SciShow Tangents - Rubber

Episode Date: January 24, 2023

You can bounce it, you can stretch it, heck... some people even chew it! That's right, it's rubber! And at long last, the Tangents team is finally talking about it! You all really wanted an episode about rubber, right? Well, we made it anyway, so you have to listen. 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!And go to https://store.dftba.com/collections/scishow-tangents to buy your very own, genuine SciShow Tangents sticker!A big thank you to Patreon subscribers Garth Riley and Tom Mosner for helping to make the show possible!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[Definition]Mesoamerican rubber recipehttps://news.mit.edu/2010/mayaball-0524[Trivia Question]Koosh ball filamentshttps://www.mentalfloss.com/article/73583/12-kooky-facts-about-koosh-balls[Fact Off]Mimicking birdsong with a rubber tubehttps://softmath.seas.harvard.edu/publication/controllable-biomimetic-birdsong/https://seas.harvard.edu/news/2011/01/simple-rubber-devices-mimic-complex-bird-songshttps://www.bbc.com/news/science-environment-12093906Mayan dental care & harvesting chicle as gumhttps://www.scielo.org.mx/scielo.php?script=sci_arttext&pid=S1870-249X2018000100007https://scholar.smu.edu/cgi/viewcontent.cgi?article=1020&context=fieldandlabhttps://www.sciencedirect.com/science/article/abs/pii/S0008621500827755https://bda.org/museum/collections/teeth-and-dentures/mayan-toothhttps://www.sciencedirect.com/science/article/abs/pii/S2352409X22000980#b0200

Hello and welcome to SciShow Tangents, the lightly competitive science knowledge showcase. I'm your host, Hank Green, and joining me this week as always is science expert sari riley hello and our resident everyman sam schultz hello i'm rubber and your glue it bounced off of me and it sticks on to you what's the worst thing anybody's ever said to you oh my god let's dig into let's get really dark a stranger a stranger it can't have context of somebody who like should be being nice to you has to be a stranger i recently um was on an airplane and i uh the woman this is gonna be too much insight into my psychology because i shouldn't have done this but the woman put her seat back before the plane took off. But after the flight attendant sat down, which I see as a no-no because this is now my space.

If the plane crashes into something, it's my nose that breaks in the back of your chair that you've put closer to my face. Is that why you're not supposed to put them down? I don't know. I assume there's a reason. You know, I assume there's a safety related reason. It's either bad for me or it's bad for her. I feel like it's worse for me to have less space in front of me.

Anyway, so I tap her on the shoulder and I say, hey, can you wait until the plane's in the air before you put your seat back? And she said to me, never touch me. And I was really scared by that. You tapped her on the shoulder? Tapped her on the shoulder. I did tap her on the shoulder, yes. Because I tried to, it was like, excuse me, but she couldn't hear me because she had her earbuds on. And you were a full-grown adult man.

This was a whole five days ago. Oh, no. You're still reeling from it. Yeah. Echoes in your head every night. Never. Judge me. Exactly.

Yes, correct. You don't have to tell me yours. I don't know if it deeply Judge me. Exactly. Yes, correct. You don't have to tell me yours. I don't know if it deeply affected me initially, but I think because I remember it, it did more than I say that it did, which is some random kid in my high school. We never talked, didn't really have a group project together or something. In front of the whole class, we were doing popcorn reading or something like that. Said, Sari, I think you'll be a serial killer someday. And I still remember that moment of like, what? Were they right?

No, I haven't murdered a single person yet so there's still time for their prediction to be accurate that's true it's true you can't really say you got a lot of time all over young yeah yeah sometimes people are really down on people and i'm like gosh but like i've known so many people and i've killed none of them so i have to be okay i have to be pretty all right do you have anything sam and i uh completely absolved if you don't want to say. Mine is kind of, this is not something particularly mean even, but something that somebody said to me that has stuck with me. When I was at food farm once checking out, I had my own bags and the guy checking me out, I guess I was taking too long handing him the bags. And he said, are you going to give me those bags are you gonna just stare at me and that i wasn't doing either i was just like

taking a perfectly normal amount of time and i wasn't looking at him i don't think but i've never been that guy still works there and i don't check out with him because i hate him that's that's an interesting the the idea that you were just sort of holding your bag and staring at him in the eyes definitely and i don and staring at him in the eyes. Definitely. And I don't look at anybody in the eyes. So I wasn't looking at him in the eyes. That's for sure. And we all survived those encounters and haven't kept them hidden in a space in our brain that constantly seeps out poison. We've dealt with them in entirely healthy ways.

