SciShow Tangents - Refrigeration

Episode Date: January 9, 2024

In this not-so-chill episode, everybody gets a little unsettled by the concepts around refrigeration. Quantum computers, thermoacoustics, molecular chemistry, elephants, the phantom letter "d" that gets added to the shortening of refrigeration...it's all just. So much.SciShow Tangents is on YouTube! Go to www.youtube.com/scishowtangents to check out this episode with the added bonus of seeing our faces! Head to www.patreon.com/SciShowTangents to find out how you can help support SciShow Tangents, and see all the cool perks you’ll get in return, like bonus episodes and a monthly newsletter! A big thank you to Patreon subscribers Garth Riley and Glenn Trewitt for helping to make the show possible!And go to https://store.dftba.com/collections/scishow-tangents to buy some great Tangents merch!Follow us on Twitter @SciShowTangents, where we’ll tweet out topics for upcoming episodes and you can ask the science couch questions! While you're at it, check out the Tangents crew on Twitter: Ceri: @ceriley Sam: @im_sam_schultz Hank: @hankgreen[This or That: Fridge or Not Fridge]Ballpoint-pen-sized device with twisted nickel-titanium and waterCredit-card-sized device plugged into your phone with lithium bromideTwo large metal balls with ammonia and water[Trivia Question]Frigidaire had an elephant stand on their refrigerator as a strength testhttps://www.mentalfloss.com/article/75945/15-icy-cool-facts-about-refrigerationhttps://www.coloradohistoricnewspapers.org/cgi-bin/colorado?a=d&d=STP19390511.2.109&e=-------en-20--1--img-txIN%7ctxCO%7ctxTA--------0------[Fact Off]Dilution refrigeration and ultra-cold LEGOshttps://nanoscience.oxinst.com/assets/uploads/NanoScience/Brochures/Principles%20of%20dilution%20refrigeration_Sept15.pdfhttps://twist.phys.virginia.edu/work/Formal_Paper.pdfhttps://www.lancaster.ac.uk/news/the-coolest-lego-in-the-universehttps://www.nature.com/articles/s41598-019-55616-7#Fig1https://www.popularmechanics.com/science/a30337510/lego-bricks-heat-tolerance-quantum-computer/Thermoacoustic refrigeration and the James Webb Space Telescope[Ask the Science Couch]Freezer smells and dehydration/oxidation affecting food tastehttps://extension.umn.edu/preserving-and-preparing/science-freezing-foodshttps://extension.psu.edu/understanding-the-process-of-freezinghttps://theconversation.com/heres-why-your-freezer-smells-so-bad-and-what-you-can-do-about-it-203058https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/emergencies/removing-odors-refrigerators-and[Butt One More Thing]USB drive found in volunteer-collected frozen leopard seal poophttps://niwa.co.nz/news/they-were-defrosting-leopard-seal-pooyou-wont-believe-what-happened-nexthttps://www.leopardseals.org/scat-poo-collection/

Hello and welcome to SciShow Tangent, since the lightly competitive science knowledge showcase. I'm your host, Hank Green, and joining this week is Forbes 30 under 30 education luminary, Sari Riley. Hello! And our resident, complexly 30 under 30 everyman, Sam Schultz! I'm 36.

36 under 36, I mean 37 under 37 luminary Sam Schultz. Thanks. under 37 luminary Sam Schultz. Last week, we had to talk all about Sari, but we also wanted to talk about what animal we are least afraid of. Of course, fish is the worst answer because that's half of the

vertebrates, and it includes some of the scariest vertebrates. Right. I get not being afraid of fish while you're on land. But if a fish jumps out of the scariest vertebrates. Right. I get not being afraid of fish while you're on land. But if a fish jumps out of the water and flops against you, it's all gooey. And I'd be like, ugh. And that counts as fear in my opinion. So I am more afraid of that than I am of other creatures.

I'll tell you what. You put a fish in my bed in the middle of the night, I will be terrified. I don't think there's an animal that would show up in my bed in the middle of the night that I wouldn't be terrified. I don't think that's true. Just my cats. My cat still startles me. I'm woken up. I go, what's this? What if you woke up and there was like a quokka in your bed? You ever seen a quokka? I feel like if I woke up and there was a quokka in my bed, I would be charmed. I would be confused and scared. I think that's a normal person response. Okay. All right. What animal can show up in your bed that is the least scary? Dust mites. Oh, no. Well, they're there anyway. The thought of them

being there is skin crawling, though. I think if I woke up and there was a weird cat in my bed, I would say, hello, weird cat. Let's go back to sleep. Even a stranger cat. Even a stranger cat. I think if it was snuggled up on my feet, I'd say, we'll deal with this in the morning, my friend. Sleep tight. I have had that almost experience, which is during one of my summers of unpaid internships,

During one of my summers of unpaid internships, instead of finding housing, I found a sketchy Airbnb knockoff. I lived in the attic of someone's house, and one day a random dog showed up. And I was like, what the hell? Here's a dog now. And it just hung out with me for, I would say, three to four hours and then walked down the stairs. Never saw it again the rest of the summer. And I wasn't freaked out by that. No. So daytime is very different than showing up in my bed, I guess. I think that the least scary animal is probably a domesticated animal because you're used to them and they're used to you.

