SciShow Tangents - Smell

Episode Date: May 18, 2021

If SciShow Tangents had a smell what would it be? It’s full of knowledge, so maybe a dusty old book? We talk a lot, so maybe all of our nasty breath?  We talk about butts a lot… you know what? Podcasts don’t smell, and maybe that’s for the best. Head to the link below 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! https://www.patreon.com/SciShowTangentsA big thank you to Patreon subscriber Eclectic Bunny 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: @slamschultz Hank: @hankgreenIf you want to learn more about any of our main topics, check out these links:[Fact Off]Rats smelling conceptshttps://www.eurekalert.org/pub_releases/2020-11/uog-tso112520.phphttps://www.sciencedaily.com/releases/2020/11/201125164455.htmhttps://royalsocietypublishing.org/doi/10.1098/rspb.2020.2327https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3000628Big cats and perfumeshttps://www.thecut.com/2020/01/big-cats-love-calvin-kleins-obsession-for-men.htmlhttps://www.nationalgeographic.com/animals/article/100624-big-cats-cologne-vin-videohttps://blogs.scientificamerican.com/thoughtful-animal/youe28099ll-never-guess-how-biologists-lure-jaguars-to-camera-traps/https://www.rsc.org/Merck-Index/monograph/m3604/civetone?q=unauthorizehttps://animaldiversity.org/accounts/Viverricula_indica/[Ask the Science Couch]Smells & memoryhttps://www.livescience.com/why-smells-trigger-memories.htmlhttps://www.discovery.com/science/Why-Smells-Trigger-Such-Vivid-Memorieshttps://pubmed.ncbi.nlm.nih.gov/23147501/[Butt One More Thing]Indole smellhttps://io9.gizmodo.com/why-is-a-compound-that-smells-like-feces-put-in-perfume-1717903411

Hello and welcome to SciShow Tangents, the lightly competitive knowledge showcase. I am your host, Hank Green, and joining me this week, as always, is science expert, Sari Reilly. Hello. And also our resident everyman, Sam Schultz. What's up? I have a question for you two that I would like to have a fight about. Uh-oh. The question is, what is the best flower?

I don't know any flower at all. You don't know any flowers? Look, Sam, have you walked around Missoula, Montana this week? It's amazing out there. I can see them. They don't have their name tags over them or anything like that. I don't know what they are. I don't really like flower smell, to be honest with you. Well, when the irises are up, you can come over to my house

and I will stick your head in a bunch of irises. And you'll change your mind. It's the best smell in the world. But anyway, I don't care what your favorite smelling flower is. That's just one part of a flower. Tell me a good flower. I don't even care if it's your actual favorite. I like bleeding hearts.

They're nice. What's a daisy? That's mine, I guess. Wow. Is that a boring one? No, it's nothing. It can be your favorite, but like, care a little bit about one of the greatest inventions of evolution.

This is like flowers are one of the great joys of my life. I'm just surprised that Sam, a man who takes a lot of joy in a lot of things. We go, Rachel's really into plants right now. And we go to the plant store every weekend or so. And she's like, Oh,

would you like to, you should pick one out too. And it's just, these are all green. They got leaves. This one's purple. This one's like orange, but they're all kind of the same. All right.

Well, you know, Sam, I'm going to let you live your life. Thank you. And I'm going to say that maybe my favorite flower is the arrow leaf balsam root. That's a stupid flower. Wow. Only because it seems to be Catherine's favorite flower, though she hasn't said this to me, but every time we're anywhere where there's a balsam root,

she's like talking about it. She's talking about it for like minutes. And I'm like, I mean, it's one of the flowers. There's others around, but like, she just loves them. Okay, every week here on SciShow Tangents, we get together to try to one-up a maze and delight each other with science facts, and we're going to try to do that to you as well.

