StarTalk Radio - Neil’s Guide to Heat Transfer Physics

Episode Date: February 27, 2024

How do you make some things stay hot and others stay cool? Neil deGrasse Tyson, with the help of comedian Chuck Nice, explains the physics of heat transfer, insulation, and why your Stanley cup can keep your drink cold during a fire. NOTE: StarTalk+ Patrons can listen to this entire episode commercial-free here: https://startalkmedia.com/show/neils-guide-to-heat-transfer-physics/Thanks to our Patrons Kiril Stoilov, aaron tanenbaum, Oswaldo Asprino, cary mannaberg, Taylor Jenkins, BeerandBrat, and J Maz for supporting us this week. Subscribe to SiriusXM Podcasts+ on Apple Podcasts to listen to new episodes ad-free and a whole week early.

I'm going to make the walls of a material that is bad at conduction, bad at convection, and bad at radiation. I got a heat prison. That's what I got. I believe what we have here is a failure to radiate. To radiate. Welcome to StarTalk. Your place in the universe where science and pop culture collide. StarTalk begins right now.

Chuck. Yeah. I'm going to talk to you about heat transfer. All right. Did heat put in for a transfer? I cannot take these conditions any longer. I put it in for a transfer right now. This is a hostile work environment.

All right. So basically, unless you pump energy into a system, a system left all by itself, energy will go from the thing that's hotter to the thing that's colder. Right. That is not some great revelation. No. That is something that you learn from your mother and father. Okay. Shut the damn door.

The hell, you trying to hit the whole neighborhood? Okay. So someone serves you a hot bowl of soup. Right. Let's say you're eating in room temperature. So it's, you know, 72 degrees. Right. What would that be Celsius? 22 degrees Celsius, something like that. Okay. 72 degrees. They serve you a cup of soup. Right. What would that be Celsius? 22 degrees Celsius, something like that.

Okay. 72 degrees. They serve you a cup of soup. All right. The soup is hotter than the air temperature. Absolutely. What happens if you wait long enough? My brother will eat the soup.

That's how that goes. Okay. Not in your household. Oh, okay. Just generally. Oh, yeah. Of course. Okay. Not in your household. Oh, okay. In a laboratory. Just generally. Oh, yeah. Of course.

The soup cools to room temperature. The soup goes down to room temperature. There you go. Right. There's a heat transfer between the soup and the air. Right. Okay. Now, the air, it takes a lot of heat to heat all the air in your room.

Right. So, it's not like the soup turned the 72 degrees into a 90 degree room. Right. All right. But that energy is in the room and it did make some tiny difference in the overall temperature of the room. Right. Okay. So now we bring out some ice cream.

Most freezers go to zero degrees Fahrenheit. Right. You bring out the ice. It's hard to scoop at that temperature, but fine. Here's a bowl of ice cream at zero degrees Fahrenheit. Right. You bring out the ice. It's hard to scoop at that temperature, but fine. Here's a bowl of ice cream at zero degrees. Okay. If you go away

and come back and we're not at your house. I was going to say, that's not a smart move. Leave an ice cream out. Eventually, what happens? If you have a bowl

of ice cream at zero degrees and you sit it on the counter, it's going to go to room temperature. It's going to go to room temperature. So,

it's going to melt first and then go to room temperature. And so in the first case with the soup, heat energy went from the soup to the air. Right. In the case of the ice cream, it went from the air to the ice cream. To the ice cream. Okay. So the heat's going to go wherever it is needed. Right.

All right. Now, how do you prevent that from happening? Okay. You eat the ice cream very quickly. Okay. Can we leave your household for a minute here? Okay. I'm sorry.

So one way to prevent that is let's put a cover over your soup. Right. Because you just went to the bathroom. Right. And I don't know how long it takes you to poop, but you want hot soup when you come back, I will cover it. Yes. Okay? Got to go clear some shelf space.

Back to this soup. Okay. So, if you cover it, the hot air immediately above the soup does not rise up, pulling heat out of the soup. It stays there. Okay? Now, what happens? That hot air gets the lid hot.

Right. Okay? But there's a time delay there. Right. And by the way, if it gets the lid hot, then the lid will make the air hot. Yes. Yes. But it'll do that via conduction. Okay.

