The Rest Is Science - How Codes Were Used To Hack The Telegram Business

Episode Date: September 16, 2026

What if a single strange word could save you a fortune? In this episode Michael opens up a Victorian telegram code book and explores how users compressed long messages into brief coded words to outwit the per word charge of the telegraph system. Coded language turned everyday phrases about everyday events into something that looked like nonsense to outsiders, and why that secrecy was often a side effect of economy rather than espionage, and how operators learned to live inside this clipped new dialect of distance and delay. ------------------- 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 + Jack Meek Animator: Sam Benson Video & Social: Bex Tyrrell Assistant Producer: Lucy Lipscombe Producer: Simona Rata Senior Producer: Lauren Armstrong-Carter Chief Digital Officer: Samuel Oakley Exec Producer: Neil Fearn Learn more about your ad choices. Visit podcastchoices.com/adchoices

Hello, welcome to The Rest of Science. I'm Hannah Frye. And I am Michael Stevens. And this is an episode of Field Notes where Hannah or I bring little treats from our lives to show you what we are mulling over, what we're playing with. And we also answer questions from you guys. We certainly do. I like how you sort of stumbled on the and I there, like Hannah or who else could it be? Someone else brings things to these. Oh, no, it's me. Okay. Well, you know what? We could. We could just pull someone off the street. and be like, what's in your pockets? What have you got? That's going to be the subject of today's episode. When we run out of stuff, Michael, let's put that on the list.

No, no, no. We're never going to run out. But I like the challenge of having to be like, okay, we found this grandmother on the street. She's got like two used tissues in her pocket. We're going to somehow talk about tissues and mucus and investigate this and make it a thrilling hour-long episode. That actually would be a really... Also, how do you get from trees to tissue paper? You know what?

actually loads there. There's loads there. Okay. Speaking of which, here's a little teaser for what's coming up later when we answer your questions. There is a way of measuring tissue and towel softness, like an actual unit of softness and tools that measure how soft a tissue is. Like, you can put some toilet paper into this machine and it'll be like, oh yeah, okay, that's a, that's a three. Ooh, that's a 12. And so look at this. Let's get the grandma now. We're already in. Let's cancel our original plans. There's no grandmas today, but there is something very old that I want to show you. I have had my eyes on this for a very long time. Look at this, Hannah. It is a codebook from the 1900s. Okay, Michael is holding it up to the camera. It's about the size of a business card, maybe slightly larger, slightly larger format. But it is leather bound and it's actually a little notebook when you turn it around. It looks very pretty. Oh, hello. Let's start. It's called an advert on the back and notice from Messes Castle and Company Limited.

The exclusive publishers of the unrivaled Let's's Diaries and other time-saving publications. Is that an advert or is that actually what it is? No. It's an advert. That's completely just an advert that they pressed into the cover. But this is a book. Yeah, it's about the size of like one of those little tiny detective pads you might see in the movies. And it has in quotes on the front, just the word Unicode.

It is unrelated to Unicode the standard used on the internet for characters. But it's a codebook, and it's not a code book for spies. It's not a code book for governments or secret companies. It's a code book for everyday people. It's a code book for telegrams. This episode is brought to you by Cancer Research UK. As if they weren't cool enough already, some astronauts have now added cancer scientists to their CV.

They are making use of microgravity conditions in space to carry out experiments. That's because the same thing that lets astronauts experience weightlessness also affects how cancer cells grow, behave, and respond to drugs. And back down on Earth, Cancer Research UK, is working with astronomers to explore tumors with technologies that are typically used to map the Milky Way, which I think gives you an idea of just how complex this disease is. That's right. There are over 200. different types of cancer. But by pushing boundaries and embracing the latest technologies,

Cancer Research UK has helped double cancer survival in the UK over the past 50 years. And today, it is continuing to save and improve lives around the world. For more information about Cancer Research UK, their research and breakthroughs and how you can support them, visit cancerresearchukuk.org slash rest of science. Hello, mid-sized business. We see your big ambitions. But how do you achieve the wins you want when your technology? is holding you back. SAP Grow is built to grow with your business, no matter its size. With AI embedded at its core, working across every system, all ready to go from day one

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and coffee plus B6 to keep your day moving or go with the flow and choose ginseng delight our new double espresso with ginseng extract. Whatever lies ahead, don't change your morning. Let your morning change you. Discover Coffee Plus on espresso.com. It's a UK book and a bookseller on Abe Books was offering it for like 40 bucks.

It was first published in 1886. This is the 1900s edition. The Universal Telegraphic phrase book. So, just because I love talking, I'm going to talk about what a telegram is really quickly. There's probably a few people out there who want to know. I want to know.

Telegrams are like the first kind of text message you could ever send. They started back in the middle of the 1800s, okay? And the way it would work is you would have to go to a telegram office and write down on a sheet of paper what message you wanted to send. And then an operator would translate it into an electronic code that was sent through wires at nearly the speed of light, you know, all the way across the country or through a cable under the ocean to another country. And then at a different office, an operator would hear that electronic message come in. They would translate it back into a written note. And then a delivery person would take that letter to the recipient.