This is it. You need it to be small. What's the smallest dog? Yeah, like a puppy. Like a small, cute puppy. Like a corgi puppy or something. If you had a corgi puppy in your bed, there's nobody in the whole world who would be scared of that. Right, right.

Because it's extremely cute. You're familiar with it. And if you had to, you could kill it. Which isn't important. That's important. Yeah. For self-defense, you could roll over and squish. If push comes to shove, I can end that animal fast.

Or remove it. Like, if you want to be, if you want to be much made, remove it from the bed. Remove it from the situation. Is light. Which I guess brings us back to fish also, because you can knock a fish off your bed pretty easily. They're so slimy though. If you moved your arm and touched a slimy fish, you would be terrified. If you moved your arm and touched a warm, fuzzy puppy, you would be delighted. A puppy could definitely bite you more than like a guppy.

So there's that but like there's just the familiarity of a puppy bite where it's like oh you know i'm not scared of a puppy bite whereas just like the existence of a guppy kind of unsettling this is weird do you just like you think it's fish sarah you think i think i'm coming around to fish. You can't don't say fish. Not fish generically. Like a very specific, like a killifish. Or something very small. A zebra fish. Like if I found a sardine in the bed, I'd be like, that's gross.

But easily remove, right? Okay, whatever. That's weird. I'm kind of moving towards nematodes at this point. Well, like the kind of animal that's just around and you don't even ever think about it. It depends really on the criteria of least afraid. Yeah.

As in, are we swinging the other direction of. Right. I actively want this here or am I just neutral to its presence? That's the alternate response to your dust mites. Instead of being like, ooh, I'm harrowed by this idea of dust mites on my face. You can be like, these are all my friends. These are my only friends. Yeah, that's true.

I'm never alone. Never really alone. Can I be lonely if I'm covered in bugs? In my hair follicles? Eating my dead skin? Look at them doing me a favor. I don't know. You can't say covered.

I can't see them. It's great. Having sex and making babies their whole lives. Oh, I thought you meant they were with you while you were doing that. True.

Also that, though. Yes, that and the other. We are always... Anyway. Every week on Tangents, we get together to try to one-up a maze and delight each other with science facts. While also trying to stay on topic, our panelists are playing for glory. But also, I will award them Hank Bucks as we play. And at the end of the episode, one of them will win.

Now, as always, we're going to introduce this week's topic with a traditional science poem. This week from Sam. For refrigerators, we're going to introduce this week's topic with a traditional science poem this week from Sam. For refrigerators, we must give it up. They keep all our food from turning to muck. Keep medicine stable and keep us all cool. To dismiss them completely would be the act of a fool. But to make it cold in that box takes a bit of hydrofluorocarbons and toxic shit that leaches into the world when they get thrown away and contribute to climate change with each passing day. But the thing about refrigerators that most bothers me

is that when shortened to fridge, it's suddenly spelled with a D. That's my whole poem. Where does the D come from? That was a weird one, Sam. Rhyme scheme threw me off some. Content threw me off some. It was a rollerco, Sam. Rhyme scheme threw me off some. Content threw me off some. It was a roller coaster of a poem.

They can't all be winners. I had to talk about the D thing. It's just the language's fault. I think we made the right choice. I think we did too, but I don't. It just, it preys on my mind. I always wanted to make a fast food restaurant called Fridge that sells stuff that you can microwave when you get home.

I feel like I would want you to microwave it for me if it's fast food. Well, then it would be called microwaves. Microwave. Fridge is such a good word. Yeah.

So really, it's all built around that idea. But that's a good point, Sari. Maybe it's like a bunch of food where it's like you take it home and you can have it a bunch of times.

And keep it in your fridge in the meantime. I just want to buy a casserole of lasagna and not have to make it myself. Well, you can. That's one of the most that things that you can do is lasagna. Where? How? At every store. Like a big one?

I want a big one. Yeah. I want like several meals. You can like buy a big tray of lasagna. Yeah. Oh, sure. In the freezer section? Really? Stouffers. Stouffers. Yeah. They're like this meals. You can like buy a big tray of lasagna? Yeah. Oh, sure. In the freezer section? Really?

