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Short Stuff: The Mpemba Effect · Stuff You Should Know

• 0:04
  Speaker 1: Hey, and welcome to the short stuff. Josh here, chuck here,
• 0:06
  Speaker 1: giddy up.
• 0:08
  Speaker 2: Yeah, we're going to tell you in part about a
• 0:11
  Speaker 2: remarkable young teenager in Tanzania in the nineteen sixties, and
• 0:15
  Speaker 2: his name was Rasto im Pimba.
• 0:18
  Speaker 1: Is it Impemba, It's in Pimpa, Okay. The reason why
• 0:24
  Speaker 1: we're talking about Rasto and Pemba today is because he
• 0:27
  Speaker 1: was a pretty remarkable kid. He stumbled upon I guess
• 0:31
  Speaker 1: you could say rediscovered a concept that just baffles physicists
• 0:37
  Speaker 1: today because it doesn't make any sense, it may violate
• 0:41
  Speaker 1: the second law of thermodynamics. And it ended up being
• 0:45
  Speaker 1: named after him because he was a persistent little cuss
• 0:48
  Speaker 1: who made this observation and just kept going until he
• 0:51
  Speaker 1: finally got the ear of somebody who could help him
• 0:54
  Speaker 1: try to figure it out.
• 0:55
  Speaker 2: You know, the first law of thermodynamics is you don't
• 0:58
  Speaker 2: talk about thermo dynamics.
• 1:00
  Speaker 1: I was thinking about that movie the other day. I
• 1:02
  Speaker 1: was like, I used to be so into that, and
• 1:04
  Speaker 1: now I'm so juvenile.
• 1:06
  Speaker 3: I know.
• 1:06
  Speaker 2: I almost put it on the other day as a
• 1:09
  Speaker 2: laundry folding movie, which I like to do just to
• 1:12
  Speaker 2: see parts of And I.
• 1:16
  Speaker 3: Had the same thought. I was like, I don't know
• 1:17
  Speaker 3: if I just even want to go down that road again.
• 1:19
  Speaker 1: Yeah, because it exists happily in the past, you know
• 1:22
  Speaker 1: what I mean exactly? I heard at the premiere Brad
• 1:25
  Speaker 1: Pitt leaned over to Edward Norton and said, I'll never
• 1:27
  Speaker 1: be in a movie this cool again, And he was right.
• 1:32
  Speaker 1: I think he was. So. Yeah, we're talking about Arresto
• 1:36
  Speaker 1: and Pemba because he discovered what's called the Mpemba effect
• 1:40
  Speaker 1: after him, and I think I said earlier that he
• 1:42
  Speaker 1: rediscovered it. It was first noticed by Aristotle, or at
• 1:46
  Speaker 1: least it was first written about all the way back
• 1:48
  Speaker 1: to Aristotle. Medieval scientist Roger Bacon mentioned it as well,
• 1:53
  Speaker 1: so did the Enlightenment philosopher Renee des Cartes. And what
• 1:57
  Speaker 1: they all noticed and what Erastom and Pemba got his
• 2:00
  Speaker 1: his name attached to, is that hot liquids placed in
• 2:05
  Speaker 1: a freezer can freeze faster than cool liquids placed in
• 2:11
  Speaker 1: the same freezer at the same time. It makes no
• 2:14
  Speaker 1: sense whatsoever.
• 2:15
  Speaker 2: Yeah, he discovered this as a thirteen year old. He
• 2:18
  Speaker 2: was in class in Tanzania and they were making in
• 2:21
  Speaker 2: school and they were making ice cream as a class.
