they calculate something called possession value. Okay? So possession value measures the impact of individual events, like individual passes and things like that that are going on on the pitch, on the probability of one team scoring within the next 10 seconds.

• 52:56Krishna Choudhary?

  And they have some like data way to train what that is. Like, for example, we've got, the example that they use is Kevin De Bruyne.

• 53:03Lester Nare?

  Ah, oh, Kevin De Bruyne.

• 53:08Krishna Choudhary?

  Yeah, and the example they use is, so for example, let's say Kevin De Bruyne is at the center.

• 53:14Lester Nare?

  Yeah.

• 53:14Krishna Choudhary?

  And then he passes it to a dangerous area in the opposition.

• 53:19Lester Nare?

  Yeah.

• 53:19Krishna Choudhary?

  Right? Like, he passes it over, so now it's closer to the goal.

• 53:24Lester Nare?

  Yes.

• 53:24Krishna Choudhary?

  Now, the possession value of that move was something like point one or point two, because he's increased the chance of getting to goal.

• 53:34Lester Nare?

  Yeah.

• 53:35Krishna Choudhary?

  Now, in order to calculate momentum, what you're gonna do is you're gonna look at the maximum possession value for each team every single minute. This is kinda cool, because what they're doing is they're comparing the two most threatening situations.

• 53:49Krishna Choudhary?

  In that minute, they're not actually doing a average over all the passes. They're looking at the extrema, like what was the most dangerous thing that team A did? Versus what was the most dangerous thing that B did?

• 54:01Lester Nare?

  In every minute interval.

• 54:02Krishna Choudhary?

  Yeah, that's kind of nice because now you're not washing out the stuff that actually matters. Because in football, like, things can happen very quickly, right? So you want to reward the maximum stuff more than like, oh, just passes here and there. If you just average, you're gonna like water down everything. So that's one thing that I thought was really cool. And a lot of times in data analytics, you have to make these kinds of choices about what is the part of the data that you care about. So they measure the possession value of that maximum move over the past minute. And they weighed it based on how long ago that happened. So they've got like some time kernel that they can evolve with.

• 54:39Lester Nare?

  That's actually a good way to do it because if you just did it on like raw possession stats, like, you know, you could have even in the Belgium-Iran game.

• 54:45Krishna Choudhary?

  Yeah.

• 54:45Lester Nare?

  Belgium would be way overweighted and they were in large pockets where they were not particularly dangerous.

• 54:51Krishna Choudhary?

  Yeah.

• 54:52Lester Nare?

  And Iran had these like, you know, moments that were much more impactful, even though they were mostly out of possession, at least in the first half.

• 55:01Krishna Choudhary?

  Yeah, exactly. That's why I think I like that they they only keep these like the the maximum part instead of averaging. And then the momentum is given by the difference between the two.

• 55:09Lester Nare?

  Yeah.

• 55:09Krishna Choudhary?

  Okay?

• 55:10Lester Nare?

  That makes sense.

• 55:10Krishna Choudhary?

  And one really cool sort of visualization that I saw was, I mean, there was a tweet by someone saying that like the match hydration breaks.

• 55:18Lester Nare?

  Boo.

• 55:19Krishna Choudhary?

  Are like.

• 55:21Lester Nare?

  Boo.

• 55:23Krishna Choudhary?

  They're showing that the match hydration breaks changed the momentum.

• 55:26Lester Nare?

  Yeah.

• 55:26Krishna Choudhary?

  Right? And this is from the, I think this is the Kurokaw versus Germany game. That's showing that like Kurokaw was just getting going and then and then the match hydration break happened. Um, I don't know what's the best way to sort of quantifiably.

• 55:43Krishna Choudhary?

