How Big Is A Piece Of Chocolate?

At what exact chemical ratio does our beloved chocolate devolve into a mere structure of fats and sugars? How far can you dilute chocolate before its fundamental identity vanishes? And what could a comically tiny novelty stool possibly reveal about Michael Stevens? Unlike a block of pure iron or a vial of chlorine, chocolate is not one single substance but a complex and heterogeneous mixture we all take for granted. Hannah and Michael explore the chemistry and nutritional boundaries of this everyday treat. Where does the stool come in? You'll have to listen to find out. ------------------- For more information about Cancer Research UK, their research, breakthroughs and how you can support them, visit ⁠⁠https://cancerresearchuk.org/restisscience⁠⁠ Cancer Research UK is a registered charity in England and Wales (1089464), Scotland (SC041666), the Isle of Man (1103) and Jersey (247). A company limited by guarantee. Registered company in England and Wales (4325234) and the Isle of Man (5713F). Registered address: 2 Redman Place, London, E20 1JQ. ------------------- Find The Rest Is Science all over the internet by ⁠⁠clicking here.⁠⁠ ------------------- Video Producer: Adam Thornton + Oli Oakley Video & Social: Bex Tyrrell Assistant Producer: Imee Marriott Senior Producer: Lauren Armstrong-Carter Head Of Digital: Samuel Oakley Exec Producer: Neil Fear Learn more about your ad choices. Visit podcastchoices.com/adchoices

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:00Speaker 00

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• 0:43Speaker 00

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• 1:26Speaker 00

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• 1:30Speaker 01

  Observe. The North American Dad. 50s. Great polo collection. He enters his vehicle information on Carvana. An offer appears in minutes. Remarkable. He squints, reads it again, smiles and says, "Dang, that's a good offer." The highest form of approval. No haggling, no hassle, no one called him "boss." He's still on the couch. Astonishing. Sell your car today on carvana.com. Pickup fees may apply.

• 2:00Michael Stevens?

  Hello and welcome to The Rest Is Science. Today, we're on an adventure. That's right, this is Field Notes. An expedition diary where Han and I trade exciting ideas. And objects and discoveries or or big questions that have been occupying our minds.

• 2:14Hannah Fry?

  Exactly. It's a it's an expedition of the brain, as it were. You are welcome to join us. Every week, we're going to bring something to show one another. It's sort of like the rest of science version of of show and tell.

• 2:25Michael Stevens?

  Now, later on, I'm going to be showing you a menagerie of things, a constellation of things, including the first book I ever wrote.

• 2:34Hannah Fry?

  Oh.

• 2:35Michael Stevens?

  Hmm. And it's it's there's even more surprises than just that.

• 2:46Hannah Fry?

  This episode is brought to you by Cancer Research UK.

• 2:48Michael Stevens?

  So when most people think of naked mole rats, their unusual relationship to cancer probably isn't the first thing that comes to mind.

• 2:56Hannah Fry?

  But maybe it should be because it is incredibly rare for them to develop cancer, which could be partly down to their unique immune system, or it might be the way that their cells respond to damage.

• 3:08Michael Stevens?

  So scientists are studying their biology for its cancer fighting secrets. It's a reminder that discoveries can sometimes come from places you don't expect.

• 3:16Hannah Fry?

  Cancer Research UK is the world's largest charitable funder of cancer research. Thousands of scientists and doctors and nurses work across more than 20 countries to help turn discoveries in the lab into new tests, new treatments, and new innovations.

• 3:32Michael Stevens?

  And the impact is clear. Over the past 50 years, the charity's pioneering work has helped double cancer survival in the UK, meaning more people living longer, better lives, free from the fear of cancer.

• 3:45Hannah Fry?

  For more information about Cancer Research UK, their research, their breakthroughs, and how you can support them, visit cancerresearchuk.org/restiscience.

• 3:55Michael Stevens?

  As we always do, we're going to start with your questions, including this one that came in from Megan. My friends and I have been arguing for a good hour about whether space has a smell. They think since it's a vacuum, it can't. I can't imagine there not being one. What do you think?

• 4:11Hannah Fry?

  Hmm. Okay, Megan, for starters, you've got what sounds like great friends. If I could meet people who would engage in in that kind of debate with me for an hour, I think I'd be happy forever. And the reality is, you're sort of both right. You're sort of both right, because in deep space where it's a, you know, a true vacuum, then agreed, there is there is no smell. However. At the same time, every astronaut who has been to space, who's been out on a spacewalk on the ISS, uh, reports that there is a very distinctive odor that they, uh, that they get when they come back inside, when they're in the, you know, after they've done

• 4:50Hannah Fry?

  a, a, a spacewalk, um, their suits and the airlock, they fill with this very unmistakable odor, the smell of space, as it were. Um, and they describe it as like burnt steak, hot metal, um, gunpowder. Chris Hadfield, uh, who's the Canadian, um, astronaut, he said it's like, uh, um, a very metallic smell. NASA astronaut Don Puttit, he's, um, he's got a slightly more poetic way of putting it. He said, um, "Is metallic a rather pleasant, sweet metallic sensation? It reminded me of my college summers where I labored for many hours with an arc welding torch, heavy equipment for a small logging outfit." That's,

• 5:29Hannah Fry?

  um, that's the smell, right? But the thing is, uh, no one's completely sure about exactly where that smell comes from. Um, and there's essentially, there's two, there's two theories. One of them is, uh, this idea that, uh, the dying stars are filling the universe with these polycyclic aromatic hydrocarbons, the P A Hs, um, is what they're known. And these are like these high energy particles kicked off by dying stars, um, and they essentially just float around the universe forever, adhere to, to, to spacecraft surfaces, which is why you can, you can smell them. And the thing is, is that these, these molecules,

• 6:11Hannah Fry?

  um, you do find them on earth. You find them in, in soot, um, in car exhaust and in charred food. So, uh, essentially when you're smelling a hamburger, um, you are, you are effectively smelling the same compounds that, um, that drift around between the stars. Um, but a slightly more accepted theory as to where this particular smell comes from. Um. This kind of goes back actually to our um the episode that we did about cosmic rays. Cause you have all of these these these charged particles that are floating around. Or or even atoms that had been stripped to their electrons because of really harsh UV radiation. Like like single um atoms of oxygen without any electrons floating around them.

• 6:53Hannah Fry?

  So the idea is that when astronauts go back into the airlock, when when the cavern is repressurized um with sort of more breathable air, these um oxygen atoms then combine with the new oxygen to create ozone. Um. And that very quick chemical reaction is the thing that makes that sort of acrid, metallic, smoky smell. That's just the boring bit in between all the interesting stuff. That's just space. But there's, I mean, there's other bits of of the universe that where we know what it smells like too, right?

• 7:24Michael Stevens?

