Nuts and Bolts

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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 Thames, The Shard is Western Europe's tallest skyscraper. At just over 1,000 feet high, the building's slender, tapering design doesn't so much stretch 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, I'm still there, it's still standing. This is Roma Odderwal, 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 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, 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 and bolts 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 Changed the World in a Big Way. 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, 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, you know, 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.

But obviously, you know, the Renaissance was a while ago now, and 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 spirit to debate with people whether they think those are the right seven, or should there be more, or fewer, or, you know, but this is my list of seven.

Today, Roma Agarwal 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 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 hammering them into a wall to put a picture. And we kind of understand how they work. We kind of get that restriction involved, or that, you know, something's 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 material. 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 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 a nail, which is how the Egyptians did it, how the ancient Romans did it for thousands of years, it's a completely different experience.

It's a very sensory experience. Okay, 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 hot is not hot enough.

And it needed to go kind of orangey-y-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. So 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 heating and hitting and heating and hitting. But obviously, the Romans would have done it in one go. It's kind of remarkable to think about that.

Almost everything Romans built, there was a blacksmith somewhere that needed to make the nails. And not just one nail. 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 had abandoned the settlement.

And they left a horde of nails. 875,428, to be precise, in the 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 construction sites in your junk drawer. But they were once a huge part of 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 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. Wow. 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 period 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 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. 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 a 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 puns. Yeah, no, I got it. I used to pull them every time.

I was like, all right, yes, it's so good. And basically it's the phrase, don't reinvent the wheel. So this is a phrase that we use in business, in work, in school, like all over the place. It's like, no, no, no, 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 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. And this was a heavy, large disc which was made either from clay, from wood, even potentially from stone. And it basically had 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 ride on top of it? It's funny, right? It took potentially somewhere between 1,000 to 2,000 years for someone to do that just to turn it on its side. 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 in a site in the North Caucasus region which is now in Russia in the Yangnaya community around the 4th 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 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 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've described. What are some of those ways in which the wheel has evolved itself?

