Short Stuff: The Mpemba Effect

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1:10Hey, and welcome to The Short Stuff. Josh here, Chuck here. Giddy up. Yeah, we're going to tell you in part about a remarkable young teenager in Tanzania in the 1960s, and his name was Erasto Mpimba. Is it Mpimba? It's Mpimba. Okay. The The reason why we're talking about Erasso and Pemba today is because he was a pretty remarkable kid. He stumbled upon, I guess you could say rediscovered, a concept that just baffles physicists today because it doesn't make any sense. It may violate the second law of thermodynamics. and it ended up being named after him because he was a persistent little cuss who made this observation and just kept going until he finally got the ear of somebody who could help him try to figure it out.

2:02You know, the first law of thermodynamics is you don't talk about thermodynamics. I was thinking about that movie the other day. I used to be so into that and now it's so juvenile. I know. I almost put it on the other day as a laundry folding movie, which I like to do just to see parts of. And I had the same thought. I was like, I don't know if I just even want to go down that road again. Yeah. Cause it exists happily in the past. You know what I mean? Yeah, exactly. I heard at the premiere, Brad Pitt leaned over to Edward Norton and said, I'll never be in a movie this cool again. And he was right.

2:39I think he was. So yeah, we're talking about Erasto Impemba because he discovered what's called the Mpemba effect after him. And I think I said earlier that he rediscovered it. It was first noticed by Aristotle, or at least it was first written about all the way back to Aristotle. Medieval scientist Roger Bacon mentioned it as well. So did the Enlightenment philosopher Rene Descartes. And what they all noticed and what Erastom Mpemba got his name attached to is that hot liquids placed in a freezer can freeze faster than cool liquids placed in the same freezer at the same time. It makes no sense whatsoever.

3:22Yeah, he discovered this as a 13-year-old. He was in class in Tanzania and they were making in school and they were making ice cream as a class. I don't know if that was for fun or if it was part of science. I like to think it was part of science. But regardless, he, you know, they added sugar to the boiling fresh milk. You let it cool. You put it in a container. You put it in the freezer. They were doing this again another day. I bet they just like an ice cream now that I think about it. Sure. He was like, hey, the freezer space is getting low, and I want to make my special ice cream. So he's like, I'm not going to let this stuff cool down.

3:56I'm just going to go grab that spot while it's available. and an hour and a half later, he was like, hey, everybody, my ice cream is ready before yours in your face. Yeah. And he said, but that doesn't make any sense because I put that hot milk in. So why would mine have frozen at all? And he went to his teacher and his teacher said, I got too much to deal with. So you run along, Erasto. Yeah. I'm not curious like you. No. And Erasto was undeterred over the years, teacher after teacher, as he made his way through middle school and high school. He would talk to them about this discovery and he was dismissed by all of them.

4:34And then finally, one day at his high school, a physicist who was a visiting physicist to the University of Dar es Salaam, he was a British guy named Dennis Osborne. He came to give a lecture and Erasto Mpemba saw his chance and said, Professor Osborne, I've got something that may knock your socks off. Check this out. Do you think in the teacher's lounge over the years, everyone was like, hey, has Mpemba hit you up about this ice cream business? Yes. They're all drinking wine and rolling their eyes. So annoying. So annoying. All the scientific curiosity out of this kid. I know. Luckily, Dennis Osborne was like, ooh, I like that.

5:13Let's talk a little more about it. He likes this kid, and he invited him in to perform experiments to see if it worked. And then by 1969, I guess Impimba is 19 years old by this point, they had written a paper on this phenomenon. And he was like, hey, buddy, we've got a name after you. Yeah, which I'm sure he was like, heck yeah. Well, let's take a break and we'll talk a little more about the Impemba effect itself. How about that? All right.

5:50New year, new goals, and in this economy, a better money plan is more necessary than ever. I am Matt. And I'm Joel. We are from the How to Money podcast, and every week we help you to spend smarter, save more, and make sense of what's going on out there. If you want 2026 to be the year you finally feel in control of your money, we're here to give you the tools and advice to help you make it happen. Listen to How to Money on the iHeartRadio app, Apple Podcasts, or wherever you get your podcasts. Hi, Kyle. Could you draw up a quick document with the basic business plan? Just one page as a Google Doc and send me the link.