  Well, yeah, using spectroscopy, we can use light to tell what molecules and atoms are in something very far away. And I mean, we we use this, first of all, to to figure out what the sun was made of. The basic point is that it was a really important moment when people were studying uh spectral lines from elements like hydrogen. And they could tell, oh, wow, look at this, you know, we're getting, we're, I don't know how it all works. But they then pointed their device at the sun and they saw the same lines that they saw from hydrogen. And they were like, wait a second, I think the sun is made of hydrogen.

• 8:10Michael Stevens?

  And that that was a huge moment because there was no way anyone could have known that. No one looked at the sun and was like, I bet that's hydrogen, you know? Like, what is the sun? It's it's could be a whole new material. Is it burning wood? Is it a god? And these guys are like, I think it's hydrogen because it's it's interacting with our instruments in the same way that hydrogen does.

• 8:32Hannah Fry?

  Cause there's no way that you would, you would, you know, at this point, if you've sort of isolated hydrogen on earth and it's this this invisible gaseous form, there's no way that you would look at this burning orb in the sky and think that the two things were the same.

• 8:46Michael Stevens?

  Well, you wouldn't. You wouldn't because it couldn't burn for for a long time if it was burning hydrogen, right?

• 8:52Hannah Fry?

  Right.

• 8:52Michael Stevens?

  Um. At at the time, they had no concept of nuclear fusion. So the idea that

• 9:01Michael Stevens?

  I don't actually know if at the time, because I don't know when they did this. But my neighbors, they they use spectroscopy to detect how much methane is in the Earth's atmosphere. And so they're really into it, right? They're always talking about like, oh, hey, you know, my son and I just, you know, did some spectroscopy on some stars. And I'm like, all right, nerds. But um.

• 9:26Hannah Fry?

  They sound like they'd be good friends with Meghan, though, to be fair, you know? I think Meghan could start up a little club.

• 9:31Michael Stevens?

  We should start a club. That's right. That's right. And a spectro- what do you call the instrument that you do spectroscopy with?

• 9:38Hannah Fry?

  Spectrometer.

• 9:39Michael Stevens?

  Spectroscope. It's embarrassing that I don't remember a spectroscope because we put a spectroscope in like the very first curiosity box. And it was one that you built yourself. We should bring that back because at the time I didn't fully know how to use it or how cool it was. But look, this is just a long way of saying that using spectroscopy, we have been able to detect compounds in distant nebulas that we have here on Earth that are that have known odors.

• 10:15Hannah Fry?

  Right, so this is astronomers were looking at the dust cloud Sagittarius B2, basically it's the center of the Milky Way, right? This is like a giant dust cloud. And they have found in there vast amounts of of ethyl formate.

• 10:32Michael Stevens?

  Ethyl formate, which smells like raspberries. It's what gives actual raspberries their characteristic smell.

• 10:41Hannah Fry?

  Right, not just raspberries, though, also rum, which means essentially the center of the Milky Way smells like a raspberry daiquiri.

• 10:50Michael Stevens?

  Well, I made a video many years ago where I bought a special little jar that was the smell of outer space and it contained ethyl formate and other odorous compounds that we have found in distant nebula. And you could open it and smell it and get the smell of space. And I bought two of them, I opened and smelled. One of them on camera and the the second one I still have not opened because once you open it it rapidly you rapidly lose it and so I don't know one of these days maybe I'll let my daughter smell space and then never again.

• 11:25Hannah Fry?

  And then never again. Thing is, I mean, you use that you can use this same trick. You can you can sort of point it at all different, you know, different parts of of space. And it tells you a lot about what you expect to find there. There's there's actually like a quite controversial story about the smell of a particular area of space and and specifically a part of Venus because they detected this spectral signature exactly as you're describing. This is in 2020 that looked exactly like phosphine. Now phosphine is actually incredibly difficult to make on Earth, right? So it's not particularly stable. You essentially need a biological creature to make it. And in particular, where you find it is in penguin

• 12:05Hannah Fry?

  poop. So the fact that they found this on Venus and not down at the ground level, but up in sort of 30 miles up in the cloud decks, this kind of this kind of Goldilocks zone at altitude, loads and loads of this phosphine that we only really, you know, only sort of really comes from penguin poop. It did start all of these questions about like, well, maybe maybe there are these like the Venetian sky penguins. As it turns out, there's like now this current argument about the actual quantities of phosphine that is in the atmosphere. But I mean, this is really genuinely how we find out a lot about the universe is by like working

• 12:48Hannah Fry?

  out what atoms there are, working out in part what it smells like, and then drawing conclusions about what could have caused those smells in the first place.

• 12:58Michael Stevens?

  Yeah.

• 12:58Hannah Fry?

  I mean, Venus is a stinky place, right? Down at the bottom, it's sulfur, so rotten eggs. And then up at the top, it's like sulfuric acid. That's the sort of top note. And then and then the accent is rotting rotting fish and penguin poop.

• 13:11Michael Stevens?

  Which is amazing. I mean, yes, space doesn't have one smell. It's got so many ways to titillate our senses. And you just need to know where to stick your nose.

• 13:21Hannah Fry?

  Yeah, I'll stick it in the raspberry daiquiri place. Thank you very much. Okay, here's a question for you, Michael. This is from Justin Corrigan. Where do even and odd numbers come from? Who said one was odd and two was even and not the other way around? Was it on purpose or happy accident that even has an even number of letters and odd has an odd number?

• 13:41Michael Stevens?

  Oh, wow. Okay, there's like two questions there. One is about sort of, I guess, the etymology of even and odd. And then the next one is about a funny property of words. Like, so, I mean, the most I know about even and odd is that, I think this is kind of cool. We don't exactly know where the word odd comes from, but it could be very old Norse, where odd was used to describe a point, like a place or a sharp point. And that means that maybe the word odd comes from a triangle. When you have two things, you've got, okay, you've got a pair. But then the third comes along and forms a triangle which has a point.

• 14:24Michael Stevens?

  And then from there, they started saying, you got one person, they can do what they want. Two people are going to have to talk to each other. But then you bring in a third, and now the voting is different. You can't have an even split. And that third person forms a triangle. We already have the word odd for that. And so odd came to mean anything that had a point, that could not be divided into two soft blunt equal groups.

• 14:48Hannah Fry?

  I like that.

• 14:49Michael Stevens?

  That's one possibility. This is all kind of unknown, but it makes sense, you know? And then as for the coincidence that the word odd has an odd number of letters and even has an even number of letters, that's just a wonderful example of an autological word, a word that describes itself. For example, the word word is in fact a word. But the word monosyllabic is not monosyllabic. If a word doesn't describe itself, it's considered a heterological.

• 15:30Michael Stevens?

