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Speaker 1: They say that any technology sufficiently advanced is indistinguishable from magic. Well,

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Speaker 1: there's one technology that people have lusted after for thousands

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Speaker 1: of years that we now rely on even find routine.

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Speaker 1: I'm talking, of course, about flight. It's been only one

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Speaker 1: hundred years since people were able to leave the ground

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Speaker 1: and fly through the air and return safely. Now it's

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Speaker 1: so routine that people sleep through it. But imagine what

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Speaker 1: that would seem like someone from a thousand or ten

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Speaker 1: thousand years ago. It's essentially like magic. Of course, we

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Speaker 1: know it's actually not. It's science because we can understand it,

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Speaker 1: and we can break it down. We can explain it.

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Speaker 1: We understand why planes fly, right, do we could we

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Speaker 1: actually explain it to visiting ancestors from the deep past?

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Speaker 1: Or is it still some kind of black magic even

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Speaker 1: for modern humans and the best aeronautical engineers. So today

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Speaker 1: on Daniel and Kelly's Extraordinary Universe, we'll be asking an

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Speaker 1: old question, why do planes fly?

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Speaker 2: Hi?

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Speaker 3: I'm Kelly Wiener Smith and my favorite way to travel

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Speaker 3: is by train.

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Speaker 1: Hi. I'm Daniel Whitson. I'm a particle physicist, which means

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Speaker 1: I have to fly around the world to get to

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Speaker 1: the biggest particle accelerator.

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Speaker 4: And what is your worst flight experience?

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Speaker 1: My worst flight experience is traveling with my own six

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Speaker 1: month old baby. We had a bascinet and we got

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Speaker 1: her to sleep in the basinet and we thought, oh,

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Speaker 1: this is going to be great. Then the stewardess came

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Speaker 1: by and said, oh, there's some turbulence. You have to

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Speaker 1: take her out and put her in a seat and

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Speaker 1: buckle her in. And he said, no, she's sleeping, and

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Speaker 1: she said sorry, it's the rules. And everyone around us went,

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Speaker 1: oh no, and they were right, because she screamed for

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Speaker 1: the rest of the eight hour flight.

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Speaker 3: Oh no, that's horrible. I'm so sorry. When you finally

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Speaker 3: get your kid asleep and something wakes them up on

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Speaker 3: a plane, it's the worst.

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Speaker 1: It's the worst. And everybody knew it was the worst,

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Speaker 1: and we all knew there's nothing we could do, but hey,

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Speaker 1: you know, them's the rules. How about you, what's your

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Speaker 1: worst traveled experience?

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Speaker 3: It also involves plane with my child. She was probably

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Speaker 3: about six months old around there also, and I brought

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Speaker 3: a change of clothes for her. I was totally prepared

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Speaker 3: for her. She was sitting on my lap and we

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Speaker 3: were about to take off, and right as the plane

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Speaker 3: started moving forward, she had a blowout poop on my

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Speaker 3: leg and so it smelled horrible. But you can't get

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Speaker 3: out of your seat until you rechruising altitude. So everybody

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Speaker 3: was like giving me dirty looks and covering their noses,

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Speaker 3: and it took like twenty minutes before we were allowed

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Speaker 3: to get out of our seats. And then you know,

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Speaker 3: I had to change her in the airplane changing room,

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Speaker 3: which is like so tiny, I thought she was gonna

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Speaker 3: fall off the little tray. And anyway, I brought a

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Speaker 3: change of clothes for her, but I didn't assume i'd

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Speaker 3: have on my pants.

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Speaker 1: Oops. Classic parenting mistake exactly.

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Speaker 3: So I smelled horrible the whole flight, and people kept

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Speaker 3: looking at me, and it wasn't a lot of fun.

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Speaker 4: But them's the breaks you got to leave the house

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Speaker 4: with kids.

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Speaker 1: Sometimes you just got to look back at those people

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Speaker 1: and say, hey, who's going to pay for your social security? Right?

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Speaker 1: Somebody's got to make the next generation. And to me,

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Speaker 1: Madame poopy Pants, I'll get a.

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Speaker 4: Little like badge that says that.

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Speaker 3: Now, whenever I see a parent with a kid, I'm like,

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Speaker 3: what can I carry for you. How can I help

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Speaker 3: like I offer to help all the time.

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Speaker 1: Yeah, exactly. And the big lesson I learned is never judge,

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Speaker 1: and you never in somebody else's family. You don't know

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Speaker 1: what they're going through or what they're struggling with or

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Speaker 1: how much they slept last night. Just help and smile. Yep.

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Speaker 3: And kids are always at their worst because they're always

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Speaker 3: the tiredest and they're not used to it, and so

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Speaker 3: like anyway, yes, don't judge. But planes are wonderful. I

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Speaker 3: needed to get from place to place, and I needed

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Speaker 3: to get there quickly. And actually I wouldn't have wanted

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Speaker 3: to take my daughter on a long train ride for

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Speaker 3: the journey that we were going on, because it would

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Speaker 3: have been days. But I was flying to London the

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Speaker 3: other day and we had kind of talked about why

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Speaker 3: do planes fly? And you said it's complicated, And while

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Speaker 3: I was, you know, above the Atlantic, I thought, how complicated?

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Speaker 4: How well do we understand this?

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Speaker 3: I hope the answer is really well, So I'm looking

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Speaker 3: forward to today's conversation.

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Speaker 1: Good Well. This question actually came to me from a listener.

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Speaker 1: Tom Johnson from Ohio wrote to me and asked if

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Speaker 1: we could explain why planes fly because he looked into

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Speaker 1: a little bit and he was kind of confused. So

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Speaker 1: he wanted a clear explanation for why it is that

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Speaker 1: planes stay in the air.

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Speaker 3: And if you have a question that you want to

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Speaker 3: ask us, we would be happy to answer them. So

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Speaker 3: send us an email at questions at Daniel and Kelly

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Speaker 3: dot org.

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Speaker 1: When I told Tom that we were going to answer

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Speaker 1: his question on the pod, he said, quote, my wife

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Speaker 1: is absolutely going to roll her eyes tonight when I

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Speaker 1: tell her over sushi, which made me wonder. Tom is

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Speaker 1: in Ohio. Where is he getting a sushi? Probably they

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Speaker 1: have it flown in so even his sushi relies on

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Speaker 1: airplane in wings.

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Speaker 3: Yeah, and you know, I lived in Ohio for a

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Speaker 3: decade or more, and I can tell you that when

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Speaker 3: sushi has to fly that far, it's not great.

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Speaker 4: You're too far from the ocean.

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Speaker 1: At that point, you're saying nobody should fly to Ohio

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Speaker 1: for sushi.

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Speaker 4: No, I'd say that.

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Speaker 3: I'm going to go on the record saying you shouldn't

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Speaker 3: fly just to Ohio for sushi.

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Speaker 4: Ohio has got other things going for it.

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Speaker 1: You should have Ohio pride. You know, I know you're

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Speaker 1: a transplanted Virginian, but like you come from Ohio. A

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Speaker 1: good thing about Ohio, for example, is it made you You.

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Speaker 3: Know, I was actually born in New Jersey, which is

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Speaker 3: an even harder state to defend, but I do actually

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Speaker 3: love New Jersey and I will defend New Jersey. But

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Speaker 3: you know, Ohio was a very safe place to grow

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Speaker 3: up where I grew up, and so that's fine. And

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Speaker 3: I think Ohio has made the most astronauts, and so

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Speaker 3: you know, we all would make jokes about you know,

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Speaker 3: what is it about Ohio that makes you want to

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Speaker 3: get as far as possible away from this planet? And

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Speaker 3: I'm not sure if Ohio is still winning an astronaut production,

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Speaker 3: but it was at some point.

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Speaker 1: All right, well, let's stop flying around the issue and

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Speaker 1: get to the question. I was wondering what people out

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Speaker 1: there thought about how planes stay in the air, how

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Speaker 1: wings work, what stories they had been told, and what

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Speaker 1: they understood about this question. So, as usual, I went

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Speaker 1: to our bank of volunteers to ask them why do

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Speaker 1: planes fly? If you would like to play for a

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Speaker 1: future episodes, please don't be shy right to us to

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Speaker 1: questions at Danielankelly dot org. In the meantime, think about

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Speaker 1: it for a moment. Why do you think planes fly?

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Speaker 1: Here's what a bunch of listeners had to say.

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Speaker 5: I believe nobody really knows. I would be glad to

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Speaker 5: learn otherwise. I know that I've read in my school

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Speaker 5: book that the air takes a longer way on the

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Speaker 5: top of the wing than on the bottom of the wing,

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Speaker 5: and therefore we have a sort of suction going on

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Speaker 5: that pulls the wing up.

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Speaker 1: Planes fly because they want to, and because of the

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Speaker 1: differential air.

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Speaker 6: Pressure forces the air to take a longer path to

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Speaker 6: go over the wing versus under the wing, and this

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Speaker 6: differential in the path length reduces the pressure on the

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Speaker 6: upper surface of the wing, and that provides lift.

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Speaker 1: There's some confusion surrounding the Bernoulli effect and the airflow

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Speaker 1: speed over the top and bottom of the wings. There's lift,

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Speaker 1: which means that the air going over the curved part

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Speaker 1: of the wing takes longer than the air going underneath

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Speaker 1: the wing, so the lift is created there.

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Speaker 2: It takes longer for the air to go over the

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Speaker 2: top of the wing.

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Speaker 6: The aerodynamics of that wing shape causes low pressure to

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Speaker 6: form over the top of the wing and high pressure

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Speaker 6: to form under the wing.

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Speaker 7: So wasn't it to do with Leonardo da Vinci came

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Speaker 7: up with the original idea to base planes on the

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Speaker 7: optron from wings of beds.

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Speaker 1: Planes fly because they can't swim.

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Speaker 2: I think that light blanes such as paper planes can

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Speaker 2: fly just because of hierodynamics, but heavy planes need engines

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Speaker 2: to generate pressure difference. But I am not entirely sure

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Speaker 2: how this works.

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Speaker 7: So you have to have thrust greater than drug and

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Speaker 7: lift greater than gravity, a higher pressure below and the

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Speaker 7: lower pressure above the top of the wing is curved,

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Speaker 7: so the air has to travel further.

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Speaker 8: I thought the planes flew because the Russian forts caused

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Speaker 8: air to flow over their wings and created a force

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Speaker 8: that pushes up on the wings.

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Speaker 2: So I think planes fly because of the way that

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Speaker 2: the wind dends around the wing.

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Speaker 6: Planes fly because the lift that they generate is greater

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Speaker 6: than the gravitational pull.

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Speaker 2: The air has.

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Speaker 4: A longer way over the wing than under the wing.

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Speaker 8: The top of the wing, because of its shape, it

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Speaker 8: makes a suction, so it's the plane up.

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Speaker 1: I'm not actually completely sure why plane flies, but I

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Speaker 1: know I've been in them and they tend to do that,

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Speaker 1: and I hope they continue to do so.

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Speaker 3: I love that the answers were a combination of people

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Speaker 3: who clearly sort of know what the answer is and

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Speaker 3: like gave good answers, and then people who are hilarious.

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Speaker 4: Because they can't swim. Made me laugh out loud. So bravo.

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Speaker 1: You know. I love that approach. You don't know the answer,

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Speaker 1: tell us a good joke.

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Speaker 3: Yeah, absolutely, I think that might be one of the

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Speaker 3: keys to life.

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Speaker 4: I think I.

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Speaker 1: Want to see that more of my physics exams. You know,

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Speaker 1: when somebody doesn't know how to solve this quantum mechanical

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Speaker 1: problemly write me a good joke. I'll give you some

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Speaker 1: points anyway.

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Speaker 4: You will give points for human sure.

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Speaker 1: Absolutely. I used to regularly have a question on exams

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Speaker 1: that was just a random New Yorker cartoon, and then

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Speaker 1: the question was, write a physics related caption for this cartoon.

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Speaker 4: Oh nice. I love that you're encouraging creativity.

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Speaker 3: I had an exam where I could get five extra

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Speaker 3: credit points if I drew a parasite, and you'd think

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Speaker 3: that that would be great, but I was like, I

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Speaker 3: hate this because I don't even do nice stick figures.

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Speaker 3: That's why I married an artist. He takes care of

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Speaker 3: all of it. But the good thing is there's a

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Speaker 3: stage of parasites where they essentially just look like a circle.

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Speaker 3: And so I just I said, oh, there's a medicinariosist done,

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Speaker 3: and I.

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Speaker 4: Didn't get full credit. All right, So where do we start?

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Speaker 1: So the beginning of the question of why planes fly

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Speaker 1: goes all the way back to the Right Brothers in

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Speaker 1: nineteen oh three. You know, the Right brothers. They were engineers,

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Speaker 1: they were not physicists. And so while the Right Brothers

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Speaker 1: made a plane fly, they actually didn't understand it at

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Speaker 1: the time. Like, they had no principles, they had no theory,

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Speaker 1: they had no real reason to think their plane was

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Speaker 1: gonna fly. They just kind of made it work. And

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Speaker 1: then they were showered, of course, with awards and fame

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Speaker 1: and all sorts of stuff, which led some people in

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Speaker 1: the physics community to get a little bit resentful.

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Speaker 3: So if they had no idea, why did they pick

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Speaker 3: the design they picked? Is it because they were building

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Speaker 3: on things that other people had made that maybe they

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Speaker 3: understood what they were doing, and so they just sort

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Speaker 3: of tinkered with that.

