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Speaker 1: Hey, Daniel, what are physicists favorite foods? Dark chocolate, heavy water,

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Speaker 1: dark chocolate.

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Speaker 2: Studded with chunks of dark matter. Now I heard that

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Speaker 2: Newton liked chicken pot pie weirdly enough.

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Speaker 1: Well, yeah, was it because of the nutrients?

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Speaker 2: I heard actually that he likes a really thick gravy

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Speaker 2: as high specific gravity.

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Speaker 1: Mmm. I heard he was more of a cookie man.

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Speaker 2: What really, Isaac Newton eating something as silly as a cookie?

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Speaker 1: Yeah? It didn't even invent the fake newtonts.

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Speaker 2: I think actually those cookies were named after the town

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Speaker 2: of Newton, Massachusetts, where they were first baked.

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Speaker 1: Uh, But then wasn't the town named after Isaac Newton,

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Speaker 1: So technically he's grandfathered in.

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Speaker 2: I think its name comes from it being invaded by

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Speaker 2: a huge swarm of Newts.

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Speaker 1: The next thing you're gonna tell me is that Einstein's

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Speaker 1: brothers bagels was not invented by iceland on his brother.

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Speaker 2: No, but if you need enough of them, youal curve space.

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Speaker 1: I feel like it's a big hole in that story.

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Speaker 2: Hi.

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Speaker 1: I'm Jorhem mccartoonists and the author of Oliver's Great Big Universe.

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Speaker 2: Hi I'm Daniel. I'm a particle physicist and a professor

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Speaker 2: at uc Erine, and I'll always love the Everything Bagel.

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Speaker 1: Do you like everything about bagels or the bagel that's

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Speaker 1: called the everything Bagel?

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Speaker 2: I like the Everything Bagel, though I expected you to

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Speaker 2: criticize it for not being accurately named. I mean, it's

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Speaker 2: not literally everything on the bagel.

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Speaker 1: If it did, it would maybe collapse into a black

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Speaker 1: hole and collapse in multiverse, as some movies would happen.

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Speaker 2: If it literally had everything on it, it would also have

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Speaker 2: to have everything bagels on it, so it'd be like

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Speaker 2: a recursive bagels with bagels on it, and bagels on those,

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Speaker 2: and bagels on those forever down to the tiniest little bagels.

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Speaker 1: It goes all the way down to the center of reality.

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Speaker 1: Big of the movie was.

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Speaker 2: Right, everything bagel, everywhere, all at once.

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Speaker 1: Welcome to our podcast Daniel and Jorge Explain the Universe,

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Speaker 1: a production of iHeartRadio.

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Speaker 2: Where we think about the universe as a huge tasty snack.

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Speaker 2: You can put smeer on it, you can slap locks

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Speaker 2: on it, or you can just try to understand it.

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Speaker 2: We hope that the universe is intellectually devourable at least

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Speaker 2: that we can gather all of the knowledge and observations

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Speaker 2: that humanity has been making for thousands of years and

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Speaker 2: somehow weigh them together into a story about how everything works,

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Speaker 2: how the tiniest little bits interact, how they come together

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Speaker 2: to make weird fluids and goofy stuff and solids and

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Speaker 2: metals that we live with all the way up to

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Speaker 2: planets and galaxies and black holes.

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Speaker 1: Yes, it is a pretty delicious universe full of amazing

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Speaker 1: things that will fill you up in your brain, fill

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Speaker 1: up your head with knowledge and amazing facts and incredible

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Speaker 1: processes going out there in the cosmos, in between galaxies,

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Speaker 1: inside of galaxies, and inside of all of us sometimes

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Speaker 1: because we ate it.

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Speaker 2: One of my favorite things about physics is that it's

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Speaker 2: fascinating at so many different levels. I mean, on this podcast,

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Speaker 2: we usually focus on the very very very tiny, trying

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Speaker 2: to understand the fundamental nature of matter, or like they're

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Speaker 2: really really big thinking about the whole universe, and it's

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Speaker 2: incredible that there are stories at both of those levels

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Speaker 2: that we can think about, that we can understand that

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Speaker 2: give us some like intuitive grasp on the workings of

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Speaker 2: the universe. But don't forget that there's lots of levels

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Speaker 2: in between, like the ones we live on, things about

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Speaker 2: a meter scale and moving kind of slowly, and so

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Speaker 2: much fascinating physics that happens here on Earth.

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Speaker 1: Wait are you saying physics is happening everywhere, all at once,

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Speaker 1: on everything, everywhere, all at once.

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Speaker 2: I'm saying you have to have physics as a topping

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Speaker 2: on your bagel if it's got everything on it, But.

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Speaker 1: Then to put it on top would require physics.

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Speaker 2: And I'm not saying physics on top of everything. You know,

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Speaker 2: I have deep love and respect for chemistry as well.

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Speaker 1: Maybe everything bagel is physics. That's why Eistein and his

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Speaker 1: brother invented the baggel.

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Speaker 2: Or haes bagel theory of the universe.

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Speaker 1: Isn't a bagel a possible shape of the universe, like

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Speaker 1: a taurus?

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Speaker 2: Yeah right, yeah, I think the mathematicians call it a

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Speaker 2: taurus or a doughnut, rarely a bagel. But yeah, that's possible.

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Speaker 2: But I think the fact that your theory is shaped

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Speaker 2: like a zero might give you a.

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Speaker 1: Clue because it's the first thing and that the universe

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Speaker 1: was made out of. It's the zero theorem.

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Speaker 2: Yeah, let's go with that. But there is so much

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Speaker 2: fascinating physics that happens, not just at the tiny scale

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Speaker 2: and at the huge scale, but right here on Earth.

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Speaker 2: The way the particles weave themselves together creates all sorts

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Speaker 2: of fascinating chemistry and biology and of course life here

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Speaker 2: on Earth. And along the way, there's lots of really

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Speaker 2: interesting questions we can ask, not about the fundamental nature

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Speaker 2: of stuff, but what that stuff does when it comes together.

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Speaker 1: Yeah, because as we said, physics is happening everywhere. It

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Speaker 1: doesn't just happen in a laboratory and a big research

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Speaker 1: institution or a university. It also happens all the time everywhere,

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Speaker 1: even in your kitchen. There are all kinds of interesting

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Speaker 1: examples of physics everywhere all around us, in the foods

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Speaker 1: we eat and the foods that you prepare, and also

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Speaker 1: in things like slime.

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Speaker 2: And a couple of years ago, during the pandemic, there

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Speaker 2: was this huge trend of kids making slime in their kitchens,

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Speaker 2: which seem to explode everywhere, all over the Internet and

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Speaker 2: all over the walls of our kitchen.

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Speaker 1: Wait literally explode or figuratively explode.

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Speaker 2: Well, my daughter made all sorts of various kinds of

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Speaker 2: slime I remember at least one of them blew up

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Speaker 2: on her.

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Speaker 1: It isn't the definition of slime that it gets all

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Speaker 1: over the place and it's a big mess. Like we

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Speaker 1: just made slime and kept it in a cup. It's

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Speaker 1: not really slime. It's only sime if you like, pick

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Speaker 1: it up and pull it apart with your fingers.

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Speaker 2: Slime is as slime does.

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Speaker 1: But yeah, there are all kinds of amazing physics we

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Speaker 1: can observe and ask questions about it in our everyday lives.

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Speaker 1: And one of those questions that we often get is

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Speaker 1: about a very specific kind of liquid.

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Speaker 2: People playing around in their kitchens and making slime and

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Speaker 2: wondering about the physics of solids and gases and liquids.

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Speaker 2: A bunch of them wrote in to ask us about

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Speaker 2: the physics of this but particular kind of goo.

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Speaker 1: So today on the podcast, we'll be asking the question,

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Speaker 1: what is a non Newtonian fluid?

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Speaker 2: Isn't that just something Newton wouldn't have on his.

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Speaker 1: Chicken or his fake newtonts. Maybe it's a a schmeir

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Speaker 1: on a Einstein bagel.

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Speaker 2: There you go. I'd like the Newton shmer and the

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Speaker 2: Einstein bagel, please.

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Speaker 1: Yeah, but not everyone likes it. You know, it's all relative.

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Speaker 1: But yeah, it's an interesting question. I feel like this

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Speaker 1: is one of those terms non Newtonian fluids that you

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Speaker 1: hear all the time, sort of in like physics shows

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Speaker 1: or physics explanations that's used like as an explanation for

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Speaker 1: a phenomenon. But it's not really an explanation to say

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Speaker 1: that the fluid that has a name on it.

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Speaker 2: Well, it's sort of weird that you define it by

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Speaker 2: what it Isn't like I could serve you dinner and say, hey,

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Speaker 2: this is not a bagel. I've made it for dinner.

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Speaker 2: Doesn't really tell you what it is, right, It could

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Speaker 2: still be lots of different things.

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Speaker 1: Oh right, Yeah, I guess maybe that only works that

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Speaker 1: there are only two kinds of something in the world,

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Speaker 1: Like is this an everything bagel or not everything bigel?

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Speaker 1: Technically every bagel doesn't have everything on it is a

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Speaker 1: non everything bagel.

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Speaker 2: It's true that every meal any human is ever eaten

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Speaker 2: is either an everything bagel or it's not an everything bagel.

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Speaker 1: Right, or nothing bige.

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Speaker 2: That sounds kind of like a nothing burger.

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Speaker 1: Exactly, it's a nothing bagel burger.

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Speaker 2: But this is not a nothing burger of physics. There

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Speaker 2: are Newtonian fluids that follow certain rules, and then weird

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Speaker 2: kinds of fluids that don't follow Newton's strict laws about

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Speaker 2: how fluids should go.

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Speaker 1: Yeah, so this is an interesting question what is a

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Speaker 1: non Newtonian fluid? And so, as usually, we were wondering

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Speaker 1: how many people out there had thought about this question

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Speaker 1: or wondered what exactly is going on in a non

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Speaker 1: Newtonian fluid.

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Speaker 2: So thanks very much to everybody who answers these questions.

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Speaker 2: If you're up for us playing your answers to questions,

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Speaker 2: please write to us to questions at Danielandjorge dot com.

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Speaker 1: So think about it for a second. Are you in

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Speaker 1: the non Newtonian or the pro Newtonian? Can here's a

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Speaker 1: depled to say.

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Speaker 3: Maybe it's when the molecules in a fluid don't react

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Speaker 3: according to Newton's laws of gravitation.

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Speaker 2: I don't know.

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Speaker 3: I've heard of non Newtonian fluids, but I'm not sure

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Speaker 3: what makes them non Newtonian. I think it means that

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Speaker 3: you don't use the usual fluid mechanics that you would

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Speaker 3: with fluids that we're used to. Examples of non Newtonian

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Speaker 3: fluids might be liquid helium, and maybe the fluid in

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Speaker 3: the interior of a neutron star, possibly ferrofluids, but that

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Speaker 3: doesn't mean I know why they're non Newtonian.

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Speaker 1: Non Newtonian fluid. I didn't know there is Newtonian fluid,

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Speaker 1: but I'm guessing that this non Newtonian fluid doesn't follow

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Speaker 1: the like three Newton's laws.

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Speaker 4: The first example that comes to mind is a mixture

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Speaker 4: of cornstarch and water. If you mix those two things

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Speaker 4: together in a glass and try to pour it out,

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Speaker 4: it will flow like a viscous fluid, but if you

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Speaker 4: impact it quickly with your finger, will solidify. So I

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Speaker 4: think a non Newtonian fluid is one that displays properties

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Speaker 4: of more than one phase of matter, either liquid, solid

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Speaker 4: or probably gas.

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Speaker 5: Well, non Neutonian fluids, that's a pretty cool one. I mean,

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Speaker 5: non Newtonia makes me thinks of quantum mechanics, So this

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Speaker 5: must be some fluids made of super small particles, elementary particles,

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Speaker 5: maybe electrons, maybe subparticles. So and then this fluid will

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Speaker 5: respond to quantum chemistry quantum physics, so it would be.

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Speaker 2: A pretty crazy fluid. What is a non Netonian food?

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Speaker 3: I don't even know what a non Newtonian fluid is,

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Speaker 3: so I'm going to say a non Newtonian fluid is

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Speaker 3: most fluid.

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Speaker 2: I don't know what a non Newtonian fluid is. I

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Speaker 2: assume it's of some sort of fluid that's not like

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Speaker 2: the ones I'm familiar with.

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Speaker 1: I have a vague feeling that a non Newtonian fluid

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Speaker 1: is one that is compressible, whereas a Newtonian one is uncompressible.

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Speaker 3: I think a non Newtonian fluid is one that doesn't

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Speaker 3: obey the equations made by Newton.

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Speaker 1: A lot of interesting answers here. I guess a lot

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Speaker 1: of people did assume that it has something to do

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Speaker 1: with Isaac Newton.