  Henry Segaman has a fantastic website where he's like listed all these autological words, some of which he thinks are reasonably clearly autological. Others are debatable or dodgy. These are wonderful, like the word pronounceable is pronounceable. The word pentasyllabic is pentasyllabic. The word old, spelled O L D E, is old.

• 15:58Hannah Fry?

  Hey.

• 16:01Hannah Fry?

  He sounds like he's got a great life. I've decided, you know, we were asked that dinner party question a while ago. I'm changing my answers. I want Meghan and this guy who's right this is on that website.

• 16:11Michael Stevens?

  Another example of a heterological word would be something like the word long. Long, L O N G. That's not very long. The word hyphenated is not hyphenated. So it's not autological, but the word unhyphenated is unhyphenated. Okay, now, this might sound like a funny little like fact about words, but it brings us to the Grellin Nelson paradox. So the Grellin Nelson paradox takes these definitions, autological, a word that describes itself, and heterological, a word that does not describe itself, and it asks, is the word heterological heterological? Right?

• 16:56Michael Stevens?

  And so if we say that the word heterological does not describe itself,

• 17:03Michael Stevens?

  that means it's heterological. But wait, now it does describe itself. And if we instead say that it does not describe itself, then that means that it is not heterological. But we already had to assume that it was.

• 17:16Hannah Fry?

  Oh, this is the word version of this statement is false, isn't it?

• 17:20Michael Stevens?

  Exactly. Exactly. If heterological is heterological, like if that is true, then that means that it does not describe itself. But a word that doesn't describe itself is heterological, so it must be. If however, we say heterological is not heterological. So that means that it does describe itself, then that means that it is heterological. So you can never win. The only way to make this work is to to say that a word is heterological if it does not describe itself and is not the word heterological.

• 17:55Hannah Fry?

  Ah, the classic Russell exclusion.

• 17:58Michael Stevens?

  Exactly. Exactly. Some Rosalian exclusions save the day once again.

• 18:04Hannah Fry?

  Yeah, just, you know, once again, get down deep enough. It's all gaffa tape. Michael, that's a good discussion.

• 18:12Michael Stevens?

  I love this question. This one came from Christian David Boer. How many times can you fold a piece of chewing gum?

• 18:22Hannah Fry?

  Okay, so I I actually, I had a good think about this, right? Because, I mean, everyone's heard that the whole idea about a piece of paper, you can only only fold it seven times. And by the way, that is, that is broadly true, broadly true. And that limit exists because of tensile strength. So every time you fold it, that outside edge, it has to stretch and the inside edge has to compress. And eventually, either the outer fibers will snap, starts to tear, or the inner fibers become too dense, they they can't bend. The thing about gum, right, which is a bit cheating, is that it's effectively a type of fluid, right? It's like a viscoelastic fluid. So when you're folding it, you're not really folding, it's more like you're kneading it.

• 19:05Hannah Fry?

  It's more like you're you're you're dealing with dough, which isn't that, um, which I appreciate isn't that satisfying an answer? Because the answer then is effectively an infinite, an unlimited number of times until it until it starts to degrade or dry out effectively. But if you could instead, let's assume for a moment that that, take that dough analogy. And if instead you um found some way to sort of fold it and keep the layers from merging into each other, like using flour, for example, um, could you make yourself a chewing gum croissant? Right, that's uh, that's that's basically what I want to know, right? I want to do pastry chef with chewing gum, that's uh, that's what I want to do.

• 19:48Hannah Fry?

  And I think that you could then, you could, but but here is where a limit occurs. Because what you could do, you know, the way that pastry chefs work is they they take the pastry, they roll it out, they fold it, they turn it around, they roll it out, they fold it, they turn it around, and so on and so on and so on. And what you're doing every time that you fold it is you're doubling the number of layers, right? You're kind of re-stretching it out so that you can continue to fold. After you've done one fold, you've got two layers, fine. After you've done ten folds, you've got one thousand and twenty four layers.

• 20:23Hannah Fry?

  Once you've done twenty four folds, you've got sixteen million layers. And once you've done thirty layers, um, at that point, each of the layers in your chewing gum croissant would be thinner than the width of a single molecule. So we know it's less than thirty. That's um, that's, that's, that's the hard upper limit. Interested in eating a chewing gum croissant, Michael?

• 20:47Michael Stevens?

  Well, yeah, of course.

• 20:49Hannah Fry?

  Apparently when they make actual croissants, they only go for like, you know, sixty four layers, maybe hundred and twenty eight layers. Nothing really in comparison.

• 20:56Michael Stevens?

  Yeah, sure, but I mean, they're using, you know, bigger dough and they're also using dough and butter, but we're talking about chewing gum and saliva.

• 21:04Hannah Fry?

  Sure.

• 21:05Michael Stevens?

  Which sounds a little better.

• 21:07Hannah Fry?

  Less French, shall we say.

• 21:09Michael Stevens?

  Less French, I think is the correct way to describe a chewing gum croissant.

• 21:16Hannah Fry?

  Okay, here's a question for you, we're staying on the food thing. Ben asks, I need to know, how small a piece of chocolate can I have? Chocolate is comprised of cocoa, sugar, cocoa butter, sometimes milk emulsifiers, but what really makes it chocolate? And not a cocoa bean is that it is a mixture of many things. Mixtures cannot be divisible down to the same scale as a chunk of pure iron or a file of chlorine. Each atom has the same properties, chocolate is different from this. Goodness me, Ben, you really have gone to town on this. Um, it's a mixture of larger molecules. At what point can you slice chocolate and it is no longer chocolate, but its components? Does that mean there is a lower bound to the size of chocolate?

• 21:57Hannah Fry?

  I think maybe I've spent too many days in a row subbing down voiceover scripts, but I feel like I could have summarized that in a single sentence.

• 22:06Michael Stevens?

  Yes, but you didn't, because we respect your words, listeners, okay? Send me a question that's like a literally an audiobook and Hannah will read it and it will be our longest podcast episode ever. But I think Ben is asking a really interesting question.

• 22:26Michael Stevens?

  What's the smallest a piece of chocolate can be? And, and so obviously, we think, okay, let me buy a chocolate bar and I can cut it into smaller and smaller pieces, and it's always chocolate. Except, chocolate isn't an element. It's not like I can eventually get down to an atom of chocolate, where if I divide it any further, it's no longer chocolate. That's true of something like gold. If I have one gold atom and I split it in half, I no longer have a gold atom. Because a gold atom is defined as an atom with a very specific number of protons, and that's it. But with chocolate, what is the smallest piece of chocolate? What form does chocolate come in at its atomic, meaning smallest indivisible, scale?

• 23:11Michael Stevens?