So we hope that you are amazed and delighted. We also will try to stay on topic and fail at that. Our panelists are playing for glory. They're also playing for Hank Bucks, which I will award as we play. And at the end of the episode, one of them will be crowned the winner. There will be no actual crowns.

Now, as always, we introduce this week's topic with the traditional science poem. This week, it's from Sari. It's just as well that your favorite smell might be very hard to divine. Transfixed like a spell makes you yell, oh, hell, or relax and feel just fine. Take an oaky smell, a smoky smell, a low-key, kind of choky, cough and croaky smell. A fire at night can be a delight but the cloud of ash might not sit quite right so take a sweet smell real neat smell heat up a treat that you want to eat smell go to townie on a brownie turn your frownie upside downie but it might not win the crownie of

the county fair so take an old smell a not quite mold smell a tome bound with gold that never sold smell flip a page and you gauge the sage wisdom and the age but it might be upstaged by something Wow. Terry wins the episode. That was amazing. That was a Mary Poppins song. Terry's like, I haven't done a poem in a while. I gotta do a good one. I'm gonna like make a children's book ready to go.

We just need an illustrator. It did have a swear word in it. So yeah, we can change the hell. That was beautiful. And our topic for the day is smell. And I guess now that I'm thinking about it, I'm going to propose to you my definition of smell. It is a thing that we can detect through the receptors that connect to our olfactory nerves. Like that is basically it. Yeah, that's it. We're done.

Well, because it's a human thing. Like a smell doesn't exist outside of us. Yes, it does. Well, it has to be sensed by something for it to be a smell. Yeah. But there are things that we don't smell, like nitrogen, that we could smell if we had receptors for it, but we don't. And that's not a smell, even though it could be a smell.

If we smelled it, I'm just trying to be as good, as eloquent as you just were in your poem. It's a smell before you smell it. Just like a chemical. It's just one of many chemicals and it's not necessarily a smell because it doesn't hit those receptors and no one's there to interpret it.

Right. And there are things that you can't smell because they're not hitting the receptors in your nose. Like a rock. Because it's a rock. You can't get in there. Sure. But there are also things that are getting there

that aren't being detected. It makes me wonder if there is like a like if there are systems that we have had to evolve to prevent ourselves from smelling the air because if we could smell the air we couldn't smell anything else there's too much of it i think there's something evolutionarily to not smelling the fluid that the smell molecule is being carried in. So like fish can smell, they have olfactory organs. For them, the molecules just travel through the fluid of water instead of the fluid of air and end up touching their olfactory receptors. So I imagine that fish also don't smell water constantly. And so in some evolutionary pathway, we didn't sense the medium that the thing is in.

So we have a lot more olfactory sensors than we do taste buds. And so like our sense of smell is just so much more complex. And the fact that we can pull these particles, I guess we're not physically pulling them, but we're inhaling air and then detecting trace amounts of things. Whereas to taste something, we have to like stick it in our mouth and like place it on the taste buds for it to be there. Chemo sensation, which is like the umbrella term of taste and smell, we're just like sensing chemicals, evolved so weirdly and so precisely to be able to let us smell. And I think that's amazing. Yeah. And I'm glad because smelling is nice. Yeah. I was going to say I love smelling stuff. Even stinky stuff is fun to smell, kind of.

For a little bit, maybe. Just to be like, ooh, I smelled that. Did you smell that, too? Sometimes you lay one and you're like, wow! A little science miracle that you've cooked up for yourself. Sari, did you find out anything interesting etymologically with regards to smell? I think that this is the first word where there isn't a good etymological origin. The Oxford English Dictionary says, quote, no doubt of old English origin, but not recorded

and not represented in any of the cognate languages. So one day we just started saying smell. Well, it makes me think that like it was something that it was like a slang term that we stuck with. Like maybe that's just the word we had for fart and then we just like it became all smells. Oh no, I hope not. Well, that means it's time to move on

