99% Invisible - 536- Nuts and Bolts

Episode Date: May 10, 2023

In her new book Nuts and Bolts: Seven Small Inventions That Changed the World (in a Big Way), structural engineer Roma Agrawal identifies and examines the seven of most basic building blocks of engine...ering that have shaped the modern world: the nail, the wheel, the spring, the lens, the magnet, the string, and the pump.Click here to get the book! Available for pre-order at W. W. Norton in the US and Bookshop.org in the UK.Nuts and Bolts

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Starting point is 00:00:00 In this episode we talk about sex in the 17th century. If you're listening with someone who may not be ready for that, you might want to preview it first. This is 99% invisible. I'm Roman Mars. Take a walk through Central London and one building is particularly hard to miss. Just off the banks of the River Tams, the shard is Western Europe's tallest skyscraper. At just over 1000 feet high, the building's slender, tapering design doesn't so much stretch
Starting point is 00:00:31 into the sky as it pierces through it. 11,000 panes of glass make up the facades which all slope gently inward, rising towards the top so that the building comes nearly to a point. Thousands and thousands of people walk past the shard every day, but there's only a select few who look up at it and breathe a sigh of relief. I just kind of wipe the sweat from my forehead going, you know, yes, thank goodness, that's so bad, it's so standing. This is Roma Agrawal, one of the structural engineers behind the shard. Her job is to make sure buildings, bridges and all sorts of other things withstand the test of time. As a structural engineer, Roma looks at the built world
Starting point is 00:01:12 with a special kind of X-ray vision. So I might consider what the skeleton of the main structure might be, you know what material is it made from, where do the main bones of it sit and so on. And I also might think, what's underground? You know what's actually holding this thing up? How deep does this thing go? So I'm trying to look beyond the visible. When Roma walks past the skyscraper or over a footbridge,
Starting point is 00:01:36 she doesn't only see the main structure. She sees all the invisible engineering that makes that design possible. The small, sometimes hidden inventions that hold up our world. And I have a nut on bolt on my desk right now and I often just hold it in my palm and think if it wasn't for this incredible piece of engineering that sits inside my palm, skyscrapers wouldn't exist. And I think that's kind of humbling and it just reminds you that great engineering, great design, can be really simple and small. Roma recently wrote a book that's actually called Nuts and Bolts, seven small inventions that change the world in a big way.
Starting point is 00:02:16 In it, she takes ordinary objects like the nail, spring, and pump, and shows us how these inventions were actually extraordinary feats of engineering in their own right. The concept of Roma's book is a twist on an old idea. So the Renaissance scientists and engineers, maybe even artists you could call them, came up with a list of six simple machines which were the lever, the wheel and axle, the pulley, the inclined plane, the wedge and the screw. They saw these as being types of machinery that made it easier to move stuff or expend energy or use energy in an efficient way. So that was quite a specific view of what machines do.
Starting point is 00:03:00 But obviously, the Renaissance was a while ago now, and the the world has moved on and things are a little bit different. And I started to think about, you know, even within the very complex technology that we now have, very different from the Renaissance era, what are the little fundamental pieces that I think make up the modern world. And I came up with seven objects, and I always have spirited debates with people, whether they think those are the right seven, or should they be more or fewer, or, you know, but this is my list of seven.