Every week here on SciShow Tangents we try to get together 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 and for Hank Bucks, which I will be awarding as we play, and at the end of the episode, one of them will be crowned the winner. Now as always, we're going to introduce

this week's topic with a traditional science poem. This week, it's from Sam. From a humble tree, a unique sap does flow, which has led us today to some things you might know. Be it hard as a rock or quite jiggly like blubber, we owe quite a bit to this thing we call rubber. Why without rubber bands, how would newspapers stay curled up nice and tight as they're delivered each day? Or how would stars of all sports, from soccer to football, be able to score all those points they make at all?

Without balls of all sizes, from round to oblique, made of rubber, sweet rubber, from which no air can leak. What of our cars, bikes, and wheelbarrows, too? Without tires, they couldn't even bring us to the zoo. And toys made of rubber, toys for children and dogs, toys shaped like ducks, smurfs, and dragons, toys shaped like frogs. And of one more and dogs. Toys shaped like ducks, smurfs, and dragons. Toys shaped like frogs. And of one more example, I'd just love to think, how about erasers? So useful and pink.

They sit on our pencils just ready to help our mistakes go away. And with that, I say, well, I'm sure there's many more things that old rubber can do, but I can't think of any more. So here's my challenge. Can you? but I can't think of anymore. So here's my challenge. Can you? Oh, I maybe can. If only I knew what rubber was, which honestly, I know that there's like a thing

that is definitely rubber that comes from rubber trees. And then there's like things that are like rubber that comes from rubber trees and do similar thing. But I'm not even sure if that even counts as rubber,

which is why the part of the show that we're entering into now will will attempt to answer this question for us the topic of the day is rubber sari what is rubber i'm going to switch it up a little bit and start with the etymology because i think that really helps us get at the root of what rubber is because rubber is such a stupid word for rubber we've chosen the worst possible word it's a great word it's a stupid word for rubber. We've chosen the worst possible word. It's a great word. It's a fun word. It's a fun word. It feels good in the mouth,

but there were so many other opportunities to name this thing. In fact, it had many other names. And yet we went with what an Englishman said in 1752. He was like,

this thing rubs. And that's it. And he was like, ah, when you make a mark with a pencil or something, you rub this substance on it and it's the rubber. Which is only really a problem

because we rub so many things with so many things. And at that point, we had rubbed a lot of stuff with a lot of stuff with the last stuff already. Yeah, it's not like it was the first rubber. No. We had brushes, scrubbers.

In the word scrubber is a subset that is rubber. So we've got a whole can of worms there that this man has created for us. I guess the idea was a little... So this is like a pencil eraser, which they call rubbers in some places, but not where I live. Call something else rubbers where we live, huh? That's correct.

That is correct. And those weren't rubber the whole time either. They were made of animal skin. As far as like, unless rubber's just anything that's... Elastic. Yeah. So that's... Elastic. Yeah. So that's where we get into. So rubber, as it was originally identified, the rubber that coined the word rubber was called cow chuck in English or cow shoe in French.

And that is because a French explorer in 1735 brought a sample of rubber from Peru to France and the native Peruvians called it something that sounded like cow shoe. And so he was like, oh, yes, I will. I will take that word. So that is another word for natural rubber. And it was what it was called by scientists and the general public, anyone who had the chance to interact with rubber for a while. And specifically, that substance was obtained from the latex, which is that substance that Sam was talking about in his poem, that came from the rubber plant, Hevea brazilensis. And there are a couple other trees in Mesoamerica that produced latex that would polymerize in such

a way that it would turn into rubber that was the main one and it now has the name rubber tree because of that but there was also um castilla elastica which are panama rubber trees basically a lot of different plants contain this milky white sap called latex. It's in poinsettias. It's in dandelions. It's in goldenrods. It's in a lot of flowering plants. Maybe not a lot. It's in some flowering plants as a defense mechanism so that when herbivores, particularly insects, munch on the stems and leaves, this gooey white substance comes out to both clot the wound and make it taste unappealing to the herbivores. So they'll stop eating the plant. It's a defense mechanism because it forms polymers.