to our quiz portion of the show. This week we're doing Blast from the Past, another Tweet of the Week. Are you ready? I have three facts for you. One of is true two of them are lies they're all smell facts because smell is a very important part of how we experience the world and so we have been making smells and things that smell and things that don't smell for a while and with more knowledge about how we define and experience smell, scientists and engineers have developed tools and technologies

to enhance our experience of scent. The following are three creations of smell science, but only one of them is a true creation of smell science. Fact number one. Scientists applied drops of scent molecules that cover the whole spectrum of smell onto an absorbing pad. And then they placed the pad into a sniff jar to create a special vapor. Because it kind of contains the whole spectrum of smell, while white contains the whole spectrum of light, they call this olfactory white.

And people say that it smells neither good nor nor bad which is i guess what you would think wait it's a smell that smells like everything at once is that basically it doesn't smell like everything at once it just smells like nothing in particular okay okay okay you know i'll be like go to and you put all the sodas in one cup yeah at the burger king yeah um and then it's like that doesn't taste like any particular soda, but no matter which ones you put in, it always tastes like that. That's like soda white. And this would be smell white.

Thank you for putting it in terms I understand. Fact number two, scientists mixed together a nasal spray made from unscented odor receptor antagonists. from unscented odor receptor antagonists. These are chemicals that can temporarily disable or blind your odor receptors and block them from taking in other odors. And when injected into the nose, the spray acts like a kind of smell blindfold

to protect the user from unsavory smells. Or, fact number three, scientists decided that they wanted to create the rosiest rose smell. So they mixed together a bunch of key scents from different roses until they made a rose smell so rosy smelling that 95% of people chose that rosy smell that they created when they asked them to pick out the rose smell from a lineup of what turned out to be rose smells. So they were all different roses, but they picked the one that they had created as the rosiest rose. So the three different facts I have for you are one, we have olfactory white, a smell that contains smells from all over the smell spectrum. Two, a nasal spray that can block out unsavory smells.

Or three, scientists making the rosiest rose that people pick when asked to pick out a rose from a lineup of roses. Yeah, I don't know. I truly don't have, like sometimes I get a scientific foothold in a truth or fail question. This, I know nothing.

I can't smell very good. I don't know very much about noses and these all sound realistic. I really liked the idea of a smell blindfold though. That seems like it would come in, that one seems like it would come in handy and the rest of them are just like, well, who cares? But maybe, maybe it's so handy that it couldn't possibly be true. Yeah, that, my brain went through that whole thing too. I was like, that one sounds the most useful. Like something that people would actually spend time and money researching is like antagonists for your nose receptors.

Your brain must work way faster than mine because it took me that long for my brain to work it all out. How did you do it without saying all of it out loud? I just don't talk very much. My brain just goes, all the time. Oh, no. I'm the exact, like, actually the exact opposite.

Because I truly don't have anything more to talk about. I'm just gonna say, I'm gonna say the rosiest rose, because it seems like something that scientists would do to prove that they could be like, ha ha, we did it and maybe sell it to a perfume company or something like that. Yeah. I think I also might go for the rosiest rose because it just seems like it would make a good headline that then after you thought about for a second, you'd be like, so what? That's good.

Okay, I'm locked in, I guess. That's the constant battle of the SciShow script where it's like, this sounds interesting until you start to write the script. And then you're like, actually, this is dumb. But anyway, that was not the true fact. You both got it wrong. It was also not the nasal spray blindfold. You were correct that if that was the thing that existed you probably would have heard of it because people would want to buy it yeah uh it was in fact olfactory white weird that one sounded the

fakest i know it totally sounds the fakest i'm sorry i made it too hard for you i tried to tried to make it a little less fake sounding by introducing the soda concept but uh yeah so so olfactory white the one my favorite thing about olfactory white is is no one can explain to you what it smells like so they asked much people what it smelled like and see here are four adjectives used to describe olfactory white. Fruity. Okay. Perfumery. Okay. So perfumery is just like, it smells like smells, but also medicinal and soapy.

