Short Stuff: The Mpemba Effect | STUFF YOU SHOULD KNOW

[Music]. Hey and welcome to the short stuff. Josh. here, Chuck here. Giddy up. >> Yeah. We're going to tell you uh in part. about a remarkable young teenager in. Tanzania in the 1960s and his name was. Arasto Impa. >> Is it Impa? >> It's Impa. >> Okay. The reason why we're talking about. Arasto Impa 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 um it ended up being. named after him because he was a. persistent little cuss who made this. observation and and just kept going. until he finally got the ear of somebody. who could help him try to figure it out. You know, the first law of. thermodynamics is you don't talk about. thermodynamics. >> Very nice. I was thinking about that.

movie the other day. I was like, I used. to be so into that and now so juvenile. >> I know. I almost put it on the other day. as a as a laundry folding uh movie, which I like to do uh 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. Because it exists happily in in. the past. You know what I mean? >> Yeah. Exactly. I heard at the premiere. um Brad Pitt leaned over to Edward. Norton and said, "I'll never be in a. movie this cool again.".

>> And he was right. >> I think he was. >> So, uh yeah, we're talking about Arasto. Impa because he discovered um the what's. called the Empa effect after him. And I. think I said earlier that he. rediscovered it. Um it was first noticed. by Aristotle or at least it was first. written about all the way back to. Aristotle. Um medieval scientist Roger. Bacon mentioned it as well. So did um. the enlightenment philosopher Renee. Deart. And what they all noticed and. what Arasto and Pembbea got his um 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. >> Yeah. He discovered this as a. 13-year-old. Uh he was in in class in. Tanzania and they were making in school. and they were making ice cream as a. class. Uh I don't know if that was for. fun or if it was part of science. I'd. like to think it was part of science, but uh regardless he um 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 liked ice cream now that. I think about it. >> Sure. >> Uh 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. I'm just going to go grab that spot. while it's available.". >> And an hour and a half later, he was. like, "Hey everybody, uh, 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. Uh, and his teacher said, "I got too much to. deal with, so you just run along, Arasto.". >> Yeah. I'm not curious like you. No. And. Araso was undeterred over the years, teacher after teacher as he made his way. through middle school and then high. school. Um he would talk to them about. this discovery and he was dismissed by. all of them. And then finally one day at. his high school a physicist uh who was a.

visiting physicist to the University of. Dar Salam, he was a British guy named. Dennis Osborne. Uh he came to give a. lecture and Eras and Pembbea saw his. chance and said, "Um, Professor Osborne, I've got something that may knock your. socks off. Check this out.". >> Do you think in the teachers lounge over. the years, everyone was like, "Hey, has. has uh Impa hit you up about this ice. cream business.". >> Yes. They're all drinking wine and. rolling. >> So annoying. So annoying. All the.

scientific curiosity out of this kid. >> I know. Luckily, Dennis Osborne was. like, "Oo, I like that. Let's talk a. little more about it. >> He likes this kid and they uh he invited. him in to to you know to perform. experiments to see if it worked. >> and then by 1969 I guess Impa is 19. years old by this point. They had. written a paper on this phenomenon and. he was like hey buddy we 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 impea. effect itself. How about that? >> All right. I'm coming. [Music]. Okay, Chuck. So what the reason that the. Empa effect is so strange is because. according to the laws of thermodynamics.

um molecules that are moving much faster. um 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 in a 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. Yeah, it would just. make intuitive sense that something. colder and closer to that temperature. would do it faster. >> Uh you can also observe this if you go. out and 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 that. will go into an icy mist instantaneously. if it's cold enough. Uh 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 that's I saw a video of it. and that's what they say is another. example. >> That's really great. >> I don't have firsthand experience. because it doesn't get that cold here. >> Very cool though. Uh 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 Pembbea. basically found that there's a foot race. between um like hot water and cold water. and that uh well, I screwed up my. analogy already. Chuck, do you want to. take it? >> Uh I believe that there's a foot race, but one racer has started sooner, yet. the one behind gets there quicker. >> Mhm. 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. Freeze. who they're racing. Isn't that funny? >> Oh, wow. So, they're clearly fans of the. Impemba effect. >> There's a track uh clearly a track guy. dressed up as Mr. Freeze. >> and they let a a person from the stands, they bring him down in the outfield and. they they give them a a pretty long like. a quarter of the distance head start. >> And then Mr. freeze starts and you. almost always lose, but a uh a young. woman the other day beat Mr. Freeze and.

