The phizz-whizzing science of Roald Dahl

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2:00What's up at Whole Foods Market. This is a science show inspired by the news or events in the news. Each week we scow the headlines and the calendars for a story or an event that catches our imagination. That starting point becomes our news, our inspiration to talk science, often springing into unexpected directions. I've already mentioned my love of hanging out at the school library. This week, our starting point is connected to an author whose books would have laden the shelves. Take a listen to this.

3:01Hello and welcome to a very special, rolled-out day. His books are loved by tens of millions of young readers the world over. I'm Matilda. Where the witch is? History Walker. They've been made into Hollywood films. The stars were out in force for the world premiere of Fantastic Mr Fox. What do you still watch? Oh, I love it. I love it. Yes, I don't know what I do without something to work and worry about all day. So, 13th September is Roll Dal Day. So Dal, who was born right here in Cardiff, where I am today, is the author of Matilda, Charlie in the Chocolate Factory, BFG, countless more, millions of kids will have imagined delicious, lickable wallpaper or life inside a giant peach or having the power to move objects with their mind or fly or become a mouse. Thanks to the worlds he created. I should say he is not an uncontroversial figure. He made anti-Semitic comments that since his death, his family have condemned and apologized for.

4:04He also definitely had a cruel streak, which bled into some of the stereotypes he used in his books. So, a few years ago, 2023, his publishers released updated versions of his children's books, reviewing some of the language that he used. He also had an extraordinary life, I'd say, writing in his two autobiographies about the horrors of his school days and the horrors of fighting in World War II. He invented language, he invented wild worlds of possibility, and even patented a brain shunt, the Wade-Dal-Till Valve. So, Roll Dal Day is to celebrate that creativity, and we're here to bounce off those ideas and back into science. Who panel wants to start? I'm super excited about this week's theme, because I don't know about you guys, but I loved Roll Dal growing up. One of my favourite books of his was Charlie and the Chocolate Factory, which, as you probably know, is about young Charlie Bucket winning a golden ticket to visit the world famous, but very mysterious, Willy Wonka's Chocolate Factory,

5:08which is this glorious place with a chocolate river, edible rooms, and so on. But what I want to talk about today is a different kind of magic. Scientists who are trying to create chocolate in the lab. Okay, so I know chocolate as something that comes from the cocoa tree, which, back in the 1700s, called Linnaeus, who gave names to lots and lots of things. He gave the cocoa tree its scientific name, which translates from Greek as food of the gods, Theobroma-Cacao. So he was clearly a fan of chocolate. I mean, the question is, why would you improve on perfection? That's a very, very question, Marty. So cocoa, which is the plant that gives us cocoa, it's been having a rough few years, and this is something that we've discussed on previous episodes, right? So basically, there's been this perfect storm of disease, climate change, deforestation, and poor farming practices in Ghana and Ivory Coast, where about 70% of the world's cocoa is grown, and that's caused a severe shortage of cocoa in recent years,

6:13which is why in the past few years, researchers have been working to find alternative ways to produce cocoa. Okay, like growing chocolate in the lab, tell us more. So there's a bunch of different companies that are looking into this. Most of them are in the US or Europe, and this one in Israel as well. They have different proprietary methods, but, broadly speaking, they all use the same approach. So first of all, they choose a cacao bean from a tree that has a special good flavor, aroma, or some other desirable property. They then take some cells from this bean, and they put it in a nutritious liquid, which makes the cells grow and multiply. And all this takes place in large bioreactors, so it's similar to the tanks that are used for brewing beer. And then after some time, they have as the cells, have them undergo fermentation, then they dry them out and mill them into cocoa powder. That's fascinating. I can see why this might be a more appealing way of producing cocoa. I mean, growing cells in bioreactors takes up way less land and fewer resources.

7:13Yeah, it's definitely more efficient. So for example, Celeste Bio, which is an Israeli food tech starter, backed by Mondaleese International, the company that owns Cadbury. So they say their process takes just one or two beans to produce the same amount of cocoa butter that would traditionally take four tons of cocoa. And 10,000 square meters of land, which is just mind blowing. Is this lab-grown chocolate actually on sale yet? So in April this year, Celeste used their lab-grown cocoa to make cocoa butter, which they then use to produce about a dozen chocolate bars at Cadbury's Bornville factory in the UK. These were just prototypes, though. They want for sale. The company says they're aiming to release lab-grown chocolates to consumers sometime next year. And that's around the same timeline that other companies in the space are kind of working towards as well. But there are some downsides to lab-grown chocolate that I like to mention, too. So even though cocoa farming can sometimes be exploitative, I mean, I'm sure you've heard of the issues with child labor and dangerous working practices.