And you're like, what? So they mixed together different numbers of different kinds of scent molecules. So they were like, they were actually scent molecules that like represent different receptors in the nose. They're trying to make sure that it's basically just completely overwhelming your system. Because one of the cool things about smell is that you can smell one compound because it's binding to multiple scent receptors. And so the signal isn't, I've bound to the lilac receptor. It's I've bound to

like these four or five receptors and all of those combined is the lilac smell because only the lilac chemical binds to those five different receptors. Super cool and weird. So they would use up to 40 different chemicals and different mixtures to create this thing if you if you mixed all of them together everything would start to smell similar no matter which chemicals you were mixing together so they they were like that must be white then i guess but you can't like buy it i was trying to figure out how to sniff this sniff i wanted to smell it i want to smell it real bad but there's not even anybody i could talk to. What do you mean? Forbidden smell? They buried it under the ocean or what? That's right. I mean, I just didn't find like an email address.

It's too powerful for any nose to behold. Yeah. Well, and I wonder like, if it's like, everything smells really bad, if you could just like toss some olfactory white in and be like, well, everything smells fine. Yeah. Not good, not bad. And then as far as smell blindfolds this isn't a thing that we have been able to create yet i don't know that people have been trying like it seems like people would be trying maybe but like anosmia when you can't smell at all it's not done because the receptors are like binded to it's because like the nerve the nerve structure gets broken down by usually some disease or chemical exposure.

And then the rose thing I just made up. The bokeh made, and I made it up together. Oh, that's lovely. Just 100% fake. So you picked the one that we picked to sound real, I guess. Yeah, yeah. You're both very smart people, so I don't feel that bad for falling for it. Uh-uh.

So we are headed into the break with a score of zero to zero it all hinges on the fact off though i will say has a slight advantage because of that problem okay well yeah Welcome back, everybody. It's time for the Fact Off. Our panelists have both brought in science facts in an attempt to blow my mind. And after they have presented the facts, I will judge them and award their hank bucks any way I see fit. And to decide who goes first, I have a trivia question. It is that bloodhounds are famous for scent tracking and their noses that do such a good job of that.

But bears have a better sense of smell than bloodhounds. How much stronger is the average black bear's sense of smell than a bloodhound's? It's probably something big. I'm going to guess 500 times bigger, better smell. I'll say 50. The answer, and you guys got to remember, the answer is always five. But in this case, it's seven. But if you'd guessed five, you would have been very close.

But the answer is seven, seven times more powerful a than a bloodhound which makes me wonder why do i keep surprising them just leave when i'm nearby well i guess bloodhounds have one job that's the sniff stuff but bears have a lot of other things going on they're thinking about other stuff yeah yeah the other the other thing is that like this this whole way of comparing isn't one-to-one. So bloodhounds can smell some things better than bears can smell them. But overall, bears can smell. There is seven times more sensitivity just in terms of the density of their nervous system, I think. Is that how they track it?

I think so. That kind of thing? Yeah, they look at how much of their nervous system is actually devoted to smelling stuff, which we have much less of, but there are some things that we can smell better than a bloodhound can. Like beets, right? Is that one of them? Yeah, like beets, for some reason. Anyway, that means that Sam gets to go first or choose who goes first.

I think I will go first. So, you know, in the movie, Ratatouille. I do. I watched it recently. The Brave Little Mouse chef, Ratatouille, he's sniffing some soup. His name is not Ratatouille. Yes, Ratatouille the mouse.

He's sniffing some soup and he's like, oh, this has tomatoes in it and oregano in it. That's something he does in Ratatouille, correct? He knows all the stuff from smelling it. But in real life, rats can also discern incredibly specific and complicated things from smells. But they ain't just smelling if soup has oregano in it. They are smelling concepts. So rats are known to share food, as seen in the movie Ratatouille, when Ratatouille shares food with all his friends.