Stouffers. Stouffers. Yeah. They're like this big. Marie Callender? They're like single serving. Go to Costco, my friend. I'm sure you could get the largest lasagna you've ever seen.

Or even just at like a Safeway or something. I feel like next to, there's the individual box box meals and then there are the family size. Yeah. Everybody send Hank some big lasagnas. My address is 555 Fifth Street, Missoula, Montana. 55555. Send me your biggest lasagna. I've heard you talk about this idea a lot,

but I didn't know that you didn't know that you could get giant frozen lasagnas. That changes the, that changes the idea. Well, maybe I want them to be fresh, but, but cold and not like frozen, frozen.

I want, I don't know. I don't know what I want. I want, what I want is for food to be good and cheap. Will refrigerators help with that? Maybe. They do.

Is that a segue? What's a refrigeration? I do have an answer to the why does it have a D. Yeah, of course you do. What is it? So refrigerator, the etymology of refrigeration, the word has been the same way from like french it basically looked the same as refrigeration latin refrigeration um comes from the word like frigid um which just means make cool and then the refrigeration is to cool down again and it was used in alchemy contexts, which I thought was interesting, or to cool down heat when you were sick and had a fever.

So you like re-cool down yourself. So as opposed to like refrigerating food, it's you're refrigerating yourself. And so the word refrigeration existed and those letters made those sounds. But then when you shorten refrigerator to fridge, you're left with basically what Hank said, F-R-I-G. But then frig, you would assume that it's that G, like flag or hog or sprig or frig. And so people were like, I don't want that word to sound like that in English

because I don't want to call, get the ham out of the frig over there. That's not good. So then we changed the spelling to mimic where it's like bridge or ridge or smidge where that DG makes that J, the soft G sound. Who's we? Merriam Webster? This was Merriam-Webster where I found this explanation. Oh my God.

Old Merriam and old Webster, the two guys. They got together. This word is disgusting. They whispered to each other and said, how do we make the G make the J sound?

But refrigeration is any time where you like use electricity to make cold, it feels like. I guess you don't have to use electricity. You could just like bring in a block of ice.

It's just any sort of making cold. Yeah don't have to use electricity could just like bring in a block of ice it's just any sort of making making cold yeah so nowadays we use electricity or refrigerants or heat pumps or some sort of technology but the simplest example of refrigeration is like a cooler you bring to your backyard where you stick ice in it and you stick other things and then the ice evaporates over time and much in the same way that when your sweat evaporates from your body it feels cooler because it takes heat takes heat or some sort of energy to make a liquid turn into a gas and evaporate the way hot turns cold and vice versa seems so simple, but is like genuinely one of the most while I was reading about it, like what the hell kind of thing. It's so complicated, I think. Yeah. I feel like, I feel like hot is very easy. Hot is like, there's jiggles. I'm

going to give my jiggles to you and make more jiggles. Whereas getting jiggles out. Whereas getting jiggles out. Good luck. Yeah. Temperature's bad. Temper dynamics are bad. This is the class that I was, I think, closest to failing. A TA looked me in the eyes and said, I don't know how to help you.

And that really shook my educational journey. You really colored the rest of your life, huh? Yeah. I did change majors after that. I passed the class, but basically if state changes of chemicals, um, so like using water as an example, you can change pressure to change it from a liquid to a gas. So there's like this thing called vapor pressure, but basically when chemicals are at higher pressure than they tend to condense into liquids. When they're at lower pressures, then they evaporate or sublimate. Evaporate is from liquid to gas. Sublimate is from solid to gas. And then another way you can change the state of a chemical is temperature. So a certain amount of temperature or heat where below that temperature,

they are generally a liquid or a solid. And then above that, then they evaporate or sublimate and turn into a gas. So all these things are related. And refrigerants are chemicals that change in temperature and pressure in ways that we can control at room temperature and at reasonable amounts. And so we use these exchanges in temperature and pressure, like squeezing them at certain times, letting them evaporate at other times. And generally that transition from a liquid to a gas,

like thinking of sweat evaporating off of your skin, takes heat or takes that energy. Heat goes with it. Heat goes with it, yeah. So heat, you need wiggles. You need the energy from the wiggle to evaporate into a gas. Yeah. And so the wiggles get sucked out of the fridge by these refrigerant chemicals that use the

wiggles to turn into gas. They just like. They carry the wiggles away. The gas doesn't then go into the atmosphere. You like capture it and then recondense it with electricity. But the wiggles, the wiggles radiate out of like the pipes that are back there. Is that right? Yeah.

That's why the back of your fridge is hot. So it's not like it doesn't go anywhere. It has to radiate out. Right, right. So and you can never cool your room down by opening your fridge because it's just going to create heat out the back. You have to stick the back of your fridge outside in the front of your fridge inside, and then it will cool off your house. And that's what air conditioners are. Okay. Now we're getting somewhere. Now I'm understanding. And we've already done the etymology. Look at us.