And that was a telegram. Now, today, we all carry around devices with us that translate. messages at light speed and we don't have to pay anyone. But back then, 200 years ago, you had to pay buy the word. So is that what the book does? Tries to give you short words. The book saves you money. So let's say you work in an industry where you're always having to ask about the length of something. What is the length of blank? You say that all the time. What's the length of your fabric? What's the length of the boards? What's the length of the boat? What's the length of? That's for words you're having to pay for.

It's expensive. And so what this book does, this particular one, has an alphabetical list of Latin words. And then a corresponding also alphabetical list of common things people need to say. And so if you go to page 174, which is where measurement codes are provided, it says, instead of writing what is the length of blank, just write Melania blank. No. Yeah, Melania. What is the length of?

Just put down Melania. So you could write down Melania tissue paper. Right. And then the recipient needs to also be on the Unicode system. They would open up their book. They'd look up Melania and they would say, oh, they want to know the length of the tissue. Got it. Got it.

Wait, can you look it up both ways? Can you look up the word Melania? Yes. You could look them both up because they're both alphabetical. So the Latin phrases are alphabetical And then the topics are alphabetical So if it's about like money You know

You just you go to the money page in the M's And it's got all the things you might want to say about money Hold on I'm desperate to know Is the word Trump in there? Because if Melania Trump means what's the length of some other noun I will be so excited I don't think Trump is in here Because again these are all like

Old school stuff Well they seem like Latin phrases I don't know if Melania, is that a Latin word? Oh, you know what? I don't even think this book goes into the tease. No, it doesn't. The last entry is sequando, which means wrote to you by this morning's post.

Meaning, like, I sent you a letter through the post, a physical letter that's going to be transported to you at the speed of like a horse. At a later date. Yeah, and you'll get it later, whereas this telegram is coming to you through a wire at light speed. But then after S, all the extra pages are words that are blank. But they start with the Vs for some reason. And this is where you can write in your own private code for just you and your recipients. But some of them are really, some of them are pretty dark too. Let's say that you knew your friend was pregnant.

Okay. It was due very soon. And you got a telegram that said amygdala. Go on. That's one word. So you look up amygdala, which is on page 35. Amygdala means gave birth today baby dead, mother weak. Oh my God.

Imagine getting a telegram and you still don't really know the news. I would say that that is one situation in which paying for the extra words was probably worth it. I hadn't even considered that, but you're right. Some messages don't need to be abbreviated. Anemone means gave birth today. It was twins, but only one is alive, a girl, and the mother as well. Wow. So that's a lot of information contained in just the one word you had to pay for.

So they've got versions of every possible permutation of the mother's health, the baby's health, the assigned genders of the babies and all this kind of stuff. So for twins, do-da-da-da, one alive, a boy, that's Annelis. I mean, look, let's be honest here, right? There's a lot of pressure riding on this telegram operator not to make a spelling mistake. Oh, that's true. For a sudden, you could completely change. You could completely change the kind of most fundamental news for some person. Oh, imagine that.

Like, you want to tell someone, help, come immediately. but then the operator misspels it and it means something like, hey, I ate some nachos today and they were spicy. A couple other fun ones are the word Carmino means my husband died today, come at once.

Wow. And Carfax means my husband died today, do not come. Lordy. Yeah, I mean, they're very close. Okay, so a couple other funny things I noticed is that here's a page. I'll show these on screen. these give you a word for when a marriage will take place in the week. And there's, of course, a different word for each day of the week.

Nata, Nolium, Norpolis. But look at a marriage happening on Tuesday. Nausea. Nausea. It's foretelling. It's foretelling. So, yeah, you get a telegram that says nausea. You look it up in the book and you go, oh, they're getting married on Tuesday.

If it says nefarious nausea, you look those two. words up, it means, oh, the wedding's in November on a Tuesday. Wow. You know what? This is reminding me of that commercial. I don't know if it ever aired in the UK, but it was a U.S. commercial for a phone service that allowed you to call and not have to pay for like a long-distance call. Okay, I'm trying to remember this all exactly. But, you know, there were services where you could call someone and they would pay for the call. Revest charge. Exactly. Can you call it reverse charge, we did something like calling collect. The money would be collected from the recipient. I did this once when I was a child. Like I had to call my mom, but I didn't have any money in my pocket

for the pay phone. So I called collect and I said, yep, call this number. But then what the operator will do is they'll call the person you want to talk to and the operator speaks first and they say, hey, you have a call from Michael Stevens. Will you accept the charges? And if the person says, no, you don't get to talk to them. Yeah. So the trick in this commercial was that this guy, wanted to call and tell his parents that he and his wife had had a baby and that it was a boy, but he didn't want to have to pay. So he gave the operator his name. He said, my name is Bob, and my last name is, we ought to baby eats a boy. So the operator calls up his parents and goes, yeah, you have a call from a Mr. Bob, we ought a baby eats a boy. And the dad goes, I don't

accept and hangs up. And the wife is like, who was that? And the dad goes, it was Bob. They had a baby. It was a boy. Amazing. So communication codes to save money have been with us for a very long time. Today we use codes. We use, you know, LOL and Raffle and BRB, but it's not to save money anymore. Now it's just because we're all so cool and busy. Lazy. Lazy. I think it was to save money, though, because the early days of text messages, you had a limited number of characters. Yeah, yeah. I think that's really, you know, the tech speak would arise that way where you'd, you start off and write out your full message and then go back through and delete all the vowels and get back through and delete more and more and more until it finally fit into one single message.