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Speaker 2: M hm, though I particularly like the suggestion that maybe

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Speaker 2: it's an anti gravity liquid.

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Speaker 1: Oh interesting, that'd be pretty awesome if you can make

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Speaker 1: that in your kitchen.

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Speaker 2: Yeah, Like Newton did so much in physics, it's not

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Speaker 2: clear what non Newtonian means, Like which of Newton's laws

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Speaker 2: are you breaking? Are you like, violating the fundamental laws

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Speaker 2: of calculus or of gravity or of motion or what?

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Speaker 1: I think the fluid kind of gives it away a

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Speaker 1: little bit, right, It's not a non Newtonian math ages

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Speaker 1: Newton's laws in relation to liquids or as they relate

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Speaker 1: to liquids.

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Speaker 2: It really is incredible that one of like the minor

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Speaker 2: things that Newton did is still an important work of physics,

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Speaker 2: one that would get any other physicists their name on

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Speaker 2: an equation forever. But for Newton it's like the ninth

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Speaker 2: and most important thing he did.

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Speaker 1: Yeah, although if if something named something after not you would,

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Speaker 1: can you still take credit for it? Like I have

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Speaker 1: invented the non Daniel Whitson particle. That would be almost

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Speaker 1: like a very passive aggressive move there.

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Speaker 2: Hey, slap my name on something famous forever as an insult,

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Speaker 2: I'll take it.

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Speaker 1: M Like if someone discovers the truth about everything, the

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Speaker 1: core nugget of reality and called it the not Weissen theorem, we.

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Speaker 2: Have the anti white syn theorem. Go ahead and do it.

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Speaker 2: You name it after me forever. Any publicity is good publicity.

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Speaker 1: All right, Well, Stasty, you heard it on the podcast.

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Speaker 1: You have it on his permission to not not name

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Speaker 1: things not after it.

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Speaker 2: You just want to be part of the conversation.

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Speaker 1: Man, I guess if your name being spoken in a

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Speaker 1: negative way, they're still talking about it.

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Speaker 2: Yeah, I mean, what if the announce like Black Panther

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Speaker 2: three not starring or hey, cham, you'd be pretty thrilled.

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Speaker 1: Still mmm, I think I'd rather just stay out of

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Speaker 1: that conversation. You know, I'm not that desperate yet. All Right, Well,

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Speaker 1: let's get back to non Newtonian fluids, and maybe let's

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Speaker 1: start at the beginning, like what is a pro neutuinin

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Speaker 1: or regular in Neetonian fluid?

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Speaker 2: Yeah, So fluids are fascinating things, right because they have

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Speaker 2: constant volume, like they don't grow or shrink, but they

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Speaker 2: don't have a fixed shape. So you can like take

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Speaker 2: a glass of water and you can pour it into

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Speaker 2: a bowl and the volume of it doesn't change, but

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Speaker 2: it'll fill the bowl, it'll take that new shape. Or

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Speaker 2: you can put it into a baggie, or you can

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Speaker 2: dump it on the floor and they can do a puddle.

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Speaker 2: Total volume of stuff won't change, but its overall shape

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Speaker 2: is totally flexible. And that's really cool because it sits

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Speaker 2: right between gases and solids. Gases don't have constant volume,

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Speaker 2: they'll grow to fill any box you put them in.

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Speaker 2: Solids have constant volume, but they also have a fixed shape.

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Speaker 2: So fluids are this fascinating sort of half step between

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Speaker 2: and solids.

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Speaker 1: Well, you just sort of blew my mind or a

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Speaker 1: little bit. I hadn't thought about the definition of the

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Speaker 1: states of matter in that way. I guess, huh, is

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Speaker 1: that basically what divides the three states of matter? Is

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Speaker 1: that the technical definition or is there something more specific

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Speaker 1: about the molecules or something.

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Speaker 2: Well, there's fascinating history there because originally, of course, we

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Speaker 2: didn't understand that matter was made out of molecules and

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Speaker 2: little particles. Now we do have a molecular understanding for

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Speaker 2: these phases of matter, but originally we didn't, and we

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Speaker 2: still define them. It was just observational, the way a

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Speaker 2: lot of physics is currently, Like, here's the kind of

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Speaker 2: stuff we see in the universe. We notice there's this

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Speaker 2: kind of stuff. There's drippy stuff, and this solid stuff,

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Speaker 2: and there's puffy stuff. And that's how we begin. We

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Speaker 2: start with observations, and we describe it, we categorize it,

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Speaker 2: and then later we hope to get a microphysical understanding

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Speaker 2: of where that comes from. Now, of course we know

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Speaker 2: that everything is made out of molecules, and in gases,

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Speaker 2: things are flying apart and basically not interacting, and in

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Speaker 2: liquids there are still some bonds there, and then in

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Speaker 2: solids they often form this crystal structure which is the

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Speaker 2: source of their rigidity. Right, So we have an understanding now,

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Speaker 2: but I think originally it just comes from observing different

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Speaker 2: kinds of drippiness and gooiness.

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Speaker 1: Yeah, that's what I mean. It's like, did we get

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Speaker 1: it right all those hundreds or thousands of years ago,

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Speaker 1: Like our physic is still using the same definition for

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Speaker 1: the states of matter.

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Speaker 2: It's changed a little bit and gotten a little bit

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Speaker 2: more complicated as we've understood the microphysics. So now there's

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Speaker 2: like thermodynamic definitions of phases and multiple versions of each

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Speaker 2: of these things. You know, water, for example, has multiple

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Speaker 2: different solid phases, not just ice. There's like ice one

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Speaker 2: through ice nine, or maybe even ice twelve. Chemistry experts

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Speaker 2: can tell you all about the different kinds of ice

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Speaker 2: because water forms lots of different crystal structures under different

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Speaker 2: pressures and temperatures.

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Speaker 1: Is that why some cultures have like a lot of

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Speaker 1: different words for snow sort of right? Sort of?

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Speaker 2: Maybe there's definitely lots of different crystal structures for ice.

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Speaker 2: I don't know if the linguistic history of some of

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Speaker 2: those languages recognizes those subtle differences, or if that's just

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Speaker 2: an accident. But it is true that there's lots of

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Speaker 2: different ways to form ices, especially waters and especially complicated

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Speaker 2: chemical other things only form one kind of solid, So

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Speaker 2: there's definitely a lot more going on once you understand it.

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Speaker 2: And there's lots of different kinds of phase transitions, the

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Speaker 2: kinds that we think about gas, liquid, solid. Those are

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Speaker 2: what we call first order phase transitions. We have like

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Speaker 2: a discontinuity in the density. Things get much thicker as

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Speaker 2: they get colder and change their density. They are also

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Speaker 2: second order phase transitions, where you don't change from like

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Speaker 2: a liquid to a solid, but you change like your

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Speaker 2: heat capacity or other thermal properties. So there's definitely a

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Speaker 2: lot more going on. But yeah, we sort of got

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Speaker 2: the big picture right early on. But you know, remember,

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Speaker 2: the physics is all about explaining the universe to humans,

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Speaker 2: and this is our experience. We see these different kinds

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Speaker 2: of things in the world. We want to understand what's

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Speaker 2: going on and have explanations for that. So we're always

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Speaker 2: going to want to explain the basic experience we have

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Speaker 2: when interacting.

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Speaker 1: With the world. Okay, So then you're saying that a

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Speaker 1: fluid is a stuff that, when you put it inside

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Speaker 1: of a cup, moves and changes its shape to adapt

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Speaker 1: to that space, that volume, but it keeps its volume.

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Speaker 1: That's the basic definition of a fluid.

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Speaker 2: H that's technically the definition of a liquid, and all

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Speaker 2: liquids are also fluids. Fluids, in addition, can encompass actually

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Speaker 2: solids because some solids can flow. We don't need to

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Speaker 2: dig into the differences between fluids and liquids. That's for

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Speaker 2: like law school types. But essentially, yes, that's what we're

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Speaker 2: talking about. Fluids, things that have constant volume but not

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Speaker 2: a fixed shape.

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Speaker 1: Oh. I see, some solids like sand can act in

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Speaker 1: a fluid way, but it's technically not in a different

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Speaker 1: state of matter.

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Speaker 2: So liquid refers to the state of matter, fluid refers

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Speaker 2: to the properties of the object, and they're very closely connected.

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Speaker 2: But they're exceptions in both directions.

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Speaker 1: I see. So which one are we talking about here? Today?

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Speaker 1: Are we talking about non Newtonian fluids or non Newtonian liquids?

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Speaker 2: We're talking about non Newtonian fluids, almost all of which are.

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Speaker 1: Liquids, but there are some that are not.

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Speaker 2: There might be, but I don't have an example for you.

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Speaker 2: The fluids themselves also have a huge range of properties,

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Speaker 2: Like you know that pouring honey is very different from

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Speaker 2: pouring water. Right, One of them flows very very quickly,

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Speaker 2: one of them flows very very slowly. Like there's a

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Speaker 2: huge range of the goopiness of the fluid itself.

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Speaker 1: Right, right, thinks are more or less viscous, But that

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Speaker 1: has nothing to do with the state of matter, right

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Speaker 1: of it, stickness of matternness of it. It's more some

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Speaker 1: sort of other dimension of properties, kind of.

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Speaker 2: Exactly within this fluid category, you have viscous fluids and

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Speaker 2: non viscous fluids, basically like how thick is the fluid?

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Speaker 2: This is like the subject of the pilot episode for

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Speaker 2: our TV show, right, the goopiness of stuff.

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Speaker 1: Our show ellenor Wonders Why which by the way, Arizona,

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Speaker 1: Pbius Kids and under streaming apps just wanted to put

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Speaker 1: that plug in.

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Speaker 2: Yeah, exactly. So you pour water into a box, it

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Speaker 2: flows very very quickly, and you pour honey into a box.

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Speaker 2: You could be standing there for ten minutes right before

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Speaker 2: the honey finally pours out of the jar, and even

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Speaker 2: once it's in the box, it takes a while else

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Speaker 2: to spread out and eventually fill up that box. Still

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Speaker 2: categorized as a fluid, it still will flow, keep the

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Speaker 2: same volume and fill out the box, but feel very

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Speaker 2: different from water because of this difference in viscosity. So

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Speaker 2: as you say, this is like another axis along which

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Speaker 2: to think about fluids.

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Speaker 1: Right, And it has maybe something to do with a

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Speaker 1: different set of sort of physics, maybe unrelated to the

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Speaker 1: states of matter, right or is it all just physics

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Speaker 1: all of one.

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Speaker 2: It's all just physics all the way down.

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Speaker 4: Man.

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Speaker 2: In the end, there is a microphysical understanding of this viscosity,

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Speaker 2: which does come from how the molecules talk to each other,

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Speaker 2: So in that sense it's kind of related to the

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Speaker 2: states of matter. But this is just within fluids. You

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Speaker 2: can understand why some things are viscous, why things are

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Speaker 2: thick and goofy, and why some things are thin, and

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Speaker 2: it does have to do with the intermolecular forces. Like basically,

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Speaker 2: in honey, the molecules grab at each other more than

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Speaker 2: they do in water. So as layers of honey slide

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Speaker 2: past each other, there tends to be more friction between

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Speaker 2: those layers, which makes it slower. We try to pour

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Speaker 2: honey down a garden hose, it would take forever to

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Speaker 2: come out the other side.

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Speaker 1: M Okay, we're getting into a bit of a sticky

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Speaker 1: subject here, and so let's get into what viscosity actually

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Speaker 1: is and what it has to do with being pro

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Speaker 1: or non Newtonia. So let's dig into that. But first

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Speaker 1: let's take a quick break. All right, we are not

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Speaker 1: talking about non Newtonian fluids today, asking the question what

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Speaker 1: are they, what makes them cool? And why are there

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Speaker 1: so many YouTube videos about them?

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Speaker 2: Non Newtoni fluids are a famous physics demonstration because they

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Speaker 2: do something weird and dramatic when you like bounce them

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Speaker 2: on top of a speaker. But we can get into that.

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Speaker 1: Yeah, and they're also kind of everywhere, right, like in

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Speaker 1: the ketchup we eat and this lime our kids play with,

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Speaker 1: even in the paint we used to thinks.

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Speaker 2: Yeah, the phrase non Newtonian gives you the impression maybe

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Speaker 2: it's like a weird edge case, like a rare exception,

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Speaker 2: but actually non Newtonian fluids are everywhere. Maybe Newtonian fluids

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Speaker 2: should be the ones that have non in front of them.

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Speaker 1: You mean they should be non non Newtonian.

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Speaker 2: Fluids I'm not not saying that.

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Speaker 1: But you're not not denying it.

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Speaker 2: Did you know that humans can process about foreign negations

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Speaker 2: in a sentence before they get totally confused?

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Speaker 1: I did not not know that.