Conduction is one way that heat transfers. A molecule touches another molecule and it says, there you go. There's some energy. There you go. Okay. You got it? Got it. Okay.

Conduction is the least efficient means of energy transfer. Okay. You got it? Got it. Okay. Conduction is the least efficient means of energy transfer. Right. Okay. Least efficient. So an example of this is you have a fireplace poker. You put one end in the fireplace. Let's say it's a yard long or something, a meter long. And you just sit there. Eventually, your handle will get hot. At some point. At some point. Right. But it's got to work its way molecule by molecule.

All the way up the poker. Up the poker. And it's going to, the molecules vibrate, sends the vibration to the next one, to the next one, to the next one, and eventually your handle will get warm. Right. Eventually. Okay. So, that's conduction. So, it delays it for get warm. Right. Eventually. Okay. So that's conduction.

So it delays it for several reasons. It traps the air, and now the lid can only just transfer heat to the air molecules that touch it. Whereas without the lid, the entire pocket of air sitting above your stoop rises up. Right. It says there's heat here. Now I have expanded and I am less dense. And if you are air that's less dense, you do what?

You rise. So that's why heated air rises. Right. It rises. Does it leave a vacuum there? No. What happens? It pulls air behind it.

And this is air that's not as hot as the air that just went up. Exactly. Okay. This is all the cooler air, the 72 degree air, because this air right above the soup is close to the temperature of the soup. So it rises, cold air comes in, it gets heated, and this cycles, and that's called convection. And you know, it's so funny. I used to have a home show on HGTV, And that was the first air conditioning, what you just described. They would put gas flames in a Coppola and then they would turn them on.

It would heat the air at the top of the house in the Coppola. It would go out into the atmosphere and pull all the other air up behind it. And that was the first air conditioning. But you couldn't just put a fan in the window? You got to burn fossil fuels to get... What the hell's wrong with these people?

Okay. All right. So, conduction is slow. Convection is fast. Right. Okay? You know what's even faster? Than convection? Yes. Radiation. Nice. Okay. You know what's even faster? In convection? Yes.

Radiation. Nice. Okay. I don't mean radiation, nuclear, just radiation. Not whole radiation. Right. Just light. Just light. Okay. So, radiation is faster. So, how does that work? The fact

that the bowl is hot. Right. If you pull out an infrared camera, shut out the lights, what would the bowl look like? It would be red and glowing. Right. Why would you see it in the infrared? It is sending light energy to, it is radiating in the infrared to you.

Nice. Okay. It is radiating. Now, radiation only goes in straight lines. This is an interesting fact. Okay. Okay? Did not know that.

Which is why if you have a fire, a fireplace, or I remember in camp, it would be a little cold at night. They'd have a fire. If somebody walks in front of you, Right. you're in their heat shed. Yeah, exactly. You're like, can you please move? I'm trying to get some fire.

That's right. You take it out of my fire, bro. Exactly. So most of the time when people huddle near a flame, it's not because the fire made the air hot, because any air it makes that's hot does what? It rises and goes up.

Rises up. It dissipates. It doesn't come out of the fireplace to reach you. Right. It goes up. Right.

Okay, so the heat you're receiving from a fireplace is radiative. Right. That is photons, in that case, infrared photons

of light coming straight to you at the speed of light. Wow. Okay? There it is. These are three ways heat moves. Okay. So, the sun, deep inside,

stars can do any combination of convection and radiation. Okay. They don't do conduction very well. Conduction is more a solid thing. Yeah. Solid to solid. Right. That's really, so that's where you get conduction.

Convection and radiation, fluids do this. Right. Okay. So when you say, oh, this thing is boiling over. Oh, no. Watch the evolution of this. Ready? Okay, here it is.

You have a pot of water. Right. And you want to boil it. Right. Put it on the stove. Right. Turn on the flame. Yep.

Okay? The water at the bottom begins to heat. Yes. Okay. Hot water is slightly less dense than the cooler water and it will rise. But you don't actually see this because of the water. But eventually, when it

gets a little more vibrant, you know what you can try to do? I think I did this with raisins. You can put test particles in the water. Okay? Just a few. And you can watch them bob up and down. Right, right. Okay? Right. And. And you can watch them bob up and down. Right, right. Okay? Right.