  There isn't one, because chocolate is a mixture. And chocolate contains, um, you know, it's not just like, oh, well, there's a chocolate molecule, and a sugar molecule, and a milk molecule. There is no such thing as a chocolate molecule. Chocolate, as we know it, contains hundreds of different types of molecules, different chemicals, um, that are all, like, you know, originally organically put in there by the plant, in the cacao bean. And these include all kinds of compounds that affect our nervous system, and have their own flavors, and textures, and all these things. So, anyway, estimates, I've, I've looked into this.

• 23:53Michael Stevens?

  The estimates of how many different kinds of chemicals are in chocolate is between about 300 and 800.

• 24:00Hannah Fry?

  What?

• 24:01Michael Stevens?

  There's a lot.

• 24:01Hannah Fry?

  Wait, hang on, when you say chemicals, are you talking, you're talking about different atoms and different molecules, stable molecules?

• 24:08Michael Stevens?

  That's right. Different stable molecules and atoms as well.

• 24:12Hannah Fry?

  300!

• 24:13Michael Stevens?

  It's, if you want to dive into this, it's actually overwhelming. Because I feel like every few months, scientists announce the discovery of a new compound in chocolate that had been there all along, but there's like trace amounts of it, and we know that it's an analog for a neurotransmitter, and that's why everyone loves chocolate, or, and that's why dogs are killed by chocolate. You know, there's, there's so much, it's so complicated. Not elemental. It's got all kinds of fats and acids and all these different types of chemicals in it. It is an organic, complex material. And when chocolate is made, we roast the cacao beans. And then there's this whole chocolate making process that separates the meltable cocoa butter from the bean.

• 24:58Michael Stevens?

  And you're left with the cocoa butter. And then what doesn't melt is called the cocoa solids. And the cocoa solids are then mixed back in with cocoa butter in very specific ratios, as well as some milk, some sugar. And that's how you make chocolate as we know it. You could also just sell people cocoa butter, right? It's a great skin moisturizer, all kinds of uses. You can use it in cooking. And you could also sell people cocoa solids by themselves. And that's what we call cocoa powder. I don't know if that's what you call it in the UK.

• 25:30Hannah Fry?

  We do, yeah, but it's very bitter.

• 25:32Michael Stevens?

  It's very, very bitter. Now, if you add sugar to cocoa powder, you haven't made chocolate. You've made sweetened cocoa powder. You need to put some of the cocoa butter back in to make chocolate. However, that's kind of like an opinion, right? You could say cocoa powder is chocolate. You could say that the cacao bean on its own is already kind of chocolate.

• 26:00Hannah Fry?

  No, not for me, not for me, Michael. It doesn't count as chocolate unless it is a square of Cadbury's Dairy Milk. And yes, I would like them as a sponsor for this podcast. Continue.

• 26:08Michael Stevens?

  Perfect, perfect. Because I think that you're getting at a fundamental issue we have to get across to answer this question. And Ben, see how hard we're working for you? I think that we need to define chocolate as something that pretty much everyone will agree is chocolate. In that case, I think we need to set this upper bound and say, you're going to need at least these, all 800 of these molecules that are in chocolate as we buy it in the store. And the most famous of those is probably theobromine. That is the like, it's what makes chocolate really characteristically chocolate. I think it might be what's toxic to dogs. But anyway, as a rough calculation.

• 26:50Michael Stevens?

  I looked at some of the most famous molecules in chocolate and how large they are. And then multiplied that by 800. Okay, to just kind of be like, look, if it's got 800 different molecules and some are larger and some are smaller than these ones that I'm looking at, then maybe we can get ourselves to an actual volume. So the problem is, it's really hard to know what volume certain molecules have. You can take the the the molar volume of a chemical like theobromine, very famous chemical in chocolate, and you can divide it by Avogadro's number. But that doesn't give you the volume, the size of an individual theobromine molecule.

• 27:32Michael Stevens?

  That gives you the amount of space that molecule occupies in the crystal structure of pure theobromine. But then I found that chemists also have calculated the like cross sectional diameter of molecules for collision calculations. And for a typical molecule in chocolate, it's about 130 angstroms across. So let's say 130 angstroms cubically is the volume of a typical molecule in chocolate. What's an angstrom? Great question. It's a tenth of a nanometer. So we're talking about really small things here. Yeah. But we've got 800 of them in order to represent every molecule that we believe is in chocolate.

• 28:17Michael Stevens?

  Problem, that's only one of each. Chocolate is chocolate and tastes like chocolate because of the ratios they have to each other. So factoring that in and then assuming that maybe it's going to take another order of magnitude to make everyone happy that like this is analogous to real chocolate. Yeah. We find ourselves with this answer. The smallest piece of chocolate that I believe everyone would agree, yes, that's chocolate, would be a zeptoliter.

• 28:49Hannah Fry?

  I don't even know what that is. 10 to the minus what?

• 28:52Michael Stevens?

  10 to the minus 21 liters.

• 28:55Hannah Fry?

  Whoa.

• 28:56Michael Stevens?

  That is very small.

• 28:59Hannah Fry?

  Could you see it?

• 28:59Michael Stevens?

  You could not see it.

• 29:01Hannah Fry?

  Could you taste it? No.

• 29:03Michael Stevens?

  A zeptoliter is sub-microscopic. It's down around the size of just like a very, very large molecule. It's smaller than any kind of nano thing we can imagine, little nanobots.

• 29:17Hannah Fry?

  Wait, is it too small to have color?

• 29:19Michael Stevens?

  I think it's going to be much too small to have color. Yes. But we're not quite at the answer that I want to give as my final answer, because this is just the smallest collection of molecules that will have the appropriate ratio and makeup as chocolate. Could you taste it? No. It is too small. The threshold for human taste requires like hundreds of billions of molecules. So I think we're talking more about something to the order of 10 to the negative 13 cubic meters. Basically, an extremely coarse grain of silt.

• 29:55Hannah Fry?

  Right.

• 29:56Michael Stevens?

  Almost sand, but not quite.

• 30:00Hannah Fry?

  Okay.

• 30:00Michael Stevens?

  You could dissolve that in some water and people could drink it and say, yeah, there's something in here and I think it might be chocolate. But any smaller than that, and you just will not be able to detect that anything's in your mouth.

• 30:14Hannah Fry?

  I have a question about the molecules that you included. A controversial question.

• 30:18Michael Stevens?

  Yeah.

• 30:19Hannah Fry?

  Did you, um, did you include butyric acid?

• 30:23Michael Stevens?

  Yes, I'm including all of these things.

• 30:25Hannah Fry?

  Okay, wait, wait, wait, wait, wait, wait, wait. This is, uh, this is not chocolate.

• 30:29Michael Stevens?

  Is butyric acid the thing that makes American chocolate bad?

• 30:33Hannah Fry?

  Yes, it is.

• 30:34Michael Stevens?

  Okay.

• 30:35Hannah Fry?