Specifically, it forms polyisoprenes. Isoprene is the kind of molecule that all these latexes that are good for rubber have in common. And it's what makes it sticky and bouncy and goopy. So in Mesoamerica, natural rubbers were created from the latex harvested from these trees and then generally mixed with the juice of a moonflower or a morning glory vine to create rubber. And synthetic rubber just refers to anything that is an elastomer in chemistry, where it doesn't necessarily need to be made out of polyisoprene. It has other additives in it, but anything that is stretchy and bouncy bouncy and rubber like is considered a

synthetic rubber for like soft robotics or for other situations but it doesn't have that precise chemical formula and natural tree or plant or flower origin but they still do harvest natural rubber around the world. Yes. Do you have any idea if it's better for stuff than the stuff that we make? I think a lot of people are trying to find more economically and environmentally sustainable ways. Because right now, people are planting a lot of trees. And the way that you harvest rubber latex from the trees is you slice into them.

And that runs out like the tree is bleeding and you collect it and then some spills onto the ground and some like collects in your collection vessel and there are all these off products in addition to the pure latex itself there's a lot of research from what i can find and i'm not sure if we were talking about it later in this episode of like growing dandelions and mass producing them. So I'm like a weed that grows easily and is really plentiful and that we can just like grow quickly, mow down, harvest the latex, um,

and make natural rubber in a more sustainable way. It's silicone rubber. It's a synthetic rubber. So it is, it has organic molecules in it, which are molecules with carbon hydrogen. And then there is also silicone, um, atoms in there. And that molecules with carbon, hydrogen, and then there is also silicon atoms in there. And that's what gives it the heat resistance, the cold resistance, the flexibility.

It's wild that you knew that. Did you know that yesterday or did you just find out? She's something of a rubber expert, so. Yeah, science expert, Sarah Riley. I studied rubber. That's it. So, so rubber. It sounds a little bit like it's exactly what you think it is.

Yeah, it's really straightforward. All right. I feel as if I am informed and understand our topic, which means that it's time for the quiz portion of our show. We're going to be playing a little game I like to call secret ingredient. So rubber is an amazing ingredient. It's used to make many things. We just talked about that.

But as great as rubber is, it's really just one ingredient among others needed to make those many varied products. You can't just make a tire out of rubber. You got to put other stuff in. So today we're going to be playing secret ingredient. I'm going to describe some kind of product made out of rubber, but I'll be leaving out one key ingredient. It's up to you to guess what that ingredient is. So to question number one, in the 19th century, the discovery of rubber vulcanization as a tool to harden rubber had enormous impact on a number of industries, and that included the condom industry. The first rubber condom was made in the 1850s with strips of raw rubber wrapped around molds. But these condoms were thick and they had a seam.

Oh, no. In 1912, a man named Julius Fromm came up with a better technique to make thinner condoms, which involved dipping a glass mold into a liquid rubber solution. But there was another ingredient involved. Was it animal intestines, gasoline, or cotton fibers? Gosh, I feel like the animal intestine one is a trick because that's some, weren't like old condoms made out of some part of a sheep or something like that.

Yeah, that's definitely the case. But hey, who knows? Maybe they kept that state involved. The tradition alive. Yes. They kept the tradition alive. Yeah. I'm going to say gasoline because that's wild. You don't want to be rubbing that around down there. But I can do it. I'm going to guess

gasoline too just because ethanol, you like spray it on a lab bench to clean it up and it evaporates really fast. And so I imagine that's what makes it up and it evaporates really fast and so i imagine that's what makes it liquidy and so you dip and then the gasoline goes into the air so smart well you said the same answer regardless of how smart or knowledgeable anybody was and it was right congratulations so before rubber condoms of course humans did use a lot of different materials for condoms you had animal intestines you had tortoise

shells not really sure how that worked linen which couldn't have been that couldn't have been that useful uh or efficacious but with the ability to vulcanize rubber people realized there was another way these early rubber condoms were expensive but they could also be reused why not so from's technique to make a better better rubber condom was called cement dipping and it required liquid rubber to make liquid rubber people needed solvents like benzene or gasoline this of course made condom making a bit of a fire hazard fortunately people later learned how to make latex, which uses water to suspend the stuff. And that led to both thinner condoms and less

flammable manufacturing conditions. Was Sari exactly right about the reason that they use gasoline? No, but in talking about solvents, you had something there where they needed to dissolve the latex. I talk out of my butt a lot. That's my key to success.