8:15This farming is still really important to many smallholder farmers in West Africa. There are roughly six million people who depend on cocoa farming for their livelihoods. And these are people who already live in poverty. So lab-grown chocolate could really aggravate this by stealing their livelihoods. Yeah, personally, for that reason, I'm going to stick with paying a lot for chocolate. That comes from an actual tree. So what about you, Tristan? What do you think? I'm mostly concerned about tastes first here, but I think also, yes, a vision of corporate responsibility bothers me quite a bit also. Some things to work out there, I think. What I think they ought to do is for small people who have different palettes. I think it just should be sugar and artificial colourings. And then grownups can have all of the cocoa. And then there's enough to go around to satisfy discerning palettes and people that just want sugar. I'm okay with this. And I think you can take it a step further is that you should ban American companies from making chocolates.

9:18This is almost trash. As an employee of the BBC, I do not have any opinions on American chocolate for Tristan, who's from Texas is allowed to. Tristan, having opened with that bombshell, where are you taking us next? Well, unlike Sandy and the rest of the crew here, I actually didn't read Roll Dolls books, but I am aware of his character, the big friendly giant, the BFG, who apparently blew dreams into children's bedrooms. And I came across some research where scientists are figuring out ways to actually design and inject pleasant dreams into patients under anesthesia. That sounds absolutely amazing. Why is it just patients under anesthesia who get to have the good dreams? I'm assuming it's a consolation prize for having your gallbladder removed. Maybe. So, dreaming during anesthesia has been documented for more than a century, and some clinicians were worried that if patients were dreaming, they might incorporate actual sites and sounds from the surgery, essentially leading to post-operative post-traumatic stress symptoms.

10:24Okay, so it sounds like doctors wouldn't want you to dream during anesthesia. Additionally, yes, but research is moving dreams during anesthesia into sort of a more common and positive space. Now, anesthesia and natural non-rapid-eye movement non-rhymed sleep share similarities, such as unresponsiveness and particular brain wave patterns. And previous research found that it was possible to influence non-rhymed dream content by getting people to perform certain repetitive tasks before falling asleep, then they would dream about those tasks. Doctors and psychologists in Hungary hypothesize that they could apply similar mechanisms to patients before they underwent surgery in order to influence their dreams. What kind of tasks are we talking about? What did they do? Well, in a study published in 2016, they led patients through a relaxation exercise before anesthesia, where they were asked to imagine their favorite place. So the researchers found that once anesthetized, those patients essentially consolidated those freshly planted memories.

11:27And upon waking, about 75% of patients recalled dreams that actually matched the memories. Okay, so it is actually possible to induce pleasant dreams in people before they go through anesthesia. Yeah, and bring this up to date a couple of months ago, Stanford University released a pilot study, saying that they had been highly effective at inducing dreams and patients developing a protocol that has raised dream recall and patients from 69% to 93%. 86% of those dreams were positive, with no particularly negative dreams. So positive dreams, and they've got a protocol that helps people remember the good stuff. What is that protocol? Doctors first speak to patients before surgery to establish positive expectations and emotions. During surgery, the drug Propofal is used as part of the anesthetic cocktail. Propofal was associated with higher dreaming frequencies. Anesthesiologists also conduct continuous monitoring to really precisely track sedation levels and allow for gradual controlled emergence from sleep.

12:32And then once awake patients are interviewed almost immediately before the dreams are lost. So interviewing within minutes of waking helps capture the details and screen for intra operative awareness, that terror that you were actually awake but paralyzed during the surgery. I should also say that some researchers are leaning into using these findings to help people with insomnia or chronic nightmares and also the treat PTSD. This is also fascinating Tristan. But what I want to know is, can I use this protocol, say tonight to get some good dreams? Same. Yep. Yeah, the science here is really applicable to your own pre-sleep routine because the brain actively replays processes and consolidates your most recent episodic memories. It may sound a little silly, but just trying to find that happy place could be something people can do. I actually try this myself before bed sometimes. Oh, go on. What's your happy place? Do we really want to know? You don't want to know. You don't want to know. Normally the last thing I want is anyone's stories of what happened in their dreams, but actually I will make exceptions this time round if listeners had a really good one under anesthetics.