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Speaker 1: Yeah, engineering is a lot of tinkering, right, So let's

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Speaker 1: try this let's try that, and sometimes things work and

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Speaker 1: then later you figure out why that thing floats or

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Speaker 1: why does this thing fly? And that's essentially what happened

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Speaker 1: with the Wright brothers. And they won this fancy award

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Speaker 1: from the Aeronautical Society, and one physicist, Colonel Fullerton, wrote

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Speaker 1: it and said, quote, I think it was a mistake

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Speaker 1: of the Aeronautical Society giving the rights of metal for

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Speaker 1: their contribution to aeronautical science. I agree with they're having

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Speaker 1: the medal, but it should have been for what they

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Speaker 1: have done. In other words, they didn't understand it. They

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Speaker 1: didn't actually advance aeronautical science. They just sort of like

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Speaker 1: made it work, and they left open the question of

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Speaker 1: like why does this work.

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Speaker 3: I still feel like there should be a medal for

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Speaker 3: the moment when you're about to push your plane off

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Speaker 3: the cliff and you're like, we don't understand what's going on.

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Speaker 1: But he the Wiley Coyote Award or something.

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Speaker 4: Maybe it's a subset of the Darwin Award.

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Speaker 1: Yeah. And this turned out to be really important politically

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Speaker 1: because this is just before World War One, right, and

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Speaker 1: so World War one is beginning and we have nations

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Speaker 1: trying to figure out like how to make planes fly,

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Speaker 1: how to make them stable, and nobody really understood like

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Speaker 1: why some things work, how to make them better. And

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Speaker 1: if you don't have like a model for why planes fly,

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Speaker 1: it's pretty hard to improve their performance. And so just

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Speaker 1: before World War One you had all these folks in

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Speaker 1: Britain and then also on the continent trying to understand

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Speaker 1: the theory of flight so they could take advantage of

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Speaker 1: it militarily.

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Speaker 3: Okay, So the Right Brothers didn't have a theory, and

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Speaker 3: nobody else had a theory either, so everyone was just

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Speaker 3: tinkering to see how it worked and that it worked

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Speaker 3: for the Right Brothers. Did the fact that it worked

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Speaker 3: for the Right Brothers give insights into why it would work,

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Speaker 3: Like did their design work because it took advantages of

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Speaker 3: some physics principle that became obvious after the facts to

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Speaker 3: the physicists.

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Speaker 1: It certainly isn't obvious after the fact, because people are

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Speaker 1: still to this day arguing why planes fly. And it's

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Speaker 1: fascinating that the divide in the field we're going to

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Speaker 1: dig into this really goes back to the split that

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Speaker 1: happened in World War One, where you had the sort

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Speaker 1: of like mathematical battle between the scientists. You had the

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Speaker 1: British trying to figure it out and you had the

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Speaker 1: Germans trying to figure it out, and they took different approaches,

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Speaker 1: and those approaches still live on and do battle in

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Speaker 1: science today. In modern aeronautical engineering, the Germans took this

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Speaker 1: approach of thinking about airs a fluid flowing over the

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Speaker 1: wing and analyzing the velocity and thinking about the pressure.

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Speaker 1: But the British didn't like that approach. It made some

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Speaker 1: approximations that made them uncomfortable, and they like using Newton's forces, Newton,

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Speaker 1: of course being British, And so to this day we

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Speaker 1: have two competing theories for why planes fly and how

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Speaker 1: they work. It's fascinating to me that we still haven't

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Speaker 1: figured this out. You're right, we had a working example

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Speaker 1: about one hundred years ago, and that definitely helps, right,

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Speaker 1: It rules some things out, it inspires experiments, So having

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Speaker 1: a working example is useful, but it doesn't always tell

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Speaker 1: you exactly why something happens.

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Speaker 3: So are these theories, which I'm sure we'll get into

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Speaker 3: the details of in a second, are they different enough

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Speaker 3: that that resulted in the British and the Germans having

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Speaker 3: planes that had different shapes during World War One? Or

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Speaker 3: do both theories sort of predict that the same plane

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Speaker 3: shape is good.

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Speaker 1: Yeah, they make different predictions about what's important in the

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Speaker 1: shape of the wing, which is fascinating. And I found

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Speaker 1: this quote from a historian David Bloor who said, on

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Speaker 1: the eve of the Great War, none of the British

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Speaker 1: workers in the field of aero dynamics had any workable

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Speaker 1: account of how an airplane could get off the ground,

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Speaker 1: which you know, makes it pretty hard to optimize the

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Speaker 1: performance of your warplanes.

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Speaker 3: And pretty scary to get into a warplane on top

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Speaker 3: of all the reasons that it's scary to get into

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Speaker 3: a warplane exactly.

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Speaker 1: And later on we'll hear about Albert Einstein's personal design

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Speaker 1: for an airplane, which really didn't work very well.

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Speaker 3: So let's dig Should we start with the Germans or

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Speaker 3: should we start with the British.

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Speaker 1: So the German story is the one that most people

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Speaker 1: have heard about. It's this theory of fluids and flow

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Speaker 1: and Bernoulli's equations and all this kind of stuff. So

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Speaker 1: we should start with there to make contact with what

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Speaker 1: people think about when they think about flight.

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Speaker 4: All right, let's do that.

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Speaker 1: So the usual story for why plane flies has to

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Speaker 1: do with the shape of the wing, and so aeronautical

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Speaker 1: engineers call this an airfoil. It's round y in the

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Speaker 1: front and it's point d in the back. It's sort

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Speaker 1: of like a long, thin tear drop. Right. The idea

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Speaker 1: that you're usually told is that the shape of this

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Speaker 1: wing creates a pressure difference, that you have lower pressure

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Speaker 1: above the wing and higher pressure below the wing, and

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Speaker 1: that creates lyft because higher pressure below and lower pressure

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Speaker 1: above basically pushes up on the wing. And it's the

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Speaker 1: shape of the wing that's crucial in creating these pressure differences,

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Speaker 1: which is what creates lyft. So that's the usual story

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Speaker 1: for why planes fly. That comes down to this particular

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Speaker 1: shape of the wing.

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Speaker 3: So you've got this curved edge moving towards the air quickly.

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Speaker 3: Why does that shape not create the same amount of

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Speaker 3: pressure on the top as it does on the bottom.

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Speaker 3: Because that shape is like symmetrical, right is it? Because

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Speaker 3: when it goes over, it has more space to sort

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Speaker 3: of spread out.

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Speaker 1: So the shape is not actually symmetrical. Right. Typically it's

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Speaker 1: like flat on the bottom and more curved on the top,

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Speaker 1: and so the shape is not actually symmetrical. Which is

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Speaker 1: why the Bernoulli story tells you that it pushes up.

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Speaker 1: Bernoulli is a guy in the seventeen hundreds who is

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Speaker 1: thinking about fluid flow and mostly about like water through

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Speaker 1: pipes and pressure and volume and like, fluids are still

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Speaker 1: something we're struggling to understand. But Bernoulli had a simplified

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Speaker 1: view of it, which oiler actually came through later and

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Speaker 1: proved all of his equations for him. But Bernoulli's principle

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Speaker 1: tells us that faster moving fluids have lower pressure and

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Speaker 1: slower moving fluids have higher pressure. So if the shape

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Speaker 1: of the wing as it moves through the air makes

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Speaker 1: the air go slower under the wing and faster above

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Speaker 1: the wing on this curved shape, then that'll generate lower

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Speaker 1: pressure above the wing and higher pressure below the wing,

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Speaker 1: and that gives you lift.

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Speaker 3: And that feels easy to test, right because you just

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Speaker 3: flip the wing over and it should do the opposite, right,

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Speaker 3: like it should send you plummeting downwards.

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Speaker 1: Yes, already you're identifying a problem with this, But before

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Speaker 1: we take this explanation apart, let's do a little bit

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Speaker 1: more to support it. Because you're right, it kind of

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Speaker 1: is easy to test and you can do a simple

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Speaker 1: test at home. You can just like take a piece

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Speaker 1: of paper and blow air above the piece of paper,

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Speaker 1: and what you see is the paper goes from being

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Speaker 1: sort of droopy to being flat, so it sort of

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Speaker 1: like lifts up. And so it's like a classic symbol

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Speaker 1: at home demonstration. Which you're doing is you're increasing the

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Speaker 1: velocity of the air above the paper, which in theory

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Speaker 1: lowers the air pressure above the paper, which provides lift

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Speaker 1: because now the pressure is higher below the paper and

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Speaker 1: lower above the paper. And you know, the story of

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Speaker 1: like the air moves faster over the wing and slower

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Speaker 1: below the wing is also verified in lots of other experiments,

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Speaker 1: Like you can do these smoke tests where essentially you

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Speaker 1: put a wing in a wind tunnel. Instead of just

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Speaker 1: blowing air over it, you blow smoke over it. Smoke

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Speaker 1: just being like a bunch of particles. You can track

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Speaker 1: those particles and you can measure the velocity. So basically

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Speaker 1: measure the velocity of the air around the wing. See

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Speaker 1: what happened, right, don't just like talk about it, you know,

384
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Speaker 1: in your salons while you're smoking cigarettes or whatever. Actually

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Speaker 1: figure it out. And this is verified, like wind tunnels

386
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Speaker 1: and smoke tests tell us that the air does move

387
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Speaker 1: faster over the top of the wing than below the wing,

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Speaker 1: And so this seems like it all sort of comes together,

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Speaker 1: but as you identify, there are some important limitations to

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Speaker 1: this explanation of why planes fly.

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Speaker 3: So when you get a window seat near the wing

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Speaker 3: and you look out, it's easier to see like it's

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Speaker 3: bunching up and it gets a little bit like kind

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Speaker 3: of white ish. Is that pressure forming? Like are you

395
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Speaker 3: sort of bunching up the air molecules to the point

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Speaker 3: where they're visible or something else happening there? Or am

397
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Speaker 3: I imagining it? And this is like an episode of

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Speaker 3: the Twilight Zone.

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Speaker 1: Nobody else sees that, Kelly, Yeah, exactly, it's just you.

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Speaker 4: That was such a great episode.

401
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Speaker 1: I love that.

402
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Speaker 7: No.

403
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Speaker 1: I think what's happening there is you're seeing more water vapor.

404
00:18:52,520 --> 00:18:54,720
Speaker 1: There are definitely changes in the air pressure below and

405
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Speaker 1: above the wing, and as you know, water is very

406
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Speaker 1: sensitive to pressure, the vapor point and all this kind

407
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Speaker 1: of stuff. What you're seeing there is not the air itself,

408
00:19:02,240 --> 00:19:04,720
Speaker 1: but water vapor forming, which can show you, just like

409
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Speaker 1: any smoke tests can show you where the air is flowing.

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Speaker 1: So that is pretty cool.

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Speaker 4: That sounds obvious now that you say it. But why

412
00:19:11,880 --> 00:19:12,399
Speaker 4: did I ask that?

413
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Speaker 3: But whatever, that's fine, okay, So we decided now we're

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Speaker 3: going to talk about the limitations. Has anybody flipped the

415
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Speaker 3: wing the other way and then saw what happened?

416
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Speaker 4: Did that plane still fly?

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Speaker 1: So? Planes fly upside down all the time? Right? A

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00:19:26,960 --> 00:19:30,240
Speaker 1: big problem with this explanation is that it predicts that

419
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Speaker 1: the asymmetry of the wing is crucial, right, that the

420
00:19:32,960 --> 00:19:35,440
Speaker 1: curb bit on the top compared to the flat bottom

421
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Speaker 1: is really important for making a lift. And so it

422
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Speaker 1: predicts that if you flip that over, planes should like

423
00:19:40,040 --> 00:19:42,960
Speaker 1: crash to the ground. Right, that an upside down wing

424
00:19:43,320 --> 00:19:46,760
Speaker 1: should have anti lift or should have net force downwards.

425
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Speaker 1: But we don't see that. You know, you can fly

426
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Speaker 1: planes upside down all the time. Everybody who's been to

427
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Speaker 1: like an aeronautics show has seen old fashioned planes or

428
00:19:55,440 --> 00:19:59,359
Speaker 1: new planes. They can fly upside down. So Bernoulli's equation

429
00:19:59,760 --> 00:20:03,040
Speaker 1: does and answered this question. This can't be the complete

430
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Speaker 1: story of why wings provide lyft because it gives the

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00:20:06,080 --> 00:20:08,840
Speaker 1: wrong explanation or upside down planes.

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Speaker 3: So you mentioned that Eiler figured out all of these

433
00:20:12,520 --> 00:20:15,920
Speaker 3: equations to support Bernoulli. Does it turn out that Oiler's

434
00:20:15,920 --> 00:20:20,080
Speaker 3: equations were missing some important factor because the equation said

435
00:20:20,119 --> 00:20:21,360
Speaker 3: it should work, but then it doesn't work.

436
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Speaker 4: So what was missing in the equations?