  Thank you for preempting. So this is, um, it's, uh, is this acid that you find, you find it in American chocolate, Hershey's in particular. Maybe we'll bleep that out in case Hershey's wants to sponsor us. But you also find it in rancid butter, in Parmesan cheese, and human vomit. So, um, and there, but there is a reason why it's in American chocolate. There is a reason. So this is early 1900s and Hershey wants to mass produce chocolate, but the problem is they were adding milk. The Swiss had this really fancy pants, expensive way of drying the milk so that it didn't spoil before it went into the chocolate, so the chocolate didn't go off really quickly. So Hershey's like, okay, I'm going to develop this process.

• 31:20Hannah Fry?

  And a byproduct of the process to stop the milk from spoiling was butyric acid that went in it. I buy into your answer. You've clearly spent a lot of time doing these calculations and I buy into your answer on the condition that butyric acid is excluded, please.

• 31:35Michael Stevens?

  Okay, fine, let's not allow butyric acid. That doesn't dramatically affect the volume of this very tiny thing. I want to put this into like a few other terms, like a very fine grain of sand, a very coarse grain of silt is on like the microgram, a single or maybe two micrograms of matter. You could taste it. And if we threw in the butyric acid so that it tasted like American chocolate and made us feel like we had just puked in our mouths, it would still be a microgram, okay? You wouldn't need to add much to give it the same ratio as Hershey's chocolate or something.

• 32:14Hannah Fry?

  That's why I want, I want an experimental version of this episode where you stir in one grain of silt into some water, taste it and they go, I know exactly what it needs. Throw in a couple of molecules.

• 32:27Michael Stevens?

  Throw in, you throw in a billion atoms of butyric acid, which by the way, is a tiny microscopic amount.

• 32:33Hannah Fry?

  And then go, tastes like childhood, tastes like my childhood.

• 32:36Michael Stevens?

  But I think, I think that, gosh, butyric acid might not even really come through in a small amount, because I'm looking this up, its flavor threshold is between one and 15 milligrams per liter.

• 32:49Hannah Fry?

  Okay.

• 32:50Michael Stevens?

  So it takes a lot of it for us to taste.

• 32:53Hannah Fry?

  A lot of human唾沫.

• 32:55Michael Stevens?

  That would mean that if you cut up a Hershey's bar small enough, you would, you would be left with some flavor compounds that were above the threshold, but the butyric acid would no longer be there. So eating that one tiny piece, just that one piece, it would once again taste like regular, nice chocolate.

• 33:14Hannah Fry?

  Maybe that's the secret. If you're ever stuck with only American chocolate to eat, just cut it up really, really, really, really small.

• 33:20Michael Stevens?

  Yes, sub-microscopic scale, you're good to go.

• 33:23Hannah Fry?

  I think we may have ruined our chances for sponsorship with Hershey's, but now all the same, shall we go to a break?

• 33:30Michael Stevens?

  Yeah.

• 33:37Hannah Fry?

  This segment is brought to you by Cancer Research UK.

• 33:40Michael Stevens?

  Now, when we think about scientific breakthroughs, we usually don't think about naked mole rats, unless you listen to this podcast a lot, in which case, we've got some more stuff for you. We also think about things like cutting-edge technology and huge amounts of data. But, you know, often, progress starts somewhere quieter, with just curiosity.

• 34:01Hannah Fry?

  Absolutely. And that brings us to a story of discovery in cancer that begins with two very unlikely places, a brewery and the sea. Yeast, sea urchins, and research that would later be recognised with the Nobel Prize.

• 34:16Michael Stevens?

  So today, we're asking, how does curiosity-led science end up changing how we understand and treat cancer?

• 34:24Hannah Fry?

  Okay, well, some of the most important advances that happen in cancer research don't actually begin with cancer at all. They begin with scientists who are following an unexpected question.

• 34:35Michael Stevens?

  Yeast and sea urchins do not seem like obvious places to start if you want to understand cancer. But scientists use organisms like them because they're simple, and they're fast, and they're easy to observe, which makes fundamental biological processes much clearer. Now, the crucial insight is that the core machinery controlling how cells behave is shared across much of life. Some of the most important proteins were established very early on. They are fundamental to life, and around half of yeast genes can be directly swapped with human ones. Now, Cancer Research UK backs this kind of foundational, curiosity-led research, including work that can take many years to reveal its value. Because understanding the basics

• 35:18Michael Stevens?

  is often essential to understanding disease.

• 35:21Hannah Fry?

  Okay, well, let's give you an example. An example about Cancer Research UK scientists, Sir Paul Nurse and Cell Division. Now, before becoming a Cancer Research UK scientist, Sir Paul Nurse, he worked in a Guinness Brewery, where he was working with yeast. And he started getting curious about the way that these yeast cells would grow and divide. And then, years later, he was working as this young researcher, and he noticed something really unusual. There were these yeast cells that kept on getting longer and longer and longer, but weren't dividing.

• 35:55Hannah Fry?

  And as a result of that, his curiosity led him to identify this gene that was acting as a control switch for cell division, later called CDC2. And then scientists together, they they methodically tested human genes one by one by one, eventually showing that this human version of the same gene could stand in for for the yeast version. And that demonstrated that the the same division control system operates in yeast all the way through to humans. And that makes it this vital insight for cancer biology, where of course, it's all about cells dividing when they shouldn't.

• 36:33Michael Stevens?

  Yeah, the circle of life. We are all bound together. Speaking of circles, let's talk about cycles, because at the same time, Cancer Research UK scientist Sir Tim Hunt was studying sea urchin embryos. And he was intrigued by this really bizarre fact that unfertilized sea urchin eggs can be triggered to start dividing on their own. And that offers a powerful way to study the earliest steps of cell division. So, okay, first of all, to understand, sea urchin eggs required a lot of sea urchin eggs, which was not easy for him to get in landlocked Cambridge. But he observed proteins that build up and then trigger cell division and then actively break down straight away.

• 37:16Michael Stevens?

  And these rise and fall proteins became known as cyclins, because their levels cycle in time with cell division. Also, Tim Hunt loves cycling. Bi-cycling. Bicycling. Anyway, all of this revealed that cell division isn't just switched on or off. It's a tightly timed and carefully regulated thing, like a like a metronome or a traffic light. And so together with the yeast work, it showed that cell division follows an ordered sequence, not a random process.

• 37:47Hannah Fry?

  Right, so you're building up this picture of how cells actually divide. And I mean, these discoveries, they helped scientists to understand, particularly when cell division control systems fail, which is one of the defining features of cancer. And then that understanding laid the groundwork for targeted treatments. And so today, I mean, this has had a gigantic impact. It's already improving outcomes in really difficult to treat breast cancers. There are trials underway across lung cancer, skin cancer, bowel cancers. There's some drugs that work by jamming the machinery that drives cell division, that slows down tumor growth in certain cancers. And all of these advances, they only exist because the researchers,

• 38:31Hannah Fry?

  they followed these unexpected clues and then they tested them rigorously again and again over many years. Now, Cancer Research UK continues to support research across this full pathway by funding early discovery science long before outcomes are guaranteed and helping to translate that knowledge into new treatments.