Starting point is 00:03:33 Ha, ha. Today, Roma Agrawal tells us about her seven basic building blocks of engineering, and how we might understand ourselves better by taking a closer look at the stuff all around us. Okay, so your book starts and you start with the nail. Why the nail? So if you're anything like me and you open your desk drawer, there will be just be, you know, a few nails kind of rolling around in the bottom of your drawer. They're cheap, you get them everywhere, we've probably all had to go
Starting point is 00:04:05 hammering them in to a wall to put a picture. And we kind of understand how they work, we kind of get that there's friction involved or that, you know, something is holding our two blocks of wood or whatever it is together. But the truth is that, you know, the story of the nail is actually a story of materials, it's a story of humans, it's a story of geopolitics, you know, there's so many different ways you can tell the story of the nail. Yeah, and one of the ways you chose to tell the story of the nail is by making one yourself, the old-fashioned way. Yeah, so another little thing that I have on my desk is this homemade nail of mine. And it was so interesting to me because I think as an engineer, as somebody who studied
Starting point is 00:04:42 science physics, I thought I understood steel and how it works based on the science of it and how the atoms work and the crystals work and so on. But actually, when you go into forge and nail, which is how the Egyptians did it, how the ancient Romans did it, thousands of years, it's a completely different experience, it's a very sensory experience. Tell me more about that. So I was in a forge. It has a particular smell. You can kind of smell the burning coke. You put the rod into the flame. It comes out sort of red. And then I was told that red heart is not hot enough. And it needed to go kind of orangey, yellow, almost glowing, and then you have to quickly take it out, whack it at the right angles in the right sequence. As it cools down, it starts to sound different
Starting point is 00:05:36 to the pitch of the clanging changes. And this is all very, very quick. And it took me like four or five cycles to make a nail of like heating and heating and then heating and then hitting, but obviously the Romans would have done it in one go. It's kind of remarkable to think about that almost everything the Romans built, there was a blacksmith somewhere that needed to make the nails. And not just one nail, like thousands and thousands of them all meticulously made by hand. Yes, so the Romans did this funny thing in what is now Scotland, where they were creating a settlement and they suddenly were called away back to Europe and they had to abandon
Starting point is 00:06:18 the settlement. And they left a hoard of nails 875,428 to be precise in a ditch which they covered up because God forbid that the local savages get hold of this incredible material, the iron, but also this incredible piece of technology, this engineering, so they preferred that it be buried for thousands of years rather than allowing somebody else to use them. I mean, I never really considered the idea that the nail could be so valuable because you just see them lying around,
Starting point is 00:06:55 construction sites and your junk drawer. But they were once a huge part of a global trade. Yeah, so the materials and the skill to make the nails were both scarce things. And there's a story about how when the British were colonizing the world, they banned the export of nails to their colonies, including the USA. So if somebody was leaving one house and going to go away and move to a new place or build another house, they actually
Starting point is 00:07:25 burned their houses down. And then from the kind of smoking ashes of their homes, they extracted all the nails, bagged them up, swung it over their shoulder, and then went on to build their next house. So in 1619, a law was actually passed in the state of Virginia to ban people from burning their own houses down and assuring them that, you know, if you were, in fact, going to leave a house and leave the nails intact, that you would be given some kind of compensation for that. That is so interesting. And, of course, screws, nuts, rivets, they're around during this time
Starting point is 00:08:06 for you too, but just not in the quantities like the nail because before the industrial revolution, making those fasteners was really hard. Like, you had to cut each individual thread on a screw manually too. Yeah, so nuts and bolts were way more challenging to create because you'd hand cut the outside thread on the bolt. And then you had'd hand cut the outside thread on the bolt, and then you had to hand cut the corresponding thread on the inside of the nut, and then hope that they fit together. And what I find really fascinating about this is that we often think that screws, nuts, and bolts, rivets are much stronger, better versions of the nail. But the nail is not redundant. The nail is still around,
Starting point is 00:08:46 and I think that's for me what makes it such a great piece of design is that it's endured. Okay, so let's move on to the wheel. Now the wheel is sort of the quintessential example of the perfect invention, but you have a bone to pick with the way that we think about the wheel. I do. I mean, there's a phrase that really grinds my gears. I'm sorry, Roman, but I have to go with these nerdy engineering partners. Yeah, I got it. The book is full of them. Every time I was like, I, yes, it's so good. And basically it's the phrase, don't reinvent the wheel. So, so this is a phrase that we use in, in business, in work, in school, like all over the place, I say, no, no,
Starting point is 00:09:39 we've done this thing before. We shouldn't reinvent the wheel. And the reason that this really frustrates me and annoys me is because basically since humans invented the wheel, we have been reinventing it. I mean, put it this way, if we had not reinvented the wheel, we would not have a single mode of transport that had a wheel on it because wheels were in fact not invented for transport. Yes, so this has been a thing that I've been quizzing people on since I've read your book and no one gets it, no one gets it. So for what purpose was the first wheel invented? So we're going back in time about 6,000 years now. We're going to Mesopotamia and people wanted to create vessels to store their food quickly, robustly, out of clay. And so your first wheel was in fact the potter's wheel.
