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Speaker 1: Hey, Daniel, do your kids ask you a lot of

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Speaker 1: physics questions?

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Speaker 2: Mmm?

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Speaker 3: Sometimes, but actually they're mostly interested in other stuff, like

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Speaker 3: horses or chemistry.

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Speaker 1: Whoa, it sounds like they're doing experiments on horses.

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Speaker 3: Not chemical experiments, fortunately.

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Speaker 1: Just the romantic chemistry kind between horses.

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Speaker 3: No comment.

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Speaker 1: Well, do there questions ever give you good ideas like

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Speaker 1: for your science?

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Speaker 3: Not yet, but I'm waiting for the day they inspire

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Speaker 3: some new physics ideas in me.

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Speaker 1: Would you give them credit or did you just say

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Speaker 1: called the whites in theory? Then it can apply to both.

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Speaker 3: No, of course I'd give them credit. I'd love to

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Speaker 3: have a paper with my kids.

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Speaker 1: Whitesin and whiteson doubule whites in.

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Speaker 3: Yeah, though I guess we might have an argument about

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Speaker 3: whose first author ooh.

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Speaker 1: Or whose last author? What are your kids? Window? Don't

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Speaker 1: kids always when.

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Speaker 3: I always put them first, even on author lists.

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Speaker 1: There you go.

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Speaker 4: Hi.

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Speaker 1: I'm hoora ma cartoonists and the author of Oliver's Great

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Speaker 1: Big Universe.

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Speaker 3: Hi, I'm Daniel. I'm a particle physicist and a professor

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Speaker 3: at uc R Vine, and I love answering kids' questions.

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Speaker 1: But do kids love the answers? Though that's always the question.

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Speaker 3: As long as I can keep them brief, they're pretty

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Speaker 3: happy to hear them.

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Speaker 1: Doesn't it depend on the kind of question, like, Hey, Dick,

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Speaker 1: can I play more Vita games?

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Speaker 2: No?

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Speaker 1: Can I play more Vida games? No? At some point,

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Speaker 1: I don't think you enjoyed those questions, do you.

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Speaker 3: That's not the kind of question I mean. I mean

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Speaker 3: when they're trying to understand something, when you can see

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Speaker 3: their brains have chewed on something and it doesn't quite

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Speaker 3: fit together and they want to know what the resolution is.

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Speaker 1: Do they ever regret asking questions like I have a question,

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Speaker 1: I'm curious, but oh wait, I forgot I'm going to

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Speaker 1: get a lecture from a physics professor.

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Speaker 3: Anything longer than like thirty seconds. And you can see

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Speaker 3: them start to tune me out.

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Speaker 1: You can see them start to think, maybe I should

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Speaker 1: have asked Wikipedia instead, not that Apedia.

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Speaker 3: Exactly. But hey, that trains me to keep my answers brief.

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Speaker 1: Oh there you go, to get it down to yes,

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Speaker 1: no answers.

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Speaker 3: What is quantum gravity? Yes?

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Speaker 1: Yes and no. There you go. It's about true and false.

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Speaker 1: Do they ever ask you questions about the like everyday

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Speaker 1: life that you can't answer.

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Speaker 3: Yeah, I mean they asked me questions about how to

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Speaker 3: navigate tricky situations, and sometimes there isn't the perfect answer.

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Speaker 1: No, I mean like everyday phenomenon that happens to them

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Speaker 1: about physics.

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Speaker 3: Yeah, all the time. There's lots of things in kids'

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Speaker 3: lives that they don't understand. Why a rainbow follows them around,

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Speaker 3: or why you can smell the rain before it comes.

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Speaker 3: All sorts of things inspire questions.

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Speaker 1: And what if you don't know the answer, or what

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Speaker 1: if there isn't an answer?

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Speaker 3: Those are my favorite because then I get to show

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Speaker 3: them how little we understand about the universe and how

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Speaker 3: close they are to the forefront of knowledge.

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Speaker 1: What if there is an answer but you don't know it,

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Speaker 1: you have to take a little Wikipeda break.

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Speaker 3: Yeah, then we try to figure it out together exactly,

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Speaker 3: and I show them how to find their own answers.

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Speaker 1: Oh, well, there you go, how to google together in

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Speaker 1: case they don't know how to do it already.

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Speaker 3: A crucial skill in today's world.

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Speaker 1: But it is interesting how sometimes there are still mysteries

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Speaker 1: that you find even in our everyday lives, right in

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Speaker 1: small effects that it kind of surprises you. The scientists

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Speaker 1: don't know the answer to.

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Speaker 3: Yeah, a lot of people have the impression that we've

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Speaker 3: mostly figured out the universe, that your everyday experience is

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Speaker 3: totally cracked and it's just like tiny little questions like

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Speaker 3: what's inside a black hole or what's dark matter made

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Speaker 3: out of the physicists are struggling over. But there's a

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Speaker 3: lot of things in your everyday experience that are still

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Speaker 3: pretty tricky.

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Speaker 5: Yeah.

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Speaker 1: I remember we had the podcast episode about ice skates, right,

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Speaker 1: isn't that a big mystery still how ice skates work?

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Speaker 3: Yeah, ice skates and bicycles and all sorts of stuff.

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Speaker 1: And sometimes we like to tackle these questions on our

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Speaker 1: podcast to hopefully demystify or at least explain the mystery

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Speaker 1: to people.

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Speaker 3: And some of the questions that scientists are still struggling

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Speaker 3: over we're inspired by actual children, teenagers.

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Speaker 1: Even so, today on the podcast, we'll be asking the

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Speaker 1: question does hot or cold water freeze faster? This seems

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Speaker 1: a bit a left field for our podcast, why because

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Speaker 1: it's chemistry kind of or it doesn't involve some distant

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Speaker 1: planet or some crazy microscopic effect.

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Speaker 3: Well, there are crazy microscopic effects here, and it is

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Speaker 3: really fascinating, But in the end, this is what physics

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Speaker 3: is about, is explaining our everyday world, what we can

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Speaker 3: see in the sky, but also what we see under

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Speaker 3: our feet. And it's a huge challenge to bring it

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Speaker 3: up from microscopic particles to explaining the fabric of our reality.

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Speaker 3: So sometimes I'd like to show how difficult it is

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Speaker 3: to really bridge that gap.

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Speaker 1: To explain it all here, even the things inside of

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Speaker 1: your fridge which may seem inexplicable and mysterious.

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Speaker 3: And this particular story really was inspired by an experiment

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Speaker 3: done by a Tanzanian teenager who wrote the first paper

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Speaker 3: on the topic.

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Speaker 1: Now, this is an interesting question. Does hot or cold

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Speaker 1: water freeze faster? Because I guess, at first glance, it

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Speaker 1: seems kind of obvious that the colder water is going

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Speaker 1: to freeze faster if you put them in a freezer.

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Speaker 3: Exactly, But it turns out the universe is not so simple,

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Speaker 3: or your freezer is not that simple. Your freezer is

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Speaker 3: part of the universe.

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Speaker 1: So yeah, although sometimes it seems like it's from another dimension.

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Speaker 1: If you look inside my freezer, there's things going in

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Speaker 1: there that have a supernatural color to them.

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Speaker 3: I think my freezer might have additional dimensions because I

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Speaker 3: keep putting ice cream in there and then it's gone.

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Speaker 1: Oh wow, yeah, it goes into a black hole maybe

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Speaker 1: called your stomach or my teenager. But anyways, welcome to

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Speaker 1: our podcast, Daniel and Jorge Explain the Universe, a production

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Speaker 1: of iHeartRadio.

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Speaker 3: In which we tackle mysteries big and small, all hot

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Speaker 3: and cold, weird and.

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Speaker 1: Wacky mysteries that you encounter every day, and mysteries that

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Speaker 1: sometimes nobody may ever encounter. We cover the whole range.

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Speaker 1: But anyways, this is kind of a seemingly simple question,

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Speaker 1: and we were wondering how many people out there had

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Speaker 1: thought about this and whether they know whether the answer

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Speaker 1: is yes or no.

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Speaker 3: Thanks very much to everybody who answers these questions. We

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Speaker 3: love this audience participation segment and we'd love to hear

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Speaker 3: your voice as part of the chorus. So please write

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Speaker 3: to me two questions at Danielanhorge dot com and I'll

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Speaker 3: set you up.

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Speaker 1: So think about it for a second. Which one do

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Speaker 1: you think freezes faster? Hot or cold water. Here's what

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Speaker 1: people have to say.

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Speaker 4: I've heard that hot water phrases faster. I'm not sure why. Possibly,

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Speaker 4: I think maybe the atoms have more speed and are

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Speaker 4: more active, so maybe they lose their heaked a little

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Speaker 4: bit quicker than colder water.

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Speaker 3: So hot water definitely freezes faster.

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Speaker 6: And I know this because in Colorado you can take

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Speaker 6: boiling water and throw it in the air on a

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Speaker 6: really cold day and it turns into freezy dusts really fast.

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Speaker 2: Well, I would imagine cold water freeze faster because freezing

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Speaker 2: is the process of slowing down your molecules to the

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Speaker 2: point where they would be measured cynthigrade. So hot water

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Speaker 2: a lot more energy than the molecules they are moving

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Speaker 2: a lot quicker, so more energy needs to be applied

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Speaker 2: over a longer duration to slow those molecules down. However,

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Speaker 2: I suspect the correct answer is probably hot because it's

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Speaker 2: the less obvious one.

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Speaker 5: It's funny because I've seen so many science shows demonstrate this,

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Speaker 5: and I clearly remember that hot water freezes faster, but

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Speaker 5: I do not remember exactly why. I think it's because

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Speaker 5: there's more energy in hot water to facilitate the phase transition,

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Speaker 5: but that's just my guess.

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Speaker 7: Well, I believe it's hot water, but I don't really

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Speaker 7: know why, other than it's always been a wives tale

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Speaker 7: of sorts. Maybe because of hot water is as more pressure,

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Speaker 7: and I know pressure is a big part of phase

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Speaker 7: changes as much as temperature.