6:24Thanks. Hey, just finished drawing up that quick one-page business plan for you. Here's the link. But there was no link. There was no business plan. It's not his fault. I hadn't programmed Kyle to be able to do that yet. My name is Evan Ratliff. I decided to create Kyle, my AI co-founder, after hearing a lot of stuff like this from OpenAI CEO Sam Altman. There's this betting pool for the first year that there's a one-person billion-dollar company, which would have been like unimaginable without AI and now will happen. I got to thinking, could I be that one person? I'd made AI agents before for my award-winning podcast, Shell Game.

6:59This season on Shell Game, I'm trying to build a real company with a real product run by fake people. Oh, hey, Evan. Good to have you join us. I found some really interesting data on adoption rates for AI agents in small to medium businesses. Listen to Shell Game on the iHeartRadio app or wherever you get your podcasts.

7:28Okay, Chuck. So the reason that the Impeba effect is so strange is because according to the laws of thermodynamics, molecules that are moving much faster than other molecules in, say, like a hot liquid and a cold liquid, they take longer to slow down. And part of the very process of slowing down, temperature, by the way, is a measurement of the excitement or movement of molecules and substance, right? Part of the process of slowing down is that it takes time. So it makes no sense intuitively, but also according to the laws of physics, that a hot liquid with faster moving molecules could get to the point of freezing faster than a cooler liquid with slower moving molecules because they're both trying to get to the point where they stop moving and are solid blocks of ice.

8:20Yeah, it would just make intuitive sense that something colder and closer to that temperature would do it faster. You can also observe this if you go out in, let's say you live in Minneapolis and it's January, and you go outside with a cup of warm water and throw it into the air. That will go into an icy mist instantaneously if it's cold enough. If you do that same thing with a glass of cold water, that won't happen. No. Yeah. Are you serious? Yeah. Are you pulling my leg? No, I mean, I saw a video of it, and that's what they say is another example. That's really great. I don't have first-hand experience because it doesn't get that cold here.

8:59Very cool, though. No, instead you can fry an egg on a sidewalk, am I right? Yeah, right. So I guess essentially a good analogy that I came up with, that's why I think it's good, is that Araso and Pemba basically found that there's a foot race between hot water and cold water. And that, well, I screwed up my analogy already, Chuck. Do you want to take it? I believe that there's a foot race, but one racer has started sooner, yet the one behind gets there quicker, even though they should supposedly be running at the same rate of speed. This happens at Braves games. Oh, and you know what? It's Mr.

9:41Freeze who they're racing. Isn't that funny? Oh, wow. So they're clearly fans of the Impeba effect. There's a track, clearly a track guy dressed up as Mr. Freeze, and they let a person from the stands, they bring him down in the outfield, and they give them a pretty long, like a quarter of the distance head start. And then Mr. Freeze starts, and you almost always lose. But a young woman the other day beat Mr. Freeze, and it's on YouTube. It's very cool to watch because you could tell that she knew what she was doing. Nice. because she was not running that hard until Mr. Freeze went. She was running at a decent clip, and then as soon as they hit the timer for Mr.

10:21Freeze to start, she kicked it into the next gear. Wow. And whipped him. It was great. That's awesome. I remember they used to have giant hammers and rulers and stuff sponsored by Home Depot Racing. They have multiple races at Braves games now? Yeah, they got Mr. Freeze, and they have the Home Depot hammer drill. I can't remember what the third one was. So silly. I got to go this year, man. Yeah, I've been to a few games. Well, let's go. They stink. Oh, really? Oh, yeah. The Braves are terrible this year. It's a very big disappointment. But, you know, what are you going to do? Poor Braves. So, yeah, that was a great analogy, Chuck.

11:02Way to go. Thanks. So it turns out that answering this weird problem has been trickier than you'd think. trickier than physicists thought because some physicists conducting experiments in the Impemba effect have shown, yep, this is definitely a thing. Other experimenters have not turned up any results and they're like, no, I don't know what you're talking about. And so the fact that it happens under some cases and not others is not only even weirder, it also suggests to dissenters, people are like, there's no such thing as the Impemba effect, that there's some variable that some experimenters aren't taking into effect.