• 38:53Michael Stevens?

  A humble yeast used for brewing beer and sea urchins in the ocean aren't where you would expect cancer research to begin, but it's exactly the kind of curiosity-led science that helps reveal how cancer really works.

• 39:08Hannah Fry?

  For more information about Cancer Research UK, their research, breakthroughs, and how you can support them, visit cancerresearchuk.org/rastiscienc.

• 39:20Speaker 04

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• 40:21Hannah Fry?

  Okay, we are back. We are refueled. We are, we are ready for the next discovery. And Michael, over to you. What have you got for us?

• 40:29Michael Stevens?

  Over to me. I've got, I've got a few things. I'm traveling at the moment and so I don't have, I've kind of had to scrape together some ideas. But look at this. Now, I won't explain why I'm traveling with this, but it is a stool sample.

• 40:47Hannah Fry?

  Wait, no.

• 40:49Michael Stevens?

  What I'm showing is a little plastic vial that contains a tiny wooden stool, a sample of a stool, if you will. A three-legged stool made of wood. It's about the size of, you know, half of my thumb. So it's just a stool sample. And there's a sticker on the vial. It says Prairie Dog Town Stool Sample. Prairie Dog Town is a little roadside attraction in Kansas and they sell some of these goofy things like, you know, a box of bees. And you open it up and it's just like the letter B painted all over the inside of the box. All right, so I had to buy this stool sample and I just carry it around. Sometimes if someone ever is like, "Michael, you gotta blow my mind right now."

• 41:33Michael Stevens?

  I'm like, "Guess what I've got." It's a, it's a good thing to have around.

• 41:37Hannah Fry?

  Is that why you continue to have that giant rucksack full of, full of stuff for all the times people ask you to instantly surprise and amaze them?

• 41:44Michael Stevens?

  Well, yeah, you know, because, because they kind of expect it. But also I like it. I like it. I like having something kind of strange with me at all times. That reminds me of a show that never actually happened because of COVID. So like just before COVID, I did a show at UC Irvine, the University of California Irvine, called Michael's Toys, where I just showed up with a bag full of toys and I just talked about them and passed them around. And it was so fun. And then with COVID, I tried to figure out a way to do the show virtually, but it was just not nearly as fun as being able to pass around a cube of tungsten

• 42:24Michael Stevens?

  and the most illegal thing I own, which by the way, I cannot find. Now, I've talked about this in a video, but I have an update on the item. Not just the fact that I may have lost it, but there's something else quite strange. Do you know what I'm talking about?

• 42:40Hannah Fry?

  Okay. Well, I mean, you've mentioned, wait, how did you describe it? Just then, the most illegal thing you own?

• 42:46Michael Stevens?

  It's the most illegal thing I own.

• 42:48Hannah Fry?

  Okay. I mean, you've mentioned quite a few things on the podcast over time. You've mentioned radioactive lead. You've mentioned enriched uranium. There's, I'm pretty sure there's, there's, there's various stories about BB guns, et cetera. So honestly, the, the mind, the mind boggles.

• 43:04Michael Stevens?

  Okay. Well, so I don't own any enriched uranium as far as anyone knows. But the thing, the thing I'm talking about is, is a totally legal material. It's the way the material is arranged that makes it illegal.

• 43:18Hannah Fry?

  Okay, go on.

• 43:19Michael Stevens?

  But maybe it's not illegal anymore. It is a counterfeit US penny.

• 43:26Hannah Fry?

  That is pretty illegal, Michael. I believe that they, they come down, they come down pretty hard.

• 43:32Michael Stevens?

  It is illegally manufactured currency and it's a penny. So someone took some copper and some, you know, they, they, they put together the, the appropriate alloy to make a penny and then they made a mold or maybe they stamped it. I'm not sure how they made it, but it is identical to a regular US penny. You could spend it and get a cent worth of value, a cent worth of goods, without actually having earned that money.

• 44:00Hannah Fry?

  And as long as it costs you less than a cent to make it, you're winning.

• 44:04Michael Stevens?

  It costs a lot more than a cent to make. It costs, or should I say, used to cost the US Mint like four or five cents to make a penny.

• 44:17Michael Stevens?

  So making counterfeit pennies is probably not going to get anyone in trouble because you're losing money doing it. I won't say who gave it to me, but it was given to me by a magician, who was a very interesting guy. And the thing that makes this counterfeit penny so special is that you can tell it's counterfeit for one tiny reason. And that reason is that the year stamped on it. Every penny in the US has a year on it, the year that it was made. The year on this penny is 2027, which hasn't happened yet. So no 2027 pennies had ever been made. The whole time I've owned this penny, it's been like a penny from the future, right?

• 45:01Michael Stevens?

  And then I thought philosophically, this is really interesting because by in the year 2027, it will cease to be a joke and it will just look like every other penny that's ever been made.

• 45:13Hannah Fry?

  It's the perfect crime.

• 45:15Michael Stevens?

  Exactly. It's novelty kind of expires. And it almost becomes more criminal in 2027 because before that happens, people can tell that it's not real. But after 2027, it could be real. But here's obviously, and I think a lot of listeners are probably thinking this. The new twist is that the United States Mint, just a few months ago, announced that it will not make any more pennies ever again.

• 45:46Hannah Fry?

  The joke lives on.

• 45:48Michael Stevens?

  That's right. So the last penny was made in 2025, which means my 2027 counterfeit penny will always have an impossible date on it. Its entire character has changed.

• 46:01Hannah Fry?

  Wait, I want to know, how did this magician get hold of it? What was the magician doing with it?

• 46:06Michael Stevens?

  Well, he was just a guy who also liked to collect curious things and had a lot of very interesting friends. And one of them was a metallurgist who made I probably made counterfeit coins, not for the purposes of counterfeiting, meaning to pass it off as real currency, but to to design special magic coins, like a quarter that's hollow or a quarter that can be folded up, you know, stuff like that. And he made this penny. And I think he said, you know what? If I'm going to make a penny, I can decide what year to stamp on it. Why don't I stamp a year far in the future? So it looks like it's from the future. That also makes it funny because it'll be even more believable in the future. But no one could have anticipated that in November of 2025,

• 46:50Michael Stevens?

  the last pennies would be made. And so suddenly I have an item with a whole new meaning.

• 46:56Hannah Fry?

  A perfect ending to the story. I do. I do remember hearing about Banksy, the artist. I don't know. Have you come across him? I don't know how well he how well known he is in America.