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Speaker 2: Well before you did not know it, you used to.

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Speaker 1: Yes, I did not know that also, which I think

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Speaker 1: puts it in like a twelve negation.

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Speaker 2: There, Yeah, which is turning my brain into a non

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Speaker 2: white Sunian fluid.

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Speaker 1: Yeah, which might be a thing out there maybe somebody

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Speaker 1: by the time we got to this point in the conversation,

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Speaker 1: somebody already invented a non whites and.

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Speaker 2: Something something good to dip your newtons into.

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Speaker 1: All right, well, I get the sense, and I know

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Speaker 1: this from what I know about non netunin fluids is

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Speaker 1: that it has to do with their viscosity. There's something

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Speaker 1: weird about the viscosity of non Tunian fluids. And so

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Speaker 1: you were talking about a little bit earlier about what

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Speaker 1: viscosity actually is or how it presents itself in some fluids.

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Speaker 1: Some fluids are thick like honey, and some fluids are

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Speaker 1: super fluid, super liquid like water, Daniel, Is there an

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Speaker 1: official definition of what viscosity is?

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Speaker 2: There is an official definition of what viscosity is and

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Speaker 2: it's a little bit technical and mathematical, but you can

440
00:21:23,400 --> 00:21:27,000
Speaker 2: get a grip on it by imagining the garden hose. Like, say,

441
00:21:27,000 --> 00:21:28,960
Speaker 2: you take a liquid and you pour it through a

442
00:21:29,000 --> 00:21:31,959
Speaker 2: garden hose, and you measure the speed of that liquid

443
00:21:32,000 --> 00:21:34,720
Speaker 2: through the garden hose. For something that's very very viscous,

444
00:21:34,760 --> 00:21:37,240
Speaker 2: you're going to get the center traveling a lot faster

445
00:21:37,440 --> 00:21:40,119
Speaker 2: than the edges because the wall of the garden hose

446
00:21:40,200 --> 00:21:43,440
Speaker 2: drags on the fluid. And then if it's a viscous fluid,

447
00:21:43,560 --> 00:21:46,480
Speaker 2: that first layer of fluid near the wall then drags

448
00:21:46,520 --> 00:21:48,200
Speaker 2: on the next one, which drags on the next one,

449
00:21:48,200 --> 00:21:50,359
Speaker 2: which drags on the next one. By the time you

450
00:21:50,359 --> 00:21:52,200
Speaker 2: get to the center, it's going a lot faster than

451
00:21:52,240 --> 00:21:55,200
Speaker 2: it is at the edges. In a non viscous fluid,

452
00:21:55,560 --> 00:21:58,080
Speaker 2: you flow it through and basically everything travels at the

453
00:21:58,080 --> 00:22:00,880
Speaker 2: same speed because the layers aren't rubbing against each other.

454
00:22:01,320 --> 00:22:04,800
Speaker 2: So the definition of viscosity relates to like how quickly

455
00:22:04,920 --> 00:22:08,119
Speaker 2: the friction adds up to slow things down. It's like

456
00:22:08,160 --> 00:22:11,440
Speaker 2: that slope between what they call the sheer stress, which

457
00:22:11,480 --> 00:22:14,520
Speaker 2: is essentially the friction and the velocity of the fluid.

458
00:22:15,240 --> 00:22:18,280
Speaker 1: Yeah, you're right that they get very technical. Well, I

459
00:22:18,280 --> 00:22:21,560
Speaker 1: guess one way that I always thought viscosity was defined

460
00:22:21,760 --> 00:22:25,359
Speaker 1: was like how hard is it to stir basically in

461
00:22:25,359 --> 00:22:28,000
Speaker 1: a cup or a bucket, Like if you have hunting

462
00:22:28,040 --> 00:22:30,119
Speaker 1: a bucket and you stick a laddle in it or

463
00:22:30,160 --> 00:22:33,080
Speaker 1: a spoon, it's really hard to move that laddle and

464
00:22:33,119 --> 00:22:36,280
Speaker 1: spoon around, whereas in water it's a lot easier, isn't

465
00:22:36,320 --> 00:22:39,440
Speaker 1: it sort of also sort of or equivalently defined by

466
00:22:39,680 --> 00:22:42,720
Speaker 1: the laddle test or sort of like what's the resistance

467
00:22:43,760 --> 00:22:45,399
Speaker 1: it gives you when you try to move through it.

468
00:22:45,480 --> 00:22:49,000
Speaker 2: I think it's technically defined as the friction inside the liquid,

469
00:22:49,480 --> 00:22:51,359
Speaker 2: So you're talking about like a lathle and the friction

470
00:22:51,560 --> 00:22:53,679
Speaker 2: on the liquid. I think if you want to be

471
00:22:53,720 --> 00:22:56,520
Speaker 2: really strict about it, probably viscosity is you know, fluid

472
00:22:56,560 --> 00:23:00,439
Speaker 2: to fluid layers of friction. But that's definitely really like

473
00:23:00,480 --> 00:23:03,240
Speaker 2: you could measure the viscosity by taking a ladle and

474
00:23:03,359 --> 00:23:06,000
Speaker 2: using it to stir one liquid versus another and measuring

475
00:23:06,000 --> 00:23:08,679
Speaker 2: the viscosity, and they probably are machines that do exactly that.

476
00:23:08,880 --> 00:23:12,399
Speaker 1: Even with the hose definition, there's still like what is

477
00:23:12,400 --> 00:23:15,720
Speaker 1: the friction of the liquid with the hose material, right.

478
00:23:15,880 --> 00:23:18,800
Speaker 2: But the viscosity is related to how the velocity changes

479
00:23:19,080 --> 00:23:21,119
Speaker 2: as you go away from the wall, So it's all

480
00:23:21,119 --> 00:23:24,120
Speaker 2: about the friction between the layers. I don't think it's

481
00:23:24,119 --> 00:23:26,240
Speaker 2: a terribly important distinction, but it is defined just in

482
00:23:26,320 --> 00:23:29,040
Speaker 2: terms of the liquid itself and not some external thing.

483
00:23:29,160 --> 00:23:32,280
Speaker 1: But like, let's say I had a teflon hose, or

484
00:23:32,320 --> 00:23:36,360
Speaker 1: a hose lined with teflon inside, or like impossibly slippery

485
00:23:36,359 --> 00:23:38,720
Speaker 1: stuff inside of the hose. If I put pressure behind it,

486
00:23:38,720 --> 00:23:41,840
Speaker 1: wouldn't all the honey's just come out like it's being extruded.

487
00:23:41,920 --> 00:23:43,760
Speaker 2: Yeah, if you had a frictionless wall, then the honey

488
00:23:43,800 --> 00:23:47,119
Speaker 2: would just slide through it. Absolutely. This definition assumes some

489
00:23:47,280 --> 00:23:50,679
Speaker 2: friction from the wall, which creates different velocities, and then

490
00:23:50,720 --> 00:23:53,760
Speaker 2: you measure the viscosity by how that velocity propagates through

491
00:23:53,800 --> 00:23:57,320
Speaker 2: the fluid. So it's this slope between the sheer stress

492
00:23:57,320 --> 00:23:58,080
Speaker 2: and the velocity.

493
00:23:58,240 --> 00:24:00,080
Speaker 1: Yeah, But then the same thing sort of happens and

494
00:24:00,119 --> 00:24:02,399
Speaker 1: you try to move a spoon through a honey, right,

495
00:24:03,400 --> 00:24:05,680
Speaker 1: there is some friction, and maybe depends on whether you

496
00:24:05,720 --> 00:24:08,359
Speaker 1: use a teflon spoon or a different kind of spoon,

497
00:24:08,440 --> 00:24:11,280
Speaker 1: but I think generally just to give people an intuitive

498
00:24:11,320 --> 00:24:13,840
Speaker 1: sense of what viscosity is. Couldn't we just sort of

499
00:24:14,000 --> 00:24:15,879
Speaker 1: say that it is sort of like how hard this

500
00:24:16,000 --> 00:24:18,000
Speaker 1: to move a spoon through it on a cup?

501
00:24:18,119 --> 00:24:20,320
Speaker 2: Yeah? Absolutely, that gives you a good intuitive sense. If

502
00:24:20,320 --> 00:24:22,919
Speaker 2: you take the same ladle with the same friction on

503
00:24:23,000 --> 00:24:26,040
Speaker 2: its surface in two different fluids, the one with higher

504
00:24:26,119 --> 00:24:28,840
Speaker 2: viscosity will be harder to stir for sure, right.

505
00:24:28,880 --> 00:24:31,960
Speaker 1: And I think at least in engineering, how we define

506
00:24:32,040 --> 00:24:34,240
Speaker 1: viscosity is like, as you move your spoon with a

507
00:24:34,240 --> 00:24:36,879
Speaker 1: different velocity through the liquid, what is the force that

508
00:24:36,920 --> 00:24:39,800
Speaker 1: it pushes back to you. That's how at least engineers

509
00:24:39,800 --> 00:24:40,199
Speaker 1: define it.

510
00:24:40,440 --> 00:24:43,280
Speaker 2: Yeah, And in the end, what's happening deep down is

511
00:24:43,320 --> 00:24:45,840
Speaker 2: that you have these molecules and either are gravy on

512
00:24:45,880 --> 00:24:48,359
Speaker 2: each other or they're not. And if they're not gravy

513
00:24:48,440 --> 00:24:50,480
Speaker 2: on each other, they can just slide past each other

514
00:24:51,000 --> 00:24:54,040
Speaker 2: and in a really not very viscous fluid. Even if

515
00:24:54,080 --> 00:24:56,280
Speaker 2: you put a rough surface laddle, it might move one

516
00:24:56,359 --> 00:24:58,960
Speaker 2: layer of that fluid, but then that fluid will slide

517
00:24:59,040 --> 00:25:01,560
Speaker 2: right by the next lege and so be very easy

518
00:25:01,600 --> 00:25:03,800
Speaker 2: to move and be very low viscosity. And so it

519
00:25:03,800 --> 00:25:06,200
Speaker 2: all comes down to how these layers of fluid grab

520
00:25:06,280 --> 00:25:09,040
Speaker 2: onto each other or don't grab onto each other. So

521
00:25:09,040 --> 00:25:11,160
Speaker 2: that's what viscosity is in these fluids.

522
00:25:12,240 --> 00:25:15,320
Speaker 1: It's sort of like the molecules of the fluid hanging

523
00:25:15,359 --> 00:25:17,480
Speaker 1: on to each other. And this is due to what

524
00:25:17,560 --> 00:25:21,479
Speaker 1: kinds of forces like chemical forces or you know, electromagnetic forces,

525
00:25:21,560 --> 00:25:24,800
Speaker 1: vendor Wolf forces, what makes the molecules hang on to

526
00:25:24,840 --> 00:25:25,879
Speaker 1: each other or not.

527
00:25:26,040 --> 00:25:28,520
Speaker 2: Yeah, well, all those things are electromagnetic, like what we

528
00:25:28,560 --> 00:25:32,400
Speaker 2: call chemical forces, covalent and ionic bonds, those are electromagnetic.

529
00:25:32,480 --> 00:25:34,399
Speaker 2: They have to do with where the electrons are and

530
00:25:34,400 --> 00:25:38,680
Speaker 2: how they're grabbing onto each other. Even Vanderwall's forces come from,

531
00:25:38,760 --> 00:25:42,560
Speaker 2: like how the electromagnetism is distributed around an atom, whether

532
00:25:42,600 --> 00:25:45,280
Speaker 2: it's a dipole or whether it's balanced or not. So

533
00:25:45,320 --> 00:25:48,480
Speaker 2: on these distant scale it's all electromagnetic forces. Like the

534
00:25:48,480 --> 00:25:51,600
Speaker 2: strong force is all tightly bound inside the proton and neutron,

535
00:25:51,720 --> 00:25:55,719
Speaker 2: the weak force is basically irrelevant, and gravity is also irrelevant.

536
00:25:56,040 --> 00:25:59,879
Speaker 2: This is all in the end emergent phenomena of electromagnetism.

537
00:26:00,440 --> 00:26:02,560
Speaker 2: Like in principle, you don't need any of this. All

538
00:26:02,600 --> 00:26:05,160
Speaker 2: you need is quantum electrodynamics, and you could predict everything,

539
00:26:05,560 --> 00:26:08,280
Speaker 2: But in practice that's a huge pain in the butt, right,

540
00:26:08,280 --> 00:26:11,440
Speaker 2: it's like trying to do calculus. Just with arithmetic take

541
00:26:11,440 --> 00:26:13,639
Speaker 2: you forever to do anything. So we like to come

542
00:26:13,680 --> 00:26:16,520
Speaker 2: up with these clever shorthands, these emergent phenomena that we

543
00:26:16,520 --> 00:26:18,280
Speaker 2: can use to describe the things we see in the

544
00:26:18,280 --> 00:26:21,240
Speaker 2: world more easily. So in the end, it's all electromagnetism

545
00:26:21,400 --> 00:26:22,480
Speaker 2: sort of zoomed out.