Yeah, she's doing it right now. It's wild. For those of you not watching on YouTube. Doing the Ace Ventura thing where she's like, yeah. Number two. In 2010, researchers reported that they had created a, quote, universal gripper, which is a gripping mechanism that wasn't designed to grab onto one particular object, but rather could hold onto just about anything. It's like my hand. Yeah, but like not made out of people.

So obviously the potential application here is a robot that can grab onto things, just any things. But to make their universal gripper, researchers attached a latex party balloon to a robot arm and connected a vacuum to the balloon but there was one other ingredient in the mix was it beeswax clay or ground coffee are these like 10 year old scientists what are we talking about here no they're doing the best they can with what they've got. I'm going to guess beeswax because that's what the reusable saran wrap is made out of. And so it's sticky, maybe. I don't know. Ground coffee, I guess you have to keep. Well, no, I'm going with ground coffee.

I think it's moldable. Don't have to keep it wet or dry or anything. It's just there. The answer is ground coffee. Sam. Sam. So to make their universal gripper, researchers filled a party answer is ground coffee. Sam. Sam. So to make their universal gripper, researchers filled a party balloon with ground coffee and then they attached a robotic arm

to it. The balloon would press down and deform around the object being grabbed, at which point the vacuum would suck the air out of the balloon to solidify its hold on the object. To release the grip, you just release the vacuum. And it works because the ground coffee acts as like a particulate material, which means that it can go from acting like a fluid to acting like a solid

when the particles can no longer slide past each other. Another way that you experience this with ground coffee is if you've got the vacuum-packed coffee, it feels like a brick, and you unseal the vacuum, and then it gets soft. So like that. Theoretically, you could also do it with rice rice or couscous deboki wrote in the document i love that uh any food item you want that's kind of granular and all right your last question mosquitoes love the smell of rubber they will even lay their eggs inside of old tires. Why not? Sometimes it often collects water in there.

And this is a fact that scientists have tried to turn against them. A group of scientists were traveling to Guatemala for research when they realized that mosquito traps they'd used to destroy mosquito eggs weren't available. But they had an old tire nearby, so they cut it up and turned it into a trap that ultimately destroyed seven times more mosquitoes compared to traditional traps. Their impromptu trap consisted of an old tire piece, water, and paper floating on the water that mosquitoes can land on.

But there was one more ingredient that made their trap so dangerous. Was it human blood, chicken egg yolks, or mosquito larva? What? It's one of those three. I hate that. It can't be human blood. It's around. It's easy to get.

I suppose. So in my mind, I was thinking soap. Because when I make a little fruit fly trap, I put a little soap in the vinegar because then they try to land on the water. But then there's no surface tension or less surface tension. So they just start drowning. That's what I would do. But I'm not the scientist. I'm not as smart to offer a blood sacrifice for the mosquitoes.

Maybe the larvae make it be like, oh, that's a nice place to lay our eggs. They don't need to discover it. They just can smell that there's already larva there. So it works faster or something. I don't know. That's what I'm going to go with. I think it just lures them with baby smell. I'm going to say the egg yolk because it makes no sense to me.

Sam, coming in with all of them. You got them all right, didn't you? I sure did. So the way that this trap works is mosquitoes would land on the strips of paper to lay their eggs. But instead of just getting rid of all the water, the user of the trap would use a cloth to filter out the larva, which would get rid of the mosquito larvae. but it would leave the water infused with all their chemical signals, which, as Sam said, would attract other mosquitoes to the trap, so they would lay their eggs to the doom of their own eggs.

Later, they would be filtered out over and over again. And they like the smell of babies. They like that baby smell. Who doesn't? We're all learning things. We're all learning things. Well, Sam's a genius. Sam knew all these things already.