13:42Please tell us the story. Also, would you eat lab green chocolate? You can email unexpected at bbc.co.uk or you can send us all WhatsApp message. The number is plus 444-330-678-3080. Still to come, what connects a chocolate cake, a hot dog and you say in bolt? Find out after this. Hello, it's Sophie here with this week's Unexpected Elements Quiz and this week we've been exploring science inspired by rolled Dal Day. One of the author's earliest books was James and the Giant Peach, which tells the story of a fantastical peach that becomes so gigantic that the orphan James is able to live inside it. In real life, we may not be able to make a peach our home, but we can still enjoy them as a tasty snack. And if you've had a peach recently, you'll know that they are covered in fine hairs or peach fuzz. But why a peach is fuzzy? Is it A, to stop flies from reaching the fruit? B, it evolved from thorns? Or C, it attracts pollinators?

14:43Have a think and I'll be back soon with the answer. You're listening to Unexpected Elements from the BBC World Service. This week our science-based chat is taking its inspiration from the works of children's authors. Now Bruce Bogtrotter is not arguably an important central character in rolled-al's story, Matilda. However, the story is not a huge deal. The story is not a big deal. But the inspiration from the works of children's author, Roldal, thanks to Roldal Day. Now Bruce Bogtrotter is not arguably an important central character in rolled-al's story, Matilda. However, he is the hero of many people's favourite part of the book. For those who've not read it, Bruce is a child caught stealing a piece of chocolate cake from the villainous head teacher, Miss Trunchbull. As revenge, she pulls him onto stage in front of the whole school and forces him to eat every last crumb of a specially made, enormous cake.

15:47She's imagining his humiliating failure and suffering, but Bruce discovers a hidden talent for stuffing his face. Obviously, we're here for the science behind Bruce's amazing abilities, and Professor James Smolger from Tufts University School of Medicine, is here to tell us about his groundbreaking study of a classic American competition, Nathan's Famous Hot Dog Eating Contest. First of all, welcome to Unexpected Elements. Thank you so much, please to be here. For listeners not aware of this annual bananzer of gluttony, can you describe Nathan's Famous Hot Dog Eating Contest? Sure. Nathan's Famous Coney Island Hot Dog Eating Contest is an annual competition, and in this competition, contestants have its change of the years either. It's a change of the years, either 10 minutes or 12 minutes to eat as many Nathan's Famous Hot Dogs with bun as they can. Tristan, bringing you in. I guess this makes me wonder, does this activity actually require training, or can anyone who's like a healthy eater just step up and do it?

16:50What happened over the years, it went from people that had a healthy appetite that said, hey, I could eat a lot of hot dogs. This sounds like fun to more of a professionalized type of competition that people actually did train for. The big change in the eating competition was in the late 90s when Takeru Kobayashi from Japan first came to the competition. At that time, the record was 20 or 25 hot dogs, and he ate that many hot dogs. I think it was in the first three minutes of the contest and then continued on to eat over 50. So, yes, now today's top competitive eaters are those that specifically train for the event. And how did you get involved in this? Why did you get interested in this topic? At some point in the 1990s, my father and I watched a documentary all about competitive eating, and at some point we also found the Kone Island Hot Dogs are getting contested. And so every year, we would tune in. It's one of those things that just so fastening, you can't take your eyes off of it.

17:50So, how do I get involved in the research is one of my things that I love and am passionate about is track and field and track and field performance. That's my background. I'm a sports scientist. And in our track and field world, there's all types of research that's been done to determine what are the limits of human performance. People have done mathematical models using historic data to try to determine what is the fastest human can run 100 meters. All right, if you've seen both has run 9.58 for the 100 meters, maybe somebody can run a 9.45 someday, but we could all agree that nobody's ever going to run the 100 meters in three seconds. At some point, mathematically, it becomes impossible. And so I just get the idea popped in my head one day. I wonder if this applies for the hot dog eating contest. And so I decide, all right, let me look and just see because I know there's historical data. And it just turned out that much like track and field and much like swimming, the historical data for the Nathan's County Island hot dog eating contest was very well documented.