437
00:20:23,160 --> 00:20:25,280
Speaker 1: Oh yeah, great question. And this really goes to the

438
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Speaker 1: heart of what's going on here. There's nothing wrong with

439
00:20:27,880 --> 00:20:31,720
Speaker 1: Bernoulli's equations. And I'm giving Oiler credit only because Oiler

440
00:20:31,760 --> 00:20:34,000
Speaker 1: came along and like did all the math BERNEULLI had

441
00:20:34,040 --> 00:20:35,919
Speaker 1: like these leaps of insight, like oh, I think this

442
00:20:36,000 --> 00:20:38,159
Speaker 1: and that and the other thing, and then Oiler came

443
00:20:38,200 --> 00:20:40,560
Speaker 1: along and actually like dotted all the i's and crossed

444
00:20:40,560 --> 00:20:42,720
Speaker 1: all the t's. And I think Oiler would have gotten

445
00:20:42,760 --> 00:20:45,280
Speaker 1: credit for these equations if he hadn't already gotten credit

446
00:20:45,320 --> 00:20:48,320
Speaker 1: for like eighty percent of everything in mathematics. It's like

447
00:20:48,760 --> 00:20:51,200
Speaker 1: so much of stuff in mathematics that like Oiler just

448
00:20:51,280 --> 00:20:53,199
Speaker 1: let somebody else take credit for because he's already got

449
00:20:53,240 --> 00:20:56,600
Speaker 1: everything else named after him, which is amazing. So there's

450
00:20:56,600 --> 00:20:59,520
Speaker 1: no problem with Bernoulli's equations. But there are always a

451
00:20:59,600 --> 00:21:03,359
Speaker 1: simple description like brenell The's equations describe fluid flow, and

452
00:21:03,359 --> 00:21:06,159
Speaker 1: they make some assumptions like you're talking about a fluid

453
00:21:06,200 --> 00:21:09,280
Speaker 1: as if it's incompressible, for example, or you're talking about

454
00:21:09,280 --> 00:21:12,600
Speaker 1: it as if it's not made of microscopic particles. That's

455
00:21:12,720 --> 00:21:15,439
Speaker 1: not true, right, Air is made of microscopic particles. It

456
00:21:15,520 --> 00:21:18,520
Speaker 1: is compressible. That doesn't mean that the equations don't apply.

457
00:21:19,000 --> 00:21:21,520
Speaker 1: It means that they apply in some limited sense. It

458
00:21:21,560 --> 00:21:23,919
Speaker 1: also might just be the wrong story. It might not

459
00:21:24,000 --> 00:21:27,399
Speaker 1: provide the answer the explanation. You know, what we're looking

460
00:21:27,440 --> 00:21:30,480
Speaker 1: for is an answer to a question which is macroscopic.

461
00:21:30,600 --> 00:21:32,399
Speaker 1: Like we see the wing go through the air, the

462
00:21:32,400 --> 00:21:35,000
Speaker 1: wing goes up. We want to know why. That's sort

463
00:21:35,000 --> 00:21:38,399
Speaker 1: of like a human question, right, it's not a mathematical question.

464
00:21:38,520 --> 00:21:41,040
Speaker 1: It's not like there's a prediction and number we're trying

465
00:21:41,080 --> 00:21:44,080
Speaker 1: to calculate. We want like a story that tells us

466
00:21:44,119 --> 00:21:46,640
Speaker 1: why this is happening. And that's a little bit more

467
00:21:46,680 --> 00:21:49,920
Speaker 1: slippery than just mathematics. It's something to do with cause

468
00:21:49,960 --> 00:21:52,639
Speaker 1: and effect and understanding, and you know, it's at the

469
00:21:52,640 --> 00:21:55,080
Speaker 1: heart of science is coming up with these stories. But

470
00:21:55,119 --> 00:21:58,200
Speaker 1: it's not always easy, especially when we're zooming out from

471
00:21:58,240 --> 00:22:01,720
Speaker 1: a microscopic universe, to try to tell a story macroscopically.

472
00:22:02,119 --> 00:22:04,600
Speaker 1: It's like economics. You know, you can ask like, why

473
00:22:04,640 --> 00:22:07,520
Speaker 1: do prices go down? Well, I have this theory of inflation.

474
00:22:07,640 --> 00:22:10,679
Speaker 1: I have a theory that involves prices and supply chains, whatever,

475
00:22:10,720 --> 00:22:12,840
Speaker 1: and that the theory can be correct, but it doesn't

476
00:22:12,880 --> 00:22:16,520
Speaker 1: always apply because the conditions it assumes aren't always relevant,

477
00:22:16,640 --> 00:22:19,000
Speaker 1: and it doesn't always answer the question that you're asking.

478
00:22:19,600 --> 00:22:22,160
Speaker 3: I feel like, the next time I get on a plane,

479
00:22:22,320 --> 00:22:25,040
Speaker 3: I'm going to think to myself, I wish it were simple.

480
00:22:25,520 --> 00:22:28,000
Speaker 4: I wish we've really understood this, But plays tend to

481
00:22:28,000 --> 00:22:30,919
Speaker 4: stay up. So that's good. So we've established that the

482
00:22:30,960 --> 00:22:34,640
Speaker 4: Germans got everything wrong and World War one? Oh wait,

483
00:22:34,640 --> 00:22:35,920
Speaker 4: was that World War One or World War two?

484
00:22:36,480 --> 00:22:38,000
Speaker 1: This is World War One we're talking about.

485
00:22:38,240 --> 00:22:39,440
Speaker 4: Well, they got it wrong both times.

486
00:22:39,480 --> 00:22:52,240
Speaker 9: Sorry guys.

487
00:22:57,040 --> 00:23:00,840
Speaker 3: Okay, so we know that when a plane over it

488
00:23:00,880 --> 00:23:02,600
Speaker 3: doesn't crash into the ground.

489
00:23:03,200 --> 00:23:04,920
Speaker 4: What was he getting wrong? Bernoulli?

490
00:23:05,480 --> 00:23:08,040
Speaker 1: So, Bernoulli's story is very nice, and it's very simple,

491
00:23:08,240 --> 00:23:10,600
Speaker 1: and there's lots of it that's correct, but as you say,

492
00:23:10,600 --> 00:23:13,359
Speaker 1: it doesn't explain some things. It doesn't explain why planes

493
00:23:13,400 --> 00:23:16,160
Speaker 1: can fly upset down, and it also doesn't explain something

494
00:23:16,200 --> 00:23:18,960
Speaker 1: really crucial at the heart of the story, which is

495
00:23:19,280 --> 00:23:21,960
Speaker 1: why is the air moving faster over the top of

496
00:23:22,000 --> 00:23:24,560
Speaker 1: the wing than the bottom of the wing. Like we said,

497
00:23:24,800 --> 00:23:26,960
Speaker 1: the wing is asymmetric, it's curbing on the top and

498
00:23:27,000 --> 00:23:29,480
Speaker 1: it's flat on the bottom. But why does that make

499
00:23:29,520 --> 00:23:32,920
Speaker 1: the air go faster over the top? And you often

500
00:23:32,960 --> 00:23:36,960
Speaker 1: hear this pop side explanation which is completely wrong, which

501
00:23:37,000 --> 00:23:39,080
Speaker 1: is that it's a longer trip over the top of

502
00:23:39,080 --> 00:23:41,800
Speaker 1: the wing, so the air has to go faster in

503
00:23:41,920 --> 00:23:45,040
Speaker 1: order to meet its air particle partners at the back

504
00:23:45,119 --> 00:23:45,680
Speaker 1: end of the wing.

505
00:23:45,960 --> 00:23:48,639
Speaker 4: Well, why would it have to exactly, why.

506
00:23:48,520 --> 00:23:51,399
Speaker 1: Would it have to It doesn't have to. It's nonsense,

507
00:23:51,680 --> 00:23:53,399
Speaker 1: But you hear this all the time. I was taught

508
00:23:53,400 --> 00:23:56,320
Speaker 1: this myself. You know that, like when air particles hit

509
00:23:56,320 --> 00:23:58,119
Speaker 1: the front of the wing, if one goes above and

510
00:23:58,119 --> 00:24:00,800
Speaker 1: one goes below, then to meet up again at the

511
00:24:00,840 --> 00:24:03,120
Speaker 1: back of the wing, the one that takes the longer

512
00:24:03,200 --> 00:24:05,960
Speaker 1: route would have to go faster. And it's an example

513
00:24:05,960 --> 00:24:08,560
Speaker 1: of like it's a compelling story, but it doesn't actually

514
00:24:08,600 --> 00:24:10,520
Speaker 1: make any sense because they don't have to take the

515
00:24:10,520 --> 00:24:14,840
Speaker 1: same time. It's fine, the universe doesn't like crash or

516
00:24:14,880 --> 00:24:17,879
Speaker 1: implode or hit a seg fault or something. If the

517
00:24:17,880 --> 00:24:19,280
Speaker 1: air particles don't meet up again.

518
00:24:19,600 --> 00:24:21,679
Speaker 3: Yeah right, they're not like buddies. They don't have to

519
00:24:21,680 --> 00:24:23,320
Speaker 3: get to the same spot at the same time. Yeah

520
00:24:23,359 --> 00:24:25,320
Speaker 3: all right, so that doesn't have to happen.

521
00:24:25,600 --> 00:24:27,879
Speaker 1: So that doesn't have to happen. That's not the explanation

522
00:24:28,200 --> 00:24:30,399
Speaker 1: for why air moves faster over the top, and so

523
00:24:30,480 --> 00:24:33,199
Speaker 1: the Bernoulli story is sort of lacking that explanation, like

524
00:24:33,320 --> 00:24:36,679
Speaker 1: why is there this pressure difference? And it opens this

525
00:24:36,760 --> 00:24:39,200
Speaker 1: door to this question of like, well, did the speed

526
00:24:39,440 --> 00:24:42,199
Speaker 1: differences cause the pressure differences or is it the pressure

527
00:24:42,200 --> 00:24:45,600
Speaker 1: differences that are causing the speed differences. Because Bernoulli's equation

528
00:24:45,680 --> 00:24:49,440
Speaker 1: doesn't give us causality, just says lower pressure, higher speed.

529
00:24:49,720 --> 00:24:51,960
Speaker 1: It doesn't say that lower pressure is caused by the

530
00:24:52,040 --> 00:24:54,720
Speaker 1: higher speed. It could also be the higher speed is

531
00:24:54,760 --> 00:24:57,199
Speaker 1: caused by the lower pressure. So that tells us that

532
00:24:57,240 --> 00:24:59,840
Speaker 1: we need more to the story. Bernulli story can't just

533
00:25:00,040 --> 00:25:02,760
Speaker 1: crowed completely. Uhy planes fly because it doesn't tell us

534
00:25:02,760 --> 00:25:05,760
Speaker 1: why planes fly upside down, and it doesn't explain why

535
00:25:05,840 --> 00:25:08,280
Speaker 1: we see air going faster over the top of the wing,

536
00:25:08,320 --> 00:25:10,320
Speaker 1: which is something we definitely see happening.

537
00:25:10,840 --> 00:25:13,200
Speaker 3: Right, So, I know we're about to talk about another explanation.

538
00:25:13,680 --> 00:25:17,320
Speaker 3: But does looking at birds help at all? Because they have,

539
00:25:17,520 --> 00:25:19,959
Speaker 3: you know, different kinds of wing shapes and they've kind

540
00:25:20,000 --> 00:25:22,600
Speaker 3: of figured it out over evolutionary time. This isn't going

541
00:25:22,680 --> 00:25:25,080
Speaker 3: to give us the pressure answer, but does it give

542
00:25:25,160 --> 00:25:28,439
Speaker 3: us some insights into like how these wings should be shaped.

543
00:25:28,640 --> 00:25:30,359
Speaker 3: I'm getting off track, but I just looked at a

544
00:25:30,359 --> 00:25:31,760
Speaker 3: picture of a bird in my office and.

545
00:25:31,720 --> 00:25:34,240
Speaker 1: Now I have to ask it does and bird wings

546
00:25:34,240 --> 00:25:37,600
Speaker 1: work with similar principles to airplane wings, except of course

547
00:25:37,640 --> 00:25:41,359
Speaker 1: for the flapping part. But for gliding they do fascinatingly.

548
00:25:41,560 --> 00:25:44,919
Speaker 1: Insect wings are even more complicated, and insect flight is

549
00:25:44,960 --> 00:25:48,000
Speaker 1: not something we understand like at all. It's really kind

550
00:25:48,000 --> 00:25:50,280
Speaker 1: of incredible. We should do a whole another episode about

551
00:25:50,280 --> 00:25:51,160
Speaker 1: why insects fly.

552
00:25:51,680 --> 00:25:54,440
Speaker 3: And if you're ever feeling depressed, there are some slow

553
00:25:54,480 --> 00:25:57,680
Speaker 3: mode videos of insects trying to take off and it.

554
00:25:57,720 --> 00:26:00,560
Speaker 4: Is the most clumsy, amazing thing I've I've ever seen.

555
00:26:00,640 --> 00:26:02,639
Speaker 3: It blows my mind that they ever get off the ground,

556
00:26:02,640 --> 00:26:04,520
Speaker 3: and it makes my daughter left so hard she peeps

557
00:26:04,520 --> 00:26:04,840
Speaker 3: a little.

558
00:26:05,119 --> 00:26:07,840
Speaker 1: So I knew a guy who did these experiments where

559
00:26:07,840 --> 00:26:10,119
Speaker 1: they put an insect on a pin that like glued

560
00:26:10,119 --> 00:26:12,360
Speaker 1: it to a pin and then they showed it videos,

561
00:26:12,600 --> 00:26:14,439
Speaker 1: so it was like thought it was flying and they

562
00:26:14,440 --> 00:26:16,600
Speaker 1: would like try to take videos of its wings moving

563
00:26:16,600 --> 00:26:18,359
Speaker 1: to understand it. It's kind of incredible.

564
00:26:18,480 --> 00:26:20,520
Speaker 3: All right, this has been an amazing tangent. I've had

565
00:26:20,560 --> 00:26:22,880
Speaker 3: a lot of fun. Let's go back to World War One,

566
00:26:22,920 --> 00:26:25,640
Speaker 3: which is less fun. So I think we've talked about

567
00:26:25,720 --> 00:26:29,200
Speaker 3: the shortfalls in Bernoulli's explanation. Are we ready to move

568
00:26:29,240 --> 00:26:31,359
Speaker 3: on to what the British folks were thinking?