His name is Remy and he's a rat just for clarity. You also called Remy a mouse earlier which I couldn't even focus on. So one way

they communicate their need for food is with solicitation behaviors which includes mostly like specific calls and gestures. However, rats are also known

to pretend to be hungry and do these solicitation behaviors to try to trick other rats into giving them food. But according to a study in 2020, rats have a way to suss out if their friend is starving to death or just trying to steal food from them. They placed rats, they placed two rats in two smell-proof boxes right next to each other. And one of the rats had a little pulley in its box that was attached to a food tray that if he pulled it, it would go to the other rat's box and give him food.

So the two rats couldn't smell each other, but the researchers pumped in the smell of a rat from a different room, and that rat was either very hungry or had just been fed. So when they pumped in the smell of the well-fed rat, the rat that was smelling the smell would get around to pulling the tray to help his friend eventually.

And it would like kind of lazily pull it like two minutes later. Then if they pumped in the hungry rat smell, then the rat would immediately start pulling and it would pull harder and faster on the pulley to get its friend the food. Wow. And they weren't just smelling food on the full to get its friend, the food. Wow. And they weren't just smelling food on the full rat's breath or something like that either

because they used mass spectrometry. And the researchers identified seven different compounds that are released in more abundance by hungry rats than full rats. But being hungry, maybe that seems like a pretty straightforward condition. And maybe it doesn't seem too weird that you'd be able to smell hungry. But what if you could smell if someone was being helpful? So in a very similar experiment, also done in 2020, but unrelated completely, as far as I could tell, researchers found evidence that rats can smell helpfulness in other rats. So they were put in the same exact setup, basically, both in two rats in two different

boxes, one with a pulley attached to a food tray. But instead of pumping hungry rat smell in, they pumped in the smell of a rat in a different box in a different room that was helping another rat get food. So it was pulling the pulley. And then when the rat smelled the helpful rat smell, it would trigger that rat to pull its pulley and help its friend. This article was paywalled, so I couldn't figure out like all the mass spectrometry stuff on this one. Or if they had determined exactly how much faster they were pulling the pulley. But I got to imagine that there were some helpfulness stink particles coming off of the helpful rat. So researchers say these findings could be applied to lots of other animals to help us figure out

like complicated social interactions that we don't know about or it could help us understand some ways that humans perceive the world that we like maybe don't think about the sense of smell as being associated with social interactions too much and if they make ratatouille too maybe they can have a scene where ratatouille can smell how disappointed his dad is in him. That's very weird and very cool. It's weird that like a rat, I mean, I guess it makes sense that like if you're being helpful, you want to have a way to transmit that information versus when you're being antagonistic. You know, you wouldn't, you'd want to deceive about that if you were an antisocial

species. But if you're a social species, you kind of want everybody to be on the same page. And rats and mice are very, very social. It's super cool. Yeah. It makes me think of like, if you had an antisocial species are we going to find out in a couple hundred years that uh like cuckoo birds while they're kicking eggs out of the nest are like secreting helpful or like gentle nose smells so it's like don't worry as they're like murdering baby birds okay mom yeah yeah i hope that i that i uh emit helpful smells i think it'd be really sad if you put me in a box and then a rat started stealing food from another rat then that would reinforce everything my therapist says not true about me i mean a zoom call is a perfect analogy for this research, where you should have a bunch of people in a Zoom call, and then you should pump in the smell of a helpful human and see if they treat each other nicer.

Because now we're having all these social interactions where we don't get to sniff each other's smells. And so who knows what's happening to our brains? We're not being as nice to each other. We're not helping each other get to food as easily as we would otherwise. Yeah. We're not pushing trays of cheese toward each other. It's a disaster. Well, Sari, what are you going to do to trump Sam's friendly smelly rats?