Just on that point, though, the idea of like sending a really horrible message, what was it, your wife is, your wife is dying or whatever it might be. Do you know the story about the sort of inspiration for the telegram in the first place? No. It's so amazing. So Samuel Morse, I mean, see if you can guess what he lent his name to afterwards. Yeah. This is around the 1820s and Samuel Morse is a painter and he's working away from home.

He's doing this commission for a painting in Washington, D.C. And back home in New Haven, his wife is pregnant with her third child. And Morse writes her a letter and he says, oh, I long to hear from you. But by the time he wrote the letter, his wife had already died. but the letter telling him he needed to come had taken so many days that he was sitting there not knowing, not knowing that she had passed away. And as soon as he got the message, he rushed home, you know, by horse, only to find that his wife had already been buried.

And he could have been there to be by her side had only the message arrived much more promptly. And so he started thinking about surely there has to be away. There has to be some way of sending through a message that doesn't require a physical piece of paper to be transported on horseback. And that's what he came up with. And it changed the world. I think it's been around for so long because we're talking about, you know, the first telegram was sent in 1844, that we kind of forget that there was a world before you were connected almost instantaneously all. around the world, in theory at least. A great book to read about how telegraphy, like sending messages across a distance at the speed of light, change the world is amusing ourselves to death. It's a book by Neil Postman about changes in society. And he was like, it all started with the

telegraph. Like, that shrunk the world so dramatically, so quickly that suddenly you could be receiving news about things that were not relevant to your life immediately. And for all of human history before 1844, only local news ever happened. You might find out that the Civil War ended a month later. And you're like, oh, there was a war going on? I didn't know. Which happened, right? I mean, there were people who weren't carrying on fighting, had no idea, or were not fighting at all and had no idea. Yeah. And Neil Postman's whole argument is that ever since,

the telegraph, we've lived in the world that we still live in today with social media, with constant access to news and information from all around the world, from a city that doesn't even concern you. And he was like, seriously, think about how much you read in a day that you consider news that does not change your plans for the day, that doesn't give you information that you need to solve a problem. And I'm like, man, that's pretty much all of it. It actually doesn't help you in any way. I know, I agree. And I think that Morse himself knew that this was something serious

because the very first telegraphically sent message was sent by Samuel Morse in 1844 to his assistant Alfred Vail. And all Morse wrote was, what hath God rot? What a guy. That's incredible. I think he knew that we were almost like. a different species now. We were not limited by space. Wow, that really genuinely gave me chills. That was 1844. Telegrams messages created through the telegraph technology peaked in the 20s, in the mid-20s, where, I mean, there were more than 100 million being sent every year.

And they continue to be sent, even though the telephone kind of like made them less necessary for a long time, they were just great keepsakes. You know, if your grandchild was born, three states away, you enjoyed getting a telegram about it because you could save that as the, like, how you got the news. You put nefarious on your wall or whatever it was, whatever the whole word was. Yeah, if you want it to be like a framed telegram, maybe don't use the code. Maybe don't use the code. In terms of the way that it changed our world, one story that I've always really loved about

the mid-1800s was Charles Babbage, who was this kind of crazy inventor, really genuinely, genuine visionary, but also just complete crackpot. He first invented the difference engine, which was essentially like this giant mechanical calculator. He was very good friends with Ada Lovelace, incidentally. And then he invented after that, he sort of got bored with it because his new fancy was the analytical engine. And the analytical engine was, as far as as anybody can tell on the basis of these plans, a fully functioning, legitimate, completely real computer. I mean, had it worked, right? And no one's ever properly built it. People have created these extraordinary computer simulations of how it would have all fitted together and so on. But

it does look like he had invented a Turing complete machine. But yeah, had it been built, had it worked, we could have been in the LOL stage of humanity, maybe 100 years earlier than we actually were. Gosh, imagine what it would be like today if we had had internet for what, like a hundred more years or something. How much sooner would the web have come along? Like a hyperlinked... A space that you could enter. Exactly. Yeah. The other thing I really like about all of this stuff is there's one of my favorite clips, sort of archival clips, is there's a clip of Arthur C. Clarke being asked about communications in the 1950s and he comes up with this incredible prediction about what he expects the future to hold and he says, in the future we will be able to be on any mountain in the world

and we'll have a device that sits in our front pocket that will allow us to communicate with any other human on the planet, right? It's like it's phenomenal the fourth. foresighted this man. And if you end the clip there, you're like, my goodness me, he was a vision. This is extraordinary. But if you play on the clip, then what he says immediately afterwards is, and then we'll all have genetically engineered monkey butlers. We're not there yet. Give it another decade, day. Give it another decade. We might skip the monkey butlers and go right to robotic butlers, but still, it's a pretty

good prediction. But yeah, we're living in the future that the past predicted in many ways. We really are. So imagine if internet had been invented a hundred years sooner than like DARPA put it together in its modern sense.