And I think I did it with raisins, but I'm trying to remember what... There's certain particles where you contract this. It goes to the bottom, gets hot, and rises. This is the fastest way that the water can heat itself. Because the hot pocket, the heated

pocket of water... I was going to say, is that a pepperoni hot pocket, the heated pocket of water. I was going to say, is that a pepperoni hot pocket? The heated pocket of water physically and bodily rises and new water has to take its place. And that new water comes from a higher level that was not as hot. And that's the very fastest way you can get that to happen. I'm Kais from Bangladesh, and I support StarTalk on Patreon.

This is StarTalk with Neil deGrasse Tyson. All right, class, tell me the three ways heat can transfer. So you got convection, conduction, and radiative. Good. So now I want to make a vessel that heat does not either go in or come out of. Okay. Okay. work come out of. Okay. Okay.

So, I'm going to make the walls of a material that is bad at conduction, bad at convection, and bad at radiation. I got a heat prism. That's what I got. I believe we have,

what we have here is a failure to radiate. Let the record show that Chuck is repeating a line from Cool Hand Luke. Cool Hand Luke. If I remember correctly. Great movie. Paul Newman. Paul Newman.

Great movie. All right. So that's the only job of this vessel. Because if I put something hot in there, I don't want it to cool off quickly. Right. If I put something cool in there, I don't want heat to get in. Right. Okay?

So, one way to do that is you have two walls. Mm-hmm. Okay? Let's make them glass for a moment because glass is moldable. Right. That's why we have

bottles and things. Of course. So let's make two layers of glass and have air in between the glass. Yeah. I mean,

a lot of windows are constructed that way. Yes, yes, yes. A lot of windows are constructed that way. When you have double-pane windows. Double-pane windows. Double-pane windows.

And that's an insulating feature of the window. Right. Insulates. Okay. Because insulation is the other word for what I'm trying. You have a better term. Heat prison. Okay?

What heat prison material you got for me? So, you have air there. So, now, if I put something hot inside, it'll make the glass hot. Right. Just by conduction. Okay, it's touching the glass. Right. Now, the glass is hot.

All right. So, now, the glass is going to heat the air. Right. But now, the air is just going to go up. Right. The air is trapped inside the thing. Where is it taking the heat? I'll tell you where.

It can't physically take the heat anywhere. It's stuck in there just like Andy Dufresne. How many movies? Andy. Andy Dufresne. I believe I was going to meet him at Montauk, Montauk Negro. Is that where that was? I don't know what it was.

It was someplace down in Mexico or whatever. Yeah, yeah. Coast of Mexico. Meet me there, Andy. So Chuck, so the original title of that was Rita Hayworth and the Shawshank Redemption. Okay. Because she was the first pinup girl that they put on the wall. I mean, very small role in the film for her to get billing.

Can't believe Stephen King gave her top billing. You know? Okay. Back to Heat Prison. Heat Prison. Heat Prison. So, we got the glass. We got conduction because it's touching.

We got the heat. That's convection. The air just goes up. But it just goes and it stays inside the bottle. Right. Okay? Any convection stays there, but it's still touching the other side of the glass. Right.

But this is delay. Well, this is delay. These are delaying tactics. Right. So now we need conduction to heat that side of the glass. Right. And then it has to get through the glass. And typically that's in another canister that surrounds it.

You're not holding onto glass. No. There's something else. So it's got to get through that. Okay? Right. So that is sort of an early version of a heat prison. The early thermoses were, I remember if you dropped them, you could break the glass.

Say goodbye to your thermos. Yeah. Oh, by the way. It had a glass inner. Yeah, yeah. That's right. That's right. And glass. Say goodbye to your thermos. Yeah. Oh, by the way. It had a glass inner. Yeah, yeah. That's right. That's right. And so then you have to throw it away because you broke the air prison that was in there.

Okay? Right. So another thing you can do, if you take out the air, then it can't even conduct to the other layer of glass. Right. That's right. Okay. Yeah, because you can't have convection without the fluid.

Without the fluid. The air is the medium or the fluid. So without that, the heat is just like, oh man, this is where the escape ends. This was a terrible plan, man. This was a terrible plan. I told you we should have crawled through the poop pipe. I told you we should have crawled through the poop pipe.