Which means that it's time to move on to the quiz portion of our show. Today, we're going to be playing a game called fridge or not fridge can be overwhelming deboki has written i and yeah totally i'm terrified of getting a new fridge our fridge broke recently like the motherboard uh fritched out and i was like it's a fridge why is it a motherboard i'm not like playing quake on this thing yeah you got you got orin playing roblox on there what oof there are so many things to think about when you get a new fridge like the layout and the color and whether or not you can play roblox on it and on top of all that there are lots of refrigerator technologies to know about.

So today we're going to play a game called Fridge or Not Fridge, where together we'll be doing some refrigerator shopping. I'm going to tell you some kind of device and you, our hopefully discerning shoppers, will have to decide whether what I'm describing to you is a fridge or not. So we're basically helping you find a new fridge. By the end of this game, you'll have your new fridge picked out, right? Correct. So round number one.

What are we going to learn about today? Well, first up, we have a thin plastic tube that is roughly the size of a ballpoint pen cartridge. Water flows into the tube at one end and out at the other. And extended through the tube is a bundle of nickel titanium wires that can twist and untwist. Is this a fridge or not a fridge? Duh. Not a fridge, but I have no idea why, which I think will be my answer for all of these. Yeah.

You'll say, that doesn't sound like a fridge. I can't put food in there. That's not any fridge I ever heard of. I can't put food in there. That's not any fridge I ever heard of. I'm also going to say, I'm going to say not a fridge also. It sounds like a water filter. Oh, yeah.

Can we guess what it is? Yeah, yeah. What do you think it is? It's a desalination machine. That's what I read. Sure, sure, sure. It is, in fact, a fridge. Wow. It's a tiny fridge it's a proof of concept to show that we might be able to use twisting and untwisting of certain materials to create

a more efficient refrigerator so scientists in the 19th century realized that stretching out rubber causes the rubber to warm up and if you let it relax the rubber will warm up. And if you let it relax, the rubber will cool back down. And that change in heat is due to the changes in entropy. Stretching the entropy makes the fibers inside more orderly and less entropy. Less entropy means the rubber has to pull in heat, warming it up.

And when the rubber is relaxed again, the entropy goes up and the rubber gets cooler. Wild, wild, wild, wild, wild. In 2019, scientists adapted that concept, trying out twisting rubber instead of stretching it. And they also tested several materials, including rubber bands, fishing line, and nickel titanium,

to see how the surface temperature changed when twisted or stretched out. Of the materials they tried, the nickel titanium actually performed particularly well. So they created this little fridge with these twisted wires and found that it could cool the water in the tube down by eight degrees celsius oh yes and refrigeration that's the other thing i gotta keep in my mind refrigeration is any sort of cooling any sort of cooling doesn't have to be doesn't have to be with like the gases and the

evaporation yeah doesn't have to make me like a nice chilled soda pop. It can be just a little, a little cool. It's just blow through the tube and air comes out a little colder on the other side as

the nickel titanium untwists. Round number two. Our next model is roughly the size of a credit card and it can be plugged into your phone.

The device is filled with water and 10 chambers, each of which hold lithium bromide that reacts to the heat from the phone. Is this a fridge or not a fridge? Oh, why you gotta cool down your phone? There's no reason. It's a battery, I bet.

Sometimes your phone gets hot. Yeah, but you just put it down for a while and walk away and come back later and it's okay i'm gonna say it is a fridge and yes it just is a fridge i don't have to guess what it is because it's a fridge i'll give you a bonus point if you tell me how you think this fridge works oh shoot it's a fridge i think it works by oh i don't know anything about lithium bromide it's like a cow's stomach but instead of each grass being more chewed, each little chamber gets a little bit more cold. And then. That's great.

It's not a fridge. It's not. Oh, but maybe you invented a new fridge. Yeah. Yeah. No, it's inspired by a phone charger that uses saltwater and oxygen to create electricity, which you can read about on Live Science by going to pocket-sized smartphone charger uses water. Our last round, Google that. Our last model consists of two steel spheres, each with a diameter of about 10 inches.

The two spheres are connected by a pipe that's shaped like an upside-down U, and that allows ammonia and water to travel along the contraption. You'll need to bring in some additional items to operate this model, though, including kerosene and a cold bath. Is this a fridge or not a fridge? This is all nonsense. I know, right? Yeah. Anytime you mess with temperature, it's a load of nonsense. Yeah. And probably if you got like microscopic enough, it's cooling down something enough to count as a fridge. Who

knows? It's a fridge. This is a fridge. The ice bath is throwing me off or the cold water. Like you have to, that seems like cheating. Right? It's already cold. It creates even more cold than the cold bath. Yeah. I'm going to Yes, it's a fridge and it's like whiskey stones.