What kind of skewmorphs would we have today? A skewmorph, do you know what that is? No. Tell me. A skewomorph is the name for a shape or a symbol that is no longer functional, but is there because it was always there in the past. So like, think about the save

icon and a lot of software and apps is a floppy disk or, or, you know, a three and a half inch disc, which we don't use anymore, but that was what you saved onto in the past. So we just kept it. And people always knew that that meant save. And kids born today are like, oh, that's what that is. okay, another, I don't know if this counts as a skew morph because it's a word, but uppercase and lowercase letters are called that because printers who would set the type with little, you know, lead pieces, they had two cases, an uppercase where all the big letters were, the magiastual, and then they had the minuscule letters in the lower case because they needed to reach those more easily. So that's what upper and lowercase means. But if the internet had been

coal-powered back in 1850. I wonder if we would not say things like, oh, you got to log in. We would say things like, oh, you've got to steam up. Or you got to, ah, here, you have to click shovel and shovel meant like log in. You know, who knows? Yeah, I just got to stoke up my router. Exactly. You wouldn't plug things in. You'd stoke them. It's good, isn't it? What could have been? Definitely one of those sliding doors moments. Should we get some questions? Let's get to some questions. All right, quick break first. This episode is brought to you by Cancer Research UK.

Think of some things that glow. Okay, fireflies, glow sticks, the northern lights. They're very cool. But what if we could replicate that glow inside our bodies and what if doing so could help us save lives? Because Cancer Research UK scientists, they're investigating whether a special fluorescent dye that sticks to prostate cancer cells

could tackle an ongoing challenge in the operating room, removing every single trace of cancer. Because when cancer cells are glowing and easy to spot, surgeons can precisely remove them, leaving healthy cells untouched, meaning there's less chance of the cancer returning and fewer nasty side effects. Cancer Research UK's vision is a world where everybody lives longer, better lives free from the fear of cancer, with breakthroughs like this leading to kinder, more effective treatments. For more information about Cancer Research UK, their research and breakthroughs and how you can support them, visit cancerarcharchuk.org slash rest is science. Okay, when I sell my business, I want the best tax and investment advice.

I want to help my kids, and I want to give back to the community. Ooh, then it's the vacation of a lifetime. I wonder if my head of office has a forever setting. An IG Private Wealth Advisor creates the clarity you need with plans that harm us. your business, your family and your dreams. Get financial advice that puts you at the center. Find your advisor at IDPrivatewealth.com. Okay. Do you know what? We've ended up with a bit of a theme on this episode, Michael, because we had a question in from Landpod on Reddit saying, why don't we dream about our

smartphones, kind of continuing on with the communication ideas that we had in the Versailles. why don't we dream about our cell phones? It's a question I've looked into a lot because people ask it on social media quite often and I love to try to tackle those. And I haven't found any good answer, especially any evidence-based answer. First of all, whenever someone asks this question,

you get kind of two responses. One is a bunch of people who reply and say, oh, not true, I dreamed about my phone last night. So people do dream about phones. They do dream about screens. But it's to most people quite surprising that we don't dream about them more, considering how much a part of our daily lives they are. You know, we dream about loved ones. We dream about locations from our lives.

But we rarely just dream that we're watching a movie or watching TV or texting someone. And there's like so little information about this that's not just Internet commenters speculating. It's quite frustrating. Like the one thing, kind of the one educated guess that's out there is in a cut article from 2018 where Alice Rob, who's a dream researcher, said, well, you know, there's this theory called threat simulation hypothesis. It's the idea that maybe our dreams are simulations of threats and our brains create these so that we can kind of experience them and be more prepared if they ever really happen. And the idea then was that we just haven't evolved long enough for our like non-conscious brain to have evolved to see technology as a threat. So we dream more about attacks or bodily illnesses or weird behaviors or falling. But we just we just haven't gotten to the point where our brains are like, oh yeah, a phone.

That's part of the environment. I don't really buy it. a lot of people don't really buy it. I don't think that Alice Robb herself was trying to say this is the reason it was just like a here's one thing that she could think of. I mean, tell me about your experience. Have you dreamt about your smartphone? No, I haven't. But then I also think, I mean, I have some sort of thoughts on this, but this is pure speculation, right? I've got no, I've got no, I've got no, no, I've not falsified any of the things I'm about to say. Okay, it's true that you don't think about your mobile phone. However, I also,

I don't really dream about clothes. I don't really dream about brushing my teeth. I don't really dream about, I mean, many things actually. I don't really dream about possessions very often at all. It's more sort of people, of course, and places, but they're much more sort of visceral. Yes. Than like objects.

They're things that drive emotional reactions, basically. those are the things that I end up dreaming about. The other thing I would say is that when you are sitting across from somebody who is on their mobile phone, I don't think that they, and you're sort of sitting watching them, they're completely unaware of their surroundings, right? I don't think that you, when you're sitting there on a phone, I don't think that you are existing in the real world like you would be if you were just holding another arbitrary object. what you're doing is you're sort of

you're kind of swapping your senses of the physical world for like what the feedback that you're getting from from this kind of virtual world and you know we do call it like the virtual world that you're in I think that you are your sort of your consciousness I'm going to make this sound way more woo-woo than

I mean it to be but I think that your conscious mind is sort of operating in a different space you're no longer fully present in the physical space that you're in. And so I think that, you know, if you were, you would be fully conscious that you were sitting there with a phone for hours and hours and hours on end and you're not. Your mind gets lost. You go down the rabbit hole, sort of blink and many hours have passed. And so I think that when you are, when you're dreaming, that's the space that you're inhabiting, right? You're inhabiting the space where you are having those emotions,

where you are kind of feeling those feelings, where you're having those experiences, not the one you're sitting in the room holding a kind of cold black square, you know? Yeah. Because you're not really fully consciously there anyway. I think that that's where the answer lies. That the virtual world is certainly full of surprises and fears and emotions. The visceral stuff that our dreams seem to be so made out of. But the phone itself is just the window we're looking through to then feel those things.