18:50So I decide, all right, let me apply these same mathematical formulas. And it follows the same attack pattern that we see in track and field and swimming. When you say historical data, do you mean like the final number of hot dogs that they ate or are you going back to the videos and watching their performances? It's mostly local newspapers or I think even New York Times and some other New York City Metro papers have reported those numbers and they'll say the contestants name a lot of times they'll say the age and pretty much in every account, they list what the time limit was of as 10 minutes or 12 minutes. And then I believe it was a Nathan's website. They also compiled all the results. And it was really interesting because I was able to cross check what Nathan's reported and also to the contemporaneous accounts in the newspapers and just make sure everything ended up. And then one other thing I did to because I actually emailed one of the vice presidents at Nathan's and inquired just to ensure has the hot dog composition been the same over the years of the contest. And the answer I got was yes that the Nathan's famous hot dog has stayed exactly the same composition for over a hundred years. Basically everything came together. I had contemporaneous records from multiple different sources.

19:58You've got your data points. You've checked your variables. So what did you come up with? You know, I ran this mathematical model and it's something called generalized extreme value theory. And this is actually one of the models mathematical models they use for studying climate change. And essentially we found that if you model the historical data that we have, it suggests that the most Nathan's famous hot dogs with buns that a human being can eat in 10 minutes is 84. At the time, Joey Chestnut, I believe had eaten 74 in 10 minutes. And so we're saying it is mathematically possible for somebody to eat 84. Okay, so the model is predicting that there are records to be broken still. There are records to be broken, but what the model doesn't say is we can't expect that necessarily in the next five years or 10 years. Atristen, you had a question. What is the actual limiting factor that like in the number of hot dogs you can eat from what we could gather.

20:58It seems like the limiting factor for the average person, the average untrained person is probably going to be stomach capacity. How much one stomach can stretch out and accommodate hot dogs. But if you take, I'll say an athlete like Joey Chestnut or Mickey Sudo, some of the top competitive eaters out there, it's unclear if it's stomach capacity or by that point, it might be chewing capacity or maybe swallowing capacity because maybe they've stretched out their stomach. So much that they could fit more dogs. They just can't eat them and swallow them quickly enough. Is that what training involves stretching your stomach? Yes, one of the main things people do is try to stretch out their stomach. Now, how do they do that? One way some people do that is by trying to ingest a large volume of a liquid such as milk or potentially soup really quickly. So that's taking chewing out of the equation. We're just trying to expand that stomach with somebody like Joey Chestnut. There's videos of him online chewing on a rubber ball, trying to maximize not only his mouth muscle strength, but probably his endurance too.

22:05Can I just say this doesn't sound good for you? I would agree. There have been deaths in eating contests. There's also one or two cases in the peer review literature of people having severe gastrointestinal distress that resulted in them going to the emergency department. And then the training itself from what we've been able to triangulate from the peer review literature on this in most sports trainings associated with some sort of short term and long term health benefit. If we're going to call hot dog eating a sport from what we can gather, it seems like instead of improving our normal physiology, we're disrupting our normal physiology. And by stretching out our stomach, we are potentially reducing the number of normal biological signals that tell us when we're full, when to stop eating. So it probably is bad for our bodies. So James, what I'm hearing is that even though there is space according to your model for making a new world record, we should probably advise don't try this at home kids.

23:07I'm going to stick to chocolate cake like Bruce Bogtrotter. Thank you very much, Professor James. Smaller effort enlightening us as to the horrors of competitive eating contests. Thank you so much for the opportunity. I had a blast. So we started off this week's episode with Roll D'Alday. The stories by this creative but controversial author have inspired us to unwrap the science behind lab-grown chocolate. We've also found out how dreams can be engineers during surgery and we just chomped our way through the supersized science of eating contests. Still to come, can you tell if a bee is enjoying its dinner just by the look on its face? And the sticky issues of conservation tagging. That's coming up after this. September's always busy. Whole Foods Market can help. Their September stock up event makes it easy to load your pantry and freezer with flavorful nourishing food.

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25:18This week is the annual celebration of children's author, Roll Dal, with Roll Dal Day on the 13th of September. Now we've reached the part of the programme where one of our panelists finds a story that's maybe gone under the radar of global news. Maybe it deserves a bit of a boost, a discussion at Unexpected Elements Towers. And as ever, if you can link it to this week's theme, I award totally pointless points. Sandy, you are up this time. What have you got for us? So I found this interesting story on Bumblebees, which I'm going to link to one of Roll Dal's short stories called Royal Jedi. So hurrah, I get to claim some pointless points. That was one of his books for adults and it's a horror story, so don't read that kids. Yes, very happy to give you the points though. What are you going to tell us about Bumblebees? So this is a new bit of research that came out just in July in the proceedings of the National Academy of Sciences Journal.