546
00:26:22,680 --> 00:26:24,520
Speaker 1: Now does it have to do with the density of

547
00:26:24,560 --> 00:26:29,360
Speaker 1: the fluid? Like I would imagine a really light fluid

548
00:26:29,440 --> 00:26:34,000
Speaker 1: or fluid that's not very dense would have a lower viscosity,

549
00:26:34,359 --> 00:26:36,480
Speaker 1: or it would be easier to push through, or would

550
00:26:36,520 --> 00:26:40,080
Speaker 1: have less friction between the layers than a really dense fluid.

551
00:26:40,240 --> 00:26:43,320
Speaker 2: Yeah, so this is where Newton's law comes in. Newton

552
00:26:43,359 --> 00:26:45,760
Speaker 2: did a bunch of studies of fluids, and he found

553
00:26:45,800 --> 00:26:49,680
Speaker 2: that the viscosity does not depend very much on the pressure.

554
00:26:50,040 --> 00:26:52,800
Speaker 2: Like you squeeze the fluid or you don't squeeze the fluid,

555
00:26:53,160 --> 00:26:56,240
Speaker 2: it doesn't really change the viscosity of the fluid very much.

556
00:26:56,600 --> 00:26:59,280
Speaker 2: What does change it is the temperature, Like you heat

557
00:26:59,280 --> 00:27:02,040
Speaker 2: the fluid up, you cool it down. That will change

558
00:27:02,080 --> 00:27:05,439
Speaker 2: the viscosity. But Newton's law of viscosity basically says that

559
00:27:05,480 --> 00:27:07,960
Speaker 2: the viscosity does not depend very much on.

560
00:27:07,960 --> 00:27:12,359
Speaker 1: The pressure of the pressure of the liquid exactly, because

561
00:27:12,359 --> 00:27:15,040
Speaker 1: I guess liquids can have different pressures, right, I guess,

562
00:27:15,080 --> 00:27:16,520
Speaker 1: like the water at the bottom of the ocean is

563
00:27:16,560 --> 00:27:19,280
Speaker 1: under a very different pressure than the water at the

564
00:27:19,280 --> 00:27:20,400
Speaker 1: top of the ocean.

565
00:27:20,080 --> 00:27:24,040
Speaker 2: Exactly, And for Newtonian fluids like water, the viscosity at

566
00:27:24,040 --> 00:27:26,239
Speaker 2: the bottom of the ocean is not very different than

567
00:27:26,240 --> 00:27:28,440
Speaker 2: the viscosity at the top of the ocean if they're

568
00:27:28,520 --> 00:27:32,720
Speaker 2: the same temperature. Water's viscosity does depend on temperature a lot,

569
00:27:32,840 --> 00:27:34,960
Speaker 2: Like if you heat water up from twenty ceed to

570
00:27:35,080 --> 00:27:38,600
Speaker 2: fifty c then it gets fifty percent less viscous. So

571
00:27:38,760 --> 00:27:42,480
Speaker 2: warm water is less viscous than cold water, but the

572
00:27:42,560 --> 00:27:45,600
Speaker 2: pressure doesn't make a big difference. And that's essentially Newton's

573
00:27:45,680 --> 00:27:46,600
Speaker 2: law of fluids.

574
00:27:46,800 --> 00:27:49,760
Speaker 1: So Newton's laws of fluids, what you're saying, has only

575
00:27:49,800 --> 00:27:51,520
Speaker 1: to do with pressure, not temperature.

576
00:27:51,640 --> 00:27:54,080
Speaker 2: That's right. You can be a Newtonian fluid and have

577
00:27:54,200 --> 00:27:56,879
Speaker 2: your riscosity depend on temperature. That's not a problem. But

578
00:27:56,920 --> 00:27:59,600
Speaker 2: if you're a Newtonian fluid, you can't have your riscosity

579
00:27:59,600 --> 00:28:01,520
Speaker 2: depend very strongly on the pressure.

580
00:28:01,600 --> 00:28:03,680
Speaker 1: Well, I guess, just to be clear, and Newton didn't

581
00:28:03,720 --> 00:28:08,600
Speaker 1: own any fluids, Well, let me say Newton's fluids. We

582
00:28:08,800 --> 00:28:12,520
Speaker 1: just kind of mean like what Newton noticed about most fluids.

583
00:28:13,359 --> 00:28:16,280
Speaker 2: Yeah, we don't mean like the literal cups of stuff

584
00:28:16,320 --> 00:28:17,160
Speaker 2: in Newton's.

585
00:28:16,920 --> 00:28:19,159
Speaker 1: Like, he didn't discover all of these fluids. He just

586
00:28:19,160 --> 00:28:22,680
Speaker 1: discovered like, hey, most fluids behave in this very sort

587
00:28:22,720 --> 00:28:25,439
Speaker 1: of nice way, right, And so that's why that's what

588
00:28:25,480 --> 00:28:29,280
Speaker 1: got named Newton's fluids or Newton's laws of fluids.

589
00:28:29,600 --> 00:28:32,440
Speaker 2: Yeah, exactly. Like if we had two kinds of mass,

590
00:28:32,560 --> 00:28:34,639
Speaker 2: one that followed eth equals MA, and we'd call it

591
00:28:34,680 --> 00:28:37,240
Speaker 2: Newtonian masses, and if there was some other weird kind

592
00:28:37,280 --> 00:28:40,240
Speaker 2: of mass that didn't obey Newton's law ethicals MA, we

593
00:28:40,320 --> 00:28:43,080
Speaker 2: might call that non Newtonian mass or something. It doesn't

594
00:28:43,080 --> 00:28:45,720
Speaker 2: mean that Newtonian mass would only describe like the stuff

595
00:28:45,800 --> 00:28:49,120
Speaker 2: Newton owned himself. So you're right, Newton noticed his behavior

596
00:28:49,120 --> 00:28:51,960
Speaker 2: in some fluids, and so we call those Newtonian fluids

597
00:28:52,160 --> 00:28:54,280
Speaker 2: ones that follow the laws that he described.

598
00:28:54,520 --> 00:28:56,760
Speaker 1: Okay, and then just to repeat for folks, what is

599
00:28:56,760 --> 00:28:57,320
Speaker 1: that law again?

600
00:28:57,520 --> 00:29:01,080
Speaker 2: Essentially it's that the viscosity doesn't on the pressure.

601
00:29:01,440 --> 00:29:04,640
Speaker 1: So, for example, water is a Newtonian fluid because it's

602
00:29:04,720 --> 00:29:07,160
Speaker 1: viscosity at the bottom of the ocean is the same

603
00:29:07,200 --> 00:29:09,400
Speaker 1: as its viscosity at the top of the ocean.

604
00:29:09,400 --> 00:29:12,480
Speaker 2: If they're at the same temperature. Right, Viscosity does depend

605
00:29:12,560 --> 00:29:14,719
Speaker 2: on temperature, and typically the bottom of the ocean can

606
00:29:14,760 --> 00:29:16,479
Speaker 2: be colder than the top of the ocean. Like if

607
00:29:16,520 --> 00:29:18,840
Speaker 2: you control for temperature, like maybe in your swimming pool,

608
00:29:19,040 --> 00:29:21,400
Speaker 2: for example, where it's all the same temperature, then the

609
00:29:21,440 --> 00:29:23,840
Speaker 2: viscosity the bottom is the same as the viscosity on

610
00:29:23,880 --> 00:29:25,560
Speaker 2: the top. You don't like get down to the bottom

611
00:29:25,560 --> 00:29:27,560
Speaker 2: of the swimming pool and find that you're suddenly swimming

612
00:29:27,600 --> 00:29:28,640
Speaker 2: through honey.

613
00:29:28,440 --> 00:29:31,880
Speaker 1: Right right, Although that sounds delicious and dangerous, you could

614
00:29:31,920 --> 00:29:35,840
Speaker 1: dip your fake mutons and bagels just by walking out

615
00:29:35,880 --> 00:29:36,680
Speaker 1: to your honeypool.

616
00:29:36,800 --> 00:29:39,360
Speaker 2: Please, folks, do not fill your pool with honey. It's

617
00:29:39,400 --> 00:29:45,760
Speaker 2: a terrible idea.

618
00:29:43,040 --> 00:29:45,960
Speaker 1: Unless you really love honey and or wanted to know

619
00:29:46,040 --> 00:29:50,240
Speaker 1: what it was like to swim in honey.

620
00:29:50,320 --> 00:29:52,600
Speaker 2: I'm terrified to even type that into my Google search

621
00:29:52,600 --> 00:29:53,320
Speaker 2: window over here.

622
00:29:53,520 --> 00:29:55,560
Speaker 1: Oh, I'm sure there are YouTube videos about it.

623
00:29:56,160 --> 00:29:57,240
Speaker 2: Some poor grizzly bear.

624
00:29:57,520 --> 00:30:01,480
Speaker 1: But so that's an interesting definition of non of a

625
00:30:01,640 --> 00:30:04,640
Speaker 1: Newtonian fluid, because the way they define it in engineering,

626
00:30:04,720 --> 00:30:06,600
Speaker 1: or at least the way I've heard it define, is

627
00:30:06,640 --> 00:30:11,600
Speaker 1: that a Newtonian fluid, or like regular viscosity, is when

628
00:30:12,000 --> 00:30:16,120
Speaker 1: the force that the liquid pushes back on you when

629
00:30:16,120 --> 00:30:18,360
Speaker 1: you try to steer it with a spoon is related

630
00:30:18,720 --> 00:30:21,600
Speaker 1: or is proportional to how fast you're trying to move

631
00:30:21,640 --> 00:30:27,560
Speaker 1: that spoon. So, like regular viscous fluid, like honey, the

632
00:30:27,640 --> 00:30:29,480
Speaker 1: faster you try to stir it, the harder it is

633
00:30:29,520 --> 00:30:32,400
Speaker 1: to stir it, but in a very linear way, like

634
00:30:32,400 --> 00:30:34,760
Speaker 1: if you try to steer it slowly, it'll push back

635
00:30:34,880 --> 00:30:36,720
Speaker 1: a little bit on you, and if you try to

636
00:30:36,720 --> 00:30:40,880
Speaker 1: steer it really hard, it'll push back on you proportionally harder.

637
00:30:41,160 --> 00:30:43,600
Speaker 1: I imagine they're the same thing, maybe, but it seems

638
00:30:43,600 --> 00:30:46,120
Speaker 1: like you're approaching it from a different point of view.

639
00:30:46,200 --> 00:30:48,360
Speaker 2: Yeah, they are the same thing. You're right that, technically,

640
00:30:48,440 --> 00:30:52,680
Speaker 2: viscosity is this relationship between velocity and sheer stress, right,

641
00:30:53,000 --> 00:30:55,560
Speaker 2: how fast the layers are sliding past each other and

642
00:30:55,600 --> 00:30:58,680
Speaker 2: the friction that they exert on each other. And Newtonian

643
00:30:58,720 --> 00:31:02,880
Speaker 2: fluids expressed in that life language. The relationship is linear, right,

644
00:31:02,960 --> 00:31:06,360
Speaker 2: So higher velocity means higher shear stress, which means more friction.

645
00:31:06,520 --> 00:31:08,640
Speaker 2: So as you say, the faster you try to stir,

646
00:31:08,800 --> 00:31:10,360
Speaker 2: the more force you're feeling.

647
00:31:10,240 --> 00:31:12,000
Speaker 1: Right, And I think you didn't sort of observe that

648
00:31:12,000 --> 00:31:15,440
Speaker 1: that relationship was linear. Like if you plot how fast

649
00:31:15,440 --> 00:31:18,400
Speaker 1: you're trying to stir the spoon versus how much force

650
00:31:18,480 --> 00:31:20,920
Speaker 1: it's pushing back on you, it's like a straight line.

651
00:31:20,960 --> 00:31:25,320
Speaker 1: That's what I thought was or heard was a Newtonian viscosity.

652
00:31:25,440 --> 00:31:27,240
Speaker 2: Yeah, I think that's totally right. I was trying to

653
00:31:27,240 --> 00:31:30,120
Speaker 2: avoid getting into the technical details of derivatives and slopes

654
00:31:30,120 --> 00:31:32,640
Speaker 2: and sheer stresses, but I underestimated your appetite for the

655
00:31:32,640 --> 00:31:33,760
Speaker 2: math of sticky fluids.

656
00:31:33,800 --> 00:31:36,760
Speaker 1: Well, I think it's important because a non neetunin fluid

657
00:31:36,800 --> 00:31:39,640
Speaker 1: then is something that doesn't have that linear relationship. Right.