And we dream about those things. But how they came to us, whether it was through the glass of my phone or the glass of my spectacles, my eyeglasses, it doesn't matter. That's incidental to what the dream is doing, which is saying, you missed a class. And personally, like I dream that one a lot, that I forgot to attend a class for like months and now I've got a final exam. Yeah. That's interesting.

And the thing is, I never, ever in the dream experience or at least remember how I came to know I'd missed the class. Like I read it on an email or on my phone or on a shoot. a paper or a letter. It's always just like, I already know, and I'm dealing with that emotion. That's the dream. Right. And what is the emotion? Do you feel sort of, is it like anxiety? Is it sort of? Yeah, it's a panic. And I haven't had that dream for a while, which means maybe my life is going better than it was back when I constantly dream that I'd forgotten something that I, it would either be the dream about missing a class in college, or it would be a dream where,

I have been cast in a play and I forgot to ever go to rehearsals. I never went to rehearsal and now it's opening night and I don't know my lines. Oh my gosh. Yeah, I can see the similarities between those two. Mine, by the way, is that I'm leaving somewhere

like leaving a house or, you know, packing up and leaving and it doesn't matter how many times I go back there's always more to do. It's always like, oh my God, how is there still this much stuff to move? There's always like, it's not a refilling well, should we say, stuff to do. And then what's the kind of core emotion? I think it's like fatigue almost. It's sort of overwhelming fatigue.

As in like, I can't, I just can't. I just can't do it again. It's like that, yeah. And then how do you feel when you wake up from that dream? Honestly, I have it so often, Michael. It sort of feels quite normal. You know what? There's going to be so many people analyzing these in the comments,

And you're like, this means that you are. Fine by me. Analyze away, guys. This isn't so much in analysis as it is just I'm glad I don't have that dream. Because I feel like waking up from that dream, you still do have a lot to do in your life. Whereas in my dream, I wake up and I go, oh, I didn't miss a class. I'm not in a play. I feel relief and I feel so happy to be alive in the real world.

But if I was dreaming about all the stuff I have to do and that it never ends, when I woke up, I'd still be in that dream. Oh, that's true. So I'm sorry, Hannah. Thank you. I appreciate it. We should definitely do some episodes properly on dreams as well, you know.

I think there's so many interesting things to say about dreams and what they mean for consciousness and all of that different kind of thing. Okay, we'll do a next question, shall we? Yeah. This is another one from Reddit. This came in from Just Some Jerk Online. Oh, no, that's their username. that's actually their username

but they have asked why does water swirl down drains why doesn't it just kind of fall through like sand in an hourglass what a lovely question basically I tell you what it's not it's not the Coriolis effect I think that there's all of these videos online

about actually some of them are quite good but some of them aren't some of them quite good about how you know when it swells down the drain in the Northern Hemisphere and the Southern Hemisphere will go in different directions. It's, I mean, theoretically, you might get some effect, but it's so weak

that even the tiniest little bump on the inside of your sink will dictate the direction. The reason why it happens is basically conservation of angular momentum. So if you have a, I mean, the classic example is if you have an ice skater who starts spinning with their arms really far out, and then they bring their arms,

in as they're spinning, they start spin really, really, really fast, right? Because you have, angling momentum is like your mass times your tangential velocity times your radius. So if you tighten up the radius, the total product needs to be the same. Keep the mass the same. So make the radius smaller, you have to make the velocity quicker. So essentially, what's the same thing is happening, that when you have got a big bathtub, say, the water is very rarely perfectly still. have to leave it for a very long time, no footprints, nothing, sort of no stomping around or anything. There's always going to be some tiny little movement in that fluid that gives it an angular momentum. And so then as the fluid starts draining down the plug hole, essentially what's happening

is the radius of that fluid is getting smaller and smaller and smaller. And so it starts to become faster and faster until you get this vortex as it goes down the drain. I think the interesting thing though. I mean, that's just like, oh, you get a little vortex and it gets faster when you get smaller. But I think what's interesting is why this doesn't happen with sand. Sand, on the other hand, doesn't, right? Like, each particle act pretty independently. Sand, on the other hand, has, like, really high internal friction. So as one particle rubs against another, it's, it takes a lot of energy for those two to rub against each other. So this is essentially why you don't get it with sand. If sand was had less friction between each sand particle, then you would get it.

But, um, but because of the exact properties of the fluid. And if sand was like that, it would be more like a liquid. Right. But sand is quite liquidy. Sand can be quite liquidy. It can be, for sure. Yeah. I, I think, I think you, you would be perfectly able to, to model sand as liquid. Look, you can take those fluid dynamics equations. You can apply them to all sorts of stuff. But would there ever be a way to get like a, a big drum of sand? unplug a hole in the bottom and actually get it to spiral out? I think you could if you started off with oil grains, make them all slippery as hell. But then is it going to feel like you've just got like a slurry of liquids?