You just make the ball really cold and then you put it in a space and then it works like a reusable ice block but it's a fridge because

you make it cold. Well it was called the icy ball and No it's not. In the it was called the Icy Ball. No, it's not. In the 1930s. No, it's not called the Icy Ball. So the beauty of this fridge is that it doesn't require electricity,

which made it very appealing for the people living in rural areas who couldn't access electricity or ice easily. Icy Ball is a vapor absorption refrigerator using a refrigerant that evaporates and in doing so cools down the surrounding temperature, similar to the effect of sweat on skin. Like Sarah was talking about. One ball is considered a hot ball. The other ball is a cold ball.

The icy ball can only... Is that how that works? Yes, sir. I'm not familiar. The icy ball can only really work in like a batch mode. You have to effectively like charge up the icy ball to get it working for the day. And that starts by heating up the hot ball over a kerosene flame and then submerging the cold ball in cold water. And that allows ammonia gas in the hot bottle to condense back into the cold ball in cold water, and that allows ammonia gas in the hot bottle to condense back into the

cold ball. And then you remove the hot ball from the flame and you put it in the cold water, which means the ammonia and the cold ball can begin to evaporate. And that evaporation causes the cold ball to cool down so that it can be kept in an insulated cold chest with all the things you want to keep cold. In summer, a charged up icy ball could keep your food cold for around a day. I love icy ball. Yeah, it looks way less dumb than I was picturing. It looks cool. Well, if we ever end up in a post-apocalyptic world and people listen to this podcast after the apocalypse, I don't know if you're doing it, maybe it's on vinyl, then you can, now you know how to make an icy ball. Go make the icy ball. I feel like the ammonia is the hard part.

We can make ammonia. You just got chickens. They're making it all the time. Evaporate it off, condense it into your icy ball. Boom. We should pivot to a post-apocalyptic survival guide. Yeah. A comedy post-apocalyptic survival guide.

The dumbest. Icy balls and other tips for the end of the world. How would you build it all from scratch? Ammonia from chickens, probably. All right, good job, everybody. But Sam came out on top. Next up, we're going to take a short break. Then it'll be time for the Fact Talk.

Our panelists have all brought science facts to present in an attempt to blow my mind. And after they have presented their facts, I will judge them and award them points. The decider goes first, though. I have a trivia question. Companies resort to all kinds of methods to demonstrate just how good their refrigerators are. For example, Frigidaire once put their refrigerator to the ultimate test. They had an elephant stand on it. In what year did Frigidaire perform that stunt? Who would care if their fridge is strong enough for an elephant to stand on it. In what year did Frigidaire perform that stunt?

Who would care if their fridge is strong enough for an elephant to stand on it? What does that matter? Elephants were new, man. They just came out. It's like a trade show carnival kind of thing. Step right up. Yeah, just like probably around the same time

Thomas Edison was electrocuting them. We had elephants to spare. I'd say the 20, no, the 00s, the 1900s. I'm going to say the 1920s. Sari was closer. It was 1939. Oh, wow. That's pretty.

That's so late to do something so silly. Well, I will say that edison electrocuted the elephant in 1903 so sam you were if you were if you were on my wavelength that was the right guess that's what i was basing it on you really colored my answer there and i mean sarah gets to go first so one of the ways that physicists get temperatures really really cold is with a technology called dilution refrigeration this is like down to two millikelvins so two thousandths of a kelvin which is barely above absolute zero and colder than the boomerang nebula which is at around one whole kelvin which is the coldest spot of outer space

that i could find uh okay cool good fact check i never know when I say things about space. You know, it's a big universe. I'm sure there's a colder spot, but... So far. But besides just trying to push boundaries, these extreme dilution refrigerators help with particle accelerator, superconductor, and quantum computing experiments for all kinds of things that require basically no heat or wiggles to work. My general understanding of how dilution refrigerators work is that there is a chamber with two types of really cold liquid helium atoms inside. So there's helium-4, which is the more common isotope we see in balloons and whatnot, with two protons and two neutrons. And then there's helium-3, which is much more rare and

has two protons but just one neutron. I'm using a little hand-waving here because I am not a super cold physicist. The gist is that a mixture of helium-4 and helium-3 atoms that gets cooled down will start to separate into two different phases, like how oil and water separate. But each of the phases have different amounts of helium-3 inside. And that shift of helium-3 atoms as the phases separate is the dilution that takes energy and therefore sucks up heat and makes everything around it colder, sort of like that evaporative cooling that we've been talking about. It's just all very extreme, so you can get things down super cold. And in addition to needing environments