569
00:26:31,720 --> 00:26:34,399
Speaker 1: Yeah, So across the English channel we had folks that

570
00:26:34,440 --> 00:26:37,080
Speaker 1: are working on a completely different theory, and not a

571
00:26:37,080 --> 00:26:40,199
Speaker 1: completely different theory just because they disagreed scientifically with the

572
00:26:40,240 --> 00:26:43,280
Speaker 1: best approach. Remember there's a war here, and so they're

573
00:26:43,359 --> 00:26:44,879
Speaker 1: not going to collaborate. They're not going to be like

574
00:26:44,880 --> 00:26:47,800
Speaker 1: going to the same conferences and sharing their ideas. It's

575
00:26:47,800 --> 00:26:50,000
Speaker 1: sort of like when evolution splits. You know, you get

576
00:26:50,000 --> 00:26:52,120
Speaker 1: all these weird animals off on an island and they

577
00:26:52,160 --> 00:26:55,600
Speaker 1: diverge into their own crazy direction and get weird pouches

578
00:26:55,600 --> 00:26:57,919
Speaker 1: for their babies or whatever. It's what happens when you

579
00:26:57,960 --> 00:27:01,439
Speaker 1: work in isolation. You get competing nations, and so we

580
00:27:01,520 --> 00:27:03,800
Speaker 1: have this fascinating sort of social experiment where you like,

581
00:27:03,840 --> 00:27:06,080
Speaker 1: isolated two groups of scientists and asked them to solve

582
00:27:06,119 --> 00:27:08,240
Speaker 1: the same problem and they took very different approaches.

583
00:27:08,640 --> 00:27:12,359
Speaker 3: So was it like Allopatrick speciation where they weren't encountering

584
00:27:12,400 --> 00:27:14,600
Speaker 3: each other at all anymore and that's why they come

585
00:27:14,680 --> 00:27:16,600
Speaker 3: up with different theories because it was no cross talk.

586
00:27:16,920 --> 00:27:20,160
Speaker 3: Or was it s Patrick expeciation where the ideas could

587
00:27:20,200 --> 00:27:22,920
Speaker 3: have flowed between each other, but they were still deciding

588
00:27:22,920 --> 00:27:25,439
Speaker 3: to stay segregated. Was it nationalism or did they just

589
00:27:25,440 --> 00:27:25,680
Speaker 3: not know?

590
00:27:25,960 --> 00:27:26,720
Speaker 4: Is what I'm wondering.

591
00:27:26,920 --> 00:27:29,800
Speaker 1: I think it started with nationalism, but then it developed

592
00:27:30,040 --> 00:27:33,399
Speaker 1: into sort of tribal camps and the Germans criticized the British,

593
00:27:33,400 --> 00:27:36,159
Speaker 1: and the British criticized the Germans. You know, even after

594
00:27:36,280 --> 00:27:38,760
Speaker 1: the First War, when these guys could have gotten together

595
00:27:38,800 --> 00:27:41,640
Speaker 1: and had like a global, unified theory of flight, they

596
00:27:41,680 --> 00:27:44,560
Speaker 1: continued working in their own direction because they were invested

597
00:27:44,600 --> 00:27:46,720
Speaker 1: in you know, this guy's advisor told him that the

598
00:27:46,720 --> 00:27:49,719
Speaker 1: German approach was nonsense, and the German guy's adviser told

599
00:27:49,760 --> 00:27:52,359
Speaker 1: him the British approach was scheiss, you know or whatever,

600
00:27:52,760 --> 00:27:53,520
Speaker 1: And so.

601
00:27:53,640 --> 00:27:54,520
Speaker 4: Do you speak German?

602
00:27:56,000 --> 00:27:59,119
Speaker 1: I do not speak German. I speak Danish, which is

603
00:27:59,119 --> 00:28:02,080
Speaker 1: sort of Germanic a little bit, but that's a big

604
00:28:02,119 --> 00:28:05,359
Speaker 1: German anyway. So the British across the English Channel didn't

605
00:28:05,440 --> 00:28:07,560
Speaker 1: like the German approach. They didn't like thinking about air

606
00:28:07,640 --> 00:28:10,680
Speaker 1: as a fluid because they were like, this is too idealized.

607
00:28:10,720 --> 00:28:14,080
Speaker 1: They can't explain what's really happening. The Germans thought, you know,

608
00:28:14,119 --> 00:28:17,240
Speaker 1: ideal fluids are a fine approximation, but the British didn't

609
00:28:17,320 --> 00:28:19,440
Speaker 1: like it. And you know, anytime you're making an explanation

610
00:28:19,480 --> 00:28:22,080
Speaker 1: in science, you're going to be making approximations. It's just

611
00:28:22,119 --> 00:28:25,200
Speaker 1: a question of what approximations you make. They're always shortcuts.

612
00:28:25,400 --> 00:28:29,200
Speaker 1: Nobody can completely describe the full complexity of the universe

613
00:28:29,600 --> 00:28:32,119
Speaker 1: in their equations. It's always a simplification. And there's an

614
00:28:32,200 --> 00:28:36,280
Speaker 1: art to that, choosing the simplification that captures the essential

615
00:28:36,359 --> 00:28:39,320
Speaker 1: details of what's happening in reality, so you can provide

616
00:28:39,320 --> 00:28:43,800
Speaker 1: a useful explanation while dismissing all the irrelevant complexities that

617
00:28:44,040 --> 00:28:47,040
Speaker 1: you don't need to worry about, which is why, for example,

618
00:28:47,080 --> 00:28:49,520
Speaker 1: we can talk about how a ball flies through the

619
00:28:49,560 --> 00:28:52,720
Speaker 1: air and often ignore air resistance and ignore the quantum

620
00:28:52,720 --> 00:28:55,160
Speaker 1: effects and ignore everything else that's happening, the tug of

621
00:28:55,280 --> 00:28:59,560
Speaker 1: Jupiter on that ball, because we judiciously choose what approximations

622
00:28:59,600 --> 00:29:03,040
Speaker 1: to make. So that's what's happening here is two subjective approaches,

623
00:29:03,520 --> 00:29:06,520
Speaker 1: and the British were focused not on this ideal fluid approach,

624
00:29:06,560 --> 00:29:09,640
Speaker 1: but instead of using just a simple approach with Newton's law,

625
00:29:09,680 --> 00:29:11,440
Speaker 1: they were just thinking about the forces.

626
00:29:11,800 --> 00:29:13,800
Speaker 3: How do forces act differently on the top and the

627
00:29:13,800 --> 00:29:15,480
Speaker 3: bottom based on that tear drop shape.

628
00:29:15,880 --> 00:29:18,880
Speaker 1: Yeah, so the Newton's approach basically ignores the tear drop

629
00:29:18,920 --> 00:29:21,040
Speaker 1: shape and it says the shape of the wing isn't

630
00:29:21,040 --> 00:29:24,400
Speaker 1: actually important. What's crucial is the angle of the wing

631
00:29:24,680 --> 00:29:27,600
Speaker 1: into the wind. So they're thinking, hey, the wing is

632
00:29:27,640 --> 00:29:30,080
Speaker 1: tilted a little bit, and so as the wing is

633
00:29:30,120 --> 00:29:33,760
Speaker 1: moving through the air, the wind gets bounced basically off

634
00:29:33,800 --> 00:29:36,640
Speaker 1: the wind and goes down. So you have wind flowing

635
00:29:36,680 --> 00:29:39,080
Speaker 1: onto the wing and you have an angle, and then

636
00:29:39,120 --> 00:29:41,520
Speaker 1: it bounces down and so the wing goes up. And

637
00:29:41,640 --> 00:29:43,880
Speaker 1: like anybody who's ridden in a car and put their

638
00:29:43,920 --> 00:29:46,720
Speaker 1: hand out at an angle knows that you can feel

639
00:29:46,800 --> 00:29:49,320
Speaker 1: lift right, your hand basically flies and your hand's not

640
00:29:49,360 --> 00:29:51,160
Speaker 1: a tear drop, it's not an air foil. It's not

641
00:29:51,200 --> 00:29:55,200
Speaker 1: like carefully germanically engineered to get lift. It's just your hand,

642
00:29:55,480 --> 00:29:57,880
Speaker 1: you know, But still you can get lift. This is

643
00:29:57,920 --> 00:30:02,240
Speaker 1: a simple application of Newton's theory. Like action reaction, the

644
00:30:02,280 --> 00:30:05,120
Speaker 1: wind gets pushed down by the angle of the wing.

645
00:30:05,360 --> 00:30:08,240
Speaker 1: The aeronautical engineers call it the angle of attack, and

646
00:30:08,280 --> 00:30:10,120
Speaker 1: so the wing gets pushed up. Very simple.

647
00:30:10,520 --> 00:30:14,440
Speaker 3: So if that's true, then you could adjust wing shape

648
00:30:14,760 --> 00:30:17,600
Speaker 3: to be even better at flying by making it bend

649
00:30:17,720 --> 00:30:20,280
Speaker 3: even more so that you're stopping even more air as

650
00:30:20,320 --> 00:30:23,520
Speaker 3: you go. Did the British try that to prove how

651
00:30:23,600 --> 00:30:24,360
Speaker 3: much better they were?

652
00:30:24,680 --> 00:30:28,200
Speaker 1: I wish you'd been around in the aeronautical society, so

653
00:30:28,360 --> 00:30:31,320
Speaker 1: clear with your questions. So what you're describe me is

654
00:30:31,320 --> 00:30:33,880
Speaker 1: actually what you see in an airplane when you take off,

655
00:30:34,160 --> 00:30:36,800
Speaker 1: if you're paying attention to the wing. Modern airplanes actually

656
00:30:36,800 --> 00:30:39,400
Speaker 1: have a changeable shape, right. They have these flaps and

657
00:30:39,440 --> 00:30:41,880
Speaker 1: these levers, right, so they can change the shape of

658
00:30:41,920 --> 00:30:44,760
Speaker 1: the wing, and during takeoff they do just that. They

659
00:30:44,760 --> 00:30:47,320
Speaker 1: push down the back of the wing so it's more

660
00:30:47,320 --> 00:30:49,640
Speaker 1: of a curvy shape. It like grabs the air a

661
00:30:49,720 --> 00:30:52,600
Speaker 1: little bit more, so you get more lift during takeoff.

662
00:30:52,840 --> 00:30:55,160
Speaker 1: And then when you're flying, they make it flatter, so

663
00:30:55,360 --> 00:30:57,720
Speaker 1: you're cruising, you get less lyft, but you also get

664
00:30:57,760 --> 00:31:01,400
Speaker 1: less drag. Drag is the force that pushes the wing backwards,

665
00:31:01,400 --> 00:31:04,600
Speaker 1: so you want upwards force lift without as much backwards

666
00:31:04,640 --> 00:31:08,080
Speaker 1: force drag. So what you're seeing is exactly what modern

667
00:31:08,120 --> 00:31:11,200
Speaker 1: airplanes do. Is they make a curveer wing you take

668
00:31:11,200 --> 00:31:12,280
Speaker 1: off to get more lift.

669
00:31:12,760 --> 00:31:13,280
Speaker 4: Very cool.

670
00:31:13,480 --> 00:31:15,479
Speaker 3: I was reading about programmable matter, and I think one

671
00:31:15,480 --> 00:31:18,800
Speaker 3: of the proposals was to have matter that responds to

672
00:31:19,040 --> 00:31:22,240
Speaker 3: the environment and makes those changes on its own without

673
00:31:22,240 --> 00:31:23,320
Speaker 3: you needing to do anything.

674
00:31:23,360 --> 00:31:25,440
Speaker 4: But I am glad we have more control over the

675
00:31:25,440 --> 00:31:28,080
Speaker 4: process right now. I'm not ready to have us let

676
00:31:28,120 --> 00:31:29,240
Speaker 4: go of that control yet.

677
00:31:29,520 --> 00:31:32,080
Speaker 1: And the nice thing about this explanation is it explains

678
00:31:32,280 --> 00:31:35,160
Speaker 1: why planes can fly upside down. They fly upside down

679
00:31:35,240 --> 00:31:37,480
Speaker 1: because they have the right angle of attack. It doesn't

680
00:31:37,480 --> 00:31:40,360
Speaker 1: matter the shape of a wing at all. It just

681
00:31:40,480 --> 00:31:43,360
Speaker 1: matters that the airplane wing is at the correct angle.

682
00:31:43,760 --> 00:31:45,520
Speaker 1: So if you fly your airplane upside down, you can

683
00:31:45,520 --> 00:31:48,120
Speaker 1: do it as long as the wing is angled into

684
00:31:48,160 --> 00:31:49,520
Speaker 1: the air at the right angle.

685
00:31:50,120 --> 00:31:54,640
Speaker 3: So does this completely explain everything? That's never how our

686
00:31:54,720 --> 00:31:58,160
Speaker 3: podcast episodes end. So what is it missing.

687
00:31:58,720 --> 00:32:01,480
Speaker 1: So this is a beautiful story of the limitations of

688
00:32:01,520 --> 00:32:05,640
Speaker 1: science because both explanations explain something, but neither of them

689
00:32:05,720 --> 00:32:08,840
Speaker 1: tell the complete story. So, for example, there's a couple

690
00:32:08,880 --> 00:32:13,200
Speaker 1: of things that the British Newton's theory force explanation doesn't describe.