Here's a way to do it. You put them in honey, okay? Okay. So with honey, you could still get a swirl, but it would be a very slow one. I mean, look, think about this in the limit, right? If you put a teaspoon of sand into a bath of water, then yeah, yeah, you'd still get the swirl. And so... Right. So somewhere in between.

Somewhere in between. It's still going to work. It's still going to work. It just depends, I guess, on the fluid properties of the sand that you're dealing with. Yeah. I do like, you know, lava is another thing that you would think is solid, but actually has these really amazing liquid properties. Snow as well, like slurry.

I really like all of those sort of taking what are solid objects, but have these fluid-like properties and then playing with the equations with them. This segment is brought to you by Cancer Research UK. Now, there are a few ways to spot a cancer scientist. Okay, lab coats, pipettes, microscopes, or you could ask them what their favorite car is. But if you do, don't expect the usual debate between convertibles or SUVs. They are way more likely to name a lab-made protein that is central to one of the most exciting breakthroughs in cancer treatment. car T cell therapy.

Which is much cooler because this particular car chase doesn't involve high speeds and sharp turns. It's about hunting down and killing cancer cells. So today we are asking, can cars help us drive cancer out of the body? I mean, that's a good pun. Come on. It's really good. That whole bit was good. Okay, so what kind of car are we talking about? We're talking about car, C-A-R, which says.

stands for chimeric antigen receptors. There are special molecules that can recognize and target specific features only found on the surface of cancer cells. So in CAR-T cell therapy, T cells are removed from a patient's blood. These are, T-cells are a kind of white blood cell that act like the elite special force of the immune system. And then genes are added to those T-cells that make them grow car proteins on their surface. those T cells are then put back into the patient's body,

and the car receptors effectively hunt down the cancer cells, bind to them, and trigger an immune attack, eliminating the cancer. Now, the benefits of CAR-T cell therapies over other cancer therapies are that, one, car-t cells live inside the body, so they're more able to check for and chase returning cancer cells. Also, they should only target cancer cells, not healthy ones. that means fewer long-term side effects, which is particularly important for children

and young people whose developing bodies face lasting harm from harsh treatments originally made for adult cancers. The point is, the journey has started. How do we make sure, though, that it doesn't run out of gas? Okay, so the thing is,

is that cancer cells, I mean, they're masters of disguise. They can change their appearance so that CART cells can't then recognize them, and that will switch off the immune systems alarms so that tumours can grow undetected. Now, scientists, they're creating carty cells that recognize two features on the surface of cancer cells, rather than just one. But a drawback to the prototype is that chasing cancer can end up exhausting your carty cells. When you're looking for

these multiple features, exhaustion ends up hitting sooner, right? You know, the cartis is like, it's like they're running our fuel, essentially, if we really want to push this analogy. And that means then if you exhaust your car T cells that you can allow cancer cells to start dividing again and the cancer end up returning, which is actually something that is quite common when treating children and young people. So Cancer Research UK, they are studying the car T cells that ended up lasting the longest in children and young people's clinical trials to find out what it was about them that gave them that extra mileage. And in doing so, they've identified this unique group of 20 genes that might be responsible for this stamina, they nickname them the Persist

Sig. The name scientists come up with, obviously, right? But here's the thing, taking Persis Sig apart to understand what's going on there and make sure that it is turned on for all car T cells. I mean, it's a bit like sort of giving a bigger battery pack, right, a better engine, something that will end up working for much longer. Yeah, that's right. So what are the challenges? Well, one of the challenges in production of CAR-T cell therapies is that they must be tailor-made for each person

from their own T-cells, from their immune cells. Well, Cancer Research UK are developing off-the-shelf therapies using a specialist type of T-cell. They can be mass-produced and they can be stored and then ready for immediate delivery. So Cancer Research UK scientists have tested this in the lab, against a type of childhood leukemia, and it worked better than traditional car T cells. Now, while car T cell therapy is newer and it's currently limited to very specific blood cancers,

these kind of innovations, they're opening up incredible new possibilities, like targeting more types of cancer in both adults and children and young people. And that's what this research is all about. Over the last 50 years, more than 35,000 children and young people with cancer in the UK have survived into adulthood thanks in part to Cancer Research UK's work. Their ambition is to revolutionise how better treatments are discovered, developed and made available to more people,

including children and young people so they can live longer, better lives, free from the fear of cancer. For more information about Cancer Research UK, their research, their breakthroughs, and how you can support them, visit cancerresearchuk.org slash rest is science. You get very far.

That's how you predict. where lava flow is going to go instantly. Okay, should you do another question? Yeah, let's do another question. This one came from our subreddit. F. Mather 22 asks, how soft a material would someone have to land on for them to survive if they jumped off the world's tallest building?

Now, what I love about this one is the word soft put in quotation marks. It's not just like how could you survive a fall off the tallest building. It's how soft. And that got me obsessed with what is softness? And as it turns out, there are ways to measure softness. But softness is a lot of different things for a mattress. We can measure something like how much force does it take to push a four inch by four inch square down a quarter of an inch, right? That's literally what mattress companies do when they measure how soft a mattress is.