Sam really brought out the science this week. Yeah, there's a lot of science. Mine is more of a Sam story, I think, this time. What's that supposed to mean? Like straightforward and snappy. Okay. So like us, non-human animals need play and some things to exercise their brains, also known as enrichment. And I feel like we often see this in the form of physical toys, or at least I think of it this way, like balls or jungle gyms or chew toys. toys, or at least I think of it this way, like balls or jungle gyms or chew toys. But a big part of enrichment can also be new smells. For example, big cat caretakers like lions, tigers, or jaguars

often spritz essential oils, perfumes, or colognes to give the cat something to sniff and consider. The cats even rub their cheeks on objects like house cats might do for a catnip spray to rub their scent on an object or get a scent that they like on their faces. And it turns out one scent that a lot of big cats seem to love is Calvin Klein obsession for men. Hashtag not sponsored. And biologists think that the main component of this cologne that makes big cats obsess over it is civet oil. Civets are a vivarid, which are a small to medium-sized, kind of cat-like, kind of weasel-like mammal. Binturongs are in this family, too. And Bizarre Beasts did a whole episode on their smelly butts.

But civets produce a musky oil from their perineal glands near their butt that humans have harvested for flavors and perfumes for a while, like many animal substances. And specifically, the smelly organic molecule in civets is called civetone. And now we can produce it synthetically from palm oil. So we're not just harvesting from them. And I'm not sure whether Calvin uses the artificial or natural one, but it's in there. Civitone is definitely an obsession. And when big cats smell civitone, they go wild, maybe because they're often predators of civets and think they smell food, but also they rub their faces all over it. So maybe it has to do with rubbing to take over

a territorial marking and civitone smells like a civet marking territory. And besides olfactory enrichment, this is also really useful for researchers in the field because sometimes they have to set up cameras to capture rare species or behaviors and a spritz of Calvin Klein's obsession for men. It was the preferred attractant for jaguars to a research site in Nicaragua in, I think, 2013. So they had troubles getting jaguar to the research site. They would spritz it on a tree branch, and then the jaguars would come and rub and, like, be on camera for a long enough time to get captured. Maybe they just want to smell sexy.

I mean, well, the great thing— So one of the things that is often overlooked in science is that you have to, like, work with what you got to a certain extent. And also it's like you want your experiment to be repeatable. So if you're saying like, OK, here's how to make the attractant that we made. And there's like a long procedure and like you could mess it up or you can't get all the materials. And like, where do you get Civitone? That's a huge problem. Like it's, it's not just like a pain in the butt.

Like it might make it impossible to replicate your science, but if it's like go on Amazon and order Calvin Klein's obsession for men, anybody can do that. And it's like the same price. And it's like, it's completely achievable and it works. This is I loved this. Sam, I loved yours. God damn it. What am I going to do?

So we have from Sam rats can smell concepts. They can smell hunger. They can smell helpfulness. And that's amazing. But Sam constantly called Remy the Ratatouille or something and also called Remy a mouse. And Sari discovered that big cats are attracted to the scent of Calvin Klein's obsession for men because it contains some kind of civet oil.

And look, I think that Sam's fact is slightly better but Sari's poem was amazing and also, Sam insulted Remy and so I'm gonna make it a tie. Oh. Okay. That's a better outcome

than I was expecting. So. Yeah, I thought you were going down for Remy Ratatouille. Yeah. For personal vendetta. Congratulations to the both of you.

And that means it's time to ask the science couch where we've got listener questions for our virtual couch of finely honed scientific minds. It's from at might be Joe and at MX demo unicorn. Is there any particular reason that smells seem to have the strongest ability to generate sensory memories? This is definitely true. It is like observably true. And it's certainly in me and also in people I've talked to before.