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Speaker 8: Well, logic would say cold water freeze faster because it's

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Speaker 8: already closer to the freezing point. But you wouldn't ask

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Speaker 8: this question if it would be that easy.

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Speaker 9: And I seem to recall that some people were chutting

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Speaker 9: boiling water into freezing air on YouTube a while back.

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Speaker 9: So my final answer is hot water freezes faster. But

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Speaker 9: I cannot tell you why.

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Speaker 6: I always thought that boiled water freezing faster was just

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Speaker 6: a myth. But you can boil water at room temperature

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Speaker 6: by lowering the pressure, so perhaps if you increase the

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Speaker 6: pressure maybe.

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Speaker 1: All right, well, let's dig into this strange question, Daniel,

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Speaker 1: What does this question even mean? What's the setup?

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Speaker 3: I love this question because it seems so simple, both experimentally,

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Speaker 3: like actually measuring this and theoretically, but it turns out

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Speaker 3: to be much more complicated in both aspects. From a

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Speaker 3: basic point of view, it's a very simple experiment you

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Speaker 3: could do while you listen to this episode. I mean,

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Speaker 3: take two cups of water, one of them hotter than

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Speaker 3: the other, put them both in the freezer and just

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Speaker 3: measure how long does it take for each one to freeze?

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Speaker 3: And now what answer the question? Does hot or cold

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Speaker 3: water freeze faster?

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Speaker 1: Which one turns into a cube of ice first?

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Speaker 3: Yeah?

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Speaker 1: Exactly does it depend on what you mean by freeze?

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Speaker 3: M We're going to get into that.

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Speaker 1: Yeah, But I guess the question is which of the

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Speaker 1: two cups, the hot one or the cold one, turns

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Speaker 1: into ice first? And so intuitively you'd assume that the

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Speaker 1: cold one freezes faster because it's closer to freezing temperature.

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Speaker 3: Exactly, if you can describe water basically in terms of

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Speaker 3: just one variable, like it's temperature, then the hot water

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Speaker 3: has to travel further along that temperature line, and so

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Speaker 3: it should take longer. Like eventually the hot water will

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Speaker 3: become the cold water, and they'll still have to progress

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Speaker 3: to freezing. So if the hot water has to pass

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Speaker 3: through the cold water point, then it's like riding the

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Speaker 3: bus home. If you get on at a further stop,

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Speaker 3: it's going to take longer to get home.

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Speaker 1: Right, Like, if you have hot water one hundred degrees

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Speaker 1: and cold water at fifty degrees, Eventually, after a while,

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Speaker 1: the hot water is going to be fifty degrees, at

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Speaker 1: which point it's basically the same starting point as the

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Speaker 1: cold water.

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Speaker 3: Yeah, and if it took time to get there, then

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Speaker 3: obviously it's going to take longer overall to get to

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Speaker 3: the freezing point.

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Speaker 1: Right. So you would think that the cold water freezes

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Speaker 1: faster because the hot water has to become the cold

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Speaker 1: water first anyways, exactly, But it sounds like physicists have

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Speaker 1: other ideas.

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Speaker 3: Yeah, and not just physicists. It's sort of an old

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Speaker 3: wives tale that people have been repeating for like centuries

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Speaker 3: or millennia that hot water freezes faster. You hear plumbers

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Speaker 3: in the northeastern part of the United States often saying

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Speaker 3: things like that hot water pipes freeze more often in

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Speaker 3: big snowstorms, like they will burst more often than the

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Speaker 3: cold water pipes. There's writings by Aristotle in the fourth

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Speaker 3: century BC who says, many people, when they want to

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Speaker 3: cool water quickly, begin by putting it in the sun.

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Speaker 2: Mm.

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Speaker 1: Interesting, give it a sunburned first, and that will freeze

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Speaker 1: it faster. Now does Aristotle count as an old wife?

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Speaker 1: Is he like the og old wife?

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Speaker 3: He's definitely one of the og physicists. But you know,

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Speaker 3: in the end it comes down to actually measuring this,

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Speaker 3: like doing the experiment. And for a long time this

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Speaker 3: is something people sort of just discussed and assumed that

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Speaker 3: the cold water freezed faster. But then there was this

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Speaker 3: event in the nineteen sixties that involved ice cream that

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Speaker 3: sort of changed the course of this question forever.

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Speaker 1: Oh my goodness, did somebody stop to eat a snag

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Speaker 1: er and accidentally drop that left some cold water in

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Speaker 1: the freezer.

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Speaker 3: No, there was a Tanzanian teenager named Erasto Pemba. He

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Speaker 3: and his science class were doing the exercise of making

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Speaker 3: ice cream, but apparently there weren't going to be enough

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Speaker 3: slots in the refrigerator. While most students were letting the

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Speaker 3: ingredients cool to room temperature, he just jammed his in

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Speaker 3: the freezer to get a spot, and he saw that

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Speaker 3: his concoction froze faster than other kids who put it

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Speaker 3: in at the same time and started cooler. So he thought, hmm,

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Speaker 3: maybe hot water does freeze.

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Speaker 1: Faster, so he did it with ice cream. But that's

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Speaker 1: not really how you make ice cream, is it. You

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Speaker 1: don't just freeze cream, do you know.

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Speaker 3: You have to freeze it and you have to mix

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Speaker 3: it at the same time. So I'm not sure if

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Speaker 3: he qualifies as ice cream.

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Speaker 1: So maybe he was just making popsicles exactly creamsicles. I

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Speaker 1: guess I'm not just trying to debug this story figure

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Speaker 1: out what is really true here, Daniel. We're doing some

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Speaker 1: heart investigating here.

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Speaker 3: That's just sort of what inspired him. And he asked

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Speaker 3: his physics teacher about it, and his physics teacher told him, no, no, no,

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Speaker 3: you're confused. That cannot happen, is physically impossible. And then

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Speaker 3: later on a physicist came to visit his school, and

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Speaker 3: he raised his hand and he told his story, and

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Speaker 3: he asked the physicist about it, and the physicist was

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Speaker 3: interested enough to invite him back to his lap where

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Speaker 3: they did a bunch of experiments confirmed the result. They

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Speaker 3: saw hot water freeze faster than cold water, and then

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Speaker 3: they wrote a paper together and that's why this is

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Speaker 3: now called the Pemba effect.

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Speaker 1: WHOA, So they actually did an experiment in a physics lab.

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Speaker 3: They actually did an experiment in a physics lab.

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Speaker 1: And what did this experiment look like?

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Speaker 3: The experiment is just two cups of water in a

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Speaker 3: freezer with thermometers in them.

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Speaker 1: M I see, pretty basic.

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Speaker 3: It was pretty basic but the paper is pretty fun

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Speaker 3: to read because it's written by a teenager. Like the

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Speaker 3: opening line of the paper is my name is Erastum Pemba,

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Speaker 3: and I'm going to tell you about my discovery, which

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Speaker 3: was due to misusing a refrigerator.

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Speaker 1: Nice, nice and direct, nice and direct, opposed to how

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Speaker 1: an adult academic would do it, which is would take

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Speaker 1: you the seven paragraphs to get to the same point exactly.

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Speaker 3: But the question you asked a minute ago about the

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Speaker 3: details of the experiment turn out to be crucial because

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Speaker 3: these experiments done in the sixties sort of established the effect,

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Speaker 3: and lots of people have tried to reproduce it in

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Speaker 3: the decades following with mixed success.

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Speaker 1: Wait, but if it's a simple experiment just putting two

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Speaker 1: cups into a freezer, you're saying people have done the

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Speaker 1: same thing, but some of sometimes the cold water beats

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Speaker 1: the hot water, and sometimes the hot water beats the

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Speaker 1: cold water to the freezing point.

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Speaker 3: Exactly. The experiments seem to be very sensitive to the

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Speaker 3: conditions in a way that we do not fully understand

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Speaker 3: because it's not just two cups of water in a freezer.

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Speaker 3: It's like the questions of the purity of the water

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Speaker 3: or the blowing of the fan through the freezer. Something

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Speaker 3: is going on which makes this very difficult to reproduce.

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Speaker 1: It's not just about putting two cups inside of a freezer.

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Speaker 1: It's about like how they're being cooled and what they're

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Speaker 1: sitting on.

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Speaker 3: Maybe perhaps I read one study that saw hot water

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Speaker 3: freeze faster and they discovered that it was because the

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Speaker 3: shelves of the freezer were covered in frost, and the

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Speaker 3: hot water basically melted that frost, which improved the thermal

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Speaker 3: contact with the shelf, the metal shelf, and that helped

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Speaker 3: it cool faster. So all sorts of little details like

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Speaker 3: that can make a difference in how you do this experiment.

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Speaker 1: Well, but I guess you know, the main headline is

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Speaker 1: that this is kind of an undecided question. It seems

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Speaker 1: like people have tried it, and sometimes the hot water

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Speaker 1: does beat the cold water to freezing.

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Speaker 3: Yeah, it's something which is not experimentally decided, like we

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Speaker 3: cannot reliably reproduce this result. It turns out to only

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Speaker 3: happen under certain conditions and be very sensitive to those conditions,

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Speaker 3: and nobody has quite isolated those and controlled them.

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Speaker 1: But I guess my question is how hard have people tried, Like,

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Speaker 1: have you spent billions of dollars you have in the

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Speaker 1: leec to figure out this question? Or is this one

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Speaker 1: of those questions that you only see, you know, physicists

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Speaker 1: publish at the on their websites.

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Speaker 3: No, there are real labs doing detailed studies because it

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Speaker 3: turns out this is a really interesting question on the

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Speaker 3: energetics of water, and so people have really tried. I

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Speaker 3: read another review of this which said, quote, there is

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Speaker 3: a wealth of experimental variation in the problem. So any

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Speaker 3: laboratory undertaking such investigations is guaranteed different results from all

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Speaker 3: the others. So this is something serious physicists and chemists

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Speaker 3: are trying to nail down because the chemistry of water

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Speaker 3: is very important. It's very important to life, it's important

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Speaker 3: to climate change, it's important to exoplanets like water is

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Speaker 3: important stuff.