You're like, no, we can't crawl through a bunch of crap. And now look at us, man. Here we are stuck in a vacuum. We cannot escape this hate prison. Is that the beginnings of your next movie script? That's what it is. It's called Rita Hayworth and the Broken Heat Prison. All right.

So. Okay. So, these are all just delaying tactics. Now, watch what happens now. There is a way for the inner glass to send heat to the outer glass. And which way is it? Radiative. Which was always there, available to it. Exactly. Okay.

Because you can radiate through air as well as convect through air. So now, you can't convect. It's not conducting. So now it's radiatively sending infrared energy across the vacuum gap to the outer layer. To the outer layer.

Okay. And then that has to absorb the infrared and then get hot and then do it to the outer layers beyond there. Exactly. Okay. So this is an improvement over air. Absolutely. It's easier to put air inside there than to create a vacuum in something you're giving your middle school children. That's really cool because you just reminded me of an article I just read yesterday about a new fiber that is being constructed using aerogel.

And the fiber itself is based on the fur of a polar bear because their fur— Based on the concept. Yeah, the concept of a polar bear. There's a lot of shaved polar bears out there. Polar bear with a mohawk. Yeah, but they're hollow. So what they do is they spin the aerogel along with another substance into these hollow fibers and then it's like the

entire garment is like a giant down jacket, but it's thin. It's not using down. It's thin as this. No geese were harmed. Yeah, no geese were harmed. Right. Exactly. And just because I work in a natural history museum, which is the only reason why I know this, but you already knew it,

that polar bears are just happy in and out of 30 degree waters, salty waters, because their fur is not normal fur. They're actually hollow tubes. Exactly. So here's the thing. If in the gap,

because putting a vacuum in there is very hard, it's a production issue. If you put air in there, but throw in stuff that prevents the air from convecting. Right. Right? Yeah. But put in anything. Put, put, put, put in.

No, no. No, that's right. Because it's got to be, it can't be pudding because that. That itself. That itself is like water or something. Right. So you put something in there that's sort of light and fluffy that prevents the convection. Like 3M.

Okay. And that, if something's there, that would also prevent the radiation. Right. Going through it. Well, it'll get absorbed by the thing and then have to, it just delays it even further. That's the whole point of these vessels that we're trying to invent. Okay.

So, the first plan is you put in air. Right. Second plan, you put in something to prevent the air from convecting. Right. Third, take out the air. Fourth, you want to prevent the radiation from going. So, what you put in is a radiative barrier. A barrier for radiation.

Right. Nice. Ooh. A barrier for reason. Right. Nice. Ooh. So now what you have is you put in a substance where the infrared comes out and reflects back. Bow.

Ooh. Oh. Oh. Oh. Now that's a good prison guard right there. Okay. That's what I'm talking about. Bust you back in.

Right. Okay. So. So. Now 3M knows this. Right. Okay. So, so, now 3M knows this. Okay. If you look at, is it Tyvek?

Tyvek, yeah. When they're putting up homes. Yeah. Okay. If you look at the materials, very thin. Very thin. All that matters is that

heat can't get through. That's it. And they're shiny on the outside. Nice. Okay. Shiny surfaces reflect not all light, but the light that you're going to care about in your heating of the outside or the inside. Okay? Shiny surfaces reflect not all light, but the light that you're going to care about

in your heating of the outside or the inside. Okay? Amazing. So, so, we finally like perfected such a vessel and you know what we call them? What?

Thermos. Yes. What a thermos is. Well, clearly there's one thermos that's been perfected beyond all others because there's a big craze about this thermos. They don't call it that. They call it the Stanley Cup or whatever.

Anyway. That's the thing with the big handle sticking out? With the big handle. It's a giant, giant cup. But this lady. Somebody gifted me one of those. And I said, I have never been that thirsty. You know what it is?

It's a plot so that you always stop at the convenience store to pee. Right. I have never been that thirsty. You know what it is? It's a plot so that you always stop at the convenience store to pee. Right. You got to buy something while you're going to the bathroom. This is a conspiracy. I'm certain of it. But this lady sees her car caught fire, and then she goes into the semi-charred remains of the car.

Wait, I think I've seen this video. Yeah. But I haven't, I didn't pay close attention to it. I paid some attention, but what, so what's the upshot? She pulls out the cup and she shakes it

and it still has ice in it. She's like, you see? It still has ice in it. Well, great. All you know is that it was rattling. It could have been marbles. It could have been marbles.