• 2:24
  Speaker 2: I don't know if that was for fun or if
• 2:25
  Speaker 2: it was part of science. I like to think it's
• 2:27
  Speaker 2: part of science. But regardless, he you know, they added
• 2:31
  Speaker 2: sugar to the boiling fresh milk. You let it cool,
• 2:34
  Speaker 2: you put it in a container, you put it in
• 2:36
  Speaker 2: the freezer. They were doing this again another day. I
• 2:38
  Speaker 2: bet they just like it ice cream now, then I
• 2:40
  Speaker 2: think about it. Sure, he was like, Hey, the freezer
• 2:44
  Speaker 2: space is getting low, and I want to make my
• 2:46
  Speaker 2: special ice cream. So he's like, I'm not going to
• 2:48
  Speaker 2: let this stuff cool down. I'm just going to go
• 2:49
  Speaker 2: grab that spot while it's available. And an hour and
• 2:53
  Speaker 2: a half later he was like, hey, everybody, my ice
• 2:57
  Speaker 2: cream is ready before yours.
• 2:58
  Speaker 3: In your face.
• 3:00
  Speaker 1: Yeah, and he said, but that doesn't make any sense
• 3:02
  Speaker 1: because I put that hot milk in, so why would
• 3:05
  Speaker 1: mine have frozen at all? And he went to his teacher,
• 3:09
  Speaker 1: and his teacher said, I got too much to deal with,
• 3:12
  Speaker 1: so you run along, Rasto.
• 3:14
  Speaker 3: Yeah, I'm not curious like you.
• 3:16
  Speaker 1: No, and Erasto was undeterred over the years. Teacher after
• 3:19
  Speaker 1: teacher as he made his way through middle school and
• 3:22
  Speaker 1: the high school, he would talk to them about this
• 3:25
  Speaker 1: discovery and he was dismissed by all of them. And
• 3:28
  Speaker 1: then finally, one day at his high school, a physicist
• 3:31
  Speaker 1: who was a visiting physicist to the University of Darus Salam.
• 3:35
  Speaker 1: He was a British guy named Dennis Osborne. He came
• 3:39
  Speaker 1: to give a lecture and Rasto and Pemba saw his
• 3:42
  Speaker 1: chance and said, Professor Osborne, I've got something that may
• 3:46
  Speaker 1: knock your socks off. Check this out, do.
• 3:49
  Speaker 2: You think In the teacher's lounge over the years, everyone
• 3:51
  Speaker 2: was like, hey, has and Pimba hit.
• 3:54
  Speaker 3: You up about this ice cream business.
• 3:57
  Speaker 2: Yes.
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  Speaker 1: Yeah, they're all drinking wine and rolling, so annoying.
• 4:00
  Speaker 3: All the scientific curiosity out of this kid.
• 4:03
  Speaker 1: I know. Luckily, Dennis Osbourne was like, ooh, I like that.
• 4:07
  Speaker 1: Let's talk a little more about it.
• 4:09
  Speaker 2: He likes this kid, and they he invited him in
• 4:12
  Speaker 2: to you know, to perform experiments to see if it worked.
• 4:15
  Speaker 2: And then by nineteen sixty nine, I guess Impemba is
• 4:19
  Speaker 2: nineteen years old. By this point, they had written a
• 4:21
  Speaker 2: paper on this phenomenon and he was like, hey, buddy,
• 4:24
  Speaker 2: we got a name after you.
• 4:26
  Speaker 1: Yeah, which I'm sure he was like, heckynah, let's take
• 4:29
  Speaker 1: a break and we'll talk a little more about the
• 4:31
  Speaker 1: Impemba effect itself. How about that, right, Okay, Chuck. So,
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  Speaker 1: the reason that the Mpemba effect is so strange is because,
• 4:58
  Speaker 1: according to the laws of thermae dynamics, molecules that are
• 5:03
  Speaker 1: moving much faster than other molecules in say, like a
• 5:07
  Speaker 1: hot liquid and a cold liquid, they take longer to
• 5:11
  Speaker 1: slow down. And part of the very process of slowing
• 5:15
  Speaker 1: down temperature, by the way, as a measurement of the
• 5:17
  Speaker 1: excitement or movement of molecules in a substance, right, part
• 5:21
  Speaker 1: of the process of slowing down is that it takes time.
• 5:25
  Speaker 1: So it makes no sense intuitively, but also according to
• 5:28
  Speaker 1: the laws of physics that a hot liquid with faster
• 5:32
  Speaker 1: moving molecules could get to the point of freezing faster
• 5:36
  Speaker 1: than a cooler liquid with slower moving molecules, because they're
• 5:39
  Speaker 1: both trying to get to the point where they stop
• 5:42
  Speaker 1: moving in are solid blocks of ice.