691
00:32:13,440 --> 00:32:15,360
Speaker 1: Number one is what's going on on the top of

692
00:32:15,360 --> 00:32:17,760
Speaker 1: the wing, right, This just focuses on the bottom of

693
00:32:17,800 --> 00:32:20,560
Speaker 1: the wing, but we see that the pressure is lower

694
00:32:20,560 --> 00:32:23,120
Speaker 1: on the top of the wing. The Newton's theory approach says,

695
00:32:23,200 --> 00:32:25,400
Speaker 1: all the lift comes from below, that you're getting this

696
00:32:25,520 --> 00:32:27,960
Speaker 1: force from the wind that's hitting it from below. But

697
00:32:28,000 --> 00:32:30,160
Speaker 1: we see this lower pressure above, and it turns out,

698
00:32:30,200 --> 00:32:32,920
Speaker 1: as we'll talk about later, that it contributes maybe even

699
00:32:33,040 --> 00:32:35,640
Speaker 1: more to the lift, the low pressure above the wing

700
00:32:35,920 --> 00:32:38,400
Speaker 1: than the high pressure does below the wing. And the

701
00:32:38,440 --> 00:32:42,240
Speaker 1: Newton's theory cannot explain this. That's number one, and.

702
00:32:42,160 --> 00:32:44,720
Speaker 3: It can't explain why there's low pressure above the wing, right,

703
00:32:44,800 --> 00:32:45,760
Speaker 3: just like the other one.

704
00:32:45,720 --> 00:32:48,000
Speaker 1: Yeah, exactly. Number two is that if you do these

705
00:32:48,000 --> 00:32:51,400
Speaker 1: smoke studies, we see that the wing affects the flow

706
00:32:51,440 --> 00:32:54,160
Speaker 1: of the air, not just below the wing. It's like

707
00:32:54,240 --> 00:32:57,280
Speaker 1: the influence of the wing on the air is larger

708
00:32:57,360 --> 00:33:00,200
Speaker 1: than just the wing, Like the air begins to flow

709
00:33:00,320 --> 00:33:03,040
Speaker 1: up above the wing before it hits the wing. There

710
00:33:03,080 --> 00:33:06,040
Speaker 1: is this upwash in advance of the wing and this

711
00:33:06,200 --> 00:33:09,520
Speaker 1: downwash after the wing. So it's not just like you

712
00:33:09,600 --> 00:33:11,680
Speaker 1: have a paddle and it's being hit by molecules and

713
00:33:11,720 --> 00:33:15,040
Speaker 1: it's getting pushed up. There's a complicated interplay here between

714
00:33:15,040 --> 00:33:17,240
Speaker 1: the wing and the flow around it and the air

715
00:33:17,320 --> 00:33:21,720
Speaker 1: itself applying pressure on itself. So you can't ignore the

716
00:33:21,760 --> 00:33:23,960
Speaker 1: sort of fluid effects of the air if you want

717
00:33:24,000 --> 00:33:25,720
Speaker 1: to completely describe what's happening.

718
00:33:25,960 --> 00:33:27,840
Speaker 3: Yeah, so while you were describing all of that, I thought,

719
00:33:27,880 --> 00:33:30,360
Speaker 3: oh man, it really feels like fluid dynamics should explained.

720
00:33:30,640 --> 00:33:34,200
Speaker 3: So maybe the German example should have worked. Why does

721
00:33:34,240 --> 00:33:37,080
Speaker 3: the fluid example not work then? With all of that

722
00:33:37,160 --> 00:33:38,760
Speaker 3: complicated stuff happening.

723
00:33:38,480 --> 00:33:40,600
Speaker 1: So the fluid example does explain some parts of it.

724
00:33:40,640 --> 00:33:42,400
Speaker 1: And so where we're going to go in the end

725
00:33:42,520 --> 00:33:45,360
Speaker 1: is this like weird hybrid of the British German theory

726
00:33:45,560 --> 00:33:48,320
Speaker 1: in order to have the most complete explanation of why

727
00:33:48,360 --> 00:33:50,560
Speaker 1: it happens. But what we're doing right now is sort

728
00:33:50,560 --> 00:33:53,560
Speaker 1: of examining like the failure of the individual ones. So

729
00:33:53,600 --> 00:33:57,920
Speaker 1: the German explanation. The fluid approach can describe the flow

730
00:33:58,080 --> 00:34:00,680
Speaker 1: of the fluid around the wing, but the British approach,

731
00:34:00,720 --> 00:34:03,520
Speaker 1: though it's simple and satisfying, can't describe all of this stuff.

732
00:34:03,680 --> 00:34:04,760
Speaker 4: Okay, spoiler alert.

733
00:34:04,960 --> 00:34:07,200
Speaker 1: Yeah, so one thing that fails to describe is the

734
00:34:07,240 --> 00:34:10,279
Speaker 1: sort of holistic flow of the air around the wing.

735
00:34:10,719 --> 00:34:14,200
Speaker 1: The other is stalling and the Newton's force approach. The

736
00:34:14,200 --> 00:34:16,920
Speaker 1: only reason you're flying is the angle of attack, and

737
00:34:16,960 --> 00:34:19,600
Speaker 1: the greater the angle, the greater the force. Right, But

738
00:34:19,640 --> 00:34:22,480
Speaker 1: anybody who flies knows that if you have too great

739
00:34:22,520 --> 00:34:25,360
Speaker 1: an angle, you're going to stall, Like if your plane

740
00:34:25,400 --> 00:34:28,040
Speaker 1: is pointed too far upwards, you're not going to get

741
00:34:28,080 --> 00:34:31,200
Speaker 1: lift anymore. And what happens technically, what we see in

742
00:34:31,320 --> 00:34:34,319
Speaker 1: wind tunnels is that if the angle of attack is

743
00:34:34,360 --> 00:34:36,920
Speaker 1: too great, then as the air flows over the top

744
00:34:37,000 --> 00:34:40,520
Speaker 1: of the wing, it doesn't merge smoothly with the air

745
00:34:40,719 --> 00:34:44,000
Speaker 1: flowing below the wing, and you get this like weird turbulence.

746
00:34:44,000 --> 00:34:46,960
Speaker 1: They call it a separation region because the air doesn't

747
00:34:47,040 --> 00:34:50,160
Speaker 1: nicely reconnect. And you know, when you're going through a fluid,

748
00:34:50,239 --> 00:34:53,719
Speaker 1: turbulence is a problem. You want to minimize turbulence. And

749
00:34:53,800 --> 00:34:56,160
Speaker 1: so if the angle is too large. This is like

750
00:34:56,320 --> 00:34:58,480
Speaker 1: gap between the air flows as they come off the

751
00:34:58,480 --> 00:35:01,000
Speaker 1: back of the wing and they don't don't merge nicely.

752
00:35:01,360 --> 00:35:04,160
Speaker 1: That's called the separation region between these flows, and that

753
00:35:04,200 --> 00:35:06,920
Speaker 1: creates the stall. You lose your lift. So you can't

754
00:35:06,960 --> 00:35:10,400
Speaker 1: explain that. Also with the Newton's explanation, you need some

755
00:35:10,640 --> 00:35:12,520
Speaker 1: fluid theory to explain.

756
00:35:12,120 --> 00:35:17,040
Speaker 3: That slightly tangential. We haven't discussed propellers. Do propellers and

757
00:35:17,160 --> 00:35:19,719
Speaker 3: jet engines play any role here or is that just

758
00:35:19,840 --> 00:35:22,400
Speaker 3: in like that moves us forward and all of the

759
00:35:22,520 --> 00:35:24,200
Speaker 3: uppiness comes from the wings.

760
00:35:25,800 --> 00:35:29,880
Speaker 1: Yeah, So basically engines just provide forward velocity so that

761
00:35:30,000 --> 00:35:32,680
Speaker 1: the wings attack the air. All The propellers are a

762
00:35:32,680 --> 00:35:35,440
Speaker 1: subtle point because propellers have a particular shape, which is

763
00:35:35,520 --> 00:35:38,440
Speaker 1: related to the shape of a wing, right, because it's

764
00:35:38,480 --> 00:35:41,200
Speaker 1: converting motion in one direction to air velocity in the

765
00:35:41,239 --> 00:35:44,240
Speaker 1: other direction. So the shape of a propeller is related

766
00:35:44,280 --> 00:35:46,320
Speaker 1: to the shape of a wing. But for the question

767
00:35:46,400 --> 00:35:48,319
Speaker 1: of why planes fly, you can think of its just

768
00:35:48,400 --> 00:35:51,120
Speaker 1: like something pushy, right, the pushy bit that gets the

769
00:35:51,160 --> 00:35:53,120
Speaker 1: plane moving through the air. Yeah.

770
00:35:53,239 --> 00:35:55,000
Speaker 3: Okay, so you've got the pushy bit, but we don't

771
00:35:55,040 --> 00:35:57,680
Speaker 3: understand what's happening around the wings yet, So how do

772
00:35:57,760 --> 00:36:01,280
Speaker 3: you move from figuring out that the German and the British

773
00:36:01,320 --> 00:36:06,279
Speaker 3: explanation are failing in some way to figuring out the

774
00:36:06,400 --> 00:36:08,440
Speaker 3: answer to what's going on? Is this like where we

775
00:36:08,480 --> 00:36:10,360
Speaker 3: are we just don't know or are there more experiments

776
00:36:10,400 --> 00:36:11,520
Speaker 3: you can do to figure it out?

777
00:36:11,600 --> 00:36:14,080
Speaker 1: So what you shouldn't do is ask the world's smartest

778
00:36:14,080 --> 00:36:18,240
Speaker 1: physicist Einstein to weigh in on this very practical engineering question.

779
00:36:18,600 --> 00:36:20,560
Speaker 3: Well, let's find out what he had to say after

780
00:36:20,600 --> 00:36:40,240
Speaker 3: the break, all right, So for most of the Daniel

781
00:36:40,280 --> 00:36:42,759
Speaker 3: led episodes, we have to walk through a what did

782
00:36:42,800 --> 00:36:46,680
Speaker 3: Einstein think? Because he just provided so many good insights

783
00:36:46,719 --> 00:36:49,400
Speaker 3: into so many things. So let's figure out what did

784
00:36:49,440 --> 00:36:50,480
Speaker 3: Einstein think about this?

785
00:36:51,040 --> 00:36:54,880
Speaker 1: Yeah, so Einstein, he's a smart guy. He developed relativity,

786
00:36:55,239 --> 00:36:58,600
Speaker 1: he struggled and failed to integrate quantum mechanics into it.

787
00:36:58,640 --> 00:37:01,080
Speaker 1: So it's not like he solved every problem he attacked.

788
00:37:01,080 --> 00:37:03,120
Speaker 1: But he was a smart guy. And you know, he

789
00:37:03,160 --> 00:37:05,920
Speaker 1: was German and this is a relevant question for the

790
00:37:05,960 --> 00:37:08,319
Speaker 1: Germans at the time, and he was interested in this

791
00:37:08,560 --> 00:37:11,480
Speaker 1: and he wrote, quote, there's a lot of obscurity surrounding

792
00:37:11,480 --> 00:37:14,360
Speaker 1: these questions and open puzzles like this, you know, they

793
00:37:14,400 --> 00:37:16,839
Speaker 1: attract smart people like, oh, maybe I can figure this out.

794
00:37:16,840 --> 00:37:20,480
Speaker 1: Maybe there's an insight, a moment of clarity that will

795
00:37:20,520 --> 00:37:24,040
Speaker 1: just untangle this whole mess. And so he thought about

796
00:37:24,080 --> 00:37:26,680
Speaker 1: flight from the German point of view, and he actually

797
00:37:26,680 --> 00:37:30,360
Speaker 1: designed his own wing shape, sort of a weird variation

798
00:37:30,600 --> 00:37:32,799
Speaker 1: on the air foril Is Einstein. Remember, he was not

799
00:37:32,920 --> 00:37:35,720
Speaker 1: just a clever physicist. He worked in the patent office

800
00:37:36,000 --> 00:37:38,000
Speaker 1: and so he had seen lots of inventions. He had

801
00:37:38,000 --> 00:37:40,919
Speaker 1: a practical mind also, So he designed his own wing

802
00:37:41,040 --> 00:37:43,640
Speaker 1: and he took it to a German aircraft company, and

803
00:37:43,680 --> 00:37:46,120
Speaker 1: you know, he was an esteemed famous scientist at this point,

804
00:37:46,160 --> 00:37:48,640
Speaker 1: so they thought, okay, sure, so they worked with him,

805
00:37:48,640 --> 00:37:51,520
Speaker 1: they collaborated with him, They built the plane, and they

806
00:37:51,560 --> 00:37:53,960
Speaker 1: sent it on a test flight, and the pilot came

807
00:37:54,000 --> 00:37:55,840
Speaker 1: back and said he would never fly the thing again

808
00:37:55,880 --> 00:37:58,359
Speaker 1: because a quote flew like a pregnant duck.

809
00:38:00,640 --> 00:38:03,640
Speaker 3: I feel like whenever a question sort of tiptoes into

810
00:38:03,640 --> 00:38:06,719
Speaker 3: biology and Einstein is involved, you want to back away. So,

811
00:38:06,760 --> 00:38:09,200
Speaker 3: you know, I think maybe most of us know that

812
00:38:09,280 --> 00:38:10,480
Speaker 3: ducks can't get pregnant.

813
00:38:10,960 --> 00:38:12,839
Speaker 4: They carry eggs, but they don't get pregnant the way

814
00:38:12,840 --> 00:38:13,040
Speaker 4: we do.