Starting point is 00:10:36 And this was a heavy large disk which was made either from clay, from wood, even potentially from stone. And it basically had like a little bulge on its underside, which sat in a little pedestal. And then you could spin the wheel within its pedestal. And it would keep spinning, thanks to momentum. And they could create pots really quickly. And so who was the first person to take this potter's wheel and turn it on its side and write on top of it? It's funny, right? It took potentially somewhere between a thousand to two thousand years for someone to do that, just to turn it on its side.
Starting point is 00:11:17 And of course, that's because the axle is actually quite a complicated piece of engineering in its own right. And the potter's wheel kind of worked because of gravity, but it wouldn't work on its side. And the first archaeological kind of solid evidence we have of a wheel is on in a site in the North Caucasus region, which is now in Russia, where archaeologists found tens of thousands of ceremonial burial mounds, some of them were created by the Yam Naya community around the fourth millennium BCE, and one of these graves actually contained a man in a seated position on top of a four-wheeled wagon. Buried with what he loved, I suppose, his own like Ford F-150. Yeah. But it's not only this, like when you talk about the reinventions of the wheel, you know, it wasn't just taking a potter's wheel and turning it on its side.
Starting point is 00:12:15 There's this sort of the innovation of the axle, which is a big deal. But also, wheels themselves have been innovated over time in numerous ways that you describe. What are some of those ways in which the wheel has evolved itself? Yeah, so the Yamnaya Carts, for example, that was found in this grave, was a solid set of wheels. They were made from three planks of wood that were sort of dulled or pegged together. So, you know, here comes the nail or one of its cousins to help us with that. And these would get dragged along by animals.
Starting point is 00:12:47 They're pretty clunky, pretty heavy things. So when our carpentry skills improved and we were able to use harder metals to create our tools, we then created spoke tweeles. And spoke tweeles, of course, are a big iconography in Southeast Asia. The Indian flag has a spoke to wheel on it. So there's this little flag reference for you, Roman.
Starting point is 00:13:13 And this was much lighter. So when you think of the Greeks or the Romans running around the Colosseum in their little carts and things, they had spoke to wheels. They're much quicker and nimble and their feet. But then when we started looking at flying machines in the 17 and 1800s, designers were thinking, well, even spoked wheels are relatively heavy. And if we want to get something up in the air flying, it needs to be as light as possible. So then the wire wheel was invented. And I should say that the spoked wheels are talking about were made out of wood, the kind
Starting point is 00:13:47 you'd see on a chariot, but the wire wheel, that's metal, and it's much lighter. It's the kind of wheel that we're used to seeing on our bikes. Yeah, it is. But again, in one of those kind of funny things, the bicycle wasn't actually invented until reasonably recently, like Sony a few hundred years old. Right. Yeah, you know, I was really intrigued by your explanation of a tire and just what a tire is. Can you say a little bit more about that? Yeah, so I mean, I think the word originates from, from Thai, like tying together a wheel.
Starting point is 00:14:19 And it was when we came up with the spoke to wheels made from wood. So you've got the hub, you've got all these different spokes that are being put into it and then a rim, but they can get shaken apart on the cobbly roads and so on. So when the iron age shifted into Europe, what people did was to heat up rings of iron and then put a ring around the rim of the wheel. But what was very clever is that they did this while the metal was still hot. And so as it cooled, it shrank a little bit and then compressed the wheel, making it super nice and robust.
Starting point is 00:14:54 And that thing is a tire. That thing is a tire. The next stop in our tour of Seven Small Inventions that make up the modern world is the spring. To tell us about the spring. So springs, I think, are one of the most versatile of the seven inventions that I've picked. So they come in a huge range of shapes, a huge range of sizes. We often think of the coiled metal ones.