• 5:45
  Speaker 2: Yeah, it would just make intuitive sense that something colder
• 5:48
  Speaker 2: and closer to that temperature would do it faster. You
• 5:52
  Speaker 2: can also observe this if you go out in Let's
• 5:55
  Speaker 2: say you live in Minneapolis and it's January. You go
• 6:00
  Speaker 2: outside with a cup of warm water and throw it
• 6:03
  Speaker 2: into the air. That will go into an icy mist
• 6:06
  Speaker 2: instantaneously if it's cold enough. If you do that same
• 6:09
  Speaker 2: thing with a glass of cold water, that won't happen.
• 6:12
  Speaker 1: No, yeah, are you serious?
• 6:14
  Speaker 3: Yeah?
• 6:15
  Speaker 1: Are you pulling my leg?
• 6:16
  Speaker 3: No?
• 6:16
  Speaker 2: I mean that's I saw a video of it, and
• 6:19
  Speaker 2: that's what they say. Is another example that's really great.
• 6:21
  Speaker 3: I don't have first hand experience because it doesn't get
• 6:23
  Speaker 3: that cold here.
• 6:24
  Speaker 1: Very cool though.
• 6:26
  Speaker 3: No.
• 6:26
  Speaker 1: Instead, you can fry an egg on a sidewalk, am
• 6:28
  Speaker 1: I right? Yeah?
• 6:29
  Speaker 3: Right?
• 6:30
  Speaker 1: So I guess essentially a good analogy that I came
• 6:33
  Speaker 1: up with, That's why I think it's good is that
• 6:35
  Speaker 1: Erasso and Pemba basically found that there's a foot race
• 6:40
  Speaker 1: between like hot water and cold water, and that, well,
• 6:45
  Speaker 1: I screwed up my analogy already, Chuck, do you want
• 6:48
  Speaker 1: to take it?
• 6:49
  Speaker 2: I believe that there's a foot race, but one racer
• 6:52
  Speaker 2: has started sooner, yet the one behind gets there quicker,
• 6:57
  Speaker 2: even though they should supposedly be running at the same
• 6:59
  Speaker 2: rate of speed. This happens at braves games. Oh and
• 7:04
  Speaker 2: you know what, it's mister Freeze who they're racing.
• 7:07
  Speaker 3: Isn't that funny?
• 7:07
  Speaker 1: Oh wow. So they're clearly fans of the Mpemba effect.
• 7:10
  Speaker 2: There's a track, clearly a track guy dressed up as
• 7:14
  Speaker 2: mister Freeze and they let a person from the stands.
• 7:17
  Speaker 2: They bring him down in the outfield and they they
• 7:20
  Speaker 2: give them a pretty long, like a quarter of the
• 7:22
  Speaker 2: distance head start, and then mister Freeze starts and you
• 7:26
  Speaker 2: almost always lose. But a young woman the other day
• 7:30
  Speaker 2: beat mister Freeze and it was it's on YouTube. It's
• 7:34
  Speaker 2: very cool to watch because you could tell that she
• 7:36
  Speaker 2: knew what she was doing.
• 7:37
  Speaker 3: Nice because she was.
• 7:39
  Speaker 2: Not running that hard until mister Freeze went. She was
• 7:42
  Speaker 2: running at a decent clip. And then as soon as
• 7:44
  Speaker 2: they hit the timer for mister Freeze to start, she kicked.
• 7:47
  Speaker 3: It into the next gear wow and whipped him. It
• 7:51
  Speaker 3: was great.
• 7:51
  Speaker 1: That's awesome. I remember they used to have giant hammers
• 7:55
  Speaker 1: and rulers and stuff. Oh they started on depot racing. Yeah,
• 7:59
  Speaker 1: they have multiple whole races at Home Braves Games. Now.
• 8:02
  Speaker 2: Yeah, they got mister Freeze and they have the home
• 8:05
  Speaker 2: Depot hammer drill.