that are super cold to tinker on quantum computing and whatnot, you also need materials that are resistant to changes in heat to keep potential wiggles out of these systems. So some scientists are developing materials that are really resistant to temperature changes and using dilution refrigerators to test them. So in other words, these materials are thermal insulators, but many are expensive and or proprietary. So all that set up to say, in a paper published in December 2019, a group of physicists at Lancaster University in the UK decided to play with their very fancy dilution refrigerator and cool down a much cheaper and more easily available material,

four Lego bricks and a minifigure. My gut from reading their press release says that part of this is like, ha ha, we have an extremely cold fridge in our nerds, so let's see what happens when we put Legos inside. But that's not to say that they didn't do real science. They tested cooling down a vertical stack of four 2x4 Lego bricks to around 4.5 millikelvins for nine days to make sure it was super, super cold all the way throughout. And then they applied increasing but still tiny amounts of heat to a plate on the top Lego,

raising it up to around one Kelvin. And we're constantly measuring a plate on the bottom Lego for any changes, and there wasn't any significant change in the plate temperature, which is in their words, quote, an order of magnitude lower thermal conductance than the best bulk thermal insulator, which is one of the fancy glass ceramic materials that's super expensive and proprietary. So Lego bricks aren't made of anything super special. It's a widely available plastic called acrylonitrile butadiene styrene or ABS. So they were really- Just that. Just-

Did you practice that or are you just that way where you can say things like that? I'm just that way. I've trained my whole life. It's the education luminary that I can just say chemicals. Yeah. But they were pleasantly surprised at the results. This is the kind of plastic that's in 3D printers nowadays or fairly common, like a thermoform plastic. And they also think that the excellent thermal insulation isn't just that plastic. It might be helped by all the air pockets in Lego bricks that are separating them in the stack.

But this feels like very quintessential, like nerds in a lab to me. Just trying something out because you can, because you have the tools there. And also maybe quantum computers will be made out of Legos someday. Who knows? Not me. I'm not a physicist. I mean, why not make the world's coldest Legos? That's very cold.

Somebody's got to do it. 1.6 millidegrees above absolute zero. I wouldn't want to go there. No. But I'm not a Lego man. He's braver than us all he's also the least scary animal i could imagine yeah i wake up with the lego in your bed might give you a little poke but that's okay hey how do you get here little guy

and then set him up on my little toy shelf and that's it no no questions asked at all is this like a thing that they could use i think what i was getting i i think the idea is that we might not need necessarily to spend as much money on really expensive materials, either plastics or ceramic glasses or other things to make these semiconductors or quantum computers. We can use plain old ABS with some air pockets inside and get a similar result. And like maybe key components need to be made

of the more expensive stuff, but like we can look cheaper. Yeah, the future is even closer than we think because we don't need all that fancy stuff we can get coal to do quantum computing just build it out of legos legos are pretty expensive though so sam what do you got refrigerators are great but like my poem, they're also sort of terrible. They're filled with toxic and global warming exacerbating chemicals, but they're also big and bulky and complicated because making hot into cold seems like it's a big ordeal because even after reading several,

explain like I'm five Reddit posts about it, I did not understand it. So that means it must be very complicated. And complicated means filled with stuff that can break and then you got to get a new fridge and then your old fridge gets thrown away and maybe all those chemicals leak out fridges have their issues basically so in an effort to make refrigeration more environmentally friendly lighter and more efficient with a sub goal of making it easier for dummies like me to understand how refrigeration works. In 2004, Penn State worked with Ben & Jerry's Ice Cream and the U.S. Navy to develop a prototype refrigerator that relied on sound waves rather than electric pumps

to pump the refrigerant coolants around a refrigerator. So getting into things I don't understand incredibly well, even more so, sound waves are pressure waves and pressure waves affect the temperature of the air high pressure raises temperatures and low pressure decreases temperatures and that is why sometimes when you spray an aerosol can for a while it can feel cold because the pressure in the can is changing from high to low and getting colder is that because there's less balls inside of wiggling or what's going on there i think it's because it's it is moving from a liquid like a compressed liquid into a gas yeah i think it's like similar to what we've been talking about of like the molecule the molecules

or atoms spacing out if anyone who has taken a chemistry class it's like pv equals nrt the ideal gas law like those things are interconnected and are the foundation of a lot of these refrigeration machines, even the liquid refrigerants in the tubes as well as the stuff. Well, anyway. Yeah. Thermo. We're not going to hit the same with the gas law. Yeah, yeah.