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Speaker 1: Yeah, I hear, it's important for horses too.

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Speaker 3: I'll have to ask my daughter about it.

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Speaker 1: All right, Well, let's dig into the details of the

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Speaker 1: chemistry of water and the details of these experiments and

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Speaker 1: how they might affect who wins first cold water or

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Speaker 1: hot water to freezing. So let's do that. But first

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Speaker 1: let's take a quick break or right, we're asking the

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Speaker 1: simple question does hot or cold water freeze faster? And

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Speaker 1: it seems like the answer is it depends, which is

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Speaker 1: wild like the idea that hot water can freeze faster

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Speaker 1: than cold water.

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Speaker 3: It comes down to lots of tricky little details. One

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Speaker 3: question you asked earlier is like, well, what do you

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Speaker 3: mean by freezing? Right? Is that the formation of crystals.

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Speaker 3: It's possible that like hot water could start forming crystals sooner,

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Speaker 3: but actually takes longer to get to zero C. Water

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Speaker 3: is very complicated stuff and it can exist in different

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Speaker 3: phases at the same temperature. Or do you really just

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Speaker 3: mean thermodynamically getting to zero C?

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Speaker 1: Well, I guess maybe I would guess that what most

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Speaker 1: people think of as freezing is when water turns into

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Speaker 1: a solid. So are you saying sometimes the hot water

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Speaker 1: turns completely into a solid.

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Speaker 3: First, Yeah, some of these experiments see hot water forming

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Speaker 3: these crystals first, right, number water is a sort of

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Speaker 3: a disordered crystal. It's possible for the water, which starts

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Speaker 3: out hot, to start forming those crystals, and crystal formation

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Speaker 3: is very stochastic.

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Speaker 2: Right.

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Speaker 3: Once you get a seed going, then you can rapidly

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Speaker 3: form more crystals, So it sot of depends on like

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Speaker 3: when you get that first seed. So hot water might

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Speaker 3: be able to like first form that seed, which gives

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Speaker 3: it an advantage even if it's still at a higher temperature.

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Speaker 1: Right. And I think freezing also kind of depends on

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Speaker 1: pressure as well, Right, But I guess you're assuming they're

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Speaker 1: both under the same amount of pressure.

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Speaker 3: Yeah, I think we're assuming that they're in a refrigerator,

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Speaker 3: which is basically like an infinite thermal bath and can

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00:17:42,400 --> 00:17:44,800
Speaker 3: provide the pressure. But there are these little details also

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Speaker 3: like evaporation, right, like did you seal your container, because

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Speaker 3: hot water will also evaporate, which lowers its volume, which

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Speaker 3: makes it easier to freeze.

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Speaker 1: I see, So the hot water, even if you stack

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Speaker 1: it in the freezer, it's going to be hot for

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Speaker 1: a while, and so some of it's going to vapor

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Speaker 1: rate out into the freezer, which means that the amount

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Speaker 1: of water left in the cup will be less than

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Speaker 1: the amount of water in the cold cup, which means

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Speaker 1: that it might be easier for it to freeze.

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Speaker 3: Mm exactly. And there's other complicated experimental issues too, like

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Speaker 3: one study discovered that it dependent on where you put

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Speaker 3: the thermometer in the cup that sometimes they could get

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00:18:20,040 --> 00:18:23,199
Speaker 3: false readings of the Impemba effect because they put the

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Speaker 3: thermometer like in the wrong place.

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Speaker 1: What do you mean, what's the right place to put

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Speaker 1: it in the cup of water?

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Speaker 3: Basically you have to have them in the same place. Really,

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Speaker 3: you should put it at the core so that you're

400
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Speaker 3: measuring the time it takes the core to get to

401
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Speaker 3: zero C for both cups. You mean for both cups.

402
00:18:36,920 --> 00:18:39,439
Speaker 3: But if you don't place the thermometer exactly in the

403
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Speaker 3: center for both of them, you can get a false

404
00:18:41,520 --> 00:18:44,240
Speaker 3: reading of the Impemba effect. So there's two things going

405
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Speaker 3: on here. One is like how treaty it is to

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Speaker 3: reproduce this effect? And the other is are all the

407
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Speaker 3: reported cases of the Mpemba effect actually real or are

408
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Speaker 3: some of them experimental mismeasurements.

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Speaker 1: Well, let's break it down. In the case is that

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Speaker 1: we think or people have thought that hot water fast

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Speaker 1: or what do you think might be going on?

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Speaker 3: It all comes down to this question of describing water

413
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Speaker 3: with one number temperature. You imagine what's happening is you

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00:19:07,960 --> 00:19:10,520
Speaker 3: have this cube of water and the outer layers in

415
00:19:10,560 --> 00:19:12,680
Speaker 3: contact with a freezer, and so it starts to chill,

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Speaker 3: and then it chills the inner layer, and then that

417
00:19:14,760 --> 00:19:17,359
Speaker 3: chills the inner layer, and eventually the whole thing cools down.

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Speaker 3: That is the simple model of the temperature dropping, and

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Speaker 3: you're really just describing the water in terms of one number.

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Speaker 3: But this is tricky because temperature is a very slippery

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Speaker 3: topic and it's not actually well defined. Out of equilibrium,

422
00:19:31,119 --> 00:19:34,439
Speaker 3: equilibrium means there's no heat transfer, right Like, when the

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00:19:34,480 --> 00:19:37,159
Speaker 3: water is cool and it's no longer changing, then you

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Speaker 3: can define it to be at the same temperature as

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Speaker 3: the rest of the freezer. But if things are changing,

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Speaker 3: then temperature is not technically defined. It's only defined for

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Speaker 3: a system in equilibrium. Out of equilibrium, things get very

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Speaker 3: complicated very quickly, and you need much more information to

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Speaker 3: actually describe the whole system.

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Speaker 1: Well, I see, we're saying, like the idea of temperature

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Speaker 1: it only works if nothing's changing. But when something's freezing

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Speaker 1: from hot water or cold water into ice, things are changing.

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Speaker 1: So if you're just going by measuring freezing as some

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Speaker 1: sort of temperature reaching a point, then you're already kind

435
00:20:11,560 --> 00:20:13,320
Speaker 1: of measuring the wrong thing.

436
00:20:13,440 --> 00:20:16,879
Speaker 3: Yeah, exactly. And the things you remember is that temperature

437
00:20:17,080 --> 00:20:20,040
Speaker 3: is a macroscopic thing. It's like our experience. It's something

438
00:20:20,080 --> 00:20:23,520
Speaker 3: we can measure using thermometers, and we try to connect

439
00:20:23,560 --> 00:20:26,280
Speaker 3: it to the microscopic to say, what's actually happening in

440
00:20:26,320 --> 00:20:29,080
Speaker 3: hot water or in cold water? What's the difference between

441
00:20:29,080 --> 00:20:31,280
Speaker 3: those two. And there's a bunch of different descriptions, a

442
00:20:31,280 --> 00:20:35,240
Speaker 3: bunch of different ways to try to explain and understand

443
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Speaker 3: our intuitive macroscopic experience of temperature in terms of the

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Speaker 3: microscopic particles. Like one very common one is the kinetic

445
00:20:42,800 --> 00:20:45,639
Speaker 3: theory says in hot water molecules move faster and in

446
00:20:45,680 --> 00:20:49,240
Speaker 3: cold water molecules move slower. That's rough because molecules can

447
00:20:49,280 --> 00:20:51,880
Speaker 3: also do other things like spin and vibrate. That's one

448
00:20:51,960 --> 00:20:55,280
Speaker 3: basic idea. But zooming out from that microscopic picture of

449
00:20:55,280 --> 00:20:58,080
Speaker 3: the little molecules and their speeds determined in the temperature

450
00:20:58,240 --> 00:21:01,520
Speaker 3: assumes that it's in equilibrium. There's a bunch of steps there,

451
00:21:01,560 --> 00:21:05,360
Speaker 3: the mathematics involved to go from like zillions and zillions

452
00:21:05,359 --> 00:21:08,240
Speaker 3: of little particles out to a single number that describes it.

453
00:21:08,280 --> 00:21:10,919
Speaker 3: Assumes that it's an equilibrium, and if it's not, it

454
00:21:11,080 --> 00:21:11,879
Speaker 3: just can't do that.

455
00:21:12,800 --> 00:21:15,160
Speaker 1: So I think what you're saying is if you're going

456
00:21:15,200 --> 00:21:18,840
Speaker 1: by freezing as when it reaches, for example, zero degree celsius,

457
00:21:18,920 --> 00:21:21,320
Speaker 1: then even if you measure it to be zero degree celsius,

458
00:21:21,480 --> 00:21:25,119
Speaker 1: maybe it's not done changing, or maybe the molecules are

459
00:21:25,119 --> 00:21:26,040
Speaker 1: still moving around.

460
00:21:26,320 --> 00:21:30,080
Speaker 3: I think I'm saying more generally that describing the whole

461
00:21:30,119 --> 00:21:32,800
Speaker 3: system as like having to move through one path to

462
00:21:32,880 --> 00:21:36,000
Speaker 3: get from hot to freezing is not an accurate way

463
00:21:36,040 --> 00:21:38,480
Speaker 3: to think about it. In reality, there's lots of different paths.

464
00:21:38,520 --> 00:21:40,760
Speaker 3: It's not like the hot water is getting on the

465
00:21:40,800 --> 00:21:43,400
Speaker 3: bus further from home. It's like the hot water might

466
00:21:43,400 --> 00:21:45,760
Speaker 3: be able to take a short cut. There's not just

467
00:21:45,880 --> 00:21:49,560
Speaker 3: one path. From one hundred degrees to zero doesn't necessarily

468
00:21:49,600 --> 00:21:53,120
Speaker 3: have to pass through fifty because temperature isn't even really

469
00:21:53,200 --> 00:21:55,600
Speaker 3: well defined for a system that's changing. It can be

470
00:21:55,640 --> 00:21:57,520
Speaker 3: one hundred, it can later be zero, and it could

471
00:21:57,560 --> 00:21:58,720
Speaker 3: have never been fifty.