Starting point is 00:15:22 And in fact, when we're typing on our our laptops that's what's stopping our keys from permanently sinking down into the depths of our computers. I mean there is a you know a platonic ideal spring in my head which is like the coiled metal thing and you press down on it and it bounces back up but I mean fundamentally and I never heard this described before until I read your book, is that a spring is this device for storing energy and being released when we need it to, which really broke open my mind of what all the things that could be spring. You know, yeah, so trying to describe what a spring is was probably one of the hardest parts of this book for me actually.
Starting point is 00:16:08 So, yeah, it kind of broke my brain as well. And I think the first example of a spring, so with my definition or my attempt at a definition, which is, you know, a material where you can deform it, and it stores energy, and then you can release that energy and use it in a way that's useful to you. The bowl of the bow and arrow is a spring. So what you're doing is you're taking a piece of wood or in the case of the Mongolian bows,
Starting point is 00:16:38 which is what I write about, quite a complex construction of animal bone and tendons and wood and so on. And you deform it by pulling a string and you've stored some energy in the bowl and then when you release the string that energy is transferred into the arrow and so the arrow can travel much further, much faster then would be possible if we just try to throw it with our arms. Yeah, yeah. So I think that is the most fundamental or the oldest form of the spring. And you mentioned the coiled metal springs that you squish. You also get coiled metal springs that you pull apart.
Starting point is 00:17:16 So on the edges of a trampoline, if you dismantle a clothespin, like one might do on a weekend, you'll find a torsion spring. So that's where you twist it, and it holds energy and twisting. So it's a very versatile piece of design. So let's talk about the way the springs are used in buildings. And specifically, you have an example about a concert hall. So how does that all work? And why do you put springs and buildings in this way? So these springs are on the opposite end of the spectrum to the small springs that we've been talking about, like in clothes pegs or even inside a mechanical watch. These are springs that, you know, I could wrap around my leg to give you some idea of the size of them. And I was really
Starting point is 00:18:01 fascinated by this concert hall in Denmark, which is called the Musicians Hoos, or House of them. And I was really fascinated by this concert hall in Denmark, which is called The Musicians' Hoos, or House of Music. And it's become famous worldwide for having incredible acoustics. So what is it about a concert hall that is special or unique, or that might attract people to pay money and to sit in that space. And when I spoke to the designers, their answer to that was silence. Achieving silence is actually extraordinarily challenging. Yeah, so I would think inside of a building that the thing that was sort of like contributing most to the idea of silence was some kind of, you know, acoustic, tiling and baffling and stuff. Where is a spring fit into this?
Starting point is 00:18:49 So the kind of thing you're describing is very important. And it forms the kind of the inside skin of the space that you're sitting in. The problem comes up when vibrations are coming into the space from the outside. So the stuff you've described, the panels and things stop echoing, as all podcasters know, it creates that nice, flat sound that you don't have bouncing sound everywhere. But if you've got a truck kind of rumbling down the street outside your home, then your panels aren't going to do very
Starting point is 00:19:23 much. So what you need at that point are springs, because what the springs do is go, oh, here's some vibrations coming in, I'm going to have a little jump and bounce around, and then I'm going to dissipate that energy into heat, and I'm going to stop that energy from going into the recording studio or the concert hall. Okay, so then describe like sort of like physically, what is the house of music in Denmark do with its springs? The house of music has got its big main concert hall, and then it's got lots of other teaching rooms and concert halls around the main concert hall. So the first problem is that you've got
Starting point is 00:20:03 music from I don't know like a queen cover band That can infiltrate your Bach concert, which I'm guessing is not a good thing And so the idea is in simple terms that you're suspending Each one of these spaces particularly the main concert hall From springs in all directions, from the ceiling, from the sides of the walls and on the floor as well. So there's basically a room within a room that's attached with springs all around it.