• 47:07Michael Stevens?

  I am Banksy.

• 47:08Hannah Fry?

  Oh, OK, so very well known.

• 47:10Michael Stevens?

  Did you not know that?

• 47:11Hannah Fry?

  Well, this is OK, a story about you, of course.

• 47:14Michael Stevens?

  I've been trying to tell people, but they all just act like, oh, who is he? I think they enjoy that more.

• 47:19Hannah Fry?

  Yeah, the Bristolian accent is just a put on that you that you do when you're covering your identity.

• 47:25Michael Stevens?

  That's right.

• 47:26Hannah Fry?

  He had. There was a stunt that he was going to do where he printed a million pounds worth of fake 10 pound notes. And where he replaced, instead of having the Queen's face on it, this is a few years ago, he put on Princess Diana's face instead. And then, instead of it being Bank of England, it was Banksy of England. Anyway, the idea was that he was going to go to some sort of town square. I think I'm remembering this right. And throw out all of this money and let people collect it. And just in advance of this big stunt, which he had planned, he went to Reading Festival and with a bunch of his friends and handed out a bunch of these like fake 10 pound notes, which looked really good. And like, go on, go and see, it'll be quite funny.

• 48:10Hannah Fry?

  Go and go and see if you can spend them. And these people went up, spent the 10 pound notes. Nobody checked them. Nobody checked them. They went through absolutely fine. And at that point, Banksy realized that what he was about to do was so phenomenally illegal.

• 48:29Hannah Fry?

  But somewhere out there in the world is this very small number of Banksy ten pound notes which were exchanged and are now worth an absolute unimaginable amount of money.

• 48:42Michael Stevens?

  Jeez, I can only imagine, yeah, but see, if it confuses people, if it tricks them into thinking it's real, then yeah, it's counterfeit money and it's illegal. There was an artist, I don't remember the artist's name, but when I was a kid, my dad and I watched a documentary about this artist who drew on a sheet of paper a one hundred dollar bill by hand, like meticulously, every little detail drawn by hand, and then took it to a store and didn't try to pass it off as a real hundred, simply said to the person at the store, hey, this isn't a real hundred dollar bill, but it looks real, doesn't it? Like, would you give me a hundred dollars worth of goods in exchange for this piece of art?

• 49:25Michael Stevens?

  And they agreed, so he bought like a hundred dollars worth of stuff with his fake hundred dollar bill, but it was more of a barter exchange than it was fooled you. So I don't think that was nearly as illegal, but as soon as you pretend it's currency and people start believing it is, then you've committed a crime.

• 49:44Hannah Fry?

  I made a documentary a few years ago about the passport, the British passport, and the number of different layers of security that they have embedded within them in order to prevent people from just copying what they look like, and it is phenomenal. I can't remember the exact number, but we're with the man who has designed a number of different British passports, but it's something like twenty different systems. Some of them are very obvious, some of them are much less obvious, you know, every single page is unique, there's like a pattern along the side, there's also this extraordinary pattern, if you look at it under UV light, that is different for every country. I mean, it's absolutely incredible, the amount of science and, well, just considered

• 50:28Hannah Fry?

  engineering that goes into making one of these things. There was a big controversy in the UK a few years ago when our passports changed from red to blue, and the passport designer said that his favorite vintage, the best passport he's ever designed, was the last red one with a paper page, because they've now got this sort of plastic page where your photograph is. So the one with the paper page was absolute counter counterfeit genius, that's what he says.

• 50:58Michael Stevens?

  But surely the plastic page makes it even harder to counterfeit.

• 51:02Hannah Fry?

  I think that there were some quite clever things about the way that you could, the transparency of that paper page changed across the course,

• 51:10Michael Stevens?

  Really?

• 51:10Hannah Fry?

  Across the grain of it, yeah.

• 51:12Michael Stevens?

  So my, my, my American passport still has all paper pages. My wife has a British passport with like a plastic page. And it doesn't feel like a book anymore. It feels like, like one of those novelty books that has like all kinds of little things inside of it, like a Klutz book. So I don't enjoy it as much, but I'm sure it's a lot more steady and less likely to get all folded or ripped by mistake.

• 51:35Hannah Fry?

  Yeah, I mean, you know.

• 51:37Michael Stevens?

  Okay, speaking of books, there's something that we teased in the beginning that I haven't gotten to yet. And, and in way of context, I wrote this book, I think, I, I don't actually know how old I was, but it's one of those books that a kid makes by taking sheets of paper, folding them in half, and then stapling them together. Now, remember that I grew up in a small town in Kansas that was quite conservative in many ways. And there was a very big debate around whether or not evolution should be taught in schools and how it should be taught. Should it be taught as what scientific consensus believes explains the diversity of animal life and life on earth? Or is it just a theory full of many problems?

• 52:22Michael Stevens?

  Because the truth is that all life on earth was created by a creator god. So I was given many, many books as a kid about how evolution was a lie and that creation science was this thing. Creation science is of course a pseudo scientific idea that maybe the world is only a few thousand years old, could be older, but that clearly nothing evolved in the way that Darwin said, that the world was obviously created by God. And so I summarized what I had learned in this book. Evolution, the lie.

• 53:00Hannah Fry?

  Wait, how old do we reckon you were when you wrote this?

• 53:02Michael Stevens?

  Like, I wish there was a year on it, but I'm going to say I was probably 10 or 11.

• 53:09Hannah Fry?

  Okay, immediate things that stick out for me, right? One, look at that E on evolution. That is, there's, there's design that's gone into that. There's like, and the different type of font that you've created for the word lie, the sort of bubble font of the word there. This is, um, look, it's typographic, everybody. There's no, there's no pictures, there's no images. It's just clean, it gets in and gets out.

• 53:31Michael Stevens?

  It's very, it's very sophisticated. I clearly, I, I must have had some kind of stencil tool. And that's how I created these different typefaces. I may have, I may have had a book of typefaces and then I traced each letter off of, um, that page, but I don't think that I came up with this on my own. Especially L I E, lie. That does not look like something I came up with.

• 53:56Hannah Fry?

  Well, it certainly looks like something, um, adults had a heavy hand in influencing somewhere or another.

• 54:02Michael Stevens?

  Basically, it just reads like a whole list of the, the typical concerns people had with evolution. They would say things like, there's a difference between evolution with a capital E and evolution with a lowercase e, where lowercase e evolution is just the way things change. You know, it's the way the, the moths in England, um, died off if they were white because of all the black soot that covered the trees. Predators could find them more easily and so the black ones became more prevalent. It might be kind of boring, but I'll, I'll, I'll read, I'll read from chapter two, Stanley Miller's experiment. Are you familiar with this experiment?

• 54:36Hannah Fry?

  Of course.

• 54:38Michael Stevens?