658
00:31:39,840 --> 00:31:42,120
Speaker 2: It still has that relationship, but it's non linear. It

659
00:31:42,160 --> 00:31:44,959
Speaker 2: still has more friction as a velocity grows. It's just

660
00:31:44,960 --> 00:31:47,560
Speaker 2: not a strictly linear relationship, right, Right.

661
00:31:47,600 --> 00:31:49,920
Speaker 1: So I think when people say a Newtonian fluid, it's

662
00:31:50,000 --> 00:31:52,240
Speaker 1: one where you kind of know what you're going to get,

663
00:31:52,320 --> 00:31:54,080
Speaker 1: like if you if it's honey, you know that the

664
00:31:54,160 --> 00:31:56,320
Speaker 1: faster that you try to stir it, the harder is

665
00:31:56,320 --> 00:31:59,160
Speaker 1: going to push back on you proportionally, right, mm hmm.

666
00:31:59,360 --> 00:32:02,720
Speaker 2: Yeah, And that's a frictory linear relationship in Newtonian.

667
00:32:02,280 --> 00:32:04,680
Speaker 1: Fluids, right, that's sort of like what need and observe,

668
00:32:04,800 --> 00:32:06,960
Speaker 1: and so that's why it's called a Newtonian fluid.

669
00:32:06,840 --> 00:32:09,880
Speaker 2: Mm hmm exactly. And what that means, sort of less mathematically,

670
00:32:10,280 --> 00:32:13,200
Speaker 2: is that the viscosity is essentially constant with pressure.

671
00:32:13,360 --> 00:32:16,040
Speaker 1: Or maybe because of viscosity is constant with pressure. That

672
00:32:16,400 --> 00:32:18,719
Speaker 1: gives that curve a linear shape.

673
00:32:18,800 --> 00:32:21,680
Speaker 2: Yeah, that's right, And viscosity is like super important in

674
00:32:21,720 --> 00:32:24,360
Speaker 2: fluid dynamics. Like the people who try to understand how

675
00:32:24,440 --> 00:32:27,960
Speaker 2: fluids flow, they have to solve these really gnarrowly differential

676
00:32:28,000 --> 00:32:31,320
Speaker 2: equations called the Navier Stokes equation, for which there is

677
00:32:31,440 --> 00:32:34,680
Speaker 2: no like nice solution. There's like a million dollar X

678
00:32:34,760 --> 00:32:38,560
Speaker 2: prize for anybody who can solve these equations. They're famously complex,

679
00:32:38,600 --> 00:32:41,760
Speaker 2: and they're complex because of the viscosity. It's like this

680
00:32:41,880 --> 00:32:45,080
Speaker 2: viscosity term in those equations, and often people just set

681
00:32:45,120 --> 00:32:48,120
Speaker 2: that to zero because otherwise it's impossible to solve. And

682
00:32:48,160 --> 00:32:50,880
Speaker 2: so viscosity is like a really important thing mathematically, and

683
00:32:50,920 --> 00:32:53,600
Speaker 2: then like fluid dynamics and understanding like the atmosphere and

684
00:32:53,640 --> 00:32:56,600
Speaker 2: the ocean and climate change. It's an important thing.

685
00:32:56,760 --> 00:32:59,400
Speaker 1: All right. Yeah, so that's a Newtonian fluid. That's what

686
00:32:59,520 --> 00:33:02,400
Speaker 1: the new To notice about most fluids. And that's because

687
00:33:02,440 --> 00:33:04,880
Speaker 1: that's kind of true for most things around us, right,

688
00:33:04,960 --> 00:33:09,240
Speaker 1: like water, milk, oil, honey. Those things all have different viscosity,

689
00:33:09,240 --> 00:33:12,320
Speaker 1: but they all sort of have this regular type of viscosity,

690
00:33:12,360 --> 00:33:15,120
Speaker 1: which is this linear viscosity, right, and.

691
00:33:15,080 --> 00:33:18,600
Speaker 2: There's a huge range. What's really amazing is how many

692
00:33:18,600 --> 00:33:22,600
Speaker 2: different kinds of fluids can be described in this way. Right.

693
00:33:22,640 --> 00:33:24,760
Speaker 2: This is why this law persists for so long, because

694
00:33:24,760 --> 00:33:27,200
Speaker 2: it describes so many different kinds of things, you know,

695
00:33:27,280 --> 00:33:29,680
Speaker 2: like honey and water and oil. These are the things

696
00:33:29,680 --> 00:33:33,120
Speaker 2: we experience. But we've also discovered things on both edges,

697
00:33:33,480 --> 00:33:37,640
Speaker 2: like super low viscosity fluids and super duper high viscosity fluids,

698
00:33:37,840 --> 00:33:39,600
Speaker 2: all of which obey these principles.

699
00:33:39,760 --> 00:33:42,680
Speaker 1: Yeah, so fluids that have a linear viscosity law. There's

700
00:33:42,800 --> 00:33:45,560
Speaker 1: stuff that has very little viscosity and stuff that has

701
00:33:45,800 --> 00:33:46,960
Speaker 1: high viscosity. Right.

702
00:33:47,080 --> 00:33:50,720
Speaker 2: Yeah, And one of my favorite experiments in science has

703
00:33:50,760 --> 00:33:53,560
Speaker 2: to do with trying to measure the viscosity of super

704
00:33:53,680 --> 00:33:57,120
Speaker 2: duper goopy stuff. There's an experiment that's been going on

705
00:33:57,320 --> 00:34:03,000
Speaker 2: since nineteen twenty seven and finished. It's still going because

706
00:34:03,040 --> 00:34:06,840
Speaker 2: it's so slow. They're trying to measure the viscosity of asphalt.

707
00:34:07,120 --> 00:34:09,200
Speaker 2: They call it pitch, but it's basically like the tar

708
00:34:09,280 --> 00:34:11,960
Speaker 2: you spread on the road, and this stuff is super

709
00:34:12,080 --> 00:34:15,560
Speaker 2: duper thick, so thick that it takes like ten years

710
00:34:15,840 --> 00:34:19,280
Speaker 2: for a single drop to form. So in nineteen twenty

711
00:34:19,280 --> 00:34:21,600
Speaker 2: seven they poured some of this thing into a funnel

712
00:34:21,719 --> 00:34:24,600
Speaker 2: and they've been watching it flow down that funnel and

713
00:34:24,680 --> 00:34:26,839
Speaker 2: make drops that come out the bottom. It's been going

714
00:34:26,880 --> 00:34:29,800
Speaker 2: for almost a century and they've only ever seen nine

715
00:34:29,960 --> 00:34:32,080
Speaker 2: drops come out the bottom.

716
00:34:32,080 --> 00:34:34,960
Speaker 1: So you're saying, asphalt, or this thing called pitch is

717
00:34:35,000 --> 00:34:38,480
Speaker 1: a fluid like it'll eventually flow down to the bottom

718
00:34:38,520 --> 00:34:41,480
Speaker 1: of a cup, but it's as super duper high viscosity,

719
00:34:41,520 --> 00:34:42,880
Speaker 1: so it's going to do it really slowly.

720
00:34:43,000 --> 00:34:46,040
Speaker 2: Yeah, it has like two hundred and thirty billion times

721
00:34:46,120 --> 00:34:49,399
Speaker 2: the viscosity of water. So imagine like trying to take

722
00:34:49,400 --> 00:34:52,040
Speaker 2: a spoon and stick it in the road and stir right,

723
00:34:52,080 --> 00:34:53,640
Speaker 2: there's a whole lot of friction there.

724
00:34:53,680 --> 00:34:55,919
Speaker 1: But you could technically do it, I think, is what

725
00:34:56,040 --> 00:34:58,719
Speaker 1: you're saying. Like it is a fluid, it is viscous.

726
00:34:58,760 --> 00:35:01,719
Speaker 1: You could stick a spoon an asphal defense their it.

727
00:35:01,880 --> 00:35:04,719
Speaker 1: But like the force at which it would push you

728
00:35:04,800 --> 00:35:06,360
Speaker 1: back is huge, right.

729
00:35:06,280 --> 00:35:08,080
Speaker 2: Yeah, it might take you more than a century or

730
00:35:08,440 --> 00:35:11,280
Speaker 2: just to get your spoon into the asphalt.

731
00:35:10,920 --> 00:35:12,879
Speaker 1: Right, or you would need a huge amount of force

732
00:35:12,920 --> 00:35:13,640
Speaker 1: to push through it.

733
00:35:13,880 --> 00:35:16,960
Speaker 2: Yeah, exactly. And this experiment is really fun because they

734
00:35:16,960 --> 00:35:19,480
Speaker 2: started it in nineteen twenty seven and you know, it

735
00:35:19,520 --> 00:35:21,880
Speaker 2: takes like ten years for a drop to fall, and

736
00:35:22,000 --> 00:35:26,160
Speaker 2: in all of that time, nobody has ever actually witnessed

737
00:35:26,320 --> 00:35:28,799
Speaker 2: a drop fall because the drop takes like a tenth

738
00:35:28,880 --> 00:35:30,520
Speaker 2: of a second to fall over.

739
00:35:30,440 --> 00:35:32,680
Speaker 1: Ten years a tenth of a second.

740
00:35:32,760 --> 00:35:35,160
Speaker 2: Once the drop actually breaks off the bottom, it falls

741
00:35:35,200 --> 00:35:37,440
Speaker 2: in like a tenth of a second, and nobody's ever

742
00:35:37,480 --> 00:35:40,160
Speaker 2: actually seen this happen. Like you can walk by this

743
00:35:40,200 --> 00:35:42,400
Speaker 2: thing every single day. You can see it drop about

744
00:35:42,480 --> 00:35:44,840
Speaker 2: to break off and fall, and people have been hoping

745
00:35:44,840 --> 00:35:47,840
Speaker 2: to actually like see it fall this incredible moment. It

746
00:35:47,880 --> 00:35:50,920
Speaker 2: takes like ten years to pass, but nobody's ever actually

747
00:35:50,960 --> 00:35:51,880
Speaker 2: been there to see it.

748
00:35:52,280 --> 00:35:54,320
Speaker 1: Mmmm. But I'm sure it's been recorded.

749
00:35:54,480 --> 00:35:57,160
Speaker 2: Well, it's actually pretty funny because they tried and in

750
00:35:57,239 --> 00:36:00,400
Speaker 2: nineteen eighty eight, the experiment was actually on display at

751
00:36:00,440 --> 00:36:04,160
Speaker 2: a World Expo when a drop fell, but nobody noticed it.

752
00:36:04,280 --> 00:36:07,160
Speaker 2: The professor who runs the experiment, Professor Mainstone, had stepped

753
00:36:07,160 --> 00:36:09,279
Speaker 2: out to get a drink and he missed it. So

754
00:36:09,360 --> 00:36:12,000
Speaker 2: ever since then they set up a webcam to watch

755
00:36:12,040 --> 00:36:15,240
Speaker 2: this thing. The next drop happened in November two thousand,

756
00:36:15,440 --> 00:36:17,440
Speaker 2: but the camera happened to be on the fritz and

757
00:36:17,480 --> 00:36:22,600
Speaker 2: so it missed it again. And then twenty fourteen was

758
00:36:22,640 --> 00:36:25,160
Speaker 2: the ninth drop, but it broke off when they were

759
00:36:25,200 --> 00:36:28,240
Speaker 2: like adjusting the experiment because the beaker below the funnel

760
00:36:28,320 --> 00:36:30,920
Speaker 2: had finally filled up and it was interfering with the experiment.

761
00:36:31,360 --> 00:36:34,680
Speaker 2: So nobody's ever actually watched a drop form from this thing.

762
00:36:34,880 --> 00:36:36,960
Speaker 2: Everybody's waiting for the tenth drop to happen.

763
00:36:37,320 --> 00:36:42,200
Speaker 1: Oh man, sounds like a lot of falling here. Maybe

764
00:36:42,200 --> 00:36:44,600
Speaker 1: I should put more than one camera on it.

765
00:36:45,600 --> 00:36:48,560
Speaker 2: And the professor who started it in nineteen twenty seven, Mainstone,

766
00:36:48,600 --> 00:36:53,400
Speaker 2: he died in twenty thirteen, never having seen a drop form.

767
00:36:52,440 --> 00:36:56,520
Speaker 1: Mmmm, should have just picked the lower viscosity fluid, I guess.

768
00:36:56,680 --> 00:36:59,520
Speaker 2: So it's a pretty awesome experiment that shows you the

769
00:36:59,560 --> 00:37:02,279
Speaker 2: incredible range of Newton's law of viscosity.

770
00:37:02,480 --> 00:37:06,560
Speaker 1: Mm. Interesting. All right, Well that's what a Newtonian fluid is.

771
00:37:06,640 --> 00:37:09,600
Speaker 1: And now let's get into what a non Newtonian fluid is.