26:18And it was written by a joint team of researchers from Australia and China who discovered that Bumblebees make facial expressions when they eat, which conveys whether they like something or they just really hate it. So now I found this research really interesting because facial expressions are something we often see in mammals, but it hasn't really been observed in Insects before. This is fascinating. What are these facial expressions like then? I'm with you. I thought that Insects all had perfect poker faces. Yeah, so did I. But the researchers actually put out this really cool video of the Bumblebees expressions online and I encourage you to Google it in your free time because it's quite cute to see these bees making these expressions. But basically the scientists conducted this experiment on 18 colonies of Bumblebees. They presented the bees with droplets of different solutions to try. So there was one made of sugar, one of salt, plain water and quinine, which is a bit of substance found in the back of the synconetry that's used to treat malaria. So as the bees were sampling all these different solutions, the researchers recorded them in slow motion video.

27:22And what they saw was that when the bees tasted something good, like the sugar solution, the insects would keep flicking out their tongues or their glossar in this kind of lapping motion. And they kept doing this even after they finished drinking the solution. But when they tasted something they didn't like. So that was the bit of quinine solution and the salt solutions. You see the bees shaking their heads vigorously and they're wiping their mouths with their front legs. Okay, I mean, how do we know this wasn't just a reflex? Great question. So the researchers tested the colonies under a range of different circumstances. So for instance, when it was hot or when the bees were already full. And they did this because they wanted to see if the bees reacted differently to the same solution. And they found that with heat exposure, for example, when the bees drank salty solutions, their reactions change from blah to yum. So it's a bit like someone offering you a salty electrolyte drink on a normal day. You might go, yeah, no thanks.

28:23But on a different day, say after you've exercised in the hot sun, that drink could be exactly what your body needed and it would taste fantastic. I know that's the case for me on a normal day versus a day when I played tennis in the sun for two hours, for example. So what is this significance of this finding? People have gotten excited about this research because it's the first to prove that insects display an emotion light behavior, which until now we thought only existed in mammals. So the researchers who did this new study say their findings indicate that the insects do have some simple capacity to feel the world around them. So in other words, they're capable of having a point of view and an inner life of sorts. Wow, that's quite a lot to build from an animal, you know, wiping its mouth or shaking its head. Yeah, you're completely right in saying that. So from what I understand about the debate is that people are comfortable with seeing that insects can sense the world around them.

29:24You know, they can process information, they can learn things and they make decisions based on the things they perceive. But they're much less comfortable saying that insects can evaluate these things as pleasant or unpleasant. And this is something the researchers of the study were careful to steer clear off. They state that their work does show evidence that insects can like or dislike something, but it doesn't prove that they feel pleasure or displeasure the way we do. One of the researchers said that we don't yet understand what the bee's truly experience, only that we can observe them displaying emotion-like behaviors. I mean, what I'm taking from this is that if you fed a bee a gin and tonic which contains quinine and the tonic water, they'd probably not enjoy it. Or they'd taste it as unpleasant, there we go, which is one step away from having an opinion on it, having an emotional response to the gin. So does this mean that the humble fruit fly is also going to show emotion-like behavior?

30:28Is this like, are we opening a Pandora's box on insects? Because once I know that an animal can experience emotions, I'm probably less likely to want to be involved in killing it and now I do swap flies at the moment. I think it's really hard to extrapolate from just one study to be honest. I think a lot more research has to be done, so yeah, what do you think, Tristan? I mean, yeah, I'm probably not going to stop swatting fruit flies, go ahead, honestly. They're really, they're, you have that, I've asked them to leave politely, they don't leave. There's not much more I can do about that, but it seems sort of straightforward to think that like living beings from like bees to trees have emotions, like they may not look like our emotions, but I think it's actually kind of weirder to believe that like the living world is made up of what are essentially organic robots. I think it's actually really strange outlook on the world, actually. It's fair enough.