We're all learning things except for Sari, who's done. She's full. She can't put anything else in. It's a genius. Sam knew all these things already. I don't know anything else, actually. We're all learning things except for Sari, who's done. She's full. She can't put anything else in. It's all over. And she's never going to get another fact right ever again on SciShow Tangents. Cool. No, I'm done. Head empty. To find out what actually will happen during the second part of this episode,

you're going to have to wait for a little quick break, and then it will be time for the Fact Talk. Hello, welcome back, everybody. It's time for the Fact Talk. Our panelists have brought science facts to present to me in an attempt to blow my mind. After they have presented their facts, I will judge them and I will award Hank Bucks any way I see fit. But to decide who goes first, I have a trivia question. In the 1980s, an engineer named Scott Stillinger found that he was having trouble playing catch with his young kids.

The balls they were using bounced too much, but if he used bean bags, they were too heavy, so he created a better ball. It had to be soft, it had to be not too bouncy, it had to be easy to grab. Starting off with a box of rubber bands, Stillinger filed for a patent for the Koosh Ball

in 1987. If you don't remember Koosh Balls, then I will just curl up Koosh ball in 1987. If you don't remember Koosh balls, then I will just curl up and blow away in dust. Yeah, we're old skeletons. But how many rubber filaments do you think there are in a standard Koosh ball? What counts as a rubber filament? Because aren't they like one one strand sticks out twice

do you think you're gonna get close enough that's gonna matter i just gotta ask the questions they make me seem smart like oh she's thinking about the kush ball aerodynamics i don't know i don't know how if one of the filaments goes through the middle and out the other side, I'm not sure how it works. 300. 300 Cush filaments. I was going to say like 10,000. Well, say what you want to say, Sam.

I will say 10,000 then. Okay. Well, unfortunately, Sari was closer despite neither of you being very close. It was 2,000. 2,000 Cush filaments in a Koosh ball. I hope that that Scott Stillinger still living large on the hill with his Koosh fortune. It's nice to help his kids play catch. I was scared of playing catch, too, and loved a Koosh ball.

They felt so nice. Some additional facts here. There were more than 200 different names for the kush ball but they went with kush uh there was a comic book called kushkins it was about six kushes named grinby boingo gg stats tk and scopes it was only a few issues so maybe that you read that sam oh no i had kushkinskins if you look them up they were kush balls with little faces on them who did you have?

did you have Grimby? well Scope sounds very familiar because the one I had had little like yeah he was a green and he had blue eye stocks coming out the top

of his head I love this I think we should pivot from a science trivia podcast to a kushkins podcast that looks so sad and rotten now though yeah I think that if you got a current

kushkin that the rubber would have broken down enough that you would not be enthusiastic about touching it sarah you get to decide who goes first oh i'm gonna make sam go first wow that's the first time that's happened in a long time yeah switching it up so lots of animals make vocalizations but when it comes to communicating with sound, birds are basically second to none. Not only do their songs sound nice for the most part, but they can be chock full of different types of information depending on the song being sung. Now, it would be quite a feat for a human to be able to remember tons of different types of songs and sing them pitch perfect over and over. And neuroscientists studying birds have generally posited that it

might be equally tough for a young bird to learn all of these songs from older birds and then make the complicated series of muscle changes required to change the shape of their syrinx, which is the organ that birds use to sing their songs, to hit all the right notes and stuff like that. But in 2017, a group of researchers at Harvard's Weiss Institute for biologically inspired engineering created a device that demonstrated that maybe bird singing isn't really as complicated as we think. Take that, birds. Basically, they stretched out a rubber tube and they blew air through it, and then they used a motor to apply pressure to the outside of the tube as the air was blowing through it. So doing this, they could produce waves in the tube that would rapidly change the pitch of the whistle that the tube was making. The researchers then created what they

called a minimal mathematical model that allowed them to mimic bird songs. And well, here are the results. First, a song of a real bingley's finch. Okay. And the biomimicked version. okay and the biomimicked version so not bad birds aren't hot shit after all i guess uh if all it takes to do that is a minimal mathematical model and a rubber tube so the researchers suggest that instead of relying on incredibly quick muscle changes to sing different notes really fast, birds might be using a simpler on-off muscle kind of situation that creates waves in their really rubbery syringes. And now that we've cracked the secret of bird language, there's really only one next logical step, and that's to get out there and trick some birds. But before I'm done, I did have a couple more bird songs,

so I want to play a really quick game of bird or bot. I'll play you a pair of bird calls, and you tell me which one is the real one. So first, here's the song of a vireo, which is apparently a kind of bird. So which one of those is real? I think the first one was real. I think the second one is real. The first one is real. The second one definitely had a distinct robotic twinge to it, I would say. Okay.