Starting point is 00:20:32 So that when the world vibrates, it's sort of like that energy is dissipated and so the inner room doesn't vibrate. And it's sort of floating in this sort of room. That's exactly right. At the very technical jargon term for it is box in box. So you're basically creating the inside box. You've got springs all around it,
Starting point is 00:20:57 and then you have the outside box, which is the ultimate structure. And acoustic engineers then spend a long time interrogating all the different sounds, you know, coming into a building, the different sounds inside a building and figuring out how do we arrange the springs in the right way at the right frequencies so that we can create that silence. So this next one is going to be just a quick detour or an interlude of sorts on our journey through the Seven Inventions, but I wanted to bring it up because the string was definitely around when people decided to list out all of the simple machines. Why did you elevate the string to this status?
Starting point is 00:21:42 One of the things that really stuns me about String is that it was invented by the Neanderthals and we found a 6mm long piece of String which had twisted fibers to make this piece of engineering and we use almost exactly the same principle to hold up some of the biggest bridges on our planet today. And if you look at a cross section of a cable from a suspension bridge, it really is just like, it's a cross section of string. It has all these little threads, or not little, big threads, put together into one big rope type of thing that's all made out of metal. It just looks, it is string. It is, completely, and that's what I really love about it. And I think the other thing I also love about it is just how beautiful it is.
Starting point is 00:22:33 String is beautiful. It creates beautiful things, not only physically beautiful things, but also music and where would we be without music? We've been a bouncy concert hall that didn't sound like anything. When we come back, Roma wraps up her list of small inventions that changed the world. And so our next entry in your seven inventions for making the modern world
Starting point is 00:23:01 is one that the engineers during the Renaissance probably never would have considered at all and that's the magnet. Tell me why you chose magnets. Yeah, I mean, I chose them because they're really attractive. As you say, I know, I know, but I'm also, so magnets, as you say, were strictly not an invention, perhaps they were discovered in the form of what we now call load stone. So, there is a form of iron called magnetite and magnetite is found naturally in the world. And so, the ancient Chinese found some of it and were known for creating some of the very early compasses using it for navigation, but we really didn't understand what magnetism
Starting point is 00:23:52 was and how it worked. And then, fast forward a few thousand years, when we figured out electricity coming into the kind of 18th, 19th centuries, we suddenly realize that electricity and magnetism are in fact very intertwined. So, when it comes to describing the importance of magnets, what objects or what sort of engineering feats did you use to explain that? Yeah, so I mean, I think magnets are really, really key. Magnetism is very key to long-range communications. And the engineer that I talk about is called Jagdish Chandra Abhors. And he's an Indian scientist, and he used to work kind of in colonial India.
Starting point is 00:24:39 So in a way, it was fortunate that he was able to do the research that he did. And what he figured out is, with this interaction between electricity and magnetism, you could use electromagnetic waves, so light is an electromagnetic wave, but he was looking at radio waves, slightly different, that you could transmit energy and transmit signals. I mean, of all the inventions in your book, I mean, this is the one where, you know, there's not a physical connection to make the thing work.
Starting point is 00:25:11 I don't know, I feel like I don't get high, but this is what I feel like if you get high, this is what you begin to think about, you know, just like how mind-blowing it is to think that a force is exerted across a room And what that means and how revolutionary that is Yeah, it is and to demonstrate this idea Dirk Dishchandrabos set up a public lecture in the late 1800s and he invited the lieutenant governor
Starting point is 00:25:43 You know like a British man who had lots of power, God am standing in his room, and then he switched on a transmitter, which generated some electromagnetic waves, and then the waves went through three solid walls and a human body, the waves then arrived at a receiver that he'd set up, and when intercepted, a bell rang, a pistol discharged, and a miniature mine exploded. This was all intentional.