31:28Thank you, Sandy. Once again, points for linking to our theme, which is the day celebrating the works of children's author, Roldo. And Tristan, I've got to bring this up. I know you weren't keen on this as a starting point for this week's show, because Roldole had some unpleasant views, right? Yeah, I think, I think his views are quite heinous, actually. The rewrites of his books from the Willy Wonka stuff he originally had the Oopalupas as the pigme tribe from deep dark Africa, his anti-Semitic views. I think these are all horrendous things to think about. And I know we're not obviously celebrating that, but it is that conversation of separating art from artists and even having to go back over, apologize for comments and rewrite stuff, I think is worth thinking about and we're thinking about who we want to honor and how we honor them. It is interesting, the rewrites on Oopalupas that he did in response to criticism and yet generally he did not respond to criticism.

32:34In fact, there's a play, I haven't seen it, but it sounds fantastic. It's called Giant. Have you heard of this? It's been on in the UK and the US, winning all sorts of awards. And it deals with one day in the 1980s where a couple of Dahl's publishers who are themselves Jewish want him to apologize for a couple of anti-Semitic things that he said that they're worried would tarnish his legacy and the discussion that happens. No, I haven't seen that, but I mean, it's definitely, I mean, it made me look around a little bit. There was some really interesting research out of like Berlin that I saw. And you know an artist is a quote unquote bad person and you look at their art, your brain automatically and involuntarily flags a bad person made this kind of within a fraction of a second. It actually appears that it's like not a choice that people can make. You can't spontaneously separate neurologically, the immediate sort of emotional experience of art from what you know about its creator. I would just started looking at this and thinking about it because I find it fascinating that your brain knows what's happening even if you don't want it to be the case.

33:40That's really interesting. That chance was something a friend of mine has said about a particular band where the lead singer has different views that he doesn't like and he used to be a huge fan of this band and is now just finds it himself not really wanting to. Listen to their music anymore. One of the annoying things about finding out about the backstory of so many great artists is just how many of them were massive walking bunch of red flags. I'd love to bring our listeners into this if anyone has any insights in navigating separating the art from the artist. You can email the show on unexpected at bbc.co.uk and our WhatsApp number is plus 44433067830. You can even send a postcard to unexpected elements, BBC World Service, Cardiff, CF104GA.

34:44That's what a lot of you do every single week. We get lovely messages, interesting stories, invitations to invest our money in online schemes and we filter those out. But we do make space for the best of the correspondence in the show. So let's take a look at the inbox. Margaret from Vancouver, Ireland and Canada has sent us an email about Mercury, which was the subject of last week's show Sandy. Do you want to read this? Sure, Margaret says, when I was in school, our teacher gave each row of students half a teaspoon of liquid mercury to feel smell and juggle from hand to hand. I would have been 14 years old. I remember being fascinated and love the squiggle of the liquid as I moved it from hand to hand. Listening to your show, I understand that we were all up close and personal with a toxic substance. I am relieved to inform you that not one student to the best of my knowledge became sick or showed any ill effects in the years to come.

35:45Presumably better informed teachers today no longer hand out liquid mercury to their students. However, I confess to having been totally spilled on with the opportunity, especially trying to break it into smaller parts in the palm of my hand. It is kind of magical stuff. It is magical stuff. And when you talk to people above a certain age, I'd say this is before health and safety. Before health and safety, everyone seems in their chemistry class was allowed to have a little bit of mercury on the bench in front of them and then just flick balls of it around. So chemistry professor at University College London and dear friend of this show Andrea Sella talked about how everyone when they talk about playing with mercury and plunging their hands into it has this guilty but enchanted smile on their face. It is clearly a very dangerous way but an effective road of engaging kids with this bizarre metal. He said that when he was a kid at school in Nairobi, they just had a broom cupboard with like a big bucket of this stuff. And it was hot as well. So there were mercury vapors as well which you definitely should not be breathing in.

36:58And they were all just like plunging their hands into this and putting their feet in it. Like mercury is the antidote to a screen time rate. Get your kids off the screen, get them to play with mercury. No, we are not endorsing that though, just to be very clear. Yeah, in the old days, kids would go out and eat 80 hot dogs in 10 minutes and then drink mercury. It was fine. Yeah, simpler times. Yeah, simpler times. With higher rates of mortality. So what we're saying is kids don't put your hands in a bucket of mercury. Still to come on the show. How to glue an animal and the mystery outside the universe. That's coming up after this. Hello again, it's Sophie here with the answer to this week's quiz. Earlier, I asked you why peaches are fuzzy. Is it A to stop flies from reaching the fruit? B the fuzz evolved from thorns? Or C it attracts pollinators? The answer is A it stops flies from reaching the fruit. One of the flies the fuzz is keeping away is a spotted wing drosophila.