772
00:37:09,840 --> 00:37:12,799
Speaker 1: What makes these weird? Why are they the subject of

773
00:37:12,840 --> 00:37:16,560
Speaker 1: so many interesting physics demonstrations online? So we'll dig into that,

774
00:37:16,600 --> 00:37:31,520
Speaker 1: but first let's take another quick break. All right, we're

775
00:37:31,560 --> 00:37:35,080
Speaker 1: talking about non Newtonian fluids, and we talked a lot

776
00:37:35,080 --> 00:37:38,160
Speaker 1: about viscosity and what it is and what makes a

777
00:37:38,200 --> 00:37:41,399
Speaker 1: Newtonian fluid. So basically a Newtonian fluid is one where

778
00:37:41,440 --> 00:37:44,560
Speaker 1: you said that the viscosity depends on pressure on the

779
00:37:44,600 --> 00:37:47,680
Speaker 1: pressure of the liquid, which sort of we agree. I

780
00:37:47,719 --> 00:37:51,360
Speaker 1: think translates to like how hard it pushes back on

781
00:37:51,400 --> 00:37:53,799
Speaker 1: you when you try to steer it or when you

782
00:37:53,840 --> 00:37:55,320
Speaker 1: try to swim through it, for example.

783
00:37:55,960 --> 00:37:58,560
Speaker 2: Yeah, I think the most accurate way to describe it

784
00:37:58,600 --> 00:38:01,520
Speaker 2: is how you did, which is a relationship between the

785
00:38:01,560 --> 00:38:04,719
Speaker 2: friction and the velocity. As layers start moving faster and

786
00:38:04,719 --> 00:38:07,120
Speaker 2: faster adjacent to each other, you get more and more

787
00:38:07,200 --> 00:38:08,840
Speaker 2: friction on those layers.

788
00:38:09,239 --> 00:38:11,600
Speaker 1: Right, So like if you try to swim at one

789
00:38:11,640 --> 00:38:13,960
Speaker 1: meter per second through honey, it's going to push you

790
00:38:14,000 --> 00:38:16,279
Speaker 1: back with a certain force. If you double your speed,

791
00:38:16,280 --> 00:38:17,840
Speaker 1: if you try to swim through it at two meters

792
00:38:17,840 --> 00:38:20,279
Speaker 1: per second, then it should push back with you with

793
00:38:20,400 --> 00:38:22,799
Speaker 1: twice the force. That's what a Newtonian fluid is.

794
00:38:22,840 --> 00:38:25,799
Speaker 2: That's a Newtonian fluid where that relationship is linear, and

795
00:38:25,840 --> 00:38:29,400
Speaker 2: the slope of that linear relationship is the viscosity. So

796
00:38:29,480 --> 00:38:32,400
Speaker 2: things that have different viscosity have a differently sloped line,

797
00:38:32,440 --> 00:38:35,120
Speaker 2: but it's always still a line. For a Newtonian fluid,

798
00:38:35,120 --> 00:38:38,279
Speaker 2: it follows this linear relationship. For non Newtonian fluids, you

799
00:38:38,280 --> 00:38:41,080
Speaker 2: get away from that line, things change in a different

800
00:38:41,120 --> 00:38:43,239
Speaker 2: way as you increase the velocity.

801
00:38:43,560 --> 00:38:47,000
Speaker 1: Right, and again, like nothing is perfectly linear, right, Like

802
00:38:47,080 --> 00:38:50,280
Speaker 1: I think maybe what Newton's was just kind of looking

803
00:38:50,320 --> 00:38:52,440
Speaker 1: at things at a first approximation and he noticed that

804
00:38:52,480 --> 00:38:54,799
Speaker 1: it's like roughly linear for all of these materials within

805
00:38:54,840 --> 00:38:57,000
Speaker 1: a certain range, and so that he's like, oh, this

806
00:38:57,040 --> 00:38:59,560
Speaker 1: is the law of viscosity. M hmm, Like in reality,

807
00:38:59,719 --> 00:39:01,640
Speaker 1: not even water is perfectly linear, is it.

808
00:39:01,719 --> 00:39:04,959
Speaker 2: Yeah, nothing is perfectly Newtonian, but these are a good approximation.

809
00:39:05,320 --> 00:39:07,080
Speaker 2: But some things, as we'll talk about in a minute,

810
00:39:07,239 --> 00:39:11,440
Speaker 2: are very non Newtonian. They deviate dramatically from this linear relationship.

811
00:39:11,920 --> 00:39:13,879
Speaker 1: All right, let's talk about no in neetonia, or let's

812
00:39:13,880 --> 00:39:17,080
Speaker 1: not not talk about Newtonians, let's not avoid talking about

813
00:39:17,120 --> 00:39:20,919
Speaker 1: netunias non Newtonian fluids. So then what is a non

814
00:39:20,960 --> 00:39:21,880
Speaker 1: Newtonian fluid?

815
00:39:22,000 --> 00:39:24,880
Speaker 2: So non Newtonian fluid is one where this relationship is

816
00:39:24,920 --> 00:39:28,120
Speaker 2: not linear, and so the amount of friction you get

817
00:39:28,200 --> 00:39:30,760
Speaker 2: as you push on it can change very very quickly

818
00:39:30,840 --> 00:39:32,880
Speaker 2: if you push on it fast or push on it slow.

819
00:39:33,200 --> 00:39:35,600
Speaker 1: So like in our assumming example, like if you're swimming

820
00:39:35,640 --> 00:39:38,480
Speaker 1: through a non Newtonian fluid at one meter per second,

821
00:39:38,600 --> 00:39:40,120
Speaker 1: is going to push it back with a certain force.

822
00:39:40,280 --> 00:39:43,200
Speaker 1: If you try to soon twice as fast, it's maybe

823
00:39:43,280 --> 00:39:45,439
Speaker 1: not going to push back with twice the amount of force.

824
00:39:45,480 --> 00:39:48,040
Speaker 1: It might push back with less than twice the amount

825
00:39:48,080 --> 00:39:50,520
Speaker 1: of force, or push back with more than twice the

826
00:39:50,560 --> 00:39:51,960
Speaker 1: amount of force, exactly.

827
00:39:52,080 --> 00:39:54,960
Speaker 2: And the classic example of a non Newtonian fluid is

828
00:39:55,000 --> 00:39:57,920
Speaker 2: this stuff called ublek, which is basically what happens when

829
00:39:57,960 --> 00:40:00,239
Speaker 2: you take cornstarch and you mix it with water into

830
00:40:00,320 --> 00:40:02,640
Speaker 2: a suspension, and what you find if you have a

831
00:40:02,680 --> 00:40:05,080
Speaker 2: bowl of oubleck is. If you push on it very gently,

832
00:40:05,360 --> 00:40:07,640
Speaker 2: you can slide through it just like it's water. Right,

833
00:40:07,640 --> 00:40:09,759
Speaker 2: It just feels normally like water. But if you try

834
00:40:09,760 --> 00:40:11,839
Speaker 2: to move really fast, all of a sudden it gets

835
00:40:12,080 --> 00:40:14,480
Speaker 2: very very stiff. So if you just stick your finger

836
00:40:14,520 --> 00:40:16,600
Speaker 2: and it slowly, you can go right through. If you

837
00:40:16,640 --> 00:40:18,880
Speaker 2: try to slap it, then it feels like a solid.

838
00:40:19,040 --> 00:40:22,040
Speaker 2: It's incredibly viscous very quickly if you try to move

839
00:40:22,080 --> 00:40:23,160
Speaker 2: through it at higher speed.

840
00:40:23,480 --> 00:40:26,360
Speaker 1: Yeah, that's the most famous kind of non Newtonian fluid.

841
00:40:26,480 --> 00:40:29,080
Speaker 1: It's so you take corn stars it's just like regular

842
00:40:29,160 --> 00:40:31,480
Speaker 1: kitchen cornstarch, and you add a little bit of water

843
00:40:31,560 --> 00:40:35,399
Speaker 1: at a time until it feels liquid when you try

844
00:40:35,400 --> 00:40:37,160
Speaker 1: to steer it really slowly. But then if you try

845
00:40:37,200 --> 00:40:39,719
Speaker 1: to steer it really fast, it suddenly feels like it's

846
00:40:39,840 --> 00:40:41,160
Speaker 1: a solid block of something.

847
00:40:41,239 --> 00:40:43,839
Speaker 2: Right, Exactly. If it was a Newtonian fluid, it still

848
00:40:43,880 --> 00:40:46,799
Speaker 2: would feel thicker as you stir it faster, but it

849
00:40:46,800 --> 00:40:49,560
Speaker 2: would be linear, and here it's very nonlinear. It suddenly

850
00:40:49,600 --> 00:40:53,200
Speaker 2: gets extraordinarily viscous as you try to move through it faster.

851
00:40:53,480 --> 00:40:55,319
Speaker 1: Yeah, it's crazy. I mean, you can look up all

852
00:40:55,400 --> 00:40:57,920
Speaker 1: kinds of demonstrations online. People have made pools of.

853
00:40:58,000 --> 00:41:00,520
Speaker 2: Ublek right, Oh my gosh, I hope no. The bears

854
00:41:00,520 --> 00:41:01,759
Speaker 2: have fallen into those pools.

855
00:41:02,600 --> 00:41:05,200
Speaker 1: Yeah, they thought it was a honeypool, but really it

856
00:41:05,200 --> 00:41:06,240
Speaker 1: was a hopit pool.

857
00:41:07,440 --> 00:41:10,319
Speaker 2: You should have gone to Newton's house. Man, he's got

858
00:41:10,360 --> 00:41:11,240
Speaker 2: a pool full of honey.

859
00:41:11,360 --> 00:41:13,280
Speaker 1: No, he's got a pool full of fick Newtons.

860
00:41:14,880 --> 00:41:16,040
Speaker 2: I don't think the bear cares.

861
00:41:17,040 --> 00:41:20,760
Speaker 1: Yeah, either way, it's delicious. I think he barely cares.

862
00:41:20,840 --> 00:41:23,239
Speaker 1: But yeah, people have made pools of this stuff, right,

863
00:41:23,320 --> 00:41:24,719
Speaker 1: And so like, if you have a pool of this,

864
00:41:24,880 --> 00:41:28,920
Speaker 1: you can actually run through it and step on it.

865
00:41:28,920 --> 00:41:31,160
Speaker 2: It acts as a solid if you're applying enough pressure,

866
00:41:31,360 --> 00:41:33,920
Speaker 2: Like you can slap the surface and it feels like concrete.

867
00:41:34,280 --> 00:41:36,120
Speaker 2: But if you very gently put your finger through it,

868
00:41:36,160 --> 00:41:37,279
Speaker 2: you pass through it just like.

869
00:41:37,320 --> 00:41:39,680
Speaker 1: Water or like I think, like if you stand on

870
00:41:39,760 --> 00:41:42,640
Speaker 1: top of it, you'll sink, but if you try to

871
00:41:42,719 --> 00:41:45,680
Speaker 1: run across it, you can actually not sink and just

872
00:41:45,800 --> 00:41:47,560
Speaker 1: stay on top of it. Or if you stay, if

873
00:41:47,600 --> 00:41:50,960
Speaker 1: you keep jumping on it, you won't sink. You'll actually

874
00:41:51,000 --> 00:41:53,040
Speaker 1: sort of bounce on it. But if you just stand

875
00:41:53,040 --> 00:41:54,560
Speaker 1: and not do anything, you're gonna sink down.

876
00:41:54,800 --> 00:41:57,120
Speaker 2: Exactly, you might wonder, like, what's going on in terms

877
00:41:57,160 --> 00:42:00,160
Speaker 2: of the microphysics, how can we understand this weird behavior?

878
00:42:00,520 --> 00:42:02,680
Speaker 2: And it has again to do with how the little

879
00:42:02,719 --> 00:42:05,720
Speaker 2: bits inside are sliding past each other or not sliding

880
00:42:05,800 --> 00:42:08,560
Speaker 2: past each other. And critically it's because you have two

881
00:42:08,600 --> 00:42:11,200
Speaker 2: different things there. It's not just water, which is a

882
00:42:11,239 --> 00:42:15,000
Speaker 2: Newtonian fluid, but it's this combination of water and corn starch,

883
00:42:15,360 --> 00:42:18,759
Speaker 2: and cornstarch in particular is very grabby. It's not very

884
00:42:18,760 --> 00:42:21,600
Speaker 2: easy for cornstars to slide past itself.

885
00:42:21,880 --> 00:42:24,120
Speaker 1: Right, And it sort of also has to do with

886
00:42:24,160 --> 00:42:26,600
Speaker 1: the fact that, like if you try to move through

887
00:42:26,719 --> 00:42:29,359
Speaker 1: Oublick too fast, you actually sort of like sort of

888
00:42:29,360 --> 00:42:31,440
Speaker 1: push the water out kind of in a way, and

889
00:42:31,480 --> 00:42:34,200
Speaker 1: so then it's just cornstarch, and so then those grab

890
00:42:34,280 --> 00:42:35,200
Speaker 1: onto each other, right.