Sorry. What was that? So thermoacoustic. I'm sure they got a lot out of it, too. Sorry. Oh, no. I'm sure they got a lot out of it too sorry thermoacoustic chillers which is a fancy science way to say fridge that uses sound waves take advantage of the high and low pressure of sound waves to control

temperature so there's a chamber filled with helium gas and their layers of copper plates arranged very specifically to coincide with the high and low pressure areas of a 173 decibel sound wave produced in the chamber. So if I'm understanding what I read correctly, the copper is positioned so that it ends up being cooled by the low pressure helium and the high pressure helium ends up getting pushed out into a heat exchanger somehow, I think by sound waves. So just like hot refrigerant is in a regular fridge pumped out. And so you have a cooling system that cuts out harmful refrigerants and cuts way down on the amount of moving parts needed to operate to basically just a speaker. So that sounds great,

but you may have noticed that 2004 was 20 years ago and that we aren't all using sound-based refrigeration. And even before the 2004 experiment, people had been working on this since like the early 80s, and a thermoacoustic fridge even went up in a space shuttle in 1992. So scientists really want this to be a thing. I'm not actually sure why it's not a thing. An article I read said it doesn't scale well to industrial applications, so that probably has something to do with it. But just because we don't have them in our houses doesn't mean that thermoacoustic refrigeration isn't being used in practical ways the james webb space telescope uses a thermo acoustic cooler to keep its mid-infrared imager at a cool seven kelvin or negative 447 degrees fahrenheit that's okay i also don't understand and i can tell that you don't so i didn't really

try that hard to understand because it was too hard the the pressure waves move through a thing and somehow it's hitting they have to arrange it just right that's what they said so that it's hitting the copper when it's cold and not when it's warm so it's very they have to put them in a very specific place, and then the copper cools down and the hot leaves somehow. I don't understand, but I do get that something's happening and that it's working. Yeah. That seems very cool. And you're just transmitting the energy through pressure waves of sound.

Yes. You're just pumping it out of a speaker into helium and making waves. But it is a shame that it has to be a very specific noise, though, right? So you can't just choose, paint it black by the stones. I like the idea that the web is up there listening to tub thumping and it's making noise. Well, if you arranged the copper plates right, then it could be tub thumping, I think. OK. Yeah, I do want the telescope to get hype.

And I want it when it gets hit by a micrometeorite. I want it to think, you know, I get back up again. That's right. That's right. I think that's true. That's right. That's right. I think that's true. I like the idea also that any rich person who wanted to or like audio engineer who was like, I want to figure out a thermoacoustic fridge for myself could theoretically make one for their favorite song. But you'd have to really commit because you'd have to rebuild your whole fridge once you get tired of that song playing you also can't hear it because this was where i wasn't entirely sure because people you can be around it and it doesn't make

your ears explode but 174 decibels is like way louder than you're ever supposed to be around but they said if it depressurizes then you can't hear it anymore because it's just can only exist in that chamber somehow okay so if it, it wouldn't make your head explode. It doesn't matter to me if I can hear it or not. It's like the story that the Mars River sings Happy Birthday to itself. I don't need to hear it. You just want something you can tell all your friends. I just want to be sad about a lonely rover.

Not even dust mites having sex on it to keep it company yeah it's too bad they could at least send two dust mites just two dust mites they're not gonna survive mars so i have to choose between dilution refrigeration resulting in ultra cold legos that are just fine apparently or cooling things down with sound in space, in a space telescope. It's going to be Sam. He's already winning. He ran away with it.

I love that. Even though none of us actually understand how it works. It does. Yeah, there's a human who totally gets it. Yeah. Because look, quantum computers, they're going to totally revolutionize the world and everything. It's coming.

It's going to be a totally, we're not prepared for what that's going to be like and very cold Lego might be involved. But I just conceptually, I want to cool things down with tub thumping. And now it's time to ask the science couch. We've got a listener question for our virtual couch

of finely honed scientific minds. Corey on Discord asks, sometimes when something has been in the freezer for a long time, it gets a sort of freezer taste to it. What exactly am I tasting?

You know, this seems like the kind of thing I would know, but I don't have any idea molecules it tastes like old water so i must water must have something to do with it right like stagnant water sarah's just letting us hang out here yeah what's up i can jump in at any time okay um yeah i mean it's always molecules taste is always molecules if it's sort of musty I can jump in at any time. Okay. Yeah. I mean, it's always molecules.

Taste is always molecules. If it's sort of musty, any sort of like enclosed container can be some combination of like dust, or VOCs, which are just like a fancy way to say organic molecules that become gas really easily and are often aromatic in some way that are pretty potent and it won't take much to have it absorb into any, anything around your fridge or like blow out into your nose and mouth. So it might be that, that you're smelling. That's just kind of like your house smells musty. Your fridge smells musty.