it was it's on YouTube. It's very cool. to watch because you could tell that she. knew what she was doing. >> Nice. >> Uh 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. Freeze 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. stuffed by Home Depot racing. They have. multiple races at home at um Braves.

games now. >> Yeah, they got Mr. Freeze and they have. the the Home Depot hammer drill. Uh 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 been following. >> very big disappointment, but you know. what are you going to do? >> Poor brace. Um, so yeah, that was a. great analogy, Chuck. Way to go. >> Thanks. >> So, it turns out that answering that.

this weird problem has been trickier. than you'd think, trickier than. physicists thought because some. physicists conducting experiments and. the impa 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 to dissenters people are. like there's no such thing as the Impa. effect, but there's some variable that.

some experimenters aren't taking into. effect. It could be different mineral. contents in the water. >> It could be convection cells in the. warmer water are 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 impa. effect. It's really just some uh. mistaken variable in in the experiments. >> Yeah, for sure. Uh and there's also an. argument about this about what freezing.

first actually means. Like you have to. if you're going to do something like. this, you got to agree what that when. you're technically freezing and and who. got there first. Um it's not like Mr. freeze running across that finish line. and hitting his chest to that tape. >> No, >> that's obvious. So, you got to agree on. freeze first. >> Uh, is that like, hey, is it the first. one to reach 32 degrees Fahrenheit, 0. degrees Celsius? Uh, if it starts to. form ice ice crystals, if it's good. enough to put in a cocktail without. getting too watered down. Uh, and I'm.

going to let you take MIT's engineering. school response because it was very uh, actually, guys, and not at all helpful. >> It totally was. There was a blog post by. them that basically said um all liquids. freeze at the same rate once they reach. the freezing temperature. So no liquid. can technically freeze faster than. another. And you got the impression they. really thought that they had solved the. Impa effect. >> Yeah, that's not what we're talking. about MIT. >> No, the rest. >> 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 once. what happens once they reach freezing. So if you 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 0° C first the freezing. point. >> Yeah. >> Um there's still a big discrepancy in. how you track this kind of stuff. Yeah.

>> Um 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 a measurement standard. that any lab could use to test the Impa. 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. Uh this is the part that. I think is the coolest is that some. researchers out there uh 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 and 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 Impa effect. Yeah, I'd love that, too. So you might say. like okay aside from just science being. curious and wanting to know the answers. to everything like what's the point in. studying the impa effect and I was very.

surprised to find that there's a lot of. reasons to understand this that just. knowing how fluid dynamics uh or systems. under fluid dynamics um relax or cool. >> um it it would actually open up or. overcome a huge hurdle that um quantum. computing is facing right now. They have. to figure out how to get quibbits, 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, um you might be able to apply. that to quantum computing and that would. be a huge leap forward for it. >> Totally. Uh yeah, because cooling those. things down takes a lot of energy. And I. want to do a episode about uh the the. AI's uh environmental cost at some point. soon. >> Okay. Sure. Uh you could also develop. new sensors, new materials, and at the. base, you could also um make better.

freezers and refrigerators, too. >> Yeah, for sure. Uh as for Empa himself, uh he overcame a lot of obstacles to. eventually have a nice long career as a. game warden. >> and uh very sadly just passed away a. couple years ago in 2023. Yeah, but he. was older, right? Uh 20. Yes. 73. That's. not I guess. >> Not a bad life. But uh our our. scientific curiosity hat is off to you, sir. >> Yes. And that means short stuff is out.

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