Wait, as a scientist, it's probably ice, but I'm not going to say it's ice until I see that it's ice. And measure that it's ice. And it's not just marbles in there. As a scientist, that's how I would do that.

I remember now that the steering wheel was all burnt out. The dashboard was all burnt out. Yes. But the cup holder, and every cup holder I've ever seen, interacted with, or thought of, is plastic. Always. The cup holder was unharmed by the heat.

Right. So maybe the dash is on fire and the police came in to, and if I remember correctly, there was water in the bottom of one of the cup holders. Right, from where they put the fire out. Where they put the fire out. So the fire was out before it reached. Before it reached that particular part of the car.

That section of the car. Right. And if it was put out, and if it wasn't hot enough to melt the plastic, it's not doing a damn thing to your big damn cup. The big old damn cup. Yeah. Exactly. With marbles. With marbles.

So, I had the cup holders themselves. I'm melting. Or even if the cup had been fused to the cup holder. You'd think that would happen. Right. It's so hot. Because it's so hot. Right.

Okay. Yeah. So, that's what you think that would happen right so hot because it's so hot right okay yeah so so i saw that that all right it's fine virality in social media does not have to correlate with truth right yeah exactly yeah tell me about it you think yeah Since we were in my office, I got stuff, okay? I happen to have aerogel. Nice. Which you just described. It's inside this cube. If you look, there's like a ghost in there.

Yes. It's that, like... It's the ghost in the cube, not the machine. But look at that. The ghost in... Let me open this up here. Now you can see in there much better. Yeah.

For those who see this on video, it's a very ghost-like substance that has one of the highest insulating properties of any substance ever created. Aerogel are these long polymer molecules with carbon in them. And if they're long and twisted, then the air doesn't know where to go. Right. Like the ideal way to trap air.

Right. So, especially if you have vapor barriers, the heat is not going anywhere. So, that's why it's not a magic thing to say that a thermos keeps hot things hot and cold things cold. Right. Because physically, what it's doing is it's preventing heat transfer.

That's it. No matter which way... Which way the heat is coming. Yeah, coming or going. You know what else is a good insulator? What? It's plastic. Right.

So I happen to have a lunchbox from Disney's awful movie, The Black Hole. Oh. When was this? Back in the 70s. All right. Ten worst movies I've ever seen. I open my lunchbox, and in there is a thermos.

Everything's plastic, of course, because it's a kid's thing, and you don't want anything breaking. It's got a plastic lid, so I open that up. And it's got a little sippy device. Fancy. Everything's plastic. Yeah, it's a high-end little thermostat. Especially from the 70s.

Damn. Yeah, so this is a black hole. So, Chuck, you've heard of the black hole in the center of the Milky Way? Of course. Yeah, of course. Like 600 million times the math. I think, last I checked. Well, here in my black hole lunchbox, I have a Milky Way in the center of the black hole. In the center of a black hole.

Now, you know what? What? Stop. Somebody needs to spank you for that. Stop. So I'm looking in here. It's plastic on the inside, plastic on the outside, but it's actually quite thick. There's a thickness to this.

Right. It is. Look at that. Wow. It's very thick. That's why the inside of a thermos is always so much smaller in volume than the outside. Because relying on stuffing things in between to prevent heat transfer. That's it.

So this is the innovation of the human brain overcoming restrictions by the laws of physics. There you go. Overcoming the laws of thermodynamics. Yes. Exploiting them to our advantage. Screw you, thermodynamics. You won't tell me how to transfer heat. So now if I put you out in space, okay?

Let me put my lunchbox back. There we go. Say goodbye to the black hole. Goodbye, black hole. Okay, there it goes. And aerogel? Oh, I don't want to say goodbye to aerogel. That stuff is so cool.

If I put you butt naked in outer space... Right. So... Space will become exceedingly more sexy. Wait. Aerogel, that stuff is so cool. If I put you butt naked in outer space, Right. So, Space will become exceedingly more sexy. Wait. So, you're not conducting, heat cannot conduct from your body to space.

Nope. Because you need physical atom contact for that. Right. Okay. And, There's no convection. There's no convection. Because it's a vacuum of space.