37:59The female flies have a long sharp, chew-like organ called an ovipositor that they insert into ripe fruit flesh to lay their eggs within it. But in 2014, researchers found that peach fuzz is an obstacle for the flies oviposition success. Basically, the flies gave up trying to lay their eggs and peaches that had a protective layer of fuzz. So next time you tuck into a peach, you can feel grateful that those tiny hairs have kept your fruit free of fly eggs. Well done if you got the answer right and if not, better luck next time. Each week we love receiving your postcards, emails and messages. But we also get pleased to help with science questions when you just can't find an answer. And being a helpful team, we are here for you. It's time for us to be unexpected. This week's question comes from Collid in Uganda who asks, if the universe is expanding, what's it expanding into?

39:13Great question. I sort of already know, Collid, what physicists are going to say. This feels like one of those ones where they go, that's not a valid question. But that's not a valid answer. We try harder than that. So we went through our contacts book and we found someone to help out. I am Adam Becker. I am a science journalist and author and I have a PhD in astrophysics from the University of Michigan. Great. Okay Adam, what is the universe expanding into? This is a classic question. The answer I'm afraid may not be particularly satisfying, but the answer is that it's not really expanding into anything. Because if you think about it, when you think about something expanding like say a balloon, well that's an object that's expanding into the space around it. But the universe isn't really like a balloon. The universe is all of that space and time that we live in.

40:15And so it's not expanding into anything. There's just more and more space coming into existence over time as the universe expands. So I realize that that's very difficult to visualize. But this is one of the challenges with advanced physics is sometimes you have to deal with concepts that are very difficult to visualize. But it's true nonetheless. The universe is not expanding into anything. It's just expanding and more and more space is coming into existence as it does so. Boo. Physicists giving me answers that I can't call for hands. This is a really tricky concept to get your head around. So we did ask Adam if he had an analogy that might help. Okay, actually let's go back to the balloon. So the balloon is expanding into the space around it. Right. But the balloon is made of rubber. The universe is made of space time. It's made of space and time. So asking what space the universe is expanding into is kind of like asking what rubber is the balloon expanding into?

41:26The answer is the balloon is made of rubber and the rubber is stretching out. Similarly, the universe is made of space time and the space time is stretching out. It's still really hard to grasp. I appreciate Adam giving us the analogy of the balloon. But I think that helps. Right. It's just the balloon stretching. Sure, it makes sense. I don't necessarily understand it, but I think I think I get the vibe. Vib based non-physicists here. You just got to feel it. Just feel the universe expanding, man. You just got to feel it, man. Any physicists listening who want to give us more analogies because they are annoyed by our vibe based understanding of some of the universe and its expansion, please do email anything into unexpected at bbc.co.uk or you can send us a voice note. The number is plus 44433067830.

42:32Each week I get the chance to link our theme to a story I'd like to tell with the help of the cavernous bbc archives. And given all of the stories rolled out told over his life, I am spoiled for choice. But I am going to go with his book The Twits, which is a nasty story of a nasty man and his repellent wife. And what always stayed with me was the way that this couple caught birds for their bird pies. Tristan, you won't have read this. Sandy, does this ring a bell? Yes, it does. I do remember that. Do you remember in the twits how they caught their birds? Oh, I don't. Was it sting shots? I think it wrong. No, no, they used really, really strong glue. And at night they just before the birds went to roost, they'd paint the tree with super strong glue. And then the birds would land and then they couldn't get away. And he'd pick them off and he'd put them in a really unappetizing looking bird pie.

43:41And that stuck in my mind, pun intended. And that meant that I got stuck into the bbc archives looking for scientists who use glue for good. Let's talk tagging animals back in 1899. Hans Christian Mortensen put those little rings around the legs of birds, starlings in order to track their migration from Denmark. And ever since then, scientists have used an ingenious array of tags, some better than others to try and reveal secrets from the animals that they study. So how do you tag an animal that needs to stay moving around? It needs to stay streamlined. Well, how about glue hunting in the archives? I found this thrilling audio of my colleague Anna and Jagatier in a boat with a bunch of scientists off the coast of Florida doing the first step of tagging a turtle, which is of course catching it.