  Okay, well, we all know about Stanley Miller's, I'm, I'm reading from the book now. We all know about Stanley Miller's, quote, "life from a test tube," unquote, experiment. He mixed gases and liquids thought to be on earth billions of years ago, i.e. before life, then shot sparks at the mixture and poof, special amino acids found in living things. Newspapers raved about, quote, "life in a test tube." That is just the same as a man stacking two bricks on each other and saying he made a 50-story skyscraper.

• 55:11Michael Stevens?

  First, those same acids can be found in dead bodies too. Just having the right acids doesn't make something alive. Second, the three needed acids weren't there. And third, many deadly acids have been formed in experiments like this. So as you can see, life can't just happen. It must come from other life. In a creationist's view, God.

• 55:34Hannah Fry?

  Okay, here's what I'm noticing from that. We've got, we've got the hook, right? You've got, you've got the excellent title right at the beginning. You've got the counterintuitive way to see the world. Here's what everybody else thinks and here's how it should really be. We've got detail on scientific minutiae. And we have got what is essentially a, an extremely fascinating monologue. Vsauce was there, it was the early beginnings.

• 56:01Michael Stevens?

  It was, yeah, it was there, it was there. You know, this is a Vsauce script. You know, no, I no longer believe that evolution is clearly false.

• 56:11Michael Stevens?

  But I do think that, you know, belief in, in a supernatural creator does not exclude belief in evolution. Exactly as Darwin said, I think that that is to make religion way too small. But you can definitely see how I was synthesizing information. And then, rather than just saying, okay, cool, I decided to create,

• 56:32Michael Stevens?

  not videos, but there was no YouTube back then, but books where I taught what I had learned. And put it into, you know, words and phrases that I thought would make it exciting.

• 56:43Hannah Fry?

  So I also actually grew up in a very religious household. Where we would often have Catholic priests who would come around and say mass in my living room. Right, it was not, it's not a big fancy house, to be absolutely clear, it was a very small living room. But nonetheless, priests would come around and say mass. Anyway, there was one time in particular where there was a priest who was giving his, his sermon, his little homily. And he was talking about how science and religion were at war with one another. And how science was seeking to destroy religion. And he was so deeply moved by the words that he was saying that he cried, and that was the first time I'd ever seen a grown man cry.

• 57:24Hannah Fry?

  And the thing is, is that while I completely understand the emotional weight behind feeling like you're, I mean, the the sort of central story to your life is under attack, right? And I I think that lots of religious people do feel like that about science. I agree with you. I don't, I have never thought that science proves that there is no God, or that science really has anything to say about God in any way whatsoever.

• 57:51Michael Stevens?

  It it can't, it can't, because claims about God are specifically beyond Newton's flaming laser sword, meaning, science cannot disprove it one way or the other. And if it thinks that it has, it's not science anymore. And so that that means that religious claims are unfalsifiable, but it doesn't mean that they therefore are false.

• 58:13Hannah Fry?

  I also think that it's it's sort of, it's dishonest to pretend that science is the hunt for truth all of the way down. I think that inevitably, once you hit the absolute limits of our knowledge, there does come a certain leaf of faith, regardless of what camp you find yourself in, whether it's religious or or scientific or both. You know, why is the speed of light an absolute constant? You know, what happened before the Big Bang?

• 58:43Michael Stevens?

  Or is the speed of light an absolute constant? We don't know. We are making some assumptions here, and there's evidence that it it hasn't changed. But how would we know? What sort of evidence should we be looking for? And that's thinking scientifically.

• 58:57Hannah Fry?

  Yeah, absolutely.

• 58:58Michael Stevens?

  It's important to me to give it a little bit more context, too, which is, first of all, when did this man cry in your home about the war between science and religion? Like, do you mind telling me approximately when?

• 59:11Hannah Fry?

  It was probably, it was probably, it was almost certainly the nineties.

• 59:14Michael Stevens?

  Okay.

• 59:14Hannah Fry?

  And my guess would be around ninety-five-ish.

• 59:20Michael Stevens?

  That's very interesting because it's probably about the time that I was hearing a lot of this too. Obviously, science and religion have been famously at odds forever. Okay, but keep in mind that, you know, my father was a chemical engineer, you know, he definitely believed in evolution as an explanatory theory. And I remember being a very young child, um, single digits old, in Sunday school. And my Sunday school teacher, who was a woman who was about 180 years old, says to all of us that science and religion are not at war. Like, of course, God used evolution to to bring about life, in exactly the way scientists say. And it wasn't until the election of George W. Bush, which was

• 1:00:03Michael Stevens?

  in 2000, that suddenly everything changed. And a lot of adults in my life, not my parents, but other adults, kept pushing creationist books on me. And I thought, what's, I thought, I thought that we all agreed, you know, that the same church now had a different position that was much more culturally motivated than it was biblically or scientifically. And it really was a big shift. And I remember that my high school biology teacher, Mr. McDonald, was really controversial because he was fighting for Kansas to allow evolution education in classrooms. And I really looked up to him for that because I didn't understand why

• 1:00:43Michael Stevens?

  it was so evil to see that evolution explained things. I didn't think there was a conflict. It was like, whether or not, you know, we have a soul is very different than whether or not, you know, mammals came, you know, after bacteria. Or, and how, and how that transition happened.

• 1:01:05Hannah Fry?

  Yeah, I totally agree. I mean, I remember, I remember very well, hearing the stories about America, um, having those discussions about evolution. I think there was a bit of a backlash here, actually. I think in around 2010, there was a real movement from a number of actually quite distinguished scientists, um, who became really vocal, quite militant, frankly, militant atheists.

• 1:01:30Hannah Fry?

  And anyway, I just would like to do things a bit nicer. I just, I just think extremism is best avoided in all directions. So maybe that's what you get with this podcast, right? That's what you get with me and Michael. We get, we're, we're nice, cuddly, all-inclusive. The world is a broad church and so is science.

• 1:01:50Michael Stevens?

  That's right. And we are always learning because we're curious. And above all, being thoughtful is what matters. So although I probably won't ever publish Evolution, the lie, it is a part of, of my journey. It's a part of my coming to understand this world that I was born into.

• 1:02:08Hannah Fry?

  Yeah, well, thank you so much for sharing with us. Well, okay, that I think concludes our, our podcast expedition for today. If you have any questions that you would like us to answer, or any stories you want to tell us, or objects you want to share with us, you can send them to us, [email protected].

• 1:02:24Michael Stevens?

  And you can join our newsletter at therestis.com/science.

• 1:02:29Hannah Fry?

  We are going to be back next Thursday with another edition of Field Notes, and on Tuesday with our normal episodes.

• 1:02:36Michael Stevens?

  That's right. Until then, stay curious, stay thoughtful. Goodbye.

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