It's a vacuum. So that leaves only one way for heat to transfer. Radiative. Radiative. So, if you are far away from any star, right, your 98.6 degree body, 37 degrees Celsius, will radiate what kind of light? Infrared.

Infrared light. Because you show up on an infrared camera in a room. Yep. It'll radiate infrared. And radiation is... Until you are dead. Until you are dead. Infrared till you're dead, baby.

You'll just... Infrared just goes and there it goes. Right. And there's nothing to stop that. Now, when you go out in the cold, okay, in cold air, right, you are still radiating in the way you would be radiating in space, but air is also in physical contact with your body. And the air that touches your body immediately gets heated by your skin

and it gets swept away. Right. So, this is why you have wind chill factors because the air touches you, takes your heat, and then wind blows it away. Right. And then new cold air comes in.

It's almost like convection, except it's not convection. It's just wind. Right. And then new cold air comes in. It's almost like convection, except it's not convection. It's just wind. Wind, the air sucks out your heat and fresh air comes in to keep that up. So you will freeze to death much faster under windy conditions than under non-windy conditions. Wow. Now, here's an interesting fact. It was Apollo 13, the ill-fated mission, where the oxygen tank blew, and they had to come back. I think that was it. The oxygen tank,

they're on their way back, and they had to conserve everything. And they couldn't heat the capsule. Otherwise, they'll run out of other resources that they needed to get back to Earth. What they figured out was, when you are in in zero G, which you are when you're just floating back to Earth, if you just stay in one position and don't move, you will heat the air that's

touching your skin, but the air won't know where to go after that. There's no gravity. Right. your skin, but the air won't know where to go after that. There's no gravity. Right. There's no gravity vector for the hot air to rise because there is no up or down. So by just staying there, you end up creating a heat suit. A heat blanket of just air. Air around you. Around you.

And the air itself makes a good insulator. And so that way, it's like you're putting on a coat. Wow. Eagle, this is control. We're not going to be able to heat you guys on the way back. But what we're thinking here is that you just stay perfectly still.

It's like, bro, no. No, bro. Uh-uh. We need a better plan. By the way, that's why clothing works. True. Think about it. Yeah.

No, that's right. You keep your hair inside your clothes. And that's why you can go out into colder conditions, and you are warmer wearing clothes than not wearing clothes. It's the whole idea behind layering. Yes. And it's also the idea behind a wetsuit. Right. Yes. Okay. In a wetsuit, remember how that works. It's a rubberized thing, but you get water inside. Inside. Right. It's cold at first. Your body

heats the water. The water stays there. Right. Okay? And the water is protected from losing its heat to the ocean because you're surrounded by rubber. Okay? Right. And rubber has air pockets inside of it as well. So you are nicely insulated in what they call a wetsuit that divers know all about.

Nice. Okay, so now you're out there freezing to death. Suppose I move you closer to a star. Let's move you closer to the sun. Oh, thank God. Okay, so now what's going on? Well, now I'm getting the sun's radiative heat. There you go.

The sun is radiating with energy way higher than infrared. Yes. So there's some distance. I don't know what that is. I'll have to calculate it. Where energy from the sun is just right for you.

Right. Okay. Where you could be buck naked in space. However. And comfortable. However, only the side of you facing the sun. Oh, God. The side of you facing the sun. Oh, God. The side of you where the sun ain't shine, don't shine. Right. That's radiating out to the rest of the universe.

Oh, man. One half of you is freezing. So you have to go on a rotisserie. You're on a rotisserie. And if you don't, you will literally freeze your ass off. Freeze your ass off. Off. Clean off.

Your body will split right down the middle. One part will vaporize, the other part will... So when they say, what is the temperature of space? That has no meaning because you have to, as a standalone question, you have to ask how close are you to the nearest source of energy.

Right. That would be providing heat to you. There you go. It's all about how heat gets around. That's it. And of course, radiation moves at the speed of light. There you go. You know.

So. What that is. It is. There you go. The heat transfer, baby. All right. Now, oh, one last thing before we land this plane. So I think we did an explainer on boiling over on the stove.