891
00:42:35,320 --> 00:42:37,960
Speaker 2: Exactly, if you're moving slowly, then it's dominated by the

892
00:42:37,960 --> 00:42:40,080
Speaker 2: water because it's time for like the water to get

893
00:42:40,120 --> 00:42:42,800
Speaker 2: between the corn starch and act like little ball bearrings.

894
00:42:43,080 --> 00:42:45,640
Speaker 2: Doesn't really matter that the corn starch is there, because

895
00:42:45,680 --> 00:42:48,600
Speaker 2: the water makes everything slippery. If you move really really fast,

896
00:42:48,640 --> 00:42:51,440
Speaker 2: the water gets pushed out between the corn starch and

897
00:42:51,440 --> 00:42:54,000
Speaker 2: then you're basically trying to push through just corn starch,

898
00:42:54,320 --> 00:42:56,480
Speaker 2: which is very, very thick. So it's sort of like

899
00:42:56,520 --> 00:42:59,120
Speaker 2: there's two different personalities to it, and one comes out

900
00:42:59,120 --> 00:43:00,640
Speaker 2: when you move and slow, and the other one comes

901
00:43:00,680 --> 00:43:02,640
Speaker 2: out when you're moving fast. It's like the juckle and

902
00:43:02,719 --> 00:43:03,799
Speaker 2: hide of fluids.

903
00:43:04,080 --> 00:43:06,120
Speaker 1: Yeah, and this is a really cool effect. Everyone can

904
00:43:06,120 --> 00:43:07,719
Speaker 1: do it at home. Just take some corn starch to

905
00:43:07,719 --> 00:43:09,759
Speaker 1: put it in a cup and add water a little

906
00:43:09,760 --> 00:43:12,640
Speaker 1: bit at a time until you get this weird liquid exactly.

907
00:43:12,680 --> 00:43:14,240
Speaker 2: And if you put it on top of a speaker,

908
00:43:14,280 --> 00:43:16,759
Speaker 2: for example, you get this really weird effect where it

909
00:43:16,840 --> 00:43:19,160
Speaker 2: just looks like a liquid, but then the balancing of

910
00:43:19,239 --> 00:43:22,960
Speaker 2: the speaker makes it suddenly solid momentarily, and so it

911
00:43:23,000 --> 00:43:25,959
Speaker 2: forms these weird globs which will like dance on top

912
00:43:26,000 --> 00:43:26,680
Speaker 2: of your speaker.

913
00:43:27,239 --> 00:43:31,279
Speaker 1: Yeah, it's pretty wild. I highly recommend that all of

914
00:43:31,320 --> 00:43:33,960
Speaker 1: you at home to try making uplick with your kids

915
00:43:34,040 --> 00:43:36,680
Speaker 1: or by yourself. I did it before I had kids.

916
00:43:36,719 --> 00:43:39,360
Speaker 2: Super fun. Yeah, it's fun, it's easy, It's only a

917
00:43:39,400 --> 00:43:41,840
Speaker 2: little bit messy. Don't try to eat it though.

918
00:43:41,800 --> 00:43:44,520
Speaker 1: Oh what happens if you eat it? You turn into

919
00:43:44,520 --> 00:43:50,920
Speaker 1: a fig neating or not. I guess In general, doing

920
00:43:51,040 --> 00:43:53,000
Speaker 1: in just high large amounts of anything.

921
00:43:53,320 --> 00:43:56,640
Speaker 2: Yeah, though there are some non Newtonian fluids which people

922
00:43:56,680 --> 00:43:59,800
Speaker 2: eat every single day. They have them on their burgers,

923
00:44:00,120 --> 00:44:01,200
Speaker 2: have them with their fries.

924
00:44:01,680 --> 00:44:04,640
Speaker 1: Yeah. Ketchup is a famous non Newtonian fluid.

925
00:44:04,440 --> 00:44:07,000
Speaker 2: Right, Yeah, ketchup is sort of the opposite kind of

926
00:44:07,040 --> 00:44:09,640
Speaker 2: non Newtonian fluid ubleck. If you try to move through

927
00:44:09,640 --> 00:44:13,040
Speaker 2: it really fast, the viscosity grows really really quickly. But

928
00:44:13,239 --> 00:44:15,560
Speaker 2: ketchup is sort of the opposite. Like, if you want

929
00:44:15,640 --> 00:44:18,520
Speaker 2: ketchup to flow better, you actually shake it. You get

930
00:44:18,560 --> 00:44:21,839
Speaker 2: it moving fast, right, you shake the bottle and then

931
00:44:22,040 --> 00:44:23,120
Speaker 2: it'll flow out.

932
00:44:23,280 --> 00:44:25,560
Speaker 1: Wait, is that why, like a ketchup you have to

933
00:44:25,640 --> 00:44:27,400
Speaker 1: hit the bottom of the bottle to put it on

934
00:44:27,440 --> 00:44:27,880
Speaker 1: your burger.

935
00:44:28,000 --> 00:44:30,000
Speaker 2: Yeah, that's exactly why. You shake the bottle or you

936
00:44:30,040 --> 00:44:32,960
Speaker 2: slap the bottom, and then suddenly it will flow. So

937
00:44:33,000 --> 00:44:35,000
Speaker 2: you like increase the pressure of this thing, the viscosity

938
00:44:35,000 --> 00:44:37,960
Speaker 2: actually goes down. You can flow better when you squeeze it.

939
00:44:38,280 --> 00:44:42,640
Speaker 1: Mmm. So it's non Newtonian because that viscosity relationship is

940
00:44:42,680 --> 00:44:46,359
Speaker 1: not linear, But it's the opposite of ublick, where like

941
00:44:46,640 --> 00:44:49,080
Speaker 1: the faster you try to strimp through ketchup, the easier

942
00:44:49,120 --> 00:44:49,920
Speaker 1: it is exactly.

943
00:44:49,960 --> 00:44:52,160
Speaker 2: So Newtonian fluids are the ones that are just along

944
00:44:52,239 --> 00:44:54,399
Speaker 2: this line, but you could be non Newtonian either above

945
00:44:54,480 --> 00:44:57,360
Speaker 2: the line or below the line, or anything that deviates

946
00:44:57,360 --> 00:45:00,319
Speaker 2: from the line. Essentially, so ketchup is super you're to

947
00:45:00,320 --> 00:45:03,239
Speaker 2: actually call it a pseudo plastic. And there isn't a

948
00:45:03,400 --> 00:45:06,880
Speaker 2: good microphysical understanding for why this works. Like we have

949
00:45:06,920 --> 00:45:09,640
Speaker 2: this whole story about water and corn starch for ubleack,

950
00:45:09,840 --> 00:45:11,960
Speaker 2: but there isn't a similar story we can tell for

951
00:45:12,040 --> 00:45:13,560
Speaker 2: what's going on in ketchup.

952
00:45:13,760 --> 00:45:15,760
Speaker 1: Wait, what do you mean? Like it's a mystery.

953
00:45:16,120 --> 00:45:18,600
Speaker 2: It's a mystery of physics. People are doing experiments trying

954
00:45:18,600 --> 00:45:21,440
Speaker 2: to understand it, but there is not a good concise

955
00:45:21,560 --> 00:45:23,799
Speaker 2: understanding for why ketchup behaves the way it does.

956
00:45:23,920 --> 00:45:25,880
Speaker 1: I guess maybe the simplest way to understand it is

957
00:45:25,880 --> 00:45:27,839
Speaker 1: like if you take a ketchup bottle and you turn

958
00:45:27,920 --> 00:45:30,600
Speaker 1: it upside down. The ketchup is not going to float

959
00:45:30,880 --> 00:45:34,799
Speaker 1: out necessarily or very fast or very quickly, but if

960
00:45:34,840 --> 00:45:38,200
Speaker 1: you sort of shake it, then it becomes a more liquid.

961
00:45:38,320 --> 00:45:40,880
Speaker 2: Exactly, the viscosity drops when you shake it, when you

962
00:45:40,920 --> 00:45:44,120
Speaker 2: apply some pressure to it, or you increase the velocity

963
00:45:44,120 --> 00:45:47,400
Speaker 2: between the layers, the viscosity drops and so then you

964
00:45:47,440 --> 00:45:49,440
Speaker 2: can slide and it flows out onto your burger.

965
00:45:49,680 --> 00:45:53,640
Speaker 1: Mmmm. All right, what are other examples of non Newtonian fluids?

966
00:45:53,760 --> 00:45:55,520
Speaker 2: So other things you might find around your house, Like

967
00:45:55,600 --> 00:45:58,360
Speaker 2: slime is a non Newtonian fluid, silly putty?

968
00:45:58,520 --> 00:46:00,920
Speaker 1: Right, what do you mean slime? That's different.

969
00:46:01,040 --> 00:46:03,560
Speaker 2: Slime is in the oublick category. Like it can flow,

970
00:46:03,600 --> 00:46:05,279
Speaker 2: but if you pick it up and you squeeze it,

971
00:46:05,400 --> 00:46:07,480
Speaker 2: you can feel more solid. Right, that's one of the

972
00:46:07,640 --> 00:46:09,600
Speaker 2: things that makes it sort of slimy. I mean, I

973
00:46:09,640 --> 00:46:11,799
Speaker 2: try to avoid playing with slime whenever my daughter makes it,

974
00:46:11,840 --> 00:46:13,319
Speaker 2: But this is what I noticed when I'm cleaning up

975
00:46:13,360 --> 00:46:13,759
Speaker 2: after her.

976
00:46:16,000 --> 00:46:18,120
Speaker 1: Yeah, So meaning like if you try to steer it,

977
00:46:18,200 --> 00:46:19,719
Speaker 1: you feel a certain resistance to it. Or if you

978
00:46:20,080 --> 00:46:22,440
Speaker 1: try to swim through slime, but you try to swim fast,

979
00:46:22,480 --> 00:46:24,480
Speaker 1: the faster it'll push back on you more.

980
00:46:24,640 --> 00:46:27,640
Speaker 2: Yeah. The viscosity is not constant. It changes depending on

981
00:46:27,719 --> 00:46:29,839
Speaker 2: the stress and the forces apply to it. You pull

982
00:46:29,840 --> 00:46:32,480
Speaker 2: it apart quickly applying a large force, it becomes very

983
00:46:32,560 --> 00:46:35,200
Speaker 2: viscous and can like break in half. So you take

984
00:46:35,280 --> 00:46:37,720
Speaker 2: like slime, you just pull on it gently, it'll stretch

985
00:46:38,040 --> 00:46:40,200
Speaker 2: you pull on it really really fast, it'll actually crack

986
00:46:40,239 --> 00:46:40,719
Speaker 2: into two.

987
00:46:40,640 --> 00:46:44,920
Speaker 1: Pieces because I guess the force gets higher the faster

988
00:46:45,000 --> 00:46:46,880
Speaker 1: you try to do it. But at some point the

989
00:46:47,440 --> 00:46:49,840
Speaker 1: material can't take it and it just breaks exactly, It

990
00:46:49,920 --> 00:46:52,400
Speaker 1: just gives up. Also, silly putty is a non newton

991
00:46:52,480 --> 00:46:53,160
Speaker 1: of fluid, right.

992
00:46:53,160 --> 00:46:55,720
Speaker 2: Yeah, silly putty in the same way. And the weirdest

993
00:46:55,760 --> 00:46:57,920
Speaker 2: non newton in fluid. The thing that surprises me most

994
00:46:58,000 --> 00:47:01,520
Speaker 2: is paint. Paint is also a non Newtonian fluid.

995
00:47:02,160 --> 00:47:02,680
Speaker 1: What do you mean?

996
00:47:03,200 --> 00:47:05,319
Speaker 2: Imagine what would happened if you painted your walls with

997
00:47:05,400 --> 00:47:08,080
Speaker 2: honey or with water. You take your brush, you dip it,

998
00:47:08,200 --> 00:47:10,319
Speaker 2: and you spread it along. You expect to see lots

999
00:47:10,320 --> 00:47:13,040
Speaker 2: of drips, right, But paint, when you apply it to

1000
00:47:13,080 --> 00:47:15,799
Speaker 2: the wall, it's very easy to apply. But then it

1001
00:47:15,800 --> 00:47:18,880
Speaker 2: becomes very very viscous, so it doesn't drip very much.

1002
00:47:19,120 --> 00:47:23,080
Speaker 2: So paint is like specially formulated chemically to not drip,

1003
00:47:23,160 --> 00:47:25,760
Speaker 2: to become viscous when you apply it to the wall.