• 8:07
  Speaker 3: I can't remember what the third.
• 8:08
  Speaker 1: One was, so silly. I gotta go this year man.
• 8:12
  Speaker 3: Yeah, I've been to a few games. Well, let's go
• 8:15
  Speaker 3: they stink?
• 8:18
  Speaker 1: Oh really?
• 8:18
  Speaker 3: Oh yeah, the braves are terrible this year. It's very
• 8:21
  Speaker 3: big disappointment. But you know, what are you gonna do?
• 8:24
  Speaker 1: Or braves? So yeah, that was a great analogy, Chuck,
• 8:27
  Speaker 1: way to go.
• 8:28
  Speaker 3: Thanks.
• 8:29
  Speaker 1: So it turns out that answering this weird problem has
• 8:33
  Speaker 1: been trickier than you'd think, Trickier than physicists thought. Yeah,
• 8:36
  Speaker 1: because some physicists conducting experiments and the Mpemba effect have
• 8:40
  Speaker 1: shown yep, this is definitely a thing. Other experimenters have
• 8:44
  Speaker 1: not turned up any results, and they're like, no, I
• 8:46
  Speaker 1: don't know what you're talking about. And so the fact
• 8:49
  Speaker 1: that it happens under some cases and not others is
• 8:52
  Speaker 1: not only even weirder, it also suggests to dissenters. People
• 8:57
  Speaker 1: are like, there's no such thing as the Impemba effect. Yeah,
• 8:59
  Speaker 1: but there's some variable that some experimenters aren't taking into effect.
• 9:04
  Speaker 1: It could be different mineral contents in the water. It
• 9:08
  Speaker 1: could be convection cells in the warmer water are causing
• 9:11
  Speaker 1: it to freeze faster. It could be that our freezers
• 9:14
  Speaker 1: work harder on warmer air than cooler air, so it'll
• 9:17
  Speaker 1: freeze faster in a freezer. They don't know, but they're like,
• 9:20
  Speaker 1: there's no such thing as the Impemba effect. It's really
• 9:22
  Speaker 1: just some mistaken variable in the experiments.
• 9:27
  Speaker 3: Yeah, for sure.
• 9:28
  Speaker 2: And there's also a long argument about this about what
• 9:30
  Speaker 2: freezing first actually means, Like you have to if you're
• 9:33
  Speaker 2: gonna do something like this, you got to agree what
• 9:34
  Speaker 2: that when you're technically freezing and who got there first.
• 9:40
  Speaker 2: It's not like mister Freeze running across that finish line
• 9:42
  Speaker 2: and hitting his chest to that tape.
• 9:44
  Speaker 3: No, that's obvious. So you got to agree on freeze first?
• 9:48
  Speaker 2: Is that? Like, hey, is it the first one to
• 9:50
  Speaker 2: reach thirty two degrees fahrenheit zero degree celsius if it
• 9:54
  Speaker 2: starts to form ice crystals, if it's good enough to
• 9:57
  Speaker 2: put in a cocktail without getting too water down. And
• 10:00
  Speaker 2: I'm gonna let you take MIT's engineering school response because
• 10:04
  Speaker 2: it was very actually, guys, and not at all helpful.
• 10:08
  Speaker 1: It totally was. There was a blog post by them
• 10:10
  Speaker 1: that basically said, all liquids freeze at the same rate
• 10:14
  Speaker 1: once they reach the freezing temperature, so no liquid can
• 10:17
  Speaker 1: technically freeze faster than another. And you got the impression
• 10:21
  Speaker 1: they really thought that they had solved the Impemba effect.
• 10:24
  Speaker 3: Yeah, that's not what we're talking about. Mit, No, the
• 10:27
  Speaker 3: one is talking about that.
• 10:28
  Speaker 1: No, the rest of the world is like, Nope, we're
• 10:30
  Speaker 1: talking about if you put a warm cup of water
• 10:32
  Speaker 1: and a cool cup of water in a freezer at
• 10:34
  Speaker 1: the same time, not once, what happens once they reach freezing.