I thought that was like recording equipment or something. I'm not getting anything right for the rest of my life. So, got to stick with it. And then the last one is The Call of the Zebra Finch. Ooh, they both sounded like robots. I think the first one's real. I think the first one's real, too. Sari stays loose, and the second one is the real one.

No! Never guess with me, Hank! What was I thinking? So the researcher said that the zebra finch was their holy grail. If they could get that one perfect, they would have nailed bird calls, because that one's really complicated. But they're still working on getting that one perfect. Sounds pretty good, though.

And all these sounds are created by Harvard researchers R.E.S. Mukherjee, Shreyas Mandre, and L. Mahadevan. So birds are just robots and we don't have to worry about it. Just like they have in sand. You're right. Wow. That is another piece of evidence. Wow, that is another piece of evidence. And there's all this worry about climate change really affecting avian populations and when they can hatch and breed and their cycles.

We don't need it. We can just have rubber tubes in trees to simulate birdsong and make us feel good. Humanities move past the need for birds. All right, Sarah, what do you got? So the history of chewing gum, as we know it today, goes hand in hand with the history of rubber. And that's because chewing gum is just natural polyisoprene or a synthetic elastomer with sugar, flavoring, and some additives to give it that good mouthfeel or a longer lasting chew. And that means we can also trace chewing gum back to Mesoamerica, specifically a few trees in the genus Manilcara that were regularly harvested by native people such as the Maya and Aztecs. The common name is the sapodilla tree. The Nahuatl

word for this latex is spelled T-Z-I-C-T-L-I and the Maya word is spelled S-I-C-T-E, neither of which I could find a pronunciation for but i imagine they sound like chicle because that's still the spanish word for chewing gum and in english we've started to call it chicle which is where the american candy company got the name chiclets from so really just an etymology whirlwind this episode. But anyway, the tree latex on its own was harvested and processed, usually by boiling, to help polymerize the proteins to a point where it was a sticky substance. It may have been burned as an incense or used as an adhesive, among other things. But the other plant chemicals in the mix, like some sugars, made for a very pleasing chew.

And from what archaeological records I could find on short notice, Aztec and Maya people not only chewed chicle rubber for fun, but also as a form of dental care to freshen breath and cleanse their teeth. Sometimes they would mix chicle with bitumen, which is petroleum tar, to add some additional zingy flavor or texture. Oh my gosh. I want to make it clear at this point that what i'm going to say next is from my own brain i don't know if this connection has been drawn before but if you want to research it go for it i don't want to be spreading uh archaeological

lies but another cool thing about mayan culture of this time is that they were really thoughtful about oral health for example they treated cavities by drilling and even added gemstone adornments for unknown purposes, but probably rituals. These tooth gems have been studied chemically, including a recent 2022 paper, and traces of various adhesives have been found from hydroxyapatite-related inorganic compounds to some organic molecules like pine resins and bitumen. And maybe this was just another use for bitumen, which is sticky and waterproof. But we still don't know what the exact chemical key was to keeping these modified teeth healthy from bacteria and inflammation and whatnot. So in my opinion, as a very, very non-expert,

they were chewing gum made of chicle and there was bitumen all in your mouth. Then maybe some of those plant-derived properties in the gum were also keeping their teeth and mouth gems healthy. The institution of chewing gum at all sounds a little like something that in 500 or 1,000 years, people will be like, can you believe that back in 20th century people would want rubber for fun?

It's just like very weird. Like it's not food. It's just a thing to chew on. But it's extra weird that we've been doing it for a long time. Like since we got a chance, we were like, what's that? Put it in your mouth. It's like not food, but it does chew. It tastes a little good. what's that put it in your mouth it's like not food but it does chew and tastes a little good that's that's nice it'd be better with just a bit of petroleum on it but yeah i don't know that bitumen is like my idea of a special fun time well they

hadn't invented sour patch kids yet so yeah and a different window. Strawberry flavoring. I hate gum. I've never enjoyed it, but, but Oren got, got a different gene and loves it. Always. He has his own gum. He's six years old.