11:39It could be different mineral contents in the water. It could be convection cells in the warmer water causing it to freeze faster. It could be that our freezers work harder on warmer air than cooler air, so it'll freeze faster in a freezer. They don't know, but they're like, there's no such thing as the Impeba effect. It's really just some mistaken variable in the experiments. Yeah, for sure. And there's also a long argument about this, about what freezing first actually means. Like you have to, if you're going to do something like this, you've got to agree what that, when you're technically freezing and who got there first.

12:15It's not like Mr. Freeze running across that finish line and hitting his chest to that tape. That's obvious. So you've got to agree on freeze first. Is that like, hey, is it the first one to reach 32 degrees Fahrenheit, zero degrees Celsius? If it starts to form ice crystals, if it's good enough to put in a cocktail without getting too watered down, And I'm going to let you take MIT's engineering school response because it was very actually, guys, and not at all helpful. It totally was. There was a blog post by them that basically said all liquids freeze at the same rate once they reach the freezing temperature.

12:51So no liquid can technically freeze faster than another. And you got the impression they really thought that they had solved the MPEMBA effect. Yeah, that's not what we're talking about, MIT. No, the rest of the world. No one is talking about that. No, the rest of the world is like, nope, we're talking about if you put a warm cup of water and a cool cup of water in a freezer at the same time, not what happens once they reach freezing. So even if you say, okay, we're going to talk about, like we're going to use as the milestone or the finish line, which of these things gets to 32 degrees Fahrenheit or zero degrees Celsius first, the freezing point.

13:28Yeah. There's still a big discrepancy in how you track this kind of stuff. Yeah. And different experimenters have been using essentially what you call like different stopwatches, even though they're not actually standing there with a stopwatch. And it wasn't until some researchers from Kyoto in 2025 basically figured out a measurement standard that any lab could use to test the Impemba effect. So now all of these experiments are going to be comparing apples to apples for results. And hopefully we'll get to the bottom of it. Yeah, for sure. Sure. This is the part that I think is the coolest, is that some researchers out there are like, hey, I guess in principle, I agree that we're not noticing some variable, but we feel like we've accounted for all the variables.

14:14And perhaps there might be some unknown variable that we haven't discovered yet. Yeah, like some force or effect in nature that's just undiscovered that we're seeing in the Impemba effect. Yeah, I'd love that to you. So you might say like, OK, aside from just science being curious and wanting to know the answers to everything, like what's the point in studying the Impenba effect? And I was very surprised to find that there's a lot of reasons to understand this, that just knowing how fluid dynamics or systems under fluid dynamics relax or cool, it would actually open up or overcome a huge hurdle that quantum computing is facing right now.

14:56they have to figure out how to get quibits, which are the quantum computing version of ones and zeros in traditional computers, back to their ground state as fast as possible. So if you can figure out how something like molecules stop moving faster than cool molecules, hot molecules, you might be able to apply that to quantum computing. And that would be a huge leap forward for it. Totally. Yeah. Because cooling those things down takes a lot of energy. And I want to do an episode about the AI's environmental cost at some point soon. Okay, sure. You could also develop new sensors, new materials, and at the base, you could also make better freezers and refrigerators, too.

15:40Yeah, for sure. As for Mpimba himself, he overcame a lot of obstacles to eventually have a nice long career as a game warden. And very sadly, just passed away a couple of years ago in 2023. But he's older, right? He has 73. That's not a bad life. But our scientific curiosity hat is off to you, sir. Yes. And that means short stuff is happening.

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16:21Hi, Kyle. Could you draw up a quick document with the basic business plan? Just one page as a Google Doc and send me the link. Thanks. Hey, just finished drawing up that quick one page business plan for you. Here's the link. But there was no link. There was no business plan. I hadn't programmed Kyle to be able to do that yet. I'm Evan Ratliff here with a story of entrepreneurship in the AI age. Listen as I attempt to build a real startup run by fake people. Check out the second season of my podcast, Shell Game, on the iHeartRadio app or wherever you get your podcasts. This is an iHeart Podcast.

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