• 10:40
  Speaker 1: So if you even if you say, okay, we're going
• 10:43
  Speaker 1: to talk about, like we're going to use as the
• 10:45
  Speaker 1: milestone or the finish line, which of these things gets
• 10:48
  Speaker 1: to thirty two years farentheight or zero degrees celsius first
• 10:52
  Speaker 1: the freezing point. Yeah, there's still a big discrepancy in
• 10:57
  Speaker 1: how you track this kind of stuff. Yeah, and different
• 11:01
  Speaker 1: experimenters have been using essentially what you call like different stopwatches,
• 11:04
  Speaker 1: even though they're not actually standing there with a stopwatch.
• 11:06
  Speaker 1: And it wasn't until some researchers from Kyoto in twenty
• 11:10
  Speaker 1: twenty five basically figured out a measurement standard that any
• 11:14
  Speaker 1: lab could use to test the Mpemba effect. So now
• 11:18
  Speaker 1: all of these experiments are going to be comparing apples
• 11:21
  Speaker 1: to apples for results and hopefully we'll get to the
• 11:23
  Speaker 1: bottom of it.
• 11:24
  Speaker 2: Yeah, for sure, this is the part that I think
• 11:26
  Speaker 2: is the coolest is that some researchers out there are like, hey,
• 11:31
  Speaker 2: I guess in principle, I agree that we're not noticing
• 11:35
  Speaker 2: some variable, but we feel like we've accounted for all
• 11:38
  Speaker 2: the variables and perhaps there might be some unknown variable
• 11:43
  Speaker 2: that we haven't discovered yet.
• 11:44
  Speaker 1: Yeah, like some force or effect in nature that's just
• 11:48
  Speaker 1: undiscovered that we're seeing in the Mpemba effect. Yeah, I'd
• 11:51
  Speaker 1: love that to you. So you might say, like, Okay,
• 11:53
  Speaker 1: aside from just science being curious and wanting to know
• 11:57
  Speaker 1: the answers to everything, like what's the point in studying
• 11:59
  Speaker 1: the by effect? And I was very surprised to find
• 12:02
  Speaker 1: that there's a lot of reasons to understand this that
• 12:05
  Speaker 1: just knowing how fluid dynamics or systems under fluid dynamics
• 12:11
  Speaker 1: relax or cool it would actually open up or overcome
• 12:17
  Speaker 1: a huge hurdle that quantum computing is facing right now.
• 12:21
  Speaker 1: They have to figure out how to get quibits, which
• 12:23
  Speaker 1: are the quantum computing version of ones and zeros and
• 12:26
  Speaker 1: traditional computers back to their ground state as fast as possible.
• 12:30
  Speaker 1: So if you can figure out how something like molecules
• 12:34
  Speaker 1: stop moving faster than cool molecules, hot molecules. You might
• 12:38
  Speaker 1: be able to apply that to quantum computing, and that
• 12:40
  Speaker 1: would be a huge leap.
• 12:41
  Speaker 2: Forward for it, totally, Yeah, because cooling those things down
• 12:46
  Speaker 2: takes a lot of energy, and I want to do
• 12:48
  Speaker 2: an episode about the AI's environmental cost at some point soon.
• 12:53
  Speaker 1: Okay, Sure, you could also develop new sensors, new materials,
• 12:58
  Speaker 1: and at the base you could also make better freezers
• 13:03
  Speaker 1: and refrigerators.
• 13:04
  Speaker 3: Too, Yeah, for sure.
• 13:06
  Speaker 2: As for Impimba himself, he overcame a lot of obstacles
• 13:09
  Speaker 2: to eventually have a nice long career as a game warden,
• 13:12
  Speaker 2: and very sadly just passed away a couple of years
• 13:15
  Speaker 2: ago in twenty twenty three.
• 13:16
  Speaker 1: But he was older, right, twenty Yes, seventy three.
• 13:19
  Speaker 3: That's not yeah, and it's not a bad life. But
• 13:22
  Speaker 3: our scientific curiosity had his off to you.
• 13:25
  Speaker 1: Sir, Yes, And that means short stuff is appen.
• 13:31
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