He gets, he has like, he like walks around with gum. Cool. That's very funny. That's one of the things he asked for for christmas he was like i want my own gum so i don't have to ask and i was like i guess so cool and i have to choose i have to choose between scientists cracking the secrets of bird language my and dental care and the

harvesting of chiclay as gum but those are both so good well i think that i think that but those are both so good. Well, I think that, I think that. Thus, Sam must come out with the episode after his excellent performance in the first round. I think I burned it at this point,

really. Yeah. Congratulations for your Hank Buck. And now it's time to ask the science couch where we've got a listener question for our virtual couch of finely honed scientific minds. At Muppet Lamp on Twitter asks, why does it do the crumbly thing after a while? And why do modern rubber products do less of the crumbly thing that we saw

the freaking coochlings were doing? I assume that there's depolymerization going on, which is going to happen in the presence of oxygen. And especially in the presence of oxygen and ultraviolet light would be my guess am i how do how did i do sari you're great that's that's it this is just a chemistry question this is like a you can find it on a problem set that someone has to do you've got a poly isoprene uh koosh ball named tk he's got so fucked up this much uv light and yeah so like polymer is like a bunch of different things all hooked together in a big long chain um and those

chains can form and they can also break and they did they tend to form um naturally when they are in their uh when they're in their sort of like ready to polymerize form, where they come out of the plant like that, or we make them like that. But then over time, they are just like any organic molecule. They're really complicated and it's kind of far away from the natural like lowest energy state. And so if you give them chances to get there, they'll find their way eventually.

So I think what this person is talking about, if anything, is just like modern day additives. So in silicone rubber, like that synthetic rubber, what are the additives in it? I don't know. That's like probably proprietary chemical information, but they add things like antioxidants or UV stabilizers or things that will uh absorb the energy from these uh really volatile reactions and keep the polymer structure intact instead but if you leave your rubber anything uh for for like 20 years 30 years at this point, like it'll look like the koosh ball. If you leave a piece of rubber still where it is exposed to light and heat and oxygen, the polymers are going to break down. If you use it, if you use a rubber band regularly,

it will probably not get as brittle and crumbly because you're moving those polymers around. And so any additives that are in there, maybe not, maybe a rubber band isn't the best example, like a tire. If you're driving on a tire, it is less likely to crumble apart than if it's sitting in a garage for a really long time because those molecules are not static. They're not completely locked in place. They're mushing around and any additives that are in there are going to get more like as the tire compresses and expands those molecules

are going to get shifted around and it's going to maintain more of that structure um whereas if you let it sit still then it's just going to crumble from the outside in and the structure is going to be a lot weaker but we but that holds long enough to be useful. But yeah, it's always like you take that stack of VHS tapes out with the rubber band around them and the rubber band's just like, I'm this big forever now. And you take it off like this. Well, if you want to ask the Science Couch your question, we've got answers for you. You can follow us on Twitter at SciShow Tangents, where we'll tweet out topics for upcoming episodes every week. Or you can join us on our SciShow Tangents Patreon and ask us on Discord.

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Thank you for joining us. I've been Hank Green. I've been Sari Reilly. And I've been Sam Schultz. SciShow Tangents was created by all of us and produced by Sam Schultz. Our associate producer is Faith Schmidt. Our editor is Seth Glicksman. Our story editor is Alex Billow. Our social media organizer is Julia Buzz Bizzio. Our editorial assistant is Deboki Chakravarti. Our sound design is by

Joseph Kunamedish. Our executive producers are Caelan Hoffmeister and me, Hank Green. We couldn't make any of this, of course, 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! Rubber bands. A tried and true office supply for bundling pencils together or keeping a poster wrapped up.

But they are also used as a hemorrhoids treatment in a procedure called rubber band ligation. That's for real. So hemorrhoids are lumps of tissue with blood vessels that can emerge inside or around the anus for various butt and bowel related reasons. And using one or more small rubber bands to cut off the blood circulation as diagnosed and done by a gastroenterologist. Please do not do this at home. Has been shown to help reduce or remove certain types of internal hemorrhoids pretty effectively. Yay. You know, do you ever have braces?

Yeah, yeah. You ever get the little rubber bands on them and they're different colors? I'm imagining it's that kind of rubber band. And I'm also picturing that you could go in on Halloween and be like, give me some black and orange ones back there, please. Give me a glow in the dark. Right on, glow in the dark. I want red, white, and blue, please.

Feeling patriotic.