45:01That's the glorious sound of a scientist jumping into the water to grab a turtle for monitoring, a process that sounds a little bit like the turtle is being mugged. Apparently, it is way less likely to cause harm to it than using nets. So that's why they do it. So you guys are going to tag this one? Yeah, we're going to put a satellite tag on this one. Inside the device is a lot of very clever technology. And it's about half the size of a cell phone, basically. It's got a wire like flexible antenna that sticks out. And of course, that is what links to the satellite so they can get a location on the turtle. How do you make sure it doesn't fall off the turtle and how do you stick it onto the turtle in the first place? The most important thing is that we make sure that the surface of the turtle's shell or carapace is cleaned and roughened up with some sandpaper.

46:12And when we put the transmitter down, it is attached using epoxy resin or polyester resin to keep the transmitter attached to the shell of the animal. So we want to get at least six months to a year out of these attachments. A slightly rough surface makes for better adhesion. Rick then builds up several layers of a special resin in the middle of the shell, which provides a base. And once they're all dried, it's time to attach the tracker. So there you go. That is them fitting the turtle for its tracker. And they put it back in the ocean. It goes merrily on its way glued to a satellite transmitter. I should say that that's from a programme called Why the Animals Migrate, which is a crowd science episode that you can find on the BBC World Service or wherever you get your podcasts. So well done to the inventors of super smart glues, especially when you look at some of the old tags that restricted an animal's movement. And some of the old tags that needed to communicate with satellites back in the 60s when they first started doing this, really heavy things.

47:20I came across a couple of reports that the Royal Society have done on what are the limits of what kind of weights you can have according to the roles and the streamline that your species needs to have. So if it's a bird, you don't want to put something like a brick on its back because it's got a fly with that, right? And amazingly, like glues allow you to put tiny, tiny, well-placed sensors on bits of an animal like a bumblebee that you can't tie things onto them particularly well. So they are incredibly helpful for tracking. What happens when you're an animal super hairy and you can't stick something on it? I know that they put collars on certain animals because they're too hairy and they don't want the animal to lose their expensive tracker too quickly. There is this really cool way that they're testing with, again, this is a Royal Society report, which was, you know, if like hairy animals sometimes get a lot of bitty bids or birds sort of sticky seeds that just stick to them.

48:31There's this whole report on how to develop a trap that means that trackers and tags about the size of these tiny seed heads can hook onto the hairy animals. So you kind of bio mimic you borrow from nature to find a way of sort of velcroing your tag onto the heriiness of the animal. You know how no one can track eels particularly well? Like there's this big mystery about where do they go? They go to the Sargassoc but, you know, we've never seen them breeding. Why do they travel so far? One of the reasons this is a mystery is because if you put a tag on a very streamlined animal like an eel, it loses its streamlined abilities and just gets picked off. So what researchers have had to do is cash these animals, and neethe ties them, do surgery on them to put the tag inside them, stitch them up, and then send them on their way, which is extreme.

49:37It's very involved. Could you just feed a small tracker to an eel instead of doing surgery? I mean, if we could put it on a bumblebee, I feel like you can sneak it into a little cracker bit for them to eat. If you make it eat it, it will come out before you want it to come out. It's not the loveliest thing to do to a fish, but I guess it's for the bigger trying to work out how to protect their migration patterns. I say trying to convince Tristan, just leave them alone. Yeah, I mean, I get it, you know, it's cool. You want to protect their migration areas. It's not getting the vibe. Just throwing stuff out there, just throwing, you know, feed it to the eel, little earring, something like that. There we go. Fiction aside, what backable facts can we glean from this week's show? We've done a sniff test on the science behind lab-grown chocolate, found the dream engineers for surgery patients, swallowed the science of competitive eating,

50:43discovered that the normally poker-faced bee has a possible emotional tell and got stuck in the archives to find out how good glue is for tagging. That is us out of time, and thank you so much to this week's panel in Helsinki, Finland. Thank you Tristan Arto. Oh, oh, wow. And in Singapore, thank you, Sandion. Thank you, Mardi. I'm Mardi Chastatin, the producer was Alice Lipscomb Southwell with Sophie Ormiston and Debbie Kilbroid. Do join us next week for more unexpected elements. At QVC, shopping is more than just checking out. It's discovering something new every day. Start with today's special value.

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