Starting point is 00:26:14 No one was hurt. But he basically demonstrated that we can use these waves to send signals far away. And when you talk about this kind of idea of how mind-blowing it really is, I think about my grandfather who was sending telegrams a few decades ago. It wasn't that long ago compared to my daughter who swipes a screen on an iPhone or a smartphone, and can place an instant video call to my family in India thanks to magnetism. You mentioned in your book that Bose is a little forgotten in history, and I imagine a lot of this has to do with where he was working and his identity,
Starting point is 00:26:58 but there's also something about his character that he didn't totally want to own this invention really. No, so I don't even know whether he would have been allowed to apply for a patent. I guess it would depend on the powers that be deciding what he could and couldn't do. But as a principle, as a scientist, as an engineer, he didn't believe that knowledge should be restricted. He believed that new knowledge was for. And he wanted to leave a legacy. He wanted to kind of almost create offerings from his life. And he didn't believe that there should be a monetary value attached to that. So even though he invented this incredible device,
Starting point is 00:27:37 specifically, which was called a kohera, which did a very difficult job of receiving an interpreting electromagnetic signals of the sort that he was passing through rooms and people. You know, the radio, Markonnie's invention wouldn't have existed without that, but he never patented it, he never restricted it. And I think which is part of the reason that his name has kind of been lost in history.
Starting point is 00:28:03 part of the reason that his name has kind of been lost in history. The next invention on your list is the lens. So tell me about the importance of the lens and how people can understand the lens better. So I think of it in two extreme ways just in my own life. So one is that I wear glasses and if I didn't wear glasses I would have quite a bad headache and not be able to see very well. So even on a very everyday basis, the lens is incredibly important to me. And then there's also the other extreme where
Starting point is 00:28:30 I wouldn't have been able to have a biological child had it not been for the lens. Oh, well, explain that more. So this entails starting from a kind of gross slash embarrassing story. OK. Okay. So I'm going to take you back to a draper who was called Antony Van Liovenhook. Okay.
Starting point is 00:28:55 And this is mid 1600s, he was a bit of a loner, a bit obsessive, and he created these very simple small magnifying glasses to look at the threat count on the stuff that he was selling. But then he also decided to put other stuff in front of this lens. So he put blood, he saw blood cells, he put pond water and saw bacteria and algae and all this kind of stuff. And he used to write these really long, descriptive, lyrical letters to the Leonard gentleman of the Royal Society in London about his discoveries. One of the letters, let's say, was written in slightly more sheepish tones, where he assured the learned men of said Royal Society that the sample that he had looked at was not, and I repeat,
Starting point is 00:29:47 that the sample that he had looked at was not, and I repeat, was not obtained by defiling himself, but were the remains after conjugal coitus. And so he was the first person recorded to see spam under the microscope. But it wasn't. Oh my goodness. But yeah, he was a great pain to say that he didn't like extract the sperm from his own body himself, that would be sinful. No. And in fact, his exact words that which has been translated from Dutch, if your Lordship
Starting point is 00:30:20 should consider that these observations may disgust or scandalize the learned. I earnestly beg your Lordship to regard them as private and to publish or destroy them as your Lordship sees fit. Wow. Another character here. Yeah, yeah, but a character. And so again, this is one of those funny situations where it took nearly 200 years before we worked
Starting point is 00:30:46 out that the sperm and the egg were both involved in the act of fertilization. And then you get to the story of John Rock and Miriam Menkin, who were the first to fertilize an egg and a sperm in the lab, you know, paving the way for IVF babies, which is what my daughter is. It's so nice. You owe it to a guy who definitely didn't jack off. Definitely not. All right, so we've arrived at the seventh and final invention, which is the pump. Tell me about the pump and its importance to the world of engineering.
Starting point is 00:31:29 So for me, pumps are about life, and I say that because they were invented to support our lives, they were invented to get clean water from a source and bring it to where we lived. They were invented to take disease-ridden sewage away from us. They were invented to irrigate crops. But one of the pumps that I actually talk about, and I'm really proud of talking about this, because I don't know many engineering books that would talk about this kind of pump, is a pump that I got very up close and personal with soon after I had my baby, and that is the breast pump.
Starting point is 00:32:06 So, talk to me about the breast pump. I mean, it's not a surprise really that I felt like a dairy cow when using these pumps because the original breast pumps were a derivation of the pumps that were in fact invented for milking cows, which was invented by a couple of men in Australia. And then you come into the sort of 19th century and even the early 20th century and there were all of these really strange contraptions that I don't want anywhere near me that kind of had these big bulbs with tubes coming off them that you had to suck on. Oh, they just look pretty awful. And I don't even know how they would have worked.