Or in metric if they're in Europe and more sensible. But carry on. Yeah, look, I'm not saying that it's, you know, the best unit to use. I'm just saying that that's an industry standard that I found in my research, which is most certainly the American standard. But then a mattress being soft is different than like pajamas being soft or a tissue being soft. Now, you could have the world's softest tissue. And I would not want to land on that if I jumped off the tallest. building. No, certainly not. In fact, I would much rather land on a big old messy pile of corrugated

aluminum sheets than it's soft tissue. Right. Because if you want to survive a fall off the tallest building, you don't want it to be like gentle, gentle like soft, you know, on your skin. What you want is something that can absorb an enormous amount of kinetic energy. Because the problem with a fall, is the blunt force trauma of hitting the ground where you accelerate really quickly. Your momentum changes really quickly. And that's what a force is. Force is the rate of change of momentum.

The faster your velocity changes, the greater that force and the more harm can be done to your body. But if you can lose your velocity, lose your downward speed slowly, then the force is much smaller. So to survive a fall off the tallest building, you're going to want to minimize the G force you experience when you stop. How much of a G force is going to kill you really depends on you.

It depends on how you fall. If you fall, like the best way to fall, from my research, initially I thought you want to fall on your legs. because they might like get shattered and broken, but at least your head and your heart. Your torso. But again, it kind of depends. I think that like the shock waves still go through your entire body.

If you fall like on your back and you just you want to increase the surface area that comes into contact with the ground to minimize the like the pressure. On each individual part that lands, yeah. on each individual part of the body. So I still don't know exactly how to fall. Because stunt people, they tend to try and fall on their backs, didn't they? Yes. Yes, exactly.

They rarely say, oh, just fall on your legs because then they'll shatter and break and break your fall. No, they don't want to break anything. So you've got to fall on a material that is going to at most subject you to like 10 or 15 Gs, I would say. you might even be able to land headfirst at 10 G's and be okay. But like, I don't know, your legs, your butt could take like a hundred if they had to. What this question reminded me of is a really cool question in Lewis Carroll Epstein's thinking physics. He points out what makes a hard hat work. And hard hats protect you from stuff hitting your head, not because they're so hard, but because they have so much give.

And in the book, he says, we should really call them give hats. Because all they do is they say, look, a hammer's going to hit your head. If a hammer hits your skull, the hammer goes from really fast to zero in like a fraction of a second. And that's an enormous force. So that's why hard hats sit up above your head. If you've ever worn one, you know that a hard hat is actually this like plastic crown that supports a little dome that just hovers over your head. And that distance means that there's time for the hammer to slow down. Right.

Of course. That's the thing that is essentially changing is the amount of time. Yes, it's a give hat. And so you want things that have give. And a single tissue on the ground might be soft in your hands, but it's going to get compressed and you're going to hit the concrete underneath immediately. But a giant pile of, you know, corrugated sheets of metal, they're going to to crumple and dent and absorb all this energy over time, making it a less painful experience,

even though each individual piece is harder. So, okay, a couple of things that this question reminds me of. One is that I once went to a factory that makes the corrugated iron, I think, that you get on motorways between the two lanes of a motorway. Oh. And I've always looked at that stuff and been like, that stuff. looks flimsy, you know? Like I felt a bit nervous about it. Like I don't want to run into that. That looks really super flimsy. But actually, the design of it is complete genius because, so in part,

it's bend sort of that W shape for exactly that reason that that will take the impact, that will crumple, that will take some of the energy of the collision. But the other thing is that what happens is the posts that it's stuck into, as your car, if you kind of come off, if you veer off and you hit it at sort of high speed, basically the posts are designed to fail, right, to a certain degree at a particular speed. And then the whole thing sort of becomes like an elastic band, right, that sort of stretches inwards and then slowly returns. And crucially, they are not designed to make you come to a complete stop.

Because if you come to a complete stop, if you crashed into it and it slows you down, for one thing, the force that you would be under would be absolutely gigantic. It'd be like, you know, hitting a concrete wall. But secondly, the cars that are immediately behind you, you would then give them much less time to be able to veer away from you. Right. So actually, what they are trying to do, if you imagine you've got sort of a helicopter view of a motorway, if you imagine that there is this spot that you are in, that your car is occupying, that is moving forwards at a particular speed, what those crash barriers are designed.

to do is to slow you down slightly and return you back into your same spot in the traffic, right? So that then you slow down while going straight and other cars have more time to move around. It's absolute genius, right? It looks like it doesn't work at all, but it's genius. And it's great for teaching physics. Even when there are concrete barricades on the side of the road, They tend to have sloped sides, like little ramped sides. So when you hit them, your wheel gets pushed back into the road. But yeah, ultimately, surviving these falls or crashes is about stopping distance being quite large.

That way you're not subjected to a big, immediate impulse. And so, like, cars built today are built to crumple. If you're in an old car that's, like, really solid and it's so well constructed and you hit something, like a brick wall, you go from 100 kilometers an hour to zero within like a centimeter and you die. But if we can slow you down to zero over the course of 30 or 60 centimeters and just have the front of the car totally crumple up and take all that energy, then you never necessarily. I mean, 100 kilometers an hour is pretty fast. Don't hit anything at that speed.