815
00:38:13,120 --> 00:38:15,279
Speaker 3: And also, like, you know, he married his cousin, which

816
00:38:15,320 --> 00:38:17,800
Speaker 3: I think is a bad idea also from a biological perspective.

817
00:38:17,800 --> 00:38:18,640
Speaker 4: But anyway, okay, So.

818
00:38:19,040 --> 00:38:22,720
Speaker 3: Einstein was great at everything, but not at designing wings.

819
00:38:22,960 --> 00:38:26,560
Speaker 1: Yeah, exactly. And so fast forward fifty years or so,

820
00:38:26,760 --> 00:38:29,479
Speaker 1: what are people talking about today in terms of why

821
00:38:29,560 --> 00:38:32,840
Speaker 1: planes fly? I went across campus here to a colleague

822
00:38:32,840 --> 00:38:36,480
Speaker 1: at UC Irvine, Haythian Taha. He's a professor of aeronautical

823
00:38:36,520 --> 00:38:40,120
Speaker 1: engineering here and he studies lyft. He works on this problem.

824
00:38:40,440 --> 00:38:43,040
Speaker 1: I asked him what is a simple explanation for lyfts?

825
00:38:43,040 --> 00:38:45,560
Speaker 1: And he said, quote, this is not settled in the

826
00:38:45,600 --> 00:38:50,360
Speaker 1: aeronautical engineering community. Please don't laugh. That's a direct quote.

827
00:38:51,120 --> 00:38:53,480
Speaker 1: So here we are laughing. It's hilarious, you know, like

828
00:38:53,880 --> 00:38:55,840
Speaker 1: these guys still haven't figured this out more than one

829
00:38:55,880 --> 00:38:57,560
Speaker 1: hundred years after their right brothers.

830
00:38:57,800 --> 00:38:59,799
Speaker 4: But yet still so much money is made us.

831
00:39:00,160 --> 00:39:01,400
Speaker 3: So it's nice to know you don't have to have

832
00:39:01,440 --> 00:39:03,480
Speaker 3: everything worked out before you commercialize something.

833
00:39:03,680 --> 00:39:06,280
Speaker 1: But let's not oversell it. It's not that we don't

834
00:39:06,400 --> 00:39:10,680
Speaker 1: understand why planes fly. It's that we don't have a compelling,

835
00:39:11,239 --> 00:39:14,920
Speaker 1: simple explanation at the sort of zoomed out level. And

836
00:39:14,960 --> 00:39:18,040
Speaker 1: again there's always a difference between life the microphysics. Can

837
00:39:18,080 --> 00:39:21,480
Speaker 1: you model what's happening with individual air molecules and the

838
00:39:21,520 --> 00:39:23,600
Speaker 1: shape of the wing and come up with a simulation

839
00:39:23,800 --> 00:39:26,719
Speaker 1: in which planes fly. Absolutely, we can, and we do.

840
00:39:27,040 --> 00:39:29,920
Speaker 1: This is why, for example, Boeing can design their airplanes

841
00:39:30,160 --> 00:39:33,120
Speaker 1: on the computer and be confident that they will fly.

842
00:39:33,200 --> 00:39:35,919
Speaker 1: They don't need to use wing tests anymore and build

843
00:39:35,920 --> 00:39:38,640
Speaker 1: a bunch of models to experiment because we have accurate

844
00:39:38,680 --> 00:39:42,000
Speaker 1: simulations for what's going on in the microphysics level. It's

845
00:39:42,040 --> 00:39:43,680
Speaker 1: just that when you zoom out and now you want

846
00:39:43,680 --> 00:39:46,600
Speaker 1: to tell a simple story about what's happening, there are

847
00:39:46,640 --> 00:39:48,880
Speaker 1: competing ways to do that, and all of them ignore

848
00:39:49,000 --> 00:39:52,160
Speaker 1: some details, and so none of them are completely satisfactory.

849
00:39:52,560 --> 00:39:55,360
Speaker 1: So when he says this is not settled, he doesn't

850
00:39:55,400 --> 00:39:58,160
Speaker 1: mean we don't know why planes fly in a sort

851
00:39:58,160 --> 00:40:02,200
Speaker 1: of microphysics point of view, means we don't have a nice, compelling,

852
00:40:02,440 --> 00:40:06,040
Speaker 1: one sentence explanation for why this happens the way we can.

853
00:40:06,080 --> 00:40:08,440
Speaker 1: For example, like a ball flying through the air, why

854
00:40:08,440 --> 00:40:10,640
Speaker 1: does a baseball fly in a parabola? We know the

855
00:40:10,640 --> 00:40:14,360
Speaker 1: answer is when you have constant acceleration, you get parabolic motion. Simple,

856
00:40:14,400 --> 00:40:17,719
Speaker 1: one sentence answer. That's what we're lacking for flight. We

857
00:40:17,760 --> 00:40:20,880
Speaker 1: have a very complex thing that's happening with microphysics, and

858
00:40:20,920 --> 00:40:23,480
Speaker 1: it's when we're struggling to come up with a simplified

859
00:40:23,520 --> 00:40:25,800
Speaker 1: explanation at the macroscopic level.

860
00:40:26,239 --> 00:40:27,600
Speaker 4: Do engineers care?

861
00:40:28,080 --> 00:40:31,160
Speaker 3: So if you can make a simulation on a computer

862
00:40:31,200 --> 00:40:33,400
Speaker 3: that tells you everything you need to know, Like, are

863
00:40:33,560 --> 00:40:36,919
Speaker 3: engineers still interested in this question or has this completely

864
00:40:37,000 --> 00:40:40,600
Speaker 3: moved to the realm of like physicists who never see

865
00:40:40,640 --> 00:40:42,879
Speaker 3: the light who are studying it in their offices, Like, yeah,

866
00:40:42,880 --> 00:40:44,160
Speaker 3: do they care what the answer is anymore?

867
00:40:44,239 --> 00:40:45,080
Speaker 4: Or do physicists care?

868
00:40:45,120 --> 00:40:50,120
Speaker 1: Only absolutely they care because engineers want simple, working models,

869
00:40:50,520 --> 00:40:52,760
Speaker 1: you know, when they want to model how a plane

870
00:40:52,800 --> 00:40:54,120
Speaker 1: is going to fly, they don't want to have to

871
00:40:54,160 --> 00:40:57,400
Speaker 1: go back to describing every single particle. They want simple

872
00:40:57,400 --> 00:40:59,680
Speaker 1: sets of equations that let them work quickly and easily

873
00:41:00,160 --> 00:41:01,960
Speaker 1: the same way. For example, we'd love to be able

874
00:41:02,040 --> 00:41:05,600
Speaker 1: to predict a hurricane without modeling every single rain drop.

875
00:41:05,840 --> 00:41:08,759
Speaker 1: Currently we have the technology, and we're building these incredibly

876
00:41:08,800 --> 00:41:13,000
Speaker 1: powerful computers just to model wind and pressure and predict

877
00:41:13,040 --> 00:41:15,759
Speaker 1: the weather. We'd love simple equations to be able to

878
00:41:15,800 --> 00:41:19,719
Speaker 1: do that right rather than having to use incredibly detailed computation.

879
00:41:20,239 --> 00:41:24,160
Speaker 1: And so anytime we can summarize complexity with simple math,

880
00:41:24,360 --> 00:41:26,600
Speaker 1: we definitely win. So people are definitely working on this

881
00:41:26,719 --> 00:41:29,800
Speaker 1: and trying to find a complete holistic approach that captures

882
00:41:29,840 --> 00:41:33,000
Speaker 1: all this behavior, that lets us do important engineering without

883
00:41:33,000 --> 00:41:37,719
Speaker 1: simulating all the tiny microphysical details. Absolutely, yeah, people care.

884
00:41:38,120 --> 00:41:40,400
Speaker 3: And I want to go on record that I apologize

885
00:41:40,400 --> 00:41:43,680
Speaker 3: for implying that physicists don't go outside.

886
00:41:44,360 --> 00:41:46,120
Speaker 1: What is this outside thing you're talking about? I was

887
00:41:46,120 --> 00:41:47,960
Speaker 1: going to ask you about that. I have heard about this,

888
00:41:48,120 --> 00:41:49,520
Speaker 1: but I've been too shy to ask.

889
00:41:49,600 --> 00:41:50,920
Speaker 4: Can you told me you've been hiking.

890
00:41:50,960 --> 00:41:53,239
Speaker 3: I know that you're maybe even more extreme than I

891
00:41:53,280 --> 00:41:55,360
Speaker 3: am in terms of outdoor adventures.

892
00:41:56,120 --> 00:41:57,799
Speaker 1: No, I do love going outside. That's why I live

893
00:41:57,840 --> 00:41:59,520
Speaker 1: in California. It's so amazing here.

894
00:42:00,000 --> 00:42:04,279
Speaker 3: Oh, the fall right now is absolutely incredible. Okay, So

895
00:42:04,320 --> 00:42:06,279
Speaker 3: we've talked about a lot of different ideas, a lot

896
00:42:06,320 --> 00:42:08,400
Speaker 3: of things we know and we don't know. I know

897
00:42:08,480 --> 00:42:10,680
Speaker 3: the answer at the end is that it's complicated. But

898
00:42:10,880 --> 00:42:14,440
Speaker 3: is there a simple ish kind of way to summarize

899
00:42:14,480 --> 00:42:16,279
Speaker 3: where we are right now in our understanding.

900
00:42:16,680 --> 00:42:19,560
Speaker 1: Yeah, So I think the simplest way to describe it

901
00:42:19,600 --> 00:42:22,680
Speaker 1: is that both of Bernoulli and Newton's stories help, but

902
00:42:22,760 --> 00:42:25,399
Speaker 1: they're both limited, and the limitation is that they're trying

903
00:42:25,440 --> 00:42:27,680
Speaker 1: to tell a story in terms of like simple causes

904
00:42:27,719 --> 00:42:30,799
Speaker 1: and simple effects. The airflows and its bounces off the wing,

905
00:42:31,040 --> 00:42:33,640
Speaker 1: or the pressure is lower above the wing because the

906
00:42:33,680 --> 00:42:36,080
Speaker 1: velocity is higher, and the real story is that the

907
00:42:36,120 --> 00:42:38,480
Speaker 1: cause and effect are not so simple. There's lots of

908
00:42:38,480 --> 00:42:41,399
Speaker 1: things happening here and they are interplaying together, so it's

909
00:42:41,440 --> 00:42:44,440
Speaker 1: not so easy to disentangle the cause and the effect.

910
00:42:44,680 --> 00:42:47,120
Speaker 1: There's a lot of things at work here, pressure and

911
00:42:47,200 --> 00:42:51,440
Speaker 1: velocity and forces all in this fantastic harmony that's making

912
00:42:51,440 --> 00:42:53,440
Speaker 1: the wing go up, which is why none of these

913
00:42:53,480 --> 00:42:57,080
Speaker 1: simple stories are satisfactory. We can weave a slightly more

914
00:42:57,120 --> 00:43:00,960
Speaker 1: complex story to explain why planes fly that involves all

915
00:43:01,000 --> 00:43:03,920
Speaker 1: of these aspects sort of working together. But you know,

916
00:43:04,000 --> 00:43:07,400
Speaker 1: humans like simple stories. Ball goes down because of gravity,

917
00:43:07,640 --> 00:43:09,840
Speaker 1: this kind of thing. We don't have that simple a

918
00:43:09,920 --> 00:43:10,840
Speaker 1: cause and effect.

919
00:43:10,960 --> 00:43:14,680
Speaker 3: I'm always amazed by things that work so well, where

920
00:43:14,680 --> 00:43:18,000
Speaker 3: when you scratch the surface, we really don't understand, like

921
00:43:18,080 --> 00:43:21,040
Speaker 3: I was talking to someone who uses deep brain stimulation

922
00:43:21,239 --> 00:43:23,760
Speaker 3: to treat epilepsy. So, like, when somebody has a seizure,

923
00:43:23,760 --> 00:43:26,000
Speaker 3: they're having like an electrical storm in their brain, and

924
00:43:26,080 --> 00:43:28,640
Speaker 3: sometimes they have electrodes implanted into the center of their

925
00:43:28,640 --> 00:43:31,600
Speaker 3: brain and they essentially just get their brains apped and

926
00:43:31,680 --> 00:43:32,200
Speaker 3: that helps.

927
00:43:32,480 --> 00:43:34,200
Speaker 4: And so I reached out to an expert and I was.

928
00:43:34,160 --> 00:43:37,799
Speaker 3: Like, why does zapping someone's brain with electricity stop the

929
00:43:38,120 --> 00:43:39,040
Speaker 3: epileptic seizure?

930
00:43:39,080 --> 00:43:40,480
Speaker 4: And they're like, we don't know.

931
00:43:41,840 --> 00:43:43,960
Speaker 3: Just like I'm a little nervous getting onto a plane

932
00:43:44,000 --> 00:43:45,279
Speaker 3: hearing why does the plane go up?

933
00:43:45,360 --> 00:43:47,520
Speaker 4: We don't know. I also would not want to hear

934
00:43:47,640 --> 00:43:48,920
Speaker 4: why are you shocking my brain?

935
00:43:49,280 --> 00:43:49,759
Speaker 3: We don't know.

936
00:43:49,960 --> 00:43:52,640
Speaker 4: But in both cases it works, and it seems to

937
00:43:52,640 --> 00:43:54,960
Speaker 4: work reliably, so we get.