472
00:21:58,920 --> 00:22:02,280
Speaker 1: Well, it sounds like you you're basically disqualifying temperature as

473
00:22:02,359 --> 00:22:06,760
Speaker 1: a gauge for this experiment, like basically don't use temperature

474
00:22:06,920 --> 00:22:09,040
Speaker 1: to measure whether something freezes or not.

475
00:22:09,240 --> 00:22:10,919
Speaker 3: Well, I think if for the starting point and the

476
00:22:11,000 --> 00:22:13,240
Speaker 3: ending point, you can use it like is it frozen,

477
00:22:13,440 --> 00:22:16,200
Speaker 3: yes or no? But while it's out of equilibrium. As

478
00:22:16,240 --> 00:22:19,159
Speaker 3: it's changing. There's a lot more complicated stuff that's going on.

479
00:22:19,400 --> 00:22:22,680
Speaker 1: Oh I see, they may trace the same history of temperature,

480
00:22:23,080 --> 00:22:25,119
Speaker 1: but actually what's going on inside the cup might be

481
00:22:25,280 --> 00:22:26,000
Speaker 1: totally different.

482
00:22:26,119 --> 00:22:28,920
Speaker 3: Yeah, exactly. The hot water cooling and the cold water

483
00:22:28,960 --> 00:22:32,160
Speaker 3: cooling might be very very different processes. Remember that water

484
00:22:32,320 --> 00:22:35,919
Speaker 3: is very very complicated stuff. It has all these strange bonds,

485
00:22:35,960 --> 00:22:40,000
Speaker 3: these hydrogen bonds between the molecules, which create lots of

486
00:22:40,040 --> 00:22:43,800
Speaker 3: counterintuitive effects. Like famously, water is less dense when it's

487
00:22:43,800 --> 00:22:46,560
Speaker 3: a solid than when it's a liquid. Right, water floats

488
00:22:46,560 --> 00:22:48,879
Speaker 3: on top of liquid water. It's like one of the

489
00:22:48,880 --> 00:22:52,160
Speaker 3: only substances that will do that. You mean ice floats, right, Yes,

490
00:22:52,280 --> 00:22:55,560
Speaker 3: solid water floats on top of liquid water. Ice floats, right,

491
00:22:55,680 --> 00:22:57,480
Speaker 3: It's one of the only things that will do that.

492
00:22:58,000 --> 00:23:01,400
Speaker 3: And so it has all of these weird counter into effects.

493
00:23:01,280 --> 00:23:03,520
Speaker 1: Like what, how would that affect how fast it freezes

494
00:23:03,640 --> 00:23:03,840
Speaker 1: or not.

495
00:23:04,000 --> 00:23:06,520
Speaker 3: So these hydrogen bonds, the sort of weak bonds between

496
00:23:06,520 --> 00:23:10,000
Speaker 3: the molecules, are crucial for forming the crystal, and if

497
00:23:10,000 --> 00:23:12,239
Speaker 3: you heat the water up, it can like destroy all

498
00:23:12,280 --> 00:23:16,199
Speaker 3: the existing ones, freeing them up to rearrange themselves. So

499
00:23:16,240 --> 00:23:18,680
Speaker 3: hot water is like more active and more loose, which

500
00:23:18,720 --> 00:23:22,880
Speaker 3: allows it to like explore the possible configurations more quickly.

501
00:23:23,080 --> 00:23:25,720
Speaker 3: Like imagine you have a box of legos and you're

502
00:23:25,760 --> 00:23:27,919
Speaker 3: shaking it around. The more you shake it around, the

503
00:23:27,920 --> 00:23:30,000
Speaker 3: more likely you are for it to end up in

504
00:23:30,040 --> 00:23:33,360
Speaker 3: some configuration. Then if you're shaking it less because you're

505
00:23:33,359 --> 00:23:37,160
Speaker 3: exploring like more combinations of legos bumping against each other.

506
00:23:37,359 --> 00:23:40,439
Speaker 3: So hot water sort of like explores all those configurations faster,

507
00:23:40,800 --> 00:23:44,080
Speaker 3: and it might find accidentally some configuration which causes a

508
00:23:44,119 --> 00:23:48,000
Speaker 3: seed of structure, a little mini crystal, which then flourishes

509
00:23:48,080 --> 00:23:49,440
Speaker 3: and forms a larger crystal.

510
00:23:49,920 --> 00:23:53,119
Speaker 1: But if the whole thing is hotter wooden, those eventually break.

511
00:23:54,000 --> 00:23:56,960
Speaker 1: Like even if if you're shaking the container of lego,

512
00:23:57,119 --> 00:24:01,760
Speaker 1: they might you know, accidentally or coincidentally you know, build themselves,

513
00:24:01,800 --> 00:24:05,359
Speaker 1: but you're still shaking, you're still shaking the canisters, they

514
00:24:05,359 --> 00:24:06,520
Speaker 1: wouldn't break apart.

515
00:24:06,640 --> 00:24:08,400
Speaker 3: Yeah, you're absolutely right. So we have to add one

516
00:24:08,400 --> 00:24:10,520
Speaker 3: more little thing to our model, which is that water

517
00:24:10,600 --> 00:24:13,480
Speaker 3: does like to stick to itself, right, there are hydrogen bonds,

518
00:24:13,480 --> 00:24:15,560
Speaker 3: So it's sort of like a box of sticky legos

519
00:24:16,080 --> 00:24:18,280
Speaker 3: and you're shaking them and some pieces come together and

520
00:24:18,440 --> 00:24:21,200
Speaker 3: like to stick together, and that's what happens with water.

521
00:24:21,280 --> 00:24:24,040
Speaker 3: Sometimes the pieces end up in exactly the right configuration

522
00:24:24,200 --> 00:24:27,080
Speaker 3: and boom, they're bound together. So even though they were hot,

523
00:24:27,359 --> 00:24:30,320
Speaker 3: now they like to stick together. That's a lower energy configuration.

524
00:24:30,680 --> 00:24:33,160
Speaker 1: So that's one way that maybe hot water can get

525
00:24:33,200 --> 00:24:35,959
Speaker 1: to being a solid faster than cold water exactly.

526
00:24:35,960 --> 00:24:38,480
Speaker 3: That's one idea that's out there, and people have done

527
00:24:38,480 --> 00:24:40,840
Speaker 3: a bunch of experiments to try to confirm this. They're

528
00:24:40,920 --> 00:24:45,040
Speaker 3: very artificial sounding experiments. They like take beads of glass

529
00:24:45,240 --> 00:24:48,520
Speaker 3: and shoot them with lasers and study these very artificial

530
00:24:48,520 --> 00:24:51,040
Speaker 3: situations where the bead of glass is like different energy

531
00:24:51,119 --> 00:24:53,119
Speaker 3: levels it can be in, but in generally prove the

532
00:24:53,160 --> 00:24:56,919
Speaker 3: principle that like high energy beads of glass find the

533
00:24:57,040 --> 00:25:01,440
Speaker 3: minimum faster. They like explore all the possible figurations more quickly,

534
00:25:01,640 --> 00:25:04,400
Speaker 3: and end up finding that minimum that most relaxed state

535
00:25:04,560 --> 00:25:07,920
Speaker 3: more quickly than a slow bead of glass. And so

536
00:25:07,960 --> 00:25:10,280
Speaker 3: some people think that that sort of proves that that's

537
00:25:10,440 --> 00:25:14,360
Speaker 3: possible in principle, though that doesn't mean it's what's actually happening,

538
00:25:14,480 --> 00:25:15,359
Speaker 3: like in water.

539
00:25:15,600 --> 00:25:18,000
Speaker 1: The way they don't think this is helping hot water

540
00:25:18,080 --> 00:25:18,639
Speaker 1: freeze faster.

541
00:25:18,760 --> 00:25:21,159
Speaker 3: A lot of people think, okay, that proves in principle

542
00:25:21,400 --> 00:25:24,359
Speaker 3: that hot things can relax faster. But you know, water

543
00:25:24,400 --> 00:25:27,040
Speaker 3: is a very complex molecule, and so like very simple

544
00:25:27,119 --> 00:25:30,399
Speaker 3: models of it don't always describe the behavior in reality.

545
00:25:30,560 --> 00:25:33,080
Speaker 3: I talked to one water chemist who said, you can't

546
00:25:33,080 --> 00:25:35,960
Speaker 3: believe anything that doesn't have a lot more details included

547
00:25:35,960 --> 00:25:36,640
Speaker 3: in the simulation.

548
00:25:37,280 --> 00:25:39,679
Speaker 1: So why don't they do these more detailed simulations.

549
00:25:39,920 --> 00:25:42,680
Speaker 3: They are doing these simulations, and people already do lots

550
00:25:42,680 --> 00:25:45,639
Speaker 3: of simulations of water for reasons We talked about like

551
00:25:45,680 --> 00:25:48,399
Speaker 3: how does water form, and what happens when asteroids hit

552
00:25:48,440 --> 00:25:50,840
Speaker 3: the atmosphere and contain ice in them? Is there a

553
00:25:50,880 --> 00:25:54,600
Speaker 3: possibility for making like basic amino acids and organic molecules.

554
00:25:55,000 --> 00:25:57,280
Speaker 3: All sorts of people are studying water for lots of reasons,

555
00:25:57,480 --> 00:26:00,520
Speaker 3: but it's hard because there are lots of interaction actions,

556
00:26:00,800 --> 00:26:03,919
Speaker 3: and so it takes like supercomputers basically to model a

557
00:26:03,960 --> 00:26:05,000
Speaker 3: little bit of water.

558
00:26:05,320 --> 00:26:07,359
Speaker 1: I guess maybe paint us a little bit of a picture.

559
00:26:07,359 --> 00:26:10,320
Speaker 1: When you say that sometimes hot water freezes faster, is

560
00:26:10,320 --> 00:26:13,719
Speaker 1: it by a lot or is it like super close

561
00:26:14,080 --> 00:26:14,880
Speaker 1: to the cold water.