It's just like those things. But it could also be because of freezer burn because there's that like plasticky watery smell. And so all freezer burn is it's a combination of dehydration and reactions with oxygen molecules so i could have guessed i could have done it i could have done it wasn't brave enough i could have just said it's probably oxygen reacting with things like everything on earth i was surprised like me like i am oxygen reacting with things. You usually just take stops. And I was surprised that this is the one, the chemistry one.

Yeah, you're too scared. Where you were like, I can't. A freezer. We really intimidated everyone on this episode with this idea of thermoacoustic refrigeration. And quantum computing and physics. quantum computing and physics. But basically foods, foods are many, many chemicals, many substances together as a temperature.

And a lot of those substances within food, meats, vegetables, whatnot is water. And so when you freeze foods, when you stick room temperature foods into the freezer and you don't sort of do like a flash freezing process. There is a, there over time as the food freezes, the water molecules in the food freezes. And if it does that slowly instead of quickly, the ice crystals that form as the water molecules come together are fairly big and chunky. After a long time, it becomes the kind of ice crystals that you see on top of ice cream that's been in your fridge for years and years and years, then that's after like multiple freeze thaw cycles. But even just

putting warm food, like a room temperature piece of meat, that's not super well sealed into your freezer. Ice crystals are going to form and that's going to like rupture some of those cell structures and that those ice crystals are going to sublimate in the freezer, especially if it's an automatically defrosting freezer, which is meant to keep water out of there, dehumidify, and things like that. And so as those cell structures rupture, you're losing water, so your food is getting dehydrated, and that changes the texture, which also changes taste because texture and taste are all intertwined in our system. And then that also opens up those cells for oxygen that is floating around in your freezer because oxygen is everywhere and lets you create a vacuum to float in and start reacting

with the molecules in there. And oxygen is reacting with everything all the time. It's why like rust happens. It's why people say like, wine breathe for a bit like you want to have a little bit of oxidation reactions happening in there with food it can be good or bad like oxidation can help with the myard reactions i think those are oxygen related reactions that give you like a crusty on pies or like on a grilled steak um but it can also cause like rancid smells and tastes. Oxidation is related to like the rancidity of certain cheeses or food spoiling or meats going bad or things like that as well. So that can just like alter the taste and or those open cells. Like if you have dust or mold or bacteria, even at very small amounts and not pathogenic stuff, like all those other gassy, volatile organic compounds that are floating around in there are just going to like seep into your food as well.

So it'll take on the odors of the freezer around it. The only way to really avoid this is like those those really sturdy ziploc bags or whatever like plastic bags or vacuum sealed stuff freezer bags yeah um where you keep the oxygen out as much as possible or you keep everything inside like keep the water in keep the oxygen out so that you prevent that dehydration, that oxidation reaction. What's the oldest thing in your freezer? Ooh, good question. Let's save that one for next time. Okay, next time we'll talk about it. Make a note of it.

Jess, make a note. I have an answer. It's chilling. Oh, no. Oh, literally. If you want to ask the SciShow Cats your question, you can follow us on Twitter and threads at SciShowTangents, you can follow us on Twitter and threads at SciShowTangents, where we will send out

topics for upcoming episodes every week. You can join us on SciShowTangents Patreon and ask us on our Discord as well. Thank you to at UngovernableG and at MelatoGelato on Twitter and everybody else who asked us your questions for this episode. If you like this show and you want to help us out, it's very

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I've been Sari Reilly. And I've been Sam Schultz. SciShow Tangents is created by all of us and produced by Jess Stempert. Our associate producer is Eve Schmidt. Our editor is Seth Glicksman. Our story editor is Alex Billow. Our social media organizer is Julia Buzz-Bazio. Our editorial assistant is Jaboki

Trocarvarti. Our sound design is by Joseph P. Lamedish. Our executive producers are Nicole Sweeney and me, Hank Green. And of course, we couldn't make any of this without our patrons on Patreon. Thank you. And remember, the mind is not a vessel to be filled, but a fire to be lighted. But one more thing. In New Zealand, the National Institute of Water and Atmospheric Research, or NIWA, relies on volunteers to help them collect leopard seal scat from beaches. NEWA relies on volunteers to help them collect leopard seal scat from beaches. They have a whole guide online with tips like using an empty ice cream tub and refrigerating the sample away from food, children, or animals.

Researchers often freeze this scat until they have time to sift through all the stuff inside to learn about the seal's digestion and health. And in a press release from February 2019, NEWA scientists reported something weirder than usual in some frozen scat, a still functioning USB stick with pictures of sea lions, not leopard seals on it. Not super useful for science, but a silly media moment to try and recruit more people collecting volunteers. Oh no. Did they eat a whole guy? He's a sturdy.

Yeah. Yeah.