938
00:43:54,800 --> 00:43:57,719
Speaker 1: By Also true, I think for bost pharmaceuticals, right, we're like, well,

939
00:43:57,760 --> 00:44:00,520
Speaker 1: it does have this effect, we don't really understand that's

940
00:44:00,520 --> 00:44:03,160
Speaker 1: a biochemistry of it, but hey, keep taking it, you know.

941
00:44:03,320 --> 00:44:03,719
Speaker 9: That's right.

942
00:44:03,800 --> 00:44:05,200
Speaker 4: Yes, we all muddle along.

943
00:44:05,360 --> 00:44:07,360
Speaker 1: And I'm not an anti vaxxer at all. I just

944
00:44:07,400 --> 00:44:08,920
Speaker 1: mean this is sort of the way science is. You

945
00:44:08,920 --> 00:44:12,120
Speaker 1: always understand science at some level, you don't always need

946
00:44:12,160 --> 00:44:15,399
Speaker 1: to understand the microphysical explanation in order to make it work.

947
00:44:15,480 --> 00:44:18,040
Speaker 1: And that's actually a huge gift. Otherwise we couldn't do

948
00:44:18,040 --> 00:44:20,400
Speaker 1: anything if we needed to understand like the nature of

949
00:44:20,440 --> 00:44:22,640
Speaker 1: quantum gravity before we made a bowl of chicken soup,

950
00:44:22,680 --> 00:44:25,520
Speaker 1: we'd never have chicken soup. We'd never understand the world.

951
00:44:25,560 --> 00:44:29,000
Speaker 1: It's lucky that the world can be understood without knowing

952
00:44:29,080 --> 00:44:31,160
Speaker 1: all the details, or science would be impossible.

953
00:44:31,239 --> 00:44:33,839
Speaker 4: It's lucky you can tinker with the world without understanding it.

954
00:44:34,160 --> 00:44:36,799
Speaker 1: Yes, that too. So we do have a story we

955
00:44:36,800 --> 00:44:39,160
Speaker 1: can tell about why planes fly. And I think the

956
00:44:39,200 --> 00:44:41,759
Speaker 1: best way to think about why a wing goes up

957
00:44:41,960 --> 00:44:44,000
Speaker 1: is to focus on pressure, pressure above the wing and

958
00:44:44,040 --> 00:44:47,720
Speaker 1: pressure below the wing. Fundamentally, wing goes up because pressure

959
00:44:47,800 --> 00:44:50,839
Speaker 1: grows below the wing and pressure falls above the wing.

960
00:44:51,320 --> 00:44:53,640
Speaker 1: And both of these are contributed to by the Bernoulli

961
00:44:53,719 --> 00:44:54,920
Speaker 1: and the Newton story.

962
00:44:55,200 --> 00:44:57,799
Speaker 3: Got it, Okay, we managed to summarize something in like

963
00:44:57,840 --> 00:44:59,480
Speaker 3: three or four sentences.

964
00:45:00,200 --> 00:45:01,640
Speaker 1: But we can also dig into it in a little

965
00:45:01,640 --> 00:45:04,040
Speaker 1: bit more detail, you know, like why does pressure grow

966
00:45:04,120 --> 00:45:06,640
Speaker 1: below the wing? Well, Newton tells us to focus on

967
00:45:06,640 --> 00:45:09,200
Speaker 1: the angle of attack, right, and that's correct. The wing

968
00:45:09,360 --> 00:45:12,160
Speaker 1: goes through the air, and the angle of attack pushes

969
00:45:12,200 --> 00:45:14,239
Speaker 1: down on the air, and the air pushes back, and

970
00:45:14,280 --> 00:45:16,720
Speaker 1: this is pressure. Just like if you're scooping up snow

971
00:45:16,800 --> 00:45:19,200
Speaker 1: with a snowshovel, right, this is going to be increase pressure.

972
00:45:19,239 --> 00:45:21,680
Speaker 1: The snow is going to get compacted. So why does

973
00:45:21,719 --> 00:45:24,840
Speaker 1: pressure form below the wing? Not that controversial. It's the

974
00:45:24,880 --> 00:45:26,280
Speaker 1: angle of attack that's crucial.

975
00:45:26,360 --> 00:45:27,759
Speaker 3: And as long as you go like this and you

976
00:45:27,800 --> 00:45:29,279
Speaker 3: just don't look at the top part of the wing,

977
00:45:29,480 --> 00:45:31,080
Speaker 3: and so I'm covering the top part of my eyes

978
00:45:31,080 --> 00:45:32,560
Speaker 3: and you don't think about the top part of the wing,

979
00:45:32,640 --> 00:45:35,400
Speaker 3: then everything is good. But we don't understand what's happening above?

980
00:45:35,520 --> 00:45:37,640
Speaker 1: Is that right well above the wing? We can also

981
00:45:37,719 --> 00:45:40,760
Speaker 1: think about the pressure. The Newton story can't explain what's happening,

982
00:45:40,840 --> 00:45:42,440
Speaker 1: but if you think about it in terms of fluid

983
00:45:42,440 --> 00:45:45,280
Speaker 1: you can. Right, So what's happening above the wing? Initially,

984
00:45:45,280 --> 00:45:47,480
Speaker 1: if you just like shoot air above the wing, then

985
00:45:47,480 --> 00:45:50,120
Speaker 1: it wants to flow straight back, which effectively creates like

986
00:45:50,160 --> 00:45:53,279
Speaker 1: a vacuum underneath. The angle of attack, working together with

987
00:45:53,360 --> 00:45:56,120
Speaker 1: the shape of the wing, creates this low pressure zone

988
00:45:56,200 --> 00:45:58,480
Speaker 1: above the wing because the air needs to go down

989
00:45:58,600 --> 00:46:01,520
Speaker 1: to flow onto that right. So that's exactly what happens,

990
00:46:01,640 --> 00:46:03,880
Speaker 1: is you create this low pressure zone, which is like

991
00:46:03,960 --> 00:46:06,520
Speaker 1: a vacuum. It pulls the air into it, and that's

992
00:46:06,600 --> 00:46:09,560
Speaker 1: pulling the wing up. So you have low pressure above

993
00:46:09,600 --> 00:46:12,200
Speaker 1: the wing created by the shape of the wing and

994
00:46:12,520 --> 00:46:15,680
Speaker 1: the angle of attack, which creates low pressure above it.

995
00:46:16,000 --> 00:46:18,319
Speaker 1: And so these two effects work in harmony. You have

996
00:46:18,360 --> 00:46:21,840
Speaker 1: a force from below and you have like suction from above.

997
00:46:22,200 --> 00:46:24,520
Speaker 1: So wings go up not just because the air below

998
00:46:24,560 --> 00:46:26,680
Speaker 1: them is pushing them up, but the air above them

999
00:46:26,760 --> 00:46:28,560
Speaker 1: is sucking them up into the sky.

1000
00:46:29,160 --> 00:46:31,160
Speaker 4: So the Germans got the top right and the British

1001
00:46:31,160 --> 00:46:31,920
Speaker 4: got the bottom right.

1002
00:46:32,239 --> 00:46:32,719
Speaker 9: Is that right?

1003
00:46:33,760 --> 00:46:34,000
Speaker 1: Okay?

1004
00:46:34,000 --> 00:46:35,480
Speaker 3: I feel like there's so many times where I hear

1005
00:46:35,520 --> 00:46:37,239
Speaker 3: that there's a debate and there's people on this side

1006
00:46:37,239 --> 00:46:39,000
Speaker 3: and people on that side, and five years later the

1007
00:46:39,000 --> 00:46:41,239
Speaker 3: answer is almost always, oh, they were both right, and

1008
00:46:41,280 --> 00:46:45,080
Speaker 3: it's some combination of things, but okay, cool.

1009
00:46:45,400 --> 00:46:47,719
Speaker 1: Yeah, And so mostly this comes from the shape of

1010
00:46:47,760 --> 00:46:49,800
Speaker 1: the front of the wing. Right. Now, the shape of

1011
00:46:49,800 --> 00:46:52,799
Speaker 1: the wing is important because you want to minimize drag. Right,

1012
00:46:52,800 --> 00:46:54,759
Speaker 1: the Newton folks tell you the shape doesn't matter. All

1013
00:46:54,760 --> 00:46:56,560
Speaker 1: that matters is you get the force from the bottom

1014
00:46:56,840 --> 00:46:58,800
Speaker 1: but what you want is to create low pressure on

1015
00:46:58,840 --> 00:47:01,800
Speaker 1: the top without creating a lot of drag and without

1016
00:47:01,800 --> 00:47:05,000
Speaker 1: creating this turbulence zone which gives you a stall. So

1017
00:47:05,080 --> 00:47:07,360
Speaker 1: that's why you have this shape. You have this shape

1018
00:47:07,400 --> 00:47:08,880
Speaker 1: in the front of the wing to give you this

1019
00:47:09,000 --> 00:47:12,120
Speaker 1: uneven pressure distribution, so you get low pressure but not

1020
00:47:12,200 --> 00:47:14,239
Speaker 1: so much that you get a stall. And then you

1021
00:47:14,320 --> 00:47:17,680
Speaker 1: have this smooth ending so the flow comes together nicely

1022
00:47:17,719 --> 00:47:20,440
Speaker 1: without creating turbulence at the end. So the shape of

1023
00:47:20,480 --> 00:47:23,399
Speaker 1: an airfoil and the angle of the attack is optimized

1024
00:47:23,560 --> 00:47:27,120
Speaker 1: to give you smooth flow, low pressure above the wing,

1025
00:47:27,520 --> 00:47:30,160
Speaker 1: and to minimize drag, which is important if you want

1026
00:47:30,200 --> 00:47:30,759
Speaker 1: to take off.

1027
00:47:31,000 --> 00:47:32,480
Speaker 3: I feel like the next time I get out of flight,

1028
00:47:32,520 --> 00:47:35,040
Speaker 3: I'm going to appreciate it all much more, having a

1029
00:47:35,080 --> 00:47:36,440
Speaker 3: better sense of how this all works.

1030
00:47:37,560 --> 00:47:39,880
Speaker 1: But you know, in terms of coming to this explanation,

1031
00:47:40,200 --> 00:47:43,480
Speaker 1: the experts still are arguing about, like how to summarize this.

1032
00:47:43,840 --> 00:47:46,160
Speaker 1: I've given you sort of a summary version of it,

1033
00:47:46,440 --> 00:47:48,799
Speaker 1: but I'm sure there are aeronautical engineers out there who

1034
00:47:48,880 --> 00:47:51,120
Speaker 1: have differing opinions and are going to write into us

1035
00:47:52,360 --> 00:47:54,960
Speaker 1: with their theory for why planes fly, or at least

1036
00:47:55,000 --> 00:47:58,320
Speaker 1: for how to describe it. Our original listener Tom Johnson

1037
00:47:58,600 --> 00:48:01,239
Speaker 1: wrote in because he saw this video from the Smithsonian

1038
00:48:01,320 --> 00:48:04,319
Speaker 1: Air and Space Museum that explained it in terms of

1039
00:48:04,440 --> 00:48:07,960
Speaker 1: just Bernoulli right, the Bernoulli explanation of low pressure on top,

1040
00:48:08,280 --> 00:48:10,600
Speaker 1: and he wasn't satisfied with this, and he wrote to

1041
00:48:10,640 --> 00:48:13,560
Speaker 1: me and he said, quote, I contacted the Smithsonian about

1042
00:48:13,560 --> 00:48:17,160
Speaker 1: this video, voicing my concerns, and I was told unequivocally

1043
00:48:17,360 --> 00:48:21,319
Speaker 1: that it's their policy that Berneulli makes planes fly. I

1044
00:48:21,360 --> 00:48:23,839
Speaker 1: wasn't aware that physics cared about policies, but I guess

1045
00:48:23,880 --> 00:48:24,640
Speaker 1: I'm mistaken.

1046
00:48:26,840 --> 00:48:30,080
Speaker 4: That's amazing. Institutions are fantastic.

1047
00:48:31,600 --> 00:48:34,840
Speaker 1: Exactly. And so again, you know, while the microphysics is

1048
00:48:34,920 --> 00:48:36,799
Speaker 1: clear about what's happening around the wing and you can

1049
00:48:36,840 --> 00:48:39,799
Speaker 1: track these individual particles, we still do struggle a little

1050
00:48:39,840 --> 00:48:43,120
Speaker 1: bit coming up with a simple explanation. It turns out

1051
00:48:43,280 --> 00:48:46,360
Speaker 1: pressure is important, and velocity is important, and the forces

1052
00:48:46,400 --> 00:48:49,200
Speaker 1: are important. So none of the sort of classic simple

1053
00:48:49,239 --> 00:48:52,640
Speaker 1: explanations can describe everything that's happening around a wing. You

1054
00:48:52,719 --> 00:48:55,840
Speaker 1: need a more complex, a fuller description of what's happening

1055
00:48:55,880 --> 00:48:59,040
Speaker 1: to explain all the phenomena why planes can fly upside down,

1056
00:48:59,160 --> 00:49:02,080
Speaker 1: Why the pressure goes down above the wing. All this

1057
00:49:02,160 --> 00:49:04,400
Speaker 1: kind of stuff. So in the end the British and

1058
00:49:04,440 --> 00:49:05,800
Speaker 1: the Germans have to work together.

1059
00:49:06,200 --> 00:49:07,799
Speaker 4: Ah, I mean that's better in the end.

1060
00:49:08,920 --> 00:49:12,480
Speaker 3: So those plane wing shapes, So I'm thinking of other

1061
00:49:12,520 --> 00:49:15,120
Speaker 3: instances where you've got like things moving through the air.