562
00:26:15,040 --> 00:26:16,879
Speaker 3: So if you look at the plot in the original

563
00:26:16,880 --> 00:26:20,399
Speaker 3: paper or the one by in Pemba. Then the variation

564
00:26:20,760 --> 00:26:24,400
Speaker 3: in the time to start freezing is in like tens

565
00:26:24,440 --> 00:26:27,720
Speaker 3: of minutes. So if you start it like eighty C,

566
00:26:28,560 --> 00:26:31,160
Speaker 3: he says, it takes thirty minutes to cool his glass,

567
00:26:31,200 --> 00:26:33,600
Speaker 3: where if you start it like twenty C, it takes

568
00:26:33,600 --> 00:26:37,199
Speaker 3: one hundred minutes. So it's a very strong effect, at

569
00:26:37,280 --> 00:26:39,520
Speaker 3: least in this original and Pemba paper.

570
00:26:39,800 --> 00:26:43,440
Speaker 1: Oh wow, Yeah, that's a big difference. And I guess

571
00:26:43,280 --> 00:26:47,160
Speaker 1: it's interesting how in his experiment the hot water wasn't

572
00:26:47,200 --> 00:26:49,520
Speaker 1: that much harder, Like it wasn't boiling water. Would this

573
00:26:49,560 --> 00:26:50,600
Speaker 1: happen with boiling water?

574
00:26:50,760 --> 00:26:52,879
Speaker 3: He did try a bunch of different temperatures from twenty

575
00:26:52,920 --> 00:26:55,359
Speaker 3: to eighty C, but he didn't try boiling water. No,

576
00:26:55,760 --> 00:26:57,679
Speaker 3: Boiling water is much harder to control, right, It's like

577
00:26:57,720 --> 00:27:00,720
Speaker 3: actively vaporizing, and so you can't really control the volume

578
00:27:00,760 --> 00:27:01,240
Speaker 3: as easily.

579
00:27:02,000 --> 00:27:04,160
Speaker 1: I see, all right, So it seems like that's one

580
00:27:04,160 --> 00:27:06,840
Speaker 1: idea about what could be going on. What else physicists

581
00:27:06,840 --> 00:27:08,080
Speaker 1: thought about could explain this.

582
00:27:08,359 --> 00:27:10,600
Speaker 3: There's a whole lot of little details that people are

583
00:27:10,640 --> 00:27:13,760
Speaker 3: thinking about, Like it could be the impurities cold water

584
00:27:13,880 --> 00:27:18,120
Speaker 3: tends to contain more dissolved gases in it just because

585
00:27:18,119 --> 00:27:20,679
Speaker 3: of the chemistry of water, and that can help actually

586
00:27:20,720 --> 00:27:23,760
Speaker 3: lower its freezing point, which means that you're not really

587
00:27:23,800 --> 00:27:27,080
Speaker 3: comparing two things that are the same. You're comparing one

588
00:27:27,080 --> 00:27:29,240
Speaker 3: which has a little bit more gas dissolved in it,

589
00:27:29,280 --> 00:27:32,160
Speaker 3: which can totally affect how long it takes to freeze.

590
00:27:32,200 --> 00:27:33,800
Speaker 1: Wait, what can you explain that again?

591
00:27:33,920 --> 00:27:36,959
Speaker 3: So cold water can have more dissolved gas in it,

592
00:27:37,240 --> 00:27:39,520
Speaker 3: Like if you try to make bubbly water and try

593
00:27:39,560 --> 00:27:42,120
Speaker 3: to get CO two dissolved into your water, it's hard

594
00:27:42,160 --> 00:27:44,800
Speaker 3: to get that CO two in unless the water is cold.

595
00:27:45,000 --> 00:27:48,320
Speaker 3: So cold water will absorb COEO two more than hot water,

596
00:27:48,480 --> 00:27:51,720
Speaker 3: and so cold water likely has more CO two in

597
00:27:51,760 --> 00:27:54,919
Speaker 3: it and other gases dissolved, and that will change the

598
00:27:54,960 --> 00:27:56,639
Speaker 3: freezing point of that water.

599
00:27:57,000 --> 00:27:59,960
Speaker 1: Wouldn't the hot water absorb gas? Is it cool?

600
00:28:00,359 --> 00:28:00,520
Speaker 2: Yeah?

601
00:28:00,560 --> 00:28:03,800
Speaker 3: Absolutely. Hot water will absorb gas once it cools, but

602
00:28:03,840 --> 00:28:05,560
Speaker 3: it doesn't have as much time. So if you've had

603
00:28:05,600 --> 00:28:07,800
Speaker 3: water that's been cold for a long time, it will

604
00:28:07,800 --> 00:28:11,040
Speaker 3: have absorbed a bunch more CO two then water that's

605
00:28:11,320 --> 00:28:13,880
Speaker 3: just been hot, like five minutes ago.

606
00:28:14,440 --> 00:28:17,160
Speaker 1: And so the gas in the water might help or

607
00:28:17,240 --> 00:28:19,600
Speaker 1: make it more difficult for the water to freeze. Yeah,

608
00:28:19,760 --> 00:28:21,359
Speaker 1: or this is I guess it makes it more, it

609
00:28:21,440 --> 00:28:23,639
Speaker 1: makes it harder. Why would it make it harder.

610
00:28:23,520 --> 00:28:25,400
Speaker 3: Well, you know, if water has to form these crystals,

611
00:28:25,440 --> 00:28:27,639
Speaker 3: and if there's a bunch of CO two involved, then

612
00:28:27,680 --> 00:28:30,159
Speaker 3: it inhibits the ability of those water molecules to like

613
00:28:30,240 --> 00:28:32,280
Speaker 3: find each other and to make those bonds.

614
00:28:32,600 --> 00:28:35,280
Speaker 1: There's just more stuff going on that's not water.

615
00:28:35,480 --> 00:28:37,560
Speaker 3: Yeah, exactly, the same way that like adding salt to

616
00:28:37,600 --> 00:28:39,160
Speaker 3: water will change its freezing point.

617
00:28:39,280 --> 00:28:41,240
Speaker 1: So the idea is that maybe when you heat it

618
00:28:41,320 --> 00:28:43,480
Speaker 1: up the water to put into your experiment, it lost

619
00:28:43,520 --> 00:28:44,280
Speaker 1: a bunch of gas.

620
00:28:44,480 --> 00:28:48,479
Speaker 3: Yeah exactly. Then there's people who argue the opposite, say

621
00:28:48,520 --> 00:28:52,959
Speaker 3: that actually having impurities in the water should seed crystals

622
00:28:53,160 --> 00:28:55,840
Speaker 3: that as it cools, if one of the two glasses

623
00:28:56,000 --> 00:28:58,960
Speaker 3: has more impurities in it, that those impurities become like

624
00:28:59,000 --> 00:29:03,240
Speaker 3: the nucleation side for crystal formation. Remember, crystal formation is

625
00:29:03,280 --> 00:29:06,120
Speaker 3: sort of a stochastic thing, Like you have a bunch

626
00:29:06,120 --> 00:29:08,920
Speaker 3: of molecules at different temperature and they have to sort

627
00:29:08,920 --> 00:29:11,360
Speaker 3: of like click together in order to start that crystal.

628
00:29:11,880 --> 00:29:14,080
Speaker 3: And we talked earlier about how maybe hot water has

629
00:29:14,120 --> 00:29:17,320
Speaker 3: an advantage because it tries more combinations per second, but

630
00:29:17,400 --> 00:29:21,040
Speaker 3: could also just be a difference experimentally in the impurities

631
00:29:21,040 --> 00:29:23,000
Speaker 3: in that water, And as you heat it up, you

632
00:29:23,040 --> 00:29:25,400
Speaker 3: might have boiled off some of those impurities, or you

633
00:29:25,480 --> 00:29:28,240
Speaker 3: may be concentrating those impurities as you heat it up

634
00:29:28,280 --> 00:29:31,240
Speaker 3: the water. So if the hot water has more impurities

635
00:29:31,240 --> 00:29:33,600
Speaker 3: in it, that could actually provide more sites for the

636
00:29:33,680 --> 00:29:36,320
Speaker 3: nucleation of those crystals, which would lead to it forming

637
00:29:36,360 --> 00:29:39,440
Speaker 3: a solid faster, even if it's not at the same temperature.

638
00:29:39,520 --> 00:29:42,240
Speaker 1: But I feel like maybe we're talking a lot about

639
00:29:42,280 --> 00:29:46,600
Speaker 1: things that might affect the formation of ice crystals. But

640
00:29:46,760 --> 00:29:49,320
Speaker 1: from a sort of a macro point of view, doesn't

641
00:29:49,320 --> 00:29:52,680
Speaker 1: the hot water just have more energy, and so wouldn't

642
00:29:52,720 --> 00:29:56,280
Speaker 1: it just technically take longer to get rid of that energy.

643
00:29:56,480 --> 00:29:59,120
Speaker 3: It's a compelling argument, and it's compelling because it's a

644
00:29:59,160 --> 00:30:01,920
Speaker 3: simple model when it basically says is a single number

645
00:30:01,960 --> 00:30:05,000
Speaker 3: you can use to describe the system. But imagine if

646
00:30:05,080 --> 00:30:07,920
Speaker 3: instead of just having energy, you also have energy in

647
00:30:08,120 --> 00:30:11,760
Speaker 3: like momentum of heat loss. What is starting from a

648
00:30:11,840 --> 00:30:16,000
Speaker 3: higher temperature means that you start losing energy more quickly

649
00:30:16,080 --> 00:30:18,400
Speaker 3: because there's a higher difference between the heat of the

650
00:30:18,440 --> 00:30:21,440
Speaker 3: water and the freezer, and that high rate of energy

651
00:30:21,440 --> 00:30:24,560
Speaker 3: transfer is somehow remembered. So now when you pass through

652
00:30:24,560 --> 00:30:27,760
Speaker 3: that fifty degree mark, you're losing heat faster than the

653
00:30:27,760 --> 00:30:30,040
Speaker 3: cold water did when it was there. It's sort of

654
00:30:30,040 --> 00:30:33,080
Speaker 3: like having somebody start a RaSE ten or fifteen meters

655
00:30:33,120 --> 00:30:36,800
Speaker 3: behind the starting line, but they get to accelerate up

656
00:30:36,840 --> 00:30:39,479
Speaker 3: to their top speed before they cross the starting line.