  Measure this difference, right? Because like you'd have to compare with all the games. You'd have to make the same kind of data analytics. But then also, like, at any given moment, match momentum shifts, right? So how do we make the judgment that it only shifted during the hydration breaks? And it could shift either way, right? It could shift to being more of Germany or more of Kurakau and things like that. So you can't really only look at, um, look at diff, like, the match momentum switching as an effect. Because it could mean that like it made the momentum even bigger for one side or the other. I don't, I don't really know. And if, if people have ideas for how to do data analytics, to like, do an A B testing of this kind of thing.

• 56:25Krishna Choudhary?

  One idea I had was to look at the time constant of how quickly the match momentum is shifting in either direction. So now you're agnostic to which direction the match momentum is shifting. And you're looking for the, the, the timing of the squiggles. And if this is true, what you would see is that the time constant of the shift should be shorter.

• 56:50Lester Nare?

  Yeah.

• 56:50Krishna Choudhary?

  During the hydration breaks, then it should be during normal gameplay.

• 56:53Lester Nare?

  Right.

• 56:54Krishna Choudhary?

  Right? Or during like the same 22 minutes for a match that didn't have match momentum. That's sort of like a first pass at how I would do the data analytics here if I was given this thing. I mean, the, the problem there is there is also already an inherent time constant in how they're measuring it, right? I can't go slower than a minute or like five minutes, depending on how they smoothed this thing.

• 57:17Lester Nare?

  Yeah.

• 57:17Krishna Choudhary?

  So it's, it's a tough question. The eye test is telling me, at least in this game, that it works, but that's N of one. So I don't know.

• 57:24Lester Nare?

  Hydration breaks are terrible and it's a stand on the game. And it should not exist. The only circumstance is if it's above X temperature Fahrenheit or centigrade or whatever. But otherwise, um, it should not exist in the game. It's, it's, it is a total catastrophe.

• 57:42Krishna Choudhary?

  Yeah.

• 57:43Lester Nare?

  It's very upsetting to me. But that's not a scientific opinion.

• 57:46Krishna Choudhary?

  Yeah, right.

• 57:48Lester Nare?

  You know, whether or not it interrupts the momentum, I think there are good arguments that it does from the eye test. This is not the beautiful game that we were raised on. An unbelievable, this World Cup has been incredible.

• 58:02Krishna Choudhary?

  Yeah, it's already been great.

• 58:03Lester Nare?

  It's the group's expanded, the group stages is exciting. We're seeing the dark horse teams are supposed to do well.

• 58:09Krishna Choudhary?

  Cape Verde.

• 58:10Lester Nare?

  Cape Verde's doing like, it's just.

• 58:12Krishna Choudhary?

  Killing it.

• 58:13Lester Nare?

  Unbelievable. We have a new top goal scorer of all time.

• 58:17Krishna Choudhary?

  Yes.

• 58:18Lester Nare?

  And Lionel Messi, Lamine Yamal has made his first World Cup goal ever. Erling Haaland has arrived. Kylian Mbappe said, do not forget about me. I'm still here. I'm still fighting. It's been super fun. The group chat, our group chat's going so crazy over all the games. It's been a blessing to have in the US. There is a lot of people who do a lot of work to make things like the World Cup happen. And it's not just the coaching staff.

• 58:44Krishna Choudhary?

  Yeah.

• 58:44Lester Nare?

  It's not just the media ecosystem.

• 58:46Krishna Choudhary?

  And some of them are scientists.

• 58:47Lester Nare?

  And some of them are scientists and the science of the World Cup is indeed very fascinating. We always, we hit another hour on this one. Even though we were trying to keep it tight, keep it light, but what happens when you're doing this is just.

• 59:03Krishna Choudhary?

  Yeah.

• 59:03Lester Nare?

  It's fun. We like to talk a lot about it. I am your host, Lester Nare, joined as always by my co-host and our resident PhD. Go Team USA, Christian Choudhary. We will see you all next week and we will be winning the World Cup in about two to three weeks from now. And so when that happens, come back and comment and let me know. And when it doesn't happen, don't come back and don't comment.