I think it's a real thing. And I have heard, I've heard that there's like a, like the brain regions are nearby to each other, but I have only like seen that on sort of like a surface level headline way. I haven't read any actual research about it. So brain regions is definitely the right direction. And for all that we don't know about smells, it seems like we are pretty sure

we have some steps towards understanding why this is. So when we smell, the chemical particle binds to something that gets transmitted to the olfactory bulb in your brain. And the signals are carried from there, I think, because it's nearby, to the amygdala, which controls emotions or generally is involved with emotions, and the hippocampus, which is generally involved in learning and memory. But non-smell senses, so like sight and taste, first go to the thalamus,

which acts like a switchboard for the rest of the brain before going into the emotion and memory centers and the sense-specific part of the brain to be processed. So scent has a more direct path to a region that is nearby and interconnected with emotion and memory. That's wild. So that makes me think that those structures evolved at different times. Probably. I don't know. I do not feel like I can confidently say expertly in this region, but like chemosensation was one of the earliest things that had to have evolved.

It's just like, oh, I i'm gonna respond to some chemicals and smell because it's so complicated feels like it evolved first and and has built up layers of complexity compared to other senses i will still occasionally smell somebody who wears like my high school girlfriend's perfume and be like stop that that is that's not bringing back good memories oh no well like that that is interesting aspect of it too and this gets into like the neuroscience of memory but it seems like oftentimes in studies smells bring back an emotional response more so than the memory and so you have like a visceral like oh oh, this is comforting or, oh, this is bad or, oh, this is like weird rather than being transported back to like a very specific moment of like, this is when for the first time my grandma peeled chocolate chip cookies out of the oven. And so that was interesting to me where we talk about scent as being linked to memory, but it's really linked to emotion.

And then that gets us back to like a cluster of memories. Cool. If you want to ask your question to the science couch, you got to follow us on Twitter at SciShow Tangents. We there, we tweet out topics for upcoming episodes every week. Thank you to at happily at Jeff Lewis and everybody else who tweeted us your questions this episode. You can also follow SciShowFangents, which is our fan Twitter that I love.

If you like this show and you want to help us out, it's very easy to do that. First, you can go to patreon.com slash SciShowTangents to become a patron. You can also leave a review wherever you listen. That helps us know what you like about the show and helps other people know what you like about the show. Finally, if you want to show your love for SciShow Tangents, just tell people about us. Thank you for joining us. I've been Hank Green. I've been Sari Reilly.

And I've been Sam Schultz. SciShow Tangents is created by all of us and produced by Caitlin Hoffmeister and Sam Schultz, who edits a lot of these episodes. Our social media organizer is Paola Garcia Prieto. Our editorial assistant is Deboki Chakravarti. Our sound design is by Joseph Tuna-Medish. And 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. Indole is a molecule that often gets added to perfumes and chocolates because of its fruity smell. But in large amounts, it actually smells like poop because it's a chemical that's in poop. What the? It's in our poop specifically. No. It's not completely clear why small? It's in our poop specifically. No. It's not completely clear why small amounts smell good and large amounts smell not good,

but that is the case. Oh, dear. I don't like that. I have also read that American chocolate has a chemical in it that is found in vomit, but that other places don't have this, so there's a slightly acidic taste to our chocolate. So we like poopy, barfy chocolate.

Yeah, I think that's caprylic acid or caproic acid. One of the goat-like acids because it's like goaty smell slash vomit slash armpit sweat, et cetera. Just all the good stuff. Honestly, I get it. I get it. I get it, too. You take a funk in the right amount, and suddenly it's good.

Sometimes when you eat a fancy chocolate, you're just like, this ain't stanky enough. You waving to a child over there? Yes, my son just walked into my office. Give him a mic. What's his favorite smell? Oren, come here. What's your favorite smell, Oren? Lilac.

Oh. Oh. He just said lilac. That's a good smell. Apparently it's lilac. That is a good smell. Not even any hesitation. No, no hesitation at all.

Must have been sniffing lilacs earlier today. Were you, bud? Yeah. Where's Mama? Did she say you could come in here okay i gotta get rid of him he's getting on the drum set