Yeah so the Yangnaya cart 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 doweled 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 and 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 spoked wheels and you know spoked wheels of course are a big iconography in Southeast Asia the Indian flag has a spoked wheel on it so this is a little flag reference for you Roman and this was much lighter so when you think of the Greeks or the Romans running around the Coliseum in their little carts and things they had spoked wheels they're much quicker and nimble on their feet but then when we started looking at flying machines in the 1700s 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 that can be seen 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 it's only a few hundred years old right 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 yes I mean I think the word originates from from tie like tying together a wheel and it was when we came up with the spoked 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 kind of 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 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 so 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 and in fact when we're typing on our laptops that's what's stopping our keys from permanently sinking down into the depths of our computers I mean there is 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 all the things that could be a spring yeah so trying to describe what a spring is was probably one of the hardest parts of this book for me actually 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 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 bow 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 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 bow and then when you release the string that energy is transferred into the arrow and so the arrow can travel much further much faster than would be possible if we just tried to throw it with our arms so I think that is the most fundamental the oldest form of the spring and you mentioned the coiled metal springs that you switch you also get coiled metal springs that you pull apart 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 in twisting so it's a very versatile piece of design so let's talk about the way 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 I could wrap around my leg to give you some idea of the size of them and I was really fascinated by this concert hall in Denmark which is called the Musikanshus 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 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 does a spring fit into this? So the kind of thing you're describing is very important and it forms 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 so you don't have bouncing sound everywhere but if you've got a truck kind of rumbling down the streets outside your home then your panels aren't going to do very much so what we need at that point are springs because what the springs do is go oh yeah some vibrations coming in i'm gonna have a little jump and bounce around and i'm gonna dissipate that energy into heat and i'm gonna 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 music from i don't know like a queen cover band that can infiltrate your bar concert which i'm guessing is not a good thing um 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 that's attached with springs all around it so that when the world vibrates it's sort of like that energy is dissipated and so the inner room doesn't vibrate exactly floating in this sort of womb that's exactly right the very technical jargon term for it is box in box so um you're basically creating the inside box you've got springs all around it 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 you know interlude of sorts on our journey through these seven dimensions but i wanted to bring it up because the string was definitely around when people decided to list out all the simple machines why did you elevate the string to this status one of the things that really stuns me about string is that it was invented by the Neanderthals and we found a six millimeter long piece of string which had twisted fibers to to make this you know 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 you know 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 string is beautiful it's it creates beautiful things not only physically beautiful things but also music and where would we be without music we'd be in a bouncy concert hall that didn't sound like anything when we come back roma wraps up her list of small inventions that change the world the respiratory therapist adjusting your oxygen the dietary aid who knows your diabetic the personal support worker helping your loved one live independently these are the allied support and community health professionals who care for patients every day in our hospitals labs and local health centers but today chronic shortages and burnout are pushing them to the breaking point it's time to stand out for the whole team that keeps care alive support them at heartbeat of care.ca a message from the national union of public and general employees and so our next entry in your seven inventions for making modern world 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 um as you say i know i know i'm sorry so so magnets as you say were strictly not an invention perhaps they were discovered um in the form of what we now call lodestone 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 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 realized that electricity and magnetism are in fact very intertwined um so you know when it comes to describing the importance of magnets um what what objects or what sort of engineering fees 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 jandra boss and he's an indian scientist and he used to work kind of in colonial india 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 i don't know i feel like i it's not 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 i think that a force is exerted across a room um and what that means and how revolutionary that is yeah it is and to demonstrate this idea jagdish jandra boss set out a public lecture in the late 1800s and he invited the lieutenant governor you know this british man who had lots of power got him standing in a 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 no one was hurt um but he basically demonstrated that we can use these waves to send signals far 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 you know a few decades ago it wasn't that long ago compared to my daughter who swipes a screen on an iphone or you know a smartphone and can place an instant video call to my family in india thanks to magnetism you mentioned your book that bose is a little forgotten in history and you know i imagine a lot of this has to do with where he was working and his identity 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 principal as a scientist as an engineer he didn't believe that knowledge should be restricted he believed that knowledge was for everyone 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 specifically which was called a coherer which did a very difficult job of receiving and interpreting electromagnetic signals of the sort that he was passing through rooms and people that you know the radio marconi's invention wouldn't have existed without that but he never patented it he never restricted it and i think it's 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 i've been in two extreme ways just in my own life the one is that i wear glasses and if i didn't wear glasses i would have quite a 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 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 okay um so i'm going to take you back to a draper um who was called anthony van leovenhoek okay 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 track count of the stuff that he was selling but then he also decided to put other stuff in front of this lens so he put bloods he saw blood cells he put palm 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 learned gentlemen 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 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 sperm under the microscope 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 a sinful no and in fact his exact words which has been translated from dutch if your lordship 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 and so again this is one of those funny situations where it took nearly 200 years before we worked 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 menken 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 that's so nice you owe it to a guy who definitely didn't jack off 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 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 so talk to me about the breast pump i mean it's 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 these really strange contraptions 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 or they just look pretty awful and i don't even know how they would have worked 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 it was really late and just if i jump back a little bit to 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 took to the 90s because it took that first you know like so you wouldn't be sucked into the machine um 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 an undercurrent in your life and the work that i know that you do is just like engineering um because women had been excluded from engineering for a long time these types of innovations um there's these huge blind spots yeah i mean from 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've got men who are very unlikely to overuse 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 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 you know 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 you know we've 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 and um thank you it'll just give you a greater appreciation for rivets you'll just walk around you see rivets you'll go i like that rivet that's pretty good right there are you saying roman that my book was riveting no i'm not saying that the book is very riveting thank you so much thank you for having me roma's book is called nuts and bolts seven small inventions that changed the world in a big way it's available in uk now and for pre-order in north america 99% invisible was produced this week by jason de leon original music by swan real sound mixed by hazik bin ahmad farid delaney hall is our senior editor kirk colstead is our digital director the rest of the team includes chris berube emmett fitzgerald martin gonzalez christopher johnson vivian lay lash maton jacob maldenato medina kelly prime joe rosenberg and me roman mars an extra special thanks and farewell to sophia klasker who has been my dear friend for decades and came here to help me take the 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 back to her true calling in the public center 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're so excited for her but we're going to miss her dearly the 99% visible logo was created by stephan lawrence we are part of the stitcher and serious exam podcast family now headquartered six blocks north in the pandora building in beautiful uptown oakland california you can find the show and join the discussion about the show on facebook you can tweet me at roman mars and the show at 99pi or on instagram reddit and tiktok too you can find links to other stitcher shows i love as well as every past episode of 99pi at 99pi.org you