1004
00:47:26,480 --> 00:47:28,319
Speaker 1: But isn't that because it's drying out.

1005
00:47:28,920 --> 00:47:30,960
Speaker 2: So the crucial thing is that you're applying paint to

1006
00:47:31,000 --> 00:47:34,319
Speaker 2: a vertical wall, right, and so the fluid starts to

1007
00:47:34,400 --> 00:47:37,800
Speaker 2: drip down the surface, but because of its non Newtonian nature,

1008
00:47:37,920 --> 00:47:41,760
Speaker 2: this acceleration then increases the velocity, so instead of slipping

1009
00:47:41,800 --> 00:47:44,520
Speaker 2: along the surface, it forms sort of large and dense

1010
00:47:44,600 --> 00:47:47,279
Speaker 2: droplets with limited dripping, So it forms like a little

1011
00:47:47,280 --> 00:47:50,320
Speaker 2: bit of texture, but the drops never actually form.

1012
00:47:50,320 --> 00:47:52,080
Speaker 1: Well what does that mean when I try to stir it?

1013
00:47:52,080 --> 00:47:54,719
Speaker 2: Though it's not as dramatic as Ubleck, but it's in

1014
00:47:54,760 --> 00:47:57,680
Speaker 2: the same direction as Ubleck that as you go faster,

1015
00:47:57,880 --> 00:48:00,799
Speaker 2: it rapidly becomes more viscous, which is what you want.

1016
00:48:00,840 --> 00:48:03,360
Speaker 2: So as drips are starting to form on the wall,

1017
00:48:03,719 --> 00:48:06,359
Speaker 2: it becomes more viscous in order to essentially prevent those

1018
00:48:06,440 --> 00:48:07,360
Speaker 2: drops from forming.

1019
00:48:08,840 --> 00:48:11,319
Speaker 1: And also I imagine it's also drying out right and

1020
00:48:11,360 --> 00:48:12,960
Speaker 1: solidifying a little bit too.

1021
00:48:13,160 --> 00:48:15,319
Speaker 2: Yeah, but you want to avoid drips forming while it's

1022
00:48:15,360 --> 00:48:18,000
Speaker 2: still liquid, because if you form drips then those dry

1023
00:48:18,080 --> 00:48:19,000
Speaker 2: it looks pretty ugly.

1024
00:48:19,440 --> 00:48:22,080
Speaker 1: Well, is there a sort of a quick explanation we

1025
00:48:22,080 --> 00:48:25,520
Speaker 1: can give us to why some things are non Newtunin

1026
00:48:25,640 --> 00:48:28,279
Speaker 1: or not, like why some things are not linear and

1027
00:48:28,360 --> 00:48:28,920
Speaker 1: some things are.

1028
00:48:29,120 --> 00:48:31,319
Speaker 2: We don't have a good overall understanding of it. It

1029
00:48:31,400 --> 00:48:35,000
Speaker 2: seems like the general direction of the explanation is that

1030
00:48:35,080 --> 00:48:39,359
Speaker 2: it comes from complex interactions between heterogeneous materials. So if

1031
00:48:39,360 --> 00:48:41,320
Speaker 2: you have something which is only made of one kind

1032
00:48:41,360 --> 00:48:43,200
Speaker 2: of thing, it's going to tend to have a pretty

1033
00:48:43,200 --> 00:48:47,239
Speaker 2: simple relationship between the velocity and the friction. If you don't.

1034
00:48:47,280 --> 00:48:49,560
Speaker 2: If you have complicated mixtures the way we do with

1035
00:48:49,640 --> 00:48:53,360
Speaker 2: oobleck water and cornstarch, then you sometimes get different relative

1036
00:48:53,400 --> 00:48:56,040
Speaker 2: densities of those two things. You can get a much

1037
00:48:56,120 --> 00:48:59,600
Speaker 2: wider range of behavior, and that behavior can emerge under

1038
00:48:59,600 --> 00:49:02,719
Speaker 2: different conditions. And so probably that's why like paint is

1039
00:49:02,800 --> 00:49:05,799
Speaker 2: non Newtonian whereas water isn't, because it has to do

1040
00:49:05,840 --> 00:49:09,080
Speaker 2: with like having droplets of these dyes in suspension and

1041
00:49:09,239 --> 00:49:12,000
Speaker 2: ketchup is a complicated combination of water and all sorts

1042
00:49:12,000 --> 00:49:15,200
Speaker 2: of other things. So how those molecules interact with each other,

1043
00:49:15,280 --> 00:49:17,000
Speaker 2: and whether you're having more of one kind of thing

1044
00:49:17,080 --> 00:49:19,840
Speaker 2: or another, it's probably the source of it. But the

1045
00:49:19,920 --> 00:49:22,840
Speaker 2: real takeaway I think is like, Wow, the world is

1046
00:49:22,920 --> 00:49:27,120
Speaker 2: complicated that these fairly basic interactions we understand about how

1047
00:49:27,239 --> 00:49:29,960
Speaker 2: molecules and particles interact with each other, but they can

1048
00:49:30,040 --> 00:49:34,160
Speaker 2: create all sorts of incredibly complicated behavior when you zoom.

1049
00:49:33,880 --> 00:49:36,080
Speaker 1: Out, Yeah, I know, it's amazing. I think you're saying,

1050
00:49:36,080 --> 00:49:38,680
Speaker 1: like it maybe has something to do with how complicated

1051
00:49:38,719 --> 00:49:41,680
Speaker 1: the liquid is inside, right, Like, if it's just one thing,

1052
00:49:41,800 --> 00:49:44,880
Speaker 1: like water molecules, only water molecules, then they sort of

1053
00:49:44,880 --> 00:49:47,040
Speaker 1: behave kind of predictively. But if you have more than water,

1054
00:49:47,080 --> 00:49:50,240
Speaker 1: if you have water and corn storage molecules, then maybe

1055
00:49:50,840 --> 00:49:53,000
Speaker 1: because they're so different, the faster you try to move

1056
00:49:53,040 --> 00:49:56,320
Speaker 1: through it, then they sort of gets into these different regimes. Maybe,

1057
00:49:56,640 --> 00:49:58,879
Speaker 1: like it it gets into things where're like, oh, now

1058
00:49:58,920 --> 00:50:02,160
Speaker 1: the cornstarch is dominant because all the water came out

1059
00:50:02,560 --> 00:50:05,120
Speaker 1: or things like that, and so the whole property how

1060
00:50:05,120 --> 00:50:06,959
Speaker 1: it behaves when you try to stir it is different

1061
00:50:07,000 --> 00:50:08,839
Speaker 1: depending on how fast you're trying to steer it.

1062
00:50:09,040 --> 00:50:11,799
Speaker 2: Yeah, exactly. So it can do many more different kind

1063
00:50:11,840 --> 00:50:14,759
Speaker 2: of complicated things because it's got two components to it,

1064
00:50:14,800 --> 00:50:16,759
Speaker 2: and sometimes you're seeing more of one and sometimes more

1065
00:50:16,800 --> 00:50:17,200
Speaker 2: of the other.

1066
00:50:17,840 --> 00:50:20,840
Speaker 1: Hmmm, all right, well that's great because I feel like,

1067
00:50:21,000 --> 00:50:23,440
Speaker 1: you know, sometimes people say, oh, they use the word

1068
00:50:23,520 --> 00:50:26,239
Speaker 1: non intonin fluid as an explanation like oh, why does

1069
00:50:26,280 --> 00:50:28,200
Speaker 1: oubleake do that or why does kets do that? And

1070
00:50:28,200 --> 00:50:29,960
Speaker 1: then people would say, oh, it's because it's a non

1071
00:50:29,960 --> 00:50:32,400
Speaker 1: intone in fluid as if that was the explanation.

1072
00:50:32,719 --> 00:50:34,920
Speaker 2: Right, Yeah, a label is not an explanation. It's just

1073
00:50:34,960 --> 00:50:36,759
Speaker 2: a name. You could give it any name, or you

1074
00:50:36,760 --> 00:50:38,840
Speaker 2: could call it a yaka block of fluid. It's not

1075
00:50:38,920 --> 00:50:39,640
Speaker 2: an explanation.

1076
00:50:40,160 --> 00:50:42,280
Speaker 1: Yeah, which is also the name of a great bagel,

1077
00:50:43,680 --> 00:50:46,040
Speaker 1: now it is. But maybe the point is that, you know,

1078
00:50:46,120 --> 00:50:49,400
Speaker 1: if you see this phenomenon, the phenomena is called the

1079
00:50:49,600 --> 00:50:52,239
Speaker 1: non Newtonian but it has maybe more to do with

1080
00:50:52,520 --> 00:50:54,000
Speaker 1: what's going on at the molecular level.

1081
00:50:54,040 --> 00:50:56,239
Speaker 2: Yeah, in the same way we think probably everything in

1082
00:50:56,239 --> 00:50:59,680
Speaker 2: the world comes out of these molecular interactions in different ways.

1083
00:51:00,239 --> 00:51:02,680
Speaker 2: But you know, it's amazing. It's not all just chaos.

1084
00:51:02,719 --> 00:51:06,440
Speaker 2: It's not just a crazy swarm of frothing nonsense. You

1085
00:51:06,520 --> 00:51:09,480
Speaker 2: get these weird behaviors that we can summarize and understand,

1086
00:51:09,520 --> 00:51:13,040
Speaker 2: and this like linear relationship between these two quantities. It's

1087
00:51:13,080 --> 00:51:15,799
Speaker 2: sort of amazing that that happens at all. So I'm

1088
00:51:15,800 --> 00:51:18,920
Speaker 2: just grateful that the universe is at all understandable at

1089
00:51:18,920 --> 00:51:19,440
Speaker 2: our level.

1090
00:51:19,960 --> 00:51:22,920
Speaker 1: Yeah, you can make lost and maybe predict things and

1091
00:51:22,960 --> 00:51:26,680
Speaker 1: then design things also, Right, it's really important for engineering

1092
00:51:26,719 --> 00:51:27,880
Speaker 1: to know how these things are going to.

1093
00:51:27,880 --> 00:51:30,880
Speaker 2: Behave, Yeah, absolutely, Thank you to all the engineers.

1094
00:51:31,040 --> 00:51:33,360
Speaker 1: Yeah, although sometimes you come up with a law and

1095
00:51:33,400 --> 00:51:36,400
Speaker 1: then people find exceptions and then they call those not laws.

1096
00:51:37,360 --> 00:51:39,319
Speaker 2: But your name is still on it, so you still win.

1097
00:51:42,000 --> 00:51:43,920
Speaker 1: I'm not sure I subscribe to the idea that all

1098
00:51:44,000 --> 00:51:46,600
Speaker 1: fame is good fame. I think there are plenty of

1099
00:51:46,719 --> 00:51:51,160
Speaker 1: examples in tabloids about that. But still, it's nice to

1100
00:51:51,200 --> 00:51:51,920
Speaker 1: be part of the mix.

1101
00:51:52,000 --> 00:51:55,520
Speaker 2: As you say, Hey, everybody remembers Benedict Arnold, right, not fondly,

1102
00:51:55,600 --> 00:51:58,640
Speaker 2: though not fondly, but they remember.

1103
00:51:58,360 --> 00:52:03,520
Speaker 1: It all right, set the future physicists, super villain.

1104
00:52:03,640 --> 00:52:05,960
Speaker 2: That's right. I'm gonna close out my movie with the

1105
00:52:06,000 --> 00:52:07,880
Speaker 2: line better to be hated than.

1106
00:52:07,760 --> 00:52:13,000
Speaker 1: Forgotten, And then people will forget your movie because they

1107
00:52:13,000 --> 00:52:16,080
Speaker 1: didn't like it because it has such a terrible message.

1108
00:52:16,160 --> 00:52:16,560
Speaker 2: Dude.

1109
00:52:17,200 --> 00:52:19,799
Speaker 1: All right, Well, as you said, it's interesting to think

1110
00:52:19,840 --> 00:52:23,680
Speaker 1: about the physics of everyday objects like cornstarch and ketchup

1111
00:52:23,719 --> 00:52:25,719
Speaker 1: and slime and even paint.

1112
00:52:25,800 --> 00:52:27,560
Speaker 2: And swimming pools filled with honey.

1113
00:52:27,600 --> 00:52:29,839
Speaker 1: Thanks for joining us, See you next time.

1114
00:52:37,760 --> 00:52:40,560
Speaker 2: Thanks for listening, and remember that. Daniel and Jorge Explain

1115
00:52:40,600 --> 00:52:44,600
Speaker 2: the Universe is a production of iHeartRadio. For more podcasts

1116
00:52:44,600 --> 00:52:49,280
Speaker 2: from iHeartRadio, visit the iHeartRadio app, Apple podcasts, or wherever

1117
00:52:49,320 --> 00:53:01,359
Speaker 2: you listen to your favorite shows.