Starting point is 00:32:52 And it's actually kind of shocked me that it was only really in the 1990s that electrical breast pumps that you could have at home came to market. I had no idea. Was that late? It was really late. And just if I jump back a little bit into the 1950s, that was the first time an engineer said, huh, let me just think about what's a safe amount of pressure on breast tissue. And let me maybe even measure how many times a minute a baby actually sucks so that the breast pump design can somewhat emulate a baby and be marginally safe for women to use. You know that took a while. Yeah well maybe that's why it
Starting point is 00:33:36 took to the 90s because it took that first. You know like so you wouldn't be sucked into the machine. Yes. But all of it seems extremely late. And it goes to, you know, it points to something that is sort of an undercurrent in your book. And I think sort of probably an undercurrent in your life and the work that I know that you do is just like engineering because women had been excluded from engineering for a long time. These types of innovations, there's these huge blind spots.
Starting point is 00:34:05 Yeah, I mean, from what I could tell, and I mean, listeners can please get in touch with me if this is not the case, but I couldn't find breast pumps designed by women until just a few years ago. So, you know, you've got men who are very unlikely to ever use them in their lives, designing things for a purpose that they don't understand, really, or they don't physically experience. And so finally, when women started really
Starting point is 00:34:35 looking at, you know, what do we actually want from the pump? We don't just want the milk. That's not the only purpose of the pump. So then we started thinking about what are actually the correct design criteria for a breast pump. And that's when we started coming up with things like it should be silent, they could be discreet, they use a smartphone, use an app that's attached to it. And finally, we came up with a design that actually fits inside your bra and that you can walk around with rather than being in a dingy room at the back of your office somewhere strapped to a milking machine. So, I mean, it definitely makes the case for why engineers need to come from all different walks of life. Well, it's such a good book. It made me very happy to read.
Starting point is 00:35:25 And thank you. It'll just give you a greater appreciation for rivets. You'll just walk around and see rivets, you'll go, I like that rivet. That's pretty good rivet right there. Are you saying, Roman, that my book was riveting? No, I'm not saying that. I am saying that.
Starting point is 00:35:42 Your book is very riveting. Thank you so much, Roma. I appreciate it. Thank you for having me. Roma's book is called Nuts and Bolts, seven small inventions that change the world in a big way. It's available in the UK now, and for pre-order in North America. 99% invisible with produced this week by Jason De Leon, original music by Swan Riaw,
Starting point is 00:36:08 sound mix by Hazik Bin Amad Farid. Delaney Hall is our senior editor, Kurt Colesette is our digital director. The rest of the team includes Chris Barube, Emmett Fitzgerald, Martin Gonzales, Christopher Johnson, Vivian Leigh, Losh Madon, Jacob Moltenado Medina, Kelly Prime, Joe Rosenberg, and me Roman Mars. An extra special thanks and farewell to Sophia Klatsker, who has been my dear friend for decades and came here to help me take this show to the next level and took care of all of us during these huge transitions in the life of the show. There is no amount of gratitude I could express that would adequately thank her for all that she did for us. She is moving
Starting point is 00:36:48 back to her true calling in the public sector as the cultural affairs manager for the city of Santa Monica. Her commitment to art and culture being the bedrock of a rich civic life is unparalleled and she's going to just rule at that job. We are so excited for her but we're going to miss her dearly. The 99% of visible logo was created by Stefan Lawrence. We are a part of the Stitcher and Sirius XM Podcast family. Now headquartered six blocks north in the Pandora building. In beautiful. Uptown, Oakland, California. You can find the show and join discussions about the show on Facebook. You can tweet at me at Roman Mars and the show at 99PI org. We're on Instagram, Reddit, and TikTok too.
Starting point is 00:37:28 You can find links to other stature shows I love, as well as every past episode of 99PI at 99PI.org. you

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