1062
00:49:15,160 --> 00:49:16,040
Speaker 4: So we've got like.

1063
00:49:16,280 --> 00:49:19,600
Speaker 3: Wind turbines, and then you've got racing cars. They don't

1064
00:49:19,600 --> 00:49:21,080
Speaker 3: want to go up, they want to go down, so

1065
00:49:21,120 --> 00:49:23,359
Speaker 3: they do the whole shape in reverse. Like, how has

1066
00:49:23,400 --> 00:49:25,359
Speaker 3: this information been used in other contexts?

1067
00:49:25,840 --> 00:49:28,839
Speaker 1: Yeah, exactly. So Formula one cars, they have a wing

1068
00:49:28,880 --> 00:49:31,080
Speaker 1: in the back, but that wing pushes the car down

1069
00:49:31,520 --> 00:49:34,160
Speaker 1: so that it maintains friction because they need friction in

1070
00:49:34,239 --> 00:49:36,600
Speaker 1: order to go forward. Right, the wheels have to get

1071
00:49:36,600 --> 00:49:38,719
Speaker 1: pushed onto the ground so the wheels can grab and

1072
00:49:38,719 --> 00:49:40,840
Speaker 1: then when they turn the wheels, the car goes forward.

1073
00:49:41,239 --> 00:49:43,160
Speaker 1: If the car lifts up above the ground, then it

1074
00:49:43,200 --> 00:49:45,960
Speaker 1: can't move forward anymore. So they design it in order

1075
00:49:46,000 --> 00:49:50,160
Speaker 1: to generate downward pressure, so they have crucially a different angle, right,

1076
00:49:50,160 --> 00:49:52,000
Speaker 1: But they also think about the foil and they do

1077
00:49:52,200 --> 00:49:55,960
Speaker 1: really complex modeling because you know, millions of dollars mean

1078
00:49:56,080 --> 00:49:58,760
Speaker 1: microseconds and that it's the difference between winning and losing.

1079
00:49:59,200 --> 00:50:01,640
Speaker 1: So yeah, absolutely, they invert all of this theory in

1080
00:50:01,760 --> 00:50:04,120
Speaker 1: order to get a wing that can push down. And

1081
00:50:04,160 --> 00:50:06,520
Speaker 1: the crucial thing there is the angle of attack, right.

1082
00:50:06,760 --> 00:50:09,560
Speaker 3: And then wind turbines. They don't want the wind turbine

1083
00:50:09,560 --> 00:50:12,640
Speaker 3: to go airborne, but they want it to spin as

1084
00:50:12,680 --> 00:50:15,440
Speaker 3: fast as it can, which feels like maybe some of

1085
00:50:15,440 --> 00:50:17,720
Speaker 3: the principles we talked about today could help that happen.

1086
00:50:18,560 --> 00:50:20,200
Speaker 4: Yeah, how does this plant to wind turbines?

1087
00:50:20,400 --> 00:50:23,120
Speaker 1: Yeah, exactly, Well, it's the same principle. Essentially, you have

1088
00:50:23,280 --> 00:50:26,360
Speaker 1: air flow across the propeller and you want to convert

1089
00:50:26,400 --> 00:50:29,200
Speaker 1: that to a sideways force, right, So you want to

1090
00:50:29,280 --> 00:50:32,040
Speaker 1: force up relative to the propeller. You don't want the

1091
00:50:32,080 --> 00:50:34,880
Speaker 1: whole propeller to fly abof the ground, right, but you

1092
00:50:34,880 --> 00:50:38,319
Speaker 1: wanted to spin around the axis, and so again the

1093
00:50:38,400 --> 00:50:41,480
Speaker 1: angle of attack and the shape of it ensures a

1094
00:50:41,560 --> 00:50:44,919
Speaker 1: force that turns it and smooth flow around it because

1095
00:50:44,920 --> 00:50:47,760
Speaker 1: you don't want turbulence in the back of your propeller blade.

1096
00:50:48,080 --> 00:50:51,640
Speaker 1: So each one of those is essentially just a little wingh.

1097
00:50:51,160 --> 00:50:54,120
Speaker 3: Very cool and guessing that we weren't racing cars before

1098
00:50:54,480 --> 00:50:57,800
Speaker 3: we had planes, so probably the plane stuff came first.

1099
00:50:58,200 --> 00:51:00,760
Speaker 1: Yeah, the plane stuff came first. Cars were pretty slow

1100
00:51:00,840 --> 00:51:03,560
Speaker 1: until kind of recently, Like you could win big car

1101
00:51:03,640 --> 00:51:05,759
Speaker 1: races by driving it like forty five miles an hour

1102
00:51:05,840 --> 00:51:07,120
Speaker 1: for many years.

1103
00:51:06,960 --> 00:51:09,680
Speaker 3: That sounds so cute. Now it's much harder to die

1104
00:51:09,719 --> 00:51:13,080
Speaker 3: at that speed. Why would you watch that exactly?

1105
00:51:13,640 --> 00:51:16,040
Speaker 1: But it's really fun to think about how we explain

1106
00:51:16,120 --> 00:51:19,279
Speaker 1: the world around us, and how challenging it can be

1107
00:51:19,360 --> 00:51:22,480
Speaker 1: to explain some things. It makes me really grateful for

1108
00:51:22,600 --> 00:51:25,360
Speaker 1: the times that we can find a very simple explanation

1109
00:51:26,040 --> 00:51:29,240
Speaker 1: and wonder like why that's possible sometimes and not other times.

1110
00:51:29,320 --> 00:51:31,640
Speaker 1: Is it because the way that we think about the world,

1111
00:51:32,120 --> 00:51:34,360
Speaker 1: or is it just something about the way the world works?

1112
00:51:34,719 --> 00:51:37,960
Speaker 1: You know, alien scientists have a better theory for why

1113
00:51:38,080 --> 00:51:40,759
Speaker 1: wings work because they started off from a completely different

1114
00:51:40,800 --> 00:51:44,280
Speaker 1: point of view mathematically or scientifically. Or is everybody struggling

1115
00:51:44,360 --> 00:51:47,880
Speaker 1: to describe some complex behaviors? Are these things just inherently

1116
00:51:47,960 --> 00:51:51,080
Speaker 1: complex or is it just our language that's making them

1117
00:51:51,120 --> 00:51:51,799
Speaker 1: a challenge?

1118
00:51:51,960 --> 00:51:54,680
Speaker 3: I wonder if part of that is there some percent

1119
00:51:54,760 --> 00:51:57,080
Speaker 3: of explanations that we have that we feel good about

1120
00:51:57,080 --> 00:51:59,360
Speaker 3: that are actually wrong if you look at them more closely.

1121
00:52:00,120 --> 00:52:01,040
Speaker 4: Stuff works anyway.

1122
00:52:01,520 --> 00:52:03,640
Speaker 3: Yeah, and then I wonder if some other stuff just

1123
00:52:03,680 --> 00:52:05,680
Speaker 3: there happens to be a metaphor that we're familiar with

1124
00:52:05,719 --> 00:52:07,040
Speaker 3: that makes it easier to understand.

1125
00:52:07,080 --> 00:52:08,920
Speaker 4: And there's just not like a ready metaphor for some

1126
00:52:08,960 --> 00:52:10,600
Speaker 4: of the more complicated things.

1127
00:52:10,640 --> 00:52:14,239
Speaker 1: But yeah, and sometimes we accept an explanation even though

1128
00:52:14,280 --> 00:52:17,000
Speaker 1: it's nonsense, like the air has to go faster over

1129
00:52:17,040 --> 00:52:19,520
Speaker 1: the top of the wing to meet its partners. Like

1130
00:52:19,560 --> 00:52:21,400
Speaker 1: a lot of people go, oh huh, yeah, that makes sense,

1131
00:52:21,520 --> 00:52:21,839
Speaker 1: but it.

1132
00:52:21,800 --> 00:52:25,280
Speaker 9: Doesn't actually make sense, you know, yep.

1133
00:52:25,719 --> 00:52:29,759
Speaker 1: And fundamentally, all of science is quote unquote wrong. If

1134
00:52:29,800 --> 00:52:32,480
Speaker 1: you zoom in far enough, you know, everything is just

1135
00:52:32,520 --> 00:52:36,040
Speaker 1: an approximate description, not like scientists are lying to us

1136
00:52:36,160 --> 00:52:39,840
Speaker 1: or we're promoting nonsense, but everything is an approximation, even

1137
00:52:39,880 --> 00:52:43,640
Speaker 1: like describe an electron as a fundamental particle, Yeah, probably

1138
00:52:43,640 --> 00:52:45,840
Speaker 1: it's not. Probably it's made of something smaller. We just

1139
00:52:45,840 --> 00:52:48,600
Speaker 1: haven't seen it yet. But our theory works so far,

1140
00:52:49,000 --> 00:52:51,360
Speaker 1: we've never been able to make an experiment where it breaks.

1141
00:52:51,400 --> 00:52:53,480
Speaker 1: And so all of science is a work in progress

1142
00:52:53,520 --> 00:52:55,719
Speaker 1: in that sense, not just like do we have the

1143
00:52:55,760 --> 00:52:58,399
Speaker 1: best explanation for it? But you know, how far can

1144
00:52:58,400 --> 00:53:00,919
Speaker 1: we push this until we see it break. And seeing

1145
00:53:01,000 --> 00:53:03,800
Speaker 1: it break is an opportunity, right, It's not a disaster.

1146
00:53:03,880 --> 00:53:06,720
Speaker 1: It's a chance to learn something deeper about the universe,

1147
00:53:06,760 --> 00:53:09,600
Speaker 1: to come up with a more accurate description, or to

1148
00:53:09,680 --> 00:53:12,640
Speaker 1: poke through reality to another level and see how it

1149
00:53:12,680 --> 00:53:15,480
Speaker 1: works underneath it all. So it's just part of the

1150
00:53:15,560 --> 00:53:16,320
Speaker 1: journey of science.

1151
00:53:16,800 --> 00:53:18,640
Speaker 3: I feel like it's a great time to be in science.

1152
00:53:18,680 --> 00:53:22,239
Speaker 3: There's still so many fundamental things left to understand at

1153
00:53:22,239 --> 00:53:24,719
Speaker 3: the same time as we gaining all this new technology

1154
00:53:24,760 --> 00:53:27,120
Speaker 3: that allows us to address questions in different ways.

1155
00:53:27,200 --> 00:53:29,399
Speaker 4: We have all these new tools. Can't wait to see

1156
00:53:29,440 --> 00:53:30,760
Speaker 4: what we learn in the next couple decades.

1157
00:53:31,239 --> 00:53:33,600
Speaker 1: Yeah, and it's not just like what's inside an electron,

1158
00:53:33,680 --> 00:53:36,480
Speaker 1: like weird, abstract fundamental stuff that you'll ever see. It's

1159
00:53:36,520 --> 00:53:38,239
Speaker 1: stuff right in front of you, stuff you can see

1160
00:53:38,280 --> 00:53:41,640
Speaker 1: with your eyes. You know, tornadoes and hurricanes and airplanes

1161
00:53:42,080 --> 00:53:45,360
Speaker 1: and fluid flow. All this stuff is complex and unsolved.

1162
00:53:45,400 --> 00:53:48,160
Speaker 1: So smart young people with energy out there go out

1163
00:53:48,160 --> 00:53:52,719
Speaker 1: there figure it out. There's lots left to do, so

1164
00:53:52,719 --> 00:53:54,600
Speaker 1: thank you very much to Tom Johnson for sending us

1165
00:53:54,680 --> 00:53:56,960
Speaker 1: this question. If you have questions about the way the

1166
00:53:56,960 --> 00:54:00,239
Speaker 1: world works or why you can't understand it. Please write

1167
00:54:00,239 --> 00:54:02,520
Speaker 1: to us two Questions at Daniel and Kelly dot org.

1168
00:54:02,760 --> 00:54:04,040
Speaker 1: We love to hear from you.

1169
00:54:04,239 --> 00:54:12,480
Speaker 4: Thanks Tom.

1170
00:54:12,600 --> 00:54:16,160
Speaker 3: Daniel and Kelly's Extraordinary Universe is produced by iHeartRadio.

1171
00:54:16,360 --> 00:54:18,920
Speaker 4: We would love to hear from you, We really would.

1172
00:54:19,080 --> 00:54:21,839
Speaker 1: We want to know what questions you have about this

1173
00:54:22,000 --> 00:54:23,680
Speaker 1: Extraordinary Universe.

1174
00:54:23,800 --> 00:54:26,759
Speaker 3: We want to know your thoughts on recent shows, suggestions

1175
00:54:26,760 --> 00:54:27,760
Speaker 3: for future shows.

1176
00:54:27,880 --> 00:54:30,239
Speaker 4: If you contact us, we will get back to you.

1177
00:54:30,440 --> 00:54:33,960
Speaker 1: We really mean it. We answer every message. Email us

1178
00:54:34,000 --> 00:54:37,080
Speaker 1: at Questions at danieland Kelly dot org, or.

1179
00:54:37,080 --> 00:54:38,320
Speaker 4: You can find us on social media.

1180
00:54:38,400 --> 00:54:42,200
Speaker 3: We have accounts on x, Instagram, Blue Sky and on

1181
00:54:42,280 --> 00:54:43,200
Speaker 3: all of those platforms.

1182
00:54:43,239 --> 00:54:46,200
Speaker 4: You can find us at d and kuniverse.

1183
00:54:46,320 --> 00:54:47,839
Speaker 1: Don't be shy, write to us