But everything I just described relates to that. Okay. Because if you have something where, okay, water is just slowly convecting up through, but then when it boils violently, what's happening is the water at the bottom, it's not just getting hot and rising. Right. It's turning into bubbles of steam. Right. And a bubble of steam is way less dense than the water.

Right. And that steam wants to get the hell out of that pot. This is who I am now, and I got to go. I got to go. I got to go. This is who I am. You cannot keep me here anymore, water. I am now steam.

I am now steam. I am now steam. And the steam is trying to get out, and you've got oatmeal in the way. Well, the bubble of steam wants to get the hell out, and it's not gentle like just rising heated water. Right. And the bubble just busts up, and if it's spaghetti, if it's any food that's in the way, it's going to take it with it. And there it goes. And it boils over, even if you're only half full,. Right. It's going to take it with it. And there it goes. And it boils over, even if you only have full, for example.

That's right. And while it is boiling over, as it comes out, Diana Ross is playing in the background. Okay. I didn't know that boiling had a soundtrack. Oh, it certainly does. And it's, I'm coming out. I want the world to know.

I forgot about that song. That's like an 80s disco song. Yeah, it is. Great song. Okay. So that's the difference between convecting water. Right. And convecting hot bubbles of gas.

Nice. Okay. So gasified water we call steam and that's what's going on when you boil. But we talked about that in another show.

But here is the full context connected to the transfer of heat. There you go. Plus, the last time we talked about it, we didn't have nearly this much fun. Oh, one more.

Just while we're talking about boiling over. Okay. When the sun dies, it will become a red giant star. That's right. It will become so large, it will engulf the orbits of Mercury, Venus, and come up and just kiss the orbit of the Earth.

And you might ask, how does the sun get so large? Right. Oh, I'll tell you. Oh, well, the outer parts of the sun, okay, as it forms larger and larger molecules, the molecules are less transparent to radiative heat transfer. So it's pushing. Exactly.

So you have what's called radiation pressure on these larger molecules that previously it would just pass right on by. And so the more these molecules form, the more radiation pressure exists underneath it, and the entire star balloons out rather rapidly given the lifetime of the star. Sun will be around for a billion years. It'll blow up. It'll not blow up explosively. It'll expand just in a matter of hundreds of thousands, at most millions of years. And then

life as we know it on Earth would have to have moved to another planet or would be extinct long ago for some other cause. Oh, definitely that. Please. I'll give you a pop quiz. Okay, so why is styrofoam make very good um ice coolers because there's a lot of air in styrofoam yeah but air convects oh that's true

uh i don't know then no because the air is trapped oh oh it's trapped in the styrofoam yeah yeah so you can you can change the temperature of the foam and the pocket of air in the foam, but the air's got nowhere to go. Right. So if there's something cold in there, then it's cold. And if there's something warm in there, then it's warm.

Right, right. And so this is why down parkas work. They trap a lot of air. Anything that's... Or you just figure out a way to prevent... Because in the old days, you look like the Michelin man with all your winter clothing. Yes. You figure out a way to prevent, because in the old days, you know, you look like the Michelin man with all your winter clothing. We figured out how to do that.

We've gotten clever about it with new materials that prevent all three of those heat transfer mechanisms. And then there's also the best solution, and that is Turks and Caicos. Okay. That's the besticos. Okay. That's it. Okay. Pestilence.

Okay. Is that in the instructions on the thermos? Yeah, that's right. It says, open me in Turks and Caicos. Now you got to worry. All right. We got to go there. All right, Chuck.

That's all I got for you. Wow, that is great. That was awesome. That was so much fun. I didn't leave anything out. No, listen. got for you wow that is great that was awesome that was so much fun i didn't leave anything out no we listen we have we have transferred all of the information about heat transfer to anybody who is watching and the better thermoses are the ones that simply take the longest for heat to either get in or heat to get out right that's all it is it's not it's not deeper than that it It's not magic. So stop it with your big stupid cup.

Stop it. All right? Let it go. Come back when it's fused to the plastic. Yeah, when it's fused to the plastic, then that's a video

we want to see. All right? All right. Chuck, always good to have you, man. Always a pleasure. This has been StarTalk. Me just blathering.

This time about heat transfer. More than you ever cared to know. But it all applies to our lives. And whether you can have a cold one waiting for you after your car burns. Neil Bass Tyson. Your personal astrophysicist. Keep looking up.