657
00:30:39,680 --> 00:30:41,720
Speaker 1: Right. That's an effect and might explain it. But it's

658
00:30:41,760 --> 00:30:43,880
Speaker 1: a bit crazy, isn't it. The idea that you can

659
00:30:43,960 --> 00:30:45,440
Speaker 1: have like temperature inertia.

660
00:30:45,600 --> 00:30:48,000
Speaker 3: Yeah, that is a bit crazy, and it totally violates

661
00:30:48,000 --> 00:30:49,880
Speaker 3: our a simple model where you can describe things just

662
00:30:49,920 --> 00:30:52,640
Speaker 3: in terms of like temperature and pressure and volume. And

663
00:30:52,680 --> 00:30:56,080
Speaker 3: that's because that only applies in equilibrium. Out of equilibrium,

664
00:30:56,120 --> 00:30:59,680
Speaker 3: things are crazy, and none of these approximations we used to,

665
00:30:59,720 --> 00:31:02,520
Speaker 3: like apple with all the crazy details of those particles,

666
00:31:02,760 --> 00:31:05,440
Speaker 3: are really applicable. And so there's lots of things that

667
00:31:05,480 --> 00:31:08,360
Speaker 3: can happen to complex liquids, much more than can be

668
00:31:08,360 --> 00:31:09,960
Speaker 3: summarized in just a few numbers.

669
00:31:10,200 --> 00:31:12,960
Speaker 1: Well, I think maybe you're not saying that the water

670
00:31:13,040 --> 00:31:15,240
Speaker 1: itself has some sort of temperature inertia, but you're saying

671
00:31:15,280 --> 00:31:18,560
Speaker 1: that maybe like the details or the complexity of how

672
00:31:18,600 --> 00:31:21,600
Speaker 1: the cup interacts with the air or around it, that

673
00:31:21,680 --> 00:31:26,040
Speaker 1: might have some effects that look like temperature inertia.

674
00:31:26,080 --> 00:31:28,520
Speaker 3: It could be both of those things, right. It certainly

675
00:31:28,560 --> 00:31:31,800
Speaker 3: could be dependent on the details of the experimental setup.

676
00:31:32,000 --> 00:31:35,200
Speaker 3: But also we just do not understand out of equilibrium

677
00:31:35,240 --> 00:31:38,600
Speaker 3: chemistry very well, So temperature inertia could be a real thing.

678
00:31:38,840 --> 00:31:41,000
Speaker 3: But it could also depend on the details of the

679
00:31:41,080 --> 00:31:45,000
Speaker 3: molecular structure, like maybe only happens for more complex substances,

680
00:31:45,360 --> 00:31:48,120
Speaker 3: maybe only happens for things with very specific kinds of

681
00:31:48,200 --> 00:31:49,320
Speaker 3: bonds that are possible.

682
00:31:49,520 --> 00:31:51,080
Speaker 1: All right, well, let's get into some of these other

683
00:31:51,160 --> 00:31:54,320
Speaker 1: ideas for what could be making hot water freeze faster

684
00:31:54,440 --> 00:31:57,440
Speaker 1: than cold water and what that means about our understanding

685
00:31:57,520 --> 00:32:02,080
Speaker 1: of water chemistry and horses. So to dig into that,

686
00:32:02,160 --> 00:32:18,120
Speaker 1: but first let's take another quick break. All right, we're

687
00:32:18,120 --> 00:32:23,200
Speaker 1: talking about Daniel raiding the freezer for ice cream and

688
00:32:23,280 --> 00:32:28,680
Speaker 1: how it seems to disappear magically, as if by magical horses.

689
00:32:28,920 --> 00:32:31,440
Speaker 3: That's right, when my teenager leaves ice cream out on

690
00:32:31,480 --> 00:32:33,200
Speaker 3: the counter, why does it cool faster?

691
00:32:33,520 --> 00:32:36,440
Speaker 1: M Wait, could he say then that he's just trying

692
00:32:36,440 --> 00:32:39,200
Speaker 1: to freeze it faster, because then he's taking it out,

693
00:32:39,320 --> 00:32:41,720
Speaker 1: leaving it out so it heats up, so then when

694
00:32:41,960 --> 00:32:45,360
Speaker 1: you finally put it in the freezer, it'll freeze faster.

695
00:32:46,000 --> 00:32:49,000
Speaker 3: Yeah, I'm sure he's just doing a chemistry experiment, right.

696
00:32:49,080 --> 00:32:51,320
Speaker 1: Yeah, that's right. He's maybe just trying to raise your

697
00:32:51,320 --> 00:32:51,920
Speaker 1: boiling point.

698
00:32:53,440 --> 00:32:55,400
Speaker 3: But you know, it's amazing to me that this is

699
00:32:55,480 --> 00:33:00,280
Speaker 3: still an open territory, both theoretically and experimentally. Lots of

700
00:33:00,280 --> 00:33:02,920
Speaker 3: people trying to understand under what conditions you can make

701
00:33:02,960 --> 00:33:05,240
Speaker 3: this happen, and a bunch of other people are trying

702
00:33:05,240 --> 00:33:07,680
Speaker 3: to understand whether it makes sense and what it means

703
00:33:07,720 --> 00:33:10,360
Speaker 3: about like the nature of matter and phases and being

704
00:33:10,400 --> 00:33:10,920
Speaker 3: a liquid.

705
00:33:11,400 --> 00:33:13,720
Speaker 1: Yeah, it's pretty interesting that we don't have an answer

706
00:33:13,760 --> 00:33:16,080
Speaker 1: to this. It sounds like we need to spend a

707
00:33:16,080 --> 00:33:18,080
Speaker 1: couple more billion dollars on this question.

708
00:33:18,320 --> 00:33:20,880
Speaker 3: That's right, billions of dollars. Where of ice cream must

709
00:33:20,920 --> 00:33:21,920
Speaker 3: be purchased.

710
00:33:23,720 --> 00:33:28,320
Speaker 1: That's right, Yes, white chocolate ice cream with bananas. Okay,

711
00:33:28,360 --> 00:33:30,160
Speaker 1: So then I don't think we're quite done. You said

712
00:33:30,200 --> 00:33:32,240
Speaker 1: there might be other factors that might be going on

713
00:33:32,280 --> 00:33:34,840
Speaker 1: that might explain why the hot water freezes faster.

714
00:33:35,040 --> 00:33:37,360
Speaker 3: Yeah, another theory I was reading about, and there's like

715
00:33:37,560 --> 00:33:40,760
Speaker 3: no shortage of theories impossible at Explanations for what might

716
00:33:40,760 --> 00:33:44,000
Speaker 3: be going on here has to do with convection, how

717
00:33:44,040 --> 00:33:48,200
Speaker 3: the water moves through the glass as it's cooling. So like,

718
00:33:48,320 --> 00:33:51,120
Speaker 3: as the water is cooling, it's going to definitely have

719
00:33:51,320 --> 00:33:54,400
Speaker 3: some currents within it, even if it started out totally stable,

720
00:33:54,480 --> 00:33:58,760
Speaker 3: because density decreases with increasing temperature. So the surface of

721
00:33:58,760 --> 00:34:00,960
Speaker 3: the water is going to be warmer than the bottom,

722
00:34:01,080 --> 00:34:03,760
Speaker 3: which sometimes they call it hot top. Now the water

723
00:34:03,920 --> 00:34:06,760
Speaker 3: primarily loses its heat to the surface, then water with

724
00:34:06,840 --> 00:34:09,040
Speaker 3: the hot top will lose heat faster than we would

725
00:34:09,040 --> 00:34:12,920
Speaker 3: expect based on its average temperature. When they initially warmer

726
00:34:12,960 --> 00:34:15,880
Speaker 3: water then cools down a little bit to the initial

727
00:34:15,920 --> 00:34:18,480
Speaker 3: temperature of the other cooler water, it's going to have

728
00:34:18,520 --> 00:34:20,160
Speaker 3: a hot top, and its rate of cooling will be

729
00:34:20,200 --> 00:34:22,400
Speaker 3: faster than the rate of cooling of the other water

730
00:34:22,440 --> 00:34:26,040
Speaker 3: at the same temperature. Anyway, it's complicated, but it has

731
00:34:26,080 --> 00:34:28,080
Speaker 3: to do with like how the water changes density in

732
00:34:28,160 --> 00:34:31,680
Speaker 3: which chunk of the water is essentially exposed to the

733
00:34:31,719 --> 00:34:32,280
Speaker 3: cool air.

734
00:34:32,600 --> 00:34:34,279
Speaker 1: Oh, I see what you're saying. Like maybe you have

735
00:34:34,320 --> 00:34:37,520
Speaker 1: a hot cup and a cold cup, and you're measuring

736
00:34:37,560 --> 00:34:40,320
Speaker 1: the temperature, and maybe they both have the same temperature

737
00:34:40,320 --> 00:34:41,960
Speaker 1: in the middle of the cup, but you're saying maybe

738
00:34:41,960 --> 00:34:46,480
Speaker 1: the warmer cup has a hotter surface or water on

739
00:34:46,520 --> 00:34:48,760
Speaker 1: the surface of it, which means it's losing heat faster,

740
00:34:49,239 --> 00:34:53,120
Speaker 1: which means it's you know, basically running faster towards freezing

741
00:34:53,160 --> 00:34:53,879
Speaker 1: than the cold water.