But the point is that we want you to slow down more slowly. Cover more distance while you're decelerating and you will have a smaller force. at any one time. Point is, you want to fall into something that can absorb all your kinetic energy and do it over a long period of time. So, ideally, it's something that's like full of a bunch of air. An airbag is great.

A net is pretty good, because what are nets made out of? Basically, just the air in between the ropes or the wires. In fact, back in 2016, a guy named Luke Atkins, skydove from 25,000 feet without a parachute. all he had to save him was a 100 foot by 100 foot net on the ground. Whoa.

Which from 25,000 feet is like the period on a sentence, okay? It was nothing. And he sky dove with two friends that did have parachutes, and they were there to make sure that he was on the right trajectory. And then at the last minute, they parachuted, right? And then they just let him use his own body as basically a sail to kind of guide himself towards that net. And this net was like 100 feet off the ground. It had air pressure cannons in it that kind of pulled the net to keep it from him from sinking too deep too fast.

But he hit the net going about 120 miles an hour and he was fine. Oh my gosh. No, thank you. Why? What did he get? No. Well, what he got was a mention on the rest is science. That's true.

That's true. So it was worth it. But I can barely watch the video. because he was wearing like a camera as he did it so you can see it. And you're just the whole time you're thinking, oh, you're too far to the left. Dude, move, move, move, move. And he does hit like the kind of the left edge of the net.

And you're like, oh, my gosh. Wow. But again, the net was just so easy for his body to move. And it had so much give that he was fine. Hitting water, as we know, at a high speed, can't move it out of the way fast enough. You may as well hit concrete. But a net is really good.

It's soft when it comes to impacts. I think I said that there was two things that this question reminded me of. One was the sort of crumpling in the car. The other thing is this really amazing essay by Holdain in the 1920s, which was called On Being the Right Size. And essentially, it was asking the question of, if you did fall from a great height, from a very tall building or an aeroplane or whatever it might be,

is there a point at which you could act as you could act as, your own parachute. And so what Haldane writes in this essay, he's imagining a sort of disused mind shaft, right? And what would happen if you threw certain animals down? No animals were harmed in the making of this essay. But what would happen if you threw certain animals down this mind shaft? And a mouse would be absolutely fine. It would be, it's small enough that it could act as a same parachute.

It's terminal velocity. It's not high enough. It's completely fine. A rat would be a bit like dazed. A dog maybe would have a few broken bones. And then in this essay, the way I remember it, right? And I am doing this off the cuff. So again, forgive me if I'm getting this wrong.

But he said that a pit pony, if it weren't sent down a disused mind shaft, could only be described as a splash at the bottom. So the other way to survive this is just be smaller. Just be smaller. Yeah. It's so funny that you bring that up, Hannah, because I literally quoted that last weekend at my daughter's birthday party. I was mentioning, we went to a place where there's a lot of climbing.

And I mentioned like, oh, yeah, I mean, a kid can climb because they just hit the ground and they're fine. But if I fell, I would splash. And this is, this is an actual just property of physics. Like when you, in geometry, if you increase the volume of an object, its surface area doesn't grow as fast. So yeah, a horse is really heavy. and it doesn't have as much surface area. Now, I don't know if I've told you this story, but I did an actual experiment on this

in a unreleased, unaired pilot for CNN called Michael Stevens Unlimited. And it was the whole idea, this was back in like, I don't know, 2013, 2014, it was like, what if Michael Stevens had unlimited money? And I was like, I want to test out, like throwing animals off of buildings. And we found out that there's no way to kill an aunt.

by throwing it off a building. Because their surface area is so large compared to their volume, their terminal velocity is just never very fast at all. I mean, they are a parachute that is alive. And so we threw ants off of this building, like a 20-story building in Los Angeles. But we thought, how are we going to know that they survived? Like, we can't just run down there and find an ant and say,

oh, it's okay. So what we had to do is we had to buy this radioactive paint from United Nuclear, and we painted the ants with a radioactive paint, threw them off the building, and then I went down onto the sidewalk with a Geiger counter and found the ants we had painted and showed that they were just fine. And they were local ants, by the way, so they were just like, hey, I'm home, but I'm in a different room now. That's amazing. That's amazing. I love that story, and I love doing that experiment. I got to get the footage one of these days. It's going to be weird to like release some at some point because I look so much younger. But it was a really fun. It was a really

fun show. Yeah. I really enjoyed that. Thank you very much for that question. F. Mather 22. Let us know if you have me F Mather 21. Doesn't feel like it would be a. The first 21 were taken. Or maybe, maybe that person was born in 1922. And maybe they were. And they're 104 and they're listening to the rest of science every day. Maybe indeed. Yes, as ever, if you would like to send us in your questions, you can send them to us at the Rested Science at goahanger.com. And we'll see you next time. Selling well.

Bye-bye. A big struggle between Britain and Russia. We assess Prime Minister. With high confidence, it was Russian. Holding the Russians accountable is World War III. They took down a British passenger jet containing 350 people. Man in the Kremlin is playing, Alex. Got to ask yourself, you want to play.

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