742
00:34:54,040 --> 00:34:56,960
Speaker 3: Yeah. It's like the hot cup is constantly exposing the

743
00:34:57,080 --> 00:35:01,040
Speaker 3: hotter water to the surface, which helps cool Where there's

744
00:35:01,040 --> 00:35:03,720
Speaker 3: the colder cup, the water is moving more slowly through it,

745
00:35:03,800 --> 00:35:06,440
Speaker 3: and so it's not like as efficient at exposing the

746
00:35:06,480 --> 00:35:09,200
Speaker 3: hottest parts of itself. The hottest parts of itself stay

747
00:35:09,200 --> 00:35:11,759
Speaker 3: in the center for the cooler cup rather than the

748
00:35:11,840 --> 00:35:14,920
Speaker 3: hot cup. And that depends on like concurrence, which depends

749
00:35:14,960 --> 00:35:18,200
Speaker 3: on like fluid dynamics, which we all know is a nightmare.

750
00:35:18,239 --> 00:35:21,000
Speaker 1: But then wouldn't the hot cup need a colder bottom?

751
00:35:21,160 --> 00:35:22,560
Speaker 3: Yeah, and this is one of the reasons why this

752
00:35:22,640 --> 00:35:25,160
Speaker 3: depends on like where are you measuring this in the cup?

753
00:35:25,320 --> 00:35:27,600
Speaker 1: But how did it get a colder bottom?

754
00:35:27,640 --> 00:35:29,200
Speaker 3: Well, the hot water is going to rise to the

755
00:35:29,239 --> 00:35:32,520
Speaker 3: surface because density decreases with increasing temperature.

756
00:35:32,719 --> 00:35:36,359
Speaker 1: Hmmm, So it might be like more dense than at

757
00:35:36,360 --> 00:35:38,360
Speaker 1: the bottom of the hot cup than at the bottom

758
00:35:38,400 --> 00:35:40,799
Speaker 1: of the cold cup, exactly. I think there's also a

759
00:35:40,840 --> 00:35:44,040
Speaker 1: theory about heat conduction, right, like maybe that when you

760
00:35:44,200 --> 00:35:48,520
Speaker 1: initially put the cup into the freezer, like, it melts

761
00:35:48,680 --> 00:35:51,920
Speaker 1: the things around it a little bit more, which helps

762
00:35:51,960 --> 00:35:55,840
Speaker 1: it maybe connect to the coldness in the freezer better.

763
00:35:56,040 --> 00:35:59,400
Speaker 3: Exactly, because heat conduction is very different from material to material.

764
00:36:00,080 --> 00:36:03,600
Speaker 3: Between water and air surfaces it's one number. Between water

765
00:36:03,640 --> 00:36:06,640
Speaker 3: and water it's another. And so as we were saying earlier,

766
00:36:06,640 --> 00:36:08,880
Speaker 3: like if you put the cup on a frosty shelf

767
00:36:08,880 --> 00:36:11,680
Speaker 3: and that melts the frost near the cup, then you

768
00:36:11,800 --> 00:36:14,920
Speaker 3: now have like a water connection to that shelf. It

769
00:36:14,920 --> 00:36:17,520
Speaker 3: can very rapidly cool it. And so all sorts of

770
00:36:17,560 --> 00:36:19,920
Speaker 3: these little details. You can even pull frost out of

771
00:36:19,960 --> 00:36:21,799
Speaker 3: the air and then melt it. You can even pull

772
00:36:21,840 --> 00:36:24,319
Speaker 3: water vapor out of the air and it can accumulate

773
00:36:24,360 --> 00:36:26,560
Speaker 3: on the sides of the cup. All these things could

774
00:36:26,560 --> 00:36:29,560
Speaker 3: have a big difference on the experimental measurements. So I

775
00:36:29,640 --> 00:36:31,759
Speaker 3: think first we have to like nail down what are

776
00:36:31,760 --> 00:36:34,600
Speaker 3: the conditions we need to make this happen. Then we

777
00:36:34,600 --> 00:36:37,600
Speaker 3: can understand on the theoretical side like, do we understand

778
00:36:37,680 --> 00:36:40,959
Speaker 3: why it happens in one configuration and not another.

779
00:36:40,840 --> 00:36:43,480
Speaker 1: Meaning like, if you stick a cold cup in the

780
00:36:43,520 --> 00:36:46,600
Speaker 1: freezer and it's like my freezer, which is full of frost,

781
00:36:46,760 --> 00:36:48,880
Speaker 1: it will basically be like putting a cold cup of

782
00:36:48,920 --> 00:36:51,799
Speaker 1: water on a bank of snow, and because the water

783
00:36:51,880 --> 00:36:54,480
Speaker 1: is cold, it's not going to melt the snow, and

784
00:36:54,520 --> 00:36:56,919
Speaker 1: so it's basically going to be sitting kind of an

785
00:36:56,960 --> 00:37:00,400
Speaker 1: insulation of fluffy snow. Whereas if you put in a

786
00:37:00,440 --> 00:37:02,560
Speaker 1: hot cup, it's going to be hot enough to melt

787
00:37:02,560 --> 00:37:06,000
Speaker 1: that snow, which basically melts and then it basically it

788
00:37:06,040 --> 00:37:09,719
Speaker 1: turns into ice around it, which means that the hot

789
00:37:09,719 --> 00:37:13,799
Speaker 1: cup's going to have basically like a fast track for

790
00:37:13,840 --> 00:37:14,960
Speaker 1: the heat to escape.

791
00:37:14,719 --> 00:37:17,279
Speaker 3: Exactly for the same reason that like wet jeans will

792
00:37:17,280 --> 00:37:21,440
Speaker 3: make you colder on a ski hill than snowy dry jeans, right,

793
00:37:21,520 --> 00:37:24,320
Speaker 3: that water will conduct heat away from you much faster

794
00:37:24,719 --> 00:37:27,680
Speaker 3: than the snow will. So if you melt the surrounding area,

795
00:37:27,840 --> 00:37:29,839
Speaker 3: then very quickly your heat is going to bleed out.

796
00:37:29,920 --> 00:37:31,560
Speaker 1: And that's the reason you don't ski, right.

797
00:37:31,719 --> 00:37:34,839
Speaker 3: That's one reason I don't ski. Absolutely. There are so.

798
00:37:34,920 --> 00:37:39,399
Speaker 1: Many Well we can fix that one pretty quick then

799
00:37:39,400 --> 00:37:40,720
Speaker 1: and just use a special socks.

800
00:37:41,080 --> 00:37:43,000
Speaker 3: No waterproof pants are the answer to that one.

801
00:37:43,360 --> 00:37:44,800
Speaker 1: Yeah, yeah, those ski and jeans.

802
00:37:44,880 --> 00:37:47,799
Speaker 3: But the physicist in me is more interested in, like,

803
00:37:47,880 --> 00:37:50,720
Speaker 3: what's happening to these particles, and how do you zoom

804
00:37:50,719 --> 00:37:53,560
Speaker 3: out from all these tiny little particles doing their thing

805
00:37:53,600 --> 00:37:57,880
Speaker 3: individually to an explanation of what's happening to the water,

806
00:37:58,360 --> 00:38:01,200
Speaker 3: right because in the world enteract with, there's not individual

807
00:38:01,239 --> 00:38:04,000
Speaker 3: particles of water in their hydrogen bonds, but like the

808
00:38:04,040 --> 00:38:05,759
Speaker 3: water in your cup, or you want to freeze your

809
00:38:05,760 --> 00:38:07,800
Speaker 3: ice cream. And in the end, what we're trying to

810
00:38:07,840 --> 00:38:11,240
Speaker 3: do is explain that universe. And it's very very difficult

811
00:38:11,280 --> 00:38:14,640
Speaker 3: sometimes to connect this picture of the microscopic particles with

812
00:38:14,800 --> 00:38:17,280
Speaker 3: our actual experience and like things we can measure.

813
00:38:17,640 --> 00:38:20,640
Speaker 1: But I guess maybe I wonder if the point is

814
00:38:20,680 --> 00:38:24,080
Speaker 1: that if you have a very simple model, or just

815
00:38:24,120 --> 00:38:27,880
Speaker 1: assume that it's like some molecules floating in a simple

816
00:38:27,960 --> 00:38:30,919
Speaker 1: canister or something, then you do expect the cold water

817
00:38:31,000 --> 00:38:33,520
Speaker 1: to freeze faster. But because we live in the real

818
00:38:33,560 --> 00:38:35,960
Speaker 1: world and there's all these different things that can happen,

819
00:38:36,520 --> 00:38:39,680
Speaker 1: and the way that the water freezes and you know,

820
00:38:39,760 --> 00:38:43,240
Speaker 1: the heat conduction depends on surfaces and what those surfaces

821
00:38:43,280 --> 00:38:48,360
Speaker 1: are touching or which direction they're pointing. Then the phenomenon

822
00:38:48,400 --> 00:38:50,720
Speaker 1: of a freezing is much more complex.

823
00:38:50,920 --> 00:38:54,480
Speaker 3: Yeah, that's exactly right. We're trying to describe a complicated

824
00:38:54,520 --> 00:38:57,480
Speaker 3: emergent behavior, and we usually start with a simple model

825
00:38:57,600 --> 00:39:00,320
Speaker 3: because we hope that works. And often this simple model,

826
00:39:00,360 --> 00:39:03,239
Speaker 3: which just has like temperature, pressure, volume, does work. It

827
00:39:03,280 --> 00:39:06,040
Speaker 3: works amazingly well, it's incredible. But we can also learn

828
00:39:06,080 --> 00:39:08,600
Speaker 3: from when it fails. And when it fails this tells

829
00:39:08,680 --> 00:39:11,640
Speaker 3: us that other details that we've ignored in our model

830
00:39:11,760 --> 00:39:14,440
Speaker 3: are now important. They may even be crucial. They may

831
00:39:14,440 --> 00:39:17,600
Speaker 3: even determine the total outcome. And that's an opportunity to

832
00:39:17,640 --> 00:39:19,840
Speaker 3: learn something, to go back and say, Okay, well, what

833
00:39:20,040 --> 00:39:22,279
Speaker 3: is it that we didn't include in our description that

834
00:39:22,360 --> 00:39:24,239
Speaker 3: give us that simple story, and how do we need

835
00:39:24,280 --> 00:39:27,280
Speaker 3: to make it more complicated to describe what we're actually doing.

836
00:39:27,520 --> 00:39:31,360
Speaker 3: Science is all about that, right, Start simple, and then refine, refine, refine.

837
00:39:31,760 --> 00:39:33,680
Speaker 1: And I feel like this question is interesting, as you

838
00:39:33,719 --> 00:39:36,960
Speaker 1: said before, because it taps into the chemistry of water

839
00:39:37,040 --> 00:39:40,279
Speaker 1: and the dynamics of water, which might be related to

840
00:39:40,960 --> 00:39:43,520
Speaker 1: how life started right here on Earth. And maybe in

841
00:39:43,560 --> 00:39:47,200
Speaker 1: other planets. Like, if we understand more how what's happening

842
00:39:47,239 --> 00:39:50,000
Speaker 1: at the molecular level with water, maybe we can understand

843
00:39:50,040 --> 00:39:52,719
Speaker 1: how likely or less likely it is or necessary it

844
00:39:52,760 --> 00:39:55,680
Speaker 1: is for water to be there for the molecules that

845
00:39:55,719 --> 00:39:57,000
Speaker 1: make life deform.

846
00:39:57,160 --> 00:40:01,040
Speaker 3: Yeah. One theory about how organic molecules we're created on

847
00:40:01,120 --> 00:40:04,600
Speaker 3: Earth involves like asteroids slamming into the Earth, and if

848
00:40:04,600 --> 00:40:08,239
Speaker 3: those asteroids have ice in them, then those very high temperature,

849
00:40:08,400 --> 00:40:12,279
Speaker 3: high pressure impacts could have created conditions needed for that

850
00:40:12,360 --> 00:40:15,840
Speaker 3: kind of chemistry to happen. So understanding exactly how water

851
00:40:15,880 --> 00:40:18,279
Speaker 3: works and all the weird forms that it can take

852
00:40:18,600 --> 00:40:21,480
Speaker 3: is crucial for understanding how life could have started here

853
00:40:21,520 --> 00:40:24,680
Speaker 3: and also what the conditions might be like on exoplanets.

854
00:40:24,960 --> 00:40:27,439
Speaker 3: We're like right on this exciting cusp of being able

855
00:40:27,480 --> 00:40:31,120
Speaker 3: to detect water vapor in the atmospheres of planets around

856
00:40:31,200 --> 00:40:34,879
Speaker 3: other Solar systems, and understanding the chemistry of that gives

857
00:40:34,960 --> 00:40:37,600
Speaker 3: us a deeper and richer picture of what it's like

858
00:40:37,719 --> 00:40:40,400
Speaker 3: on those surfaces and what it might be like to

859
00:40:40,440 --> 00:40:43,600
Speaker 3: be a squigly blob crawling around and waiting for your

860
00:40:43,640 --> 00:40:44,520
Speaker 3: ice cream to cool.

861
00:40:44,880 --> 00:40:47,160
Speaker 1: Yeah, or not even maybe that far like even in

862
00:40:47,200 --> 00:40:49,520
Speaker 1: our solar system. The moon, one of the moons of

863
00:40:49,560 --> 00:40:52,839
Speaker 1: Jupiter Europa, Right, it's made out of ice on top,

864
00:40:52,960 --> 00:40:55,040
Speaker 1: and it's got an ocean of liquid water inside. So

865
00:40:55,200 --> 00:40:57,160
Speaker 1: we kind of want to know, is it possible for

866
00:40:57,239 --> 00:40:58,279
Speaker 1: life to exist there?

867
00:40:58,320 --> 00:41:00,960
Speaker 3: Oh yeah, you're absolutely right. I'm that close to home.

868
00:41:01,080 --> 00:41:05,160
Speaker 3: There's exciting water chemistry happening in our solar system. It's

869
00:41:05,200 --> 00:41:08,359
Speaker 3: crazy to imagine this, like frozen crust of ice under

870
00:41:08,360 --> 00:41:11,760
Speaker 3: which there's like a mile deep ocean of super cold

871
00:41:11,840 --> 00:41:14,400
Speaker 3: water in which maybe life has started.

872
00:41:14,440 --> 00:41:17,600
Speaker 1: We just don't know, Yeah, because we know there's life underneath,

873
00:41:17,640 --> 00:41:22,360
Speaker 1: like the ice shelf in Antarctica. But maybe, like you

874
00:41:22,440 --> 00:41:25,960
Speaker 1: need some special conditions for life to start. Maybe they

875
00:41:25,960 --> 00:41:27,960
Speaker 1: can start in somewhere like EUROPEA.

876
00:41:28,200 --> 00:41:30,200
Speaker 3: Yeah, I wonder if you take two moons of Jupiter

877
00:41:30,280 --> 00:41:31,440
Speaker 3: and one of them is hotter and one of them

878
00:41:31,480 --> 00:41:33,240
Speaker 3: is colder, which one will freeze first?

879
00:41:33,560 --> 00:41:35,560
Speaker 1: Yeah, you need a pretty big freezer for that bo

880
00:41:36,560 --> 00:41:37,800
Speaker 1: like maybe space.

881
00:41:39,360 --> 00:41:42,200
Speaker 3: Now, imagining a moon size chunk of ice cream.

882
00:41:42,320 --> 00:41:46,000
Speaker 1: There you go, a giant scoop the ship the size

883
00:41:46,040 --> 00:41:49,359
Speaker 1: of the moons. That's no moon, that's a giant ball

884
00:41:49,400 --> 00:41:50,279
Speaker 1: of ice cream.

885
00:41:51,880 --> 00:41:52,880
Speaker 3: That'll be the death of me.

886
00:41:53,160 --> 00:41:55,600
Speaker 1: I can hear the cries of a thousand white suns

887
00:41:56,360 --> 00:41:59,560
Speaker 1: or a billion white sons crying out fur their ice.

888
00:41:59,440 --> 00:42:02,760
Speaker 3: Cream as our cholesterol rises and temperature drops.

889
00:42:03,440 --> 00:42:07,279
Speaker 1: That's right, and our mass increases as well. Okay, So

890
00:42:07,320 --> 00:42:09,439
Speaker 1: what would you do, Daniel if your daughter asks you

891
00:42:09,680 --> 00:42:12,040
Speaker 1: what would happen if you stuck a cold horse and

892
00:42:12,360 --> 00:42:15,719
Speaker 1: a warmer horse in a freezer? Would you be concerned?

893
00:42:16,239 --> 00:42:19,399
Speaker 1: Would you be like, oh, interesting questions? Sit down, let

894
00:42:19,400 --> 00:42:20,239
Speaker 1: me explain this to you.

895
00:42:20,520 --> 00:42:23,320
Speaker 3: I try to summarize this entire podcast in thirty seconds,

896
00:42:23,520 --> 00:42:27,360
Speaker 3: and I would fail. It's hard, man, it's hard.

897
00:42:27,680 --> 00:42:30,760
Speaker 1: Well, yeah, it kind of has an impact on horses

898
00:42:30,800 --> 00:42:31,959
Speaker 1: and cold laces, right.

899
00:42:31,920 --> 00:42:34,360
Speaker 3: Yeah, absolutely No. I tell her that we don't know

900
00:42:34,360 --> 00:42:36,600
Speaker 3: the answer to that, that it's too complicated, and maybe

901
00:42:36,640 --> 00:42:38,439
Speaker 3: she should grow up and figure it out.

902
00:42:38,560 --> 00:42:41,080
Speaker 1: Mmm, become a horse chemist.

903
00:42:42,200 --> 00:42:43,760
Speaker 3: Better than a horse particle collider.

904
00:42:44,600 --> 00:42:49,399
Speaker 1: Yeah, that would be a nea career you want to pursue.

905
00:42:51,000 --> 00:42:52,960
Speaker 3: That's not science, that's just horsing around.

906
00:42:53,719 --> 00:42:56,960
Speaker 1: Yeah. Yeah, don't look at gift horse and the particle collider.

907
00:42:58,600 --> 00:43:00,320
Speaker 3: I don't know what that means, but I laughed anyway.

908
00:43:01,360 --> 00:43:05,879
Speaker 1: I don't know either, it's horse nonsense, all right. Well,

909
00:43:05,880 --> 00:43:09,480
Speaker 1: another reminder that there are still mysteries in the universe,

910
00:43:09,560 --> 00:43:11,400
Speaker 1: and some of them that you could even do at

911
00:43:11,400 --> 00:43:14,880
Speaker 1: home and experiment and see for yourself how weird things

912
00:43:14,920 --> 00:43:17,520
Speaker 1: can happen and how complicated even something as simple as

913
00:43:17,520 --> 00:43:18,360
Speaker 1: making ice can be.

914
00:43:18,560 --> 00:43:22,120
Speaker 3: Teenagers out there, your questions to your science teacher could

915
00:43:22,200 --> 00:43:27,280
Speaker 3: kick off a multi decade exploration and reveal deeper understandings

916
00:43:27,320 --> 00:43:30,520
Speaker 3: of the natures of liquids and solids. So keep thinking,

917
00:43:30,680 --> 00:43:33,360
Speaker 3: keep asking questions, and keep eating ice cream.

918
00:43:33,560 --> 00:43:36,440
Speaker 1: We hope you enjoyed that. Thanks for joining us, See

919
00:43:36,480 --> 00:43:37,000
Speaker 1: you next time.

920
00:43:41,560 --> 00:43:44,360
Speaker 3: For more science and curiosity, come find us on social

921
00:43:44,440 --> 00:43:48,960
Speaker 3: media where we answer questions and post videos. We're on Twitter, Discboard,

922
00:43:49,040 --> 00:43:52,400
Speaker 3: Instant and now TikTok. Thanks for listening and remember that

923
00:43:52,560 --> 00:43:56,360
Speaker 3: Daniel and Jorge Explain the Universe is a production of iHeartRadio.

924
00:43:56,640 --> 00:44:00,560
Speaker 3: For more podcasts from iHeartRadio, visit the iheartradi, your app,

925
00:44:00,840 --> 00:44:04,280
Speaker 3: Apple Podcasts, or wherever you listen to your favorite shows.

926
00:44:08,719 --> 00:44:09,200
Speaker 4: Mm hmm.