How is metal made?
29 min
•Dec 2, 20255 months agoSummary
This Brains On! episode explores how metal is made, from its cosmic origins in exploding stars to ancient human discovery and smelting techniques. The episode traces metal's history through archaeological evidence like Ötzi the Iceman's copper axe and explains how different cultures independently developed iron and steel-making technologies.
Insights
- Most metals originate from stellar nucleosynthesis in massive stars, not Earth-based creation, making them literally cosmic materials
- Early humans discovered metal through both ground deposits and meteorite falls, with iron meteorites considered divine gifts in ancient civilizations
- Smelting technology emerged independently across multiple continents (Middle East, Africa, India, China) around 5,000+ years ago, indicating universal human problem-solving
- Termite mound mud's heat-reflective properties enabled sophisticated kiln construction in Tanzania 2,000 years ago, demonstrating indigenous engineering innovation
- Metal alloy development (copper+tin=bronze, iron+carbon=steel) drove human technological advancement and civilization building
Trends
Educational content increasingly emphasizes cosmic/scientific origins of everyday materials to build scientific literacy in childrenPodcast networks expanding live event touring as revenue diversification strategy beyond ad-supported modelsIndependent podcast production models relying on membership/subscription (SmartyPass) rather than traditional advertisingMulti-part episodic storytelling in educational content to maintain audience engagement and encourage series completionIntegration of listener participation (questions, artwork, mystery sounds) as core content generation and community building mechanism
Topics
Metal smelting and casting techniquesStellar nucleosynthesis and cosmic metal originsAncient metallurgy and archaeological evidenceIron meteorites in ancient civilizationsBronze and steel alloy developmentIndigenous engineering and kiln constructionÖtzi the Iceman murder mysteryCopper working in ancient ItalyHaya people metallurgical innovationMetal properties and applicationsPodcast business models and monetizationEducational content for childrenLive event touring strategyListener engagement and community buildingMulti-part episodic content structure
Companies
Atlas Obscura
Dylan Thurris from Atlas Obscura co-authored 'The Atlas Obscura Explorer's Guide to Inventing the World' and provided...
Brains On! Universe
Independent podcast network that recently moved to new headquarters and launched SmartyPass membership model for ad-f...
People
Dylan Thurris
Atlas Obscura contributor and co-author who provided expert historical analysis of metal discovery, smelting, and anc...
Ötzi the Iceman
5,300-year-old mummified hunter-gatherer whose copper axe and murder case provided archaeological evidence of ancient...
Quotes
"Metal is a name we use to talk about a lot of different materials. Yeah, sort of like saying fish. There are groupers, salmon, tuna, marlins. All are unique, but they're also all fish."
Molly Bloom•Early in episode
"The raw stuff, the origins of metal, that comes from massive exploding stars."
Molly Bloom•Mid-episode
"These things were kind of truly considered like a gift from the gods."
Dylan Thurris•Discussing iron meteorites
"Smelting is a way of heating up certain rocks to sort of melt out the metal trapped inside of them."
Dylan Thurris•Explaining ancient techniques
"Once humans master making it, they rebuild the world using it."
Dylan Thurris•Discussing steel's impact
Full Transcript
Hi friends, you might have heard that Bark, Sandin and I are on the road this spring with brains on live. We've been to several cities so far and it has been so much fun. Our next two stops are Atlanta and Fort Lauderdale. That's at the end of March. Then we just announced that we added Lawrence, Kansas in May and Columbus, Ohio in June. We're also heading to Chattanooga, Durham, Milwaukee, Portland, Buffalo and Ann Arbor, Michigan. We hope you'll be able to join us at one of those shows. We can't wait to see you to get tickets and get more information. You can head to brainson.org slash events. That's brainson.org slash events. Brains on Universe. You're listening to Brains On where we're serious about being curious. Imagine an amazing material. It's hard but you can make it soft and gooey like honey. You can shape it into the most powerful tools, dangerous weapons or incredible armor. It's strong enough to hold up entire cities and it can help power them too. It can even send messages around the world. This isn't science fiction. This super material is real. It's metal. Human beings have been obsessed with metal for pretty much as long as we can tell. It's hard, it's moldable, shapeable. It is kind of a magical material. That's Dylan Thuris from Atlas Obscura and this is part one of a three-part look at how metal changed the world from ancient times to today. Check it out. That box goes in the sandwich closet, Mark. No, no, no. The other sandwich closet. Oh, oh hey! We're still busy moving into our ginormous new Brains On Universe headquarters. Molly, does it make sense to have two sandwich closets? You're right. We should have three. Better install another. On it. Now that we're independent, we make all the decisions from what questions to answer to how many sandwich closets is the right number of sandwich closets. Actually, I think it's five, Mark. I was thinking the same thing. I'll add another. Being independent also means your support keeps us going. We made it super easy. Just join SmartyPass. You'll get ad-free versions of all of our shows, invites to special hangouts with me, Mark and Sandin, discounts on merch and live events. You can even get a custom message from me. Just go to BrainsOn.org to sign up. Five is an odd number. Why not make it an even 10? That's excessive. Totally. Do it. Right now. If you're a SmartyPass member, thank you times a million will dedicate a sandwich closet in your honor. If you're not a member yet, it's the best way to make sure smart kid first shows like this one stick around. So sign up at BrainsOn.org. Thanks. Molly, Mark, a shipment of 100 very delicious looking sandwiches just came in. Do we have anywhere to put them? Oh boy, do we ever. BrainsOn! You're listening to BrainsOn, part of the BrainsOn universe. I'm Molly Bloom and my co-host today is Ava from West Melbourne, Florida. Hi, Ava. Hi, Molly. So cool to be in your new place. Did you see the Lego chandelier? Loved it. The burrito bushes? Ate it. The corner where we keep a deep and expansive void that stares back at you? Consumplated it. We're pretty happy with the new place, even if it's a work in progress. But I had to stop unpacking to help answer your question. Yeah, I asked how is metal made? Great question. So Ava, when you picture metal, like what's the first thing that pops into your mind? Jewelry or technology? Do you have a favorite kind of metal? Gold. Very nice. Metal is a name we use to talk about a lot of different materials. Yeah, sort of like saying fish. There are groupers, salmon, tuna, marlins. All are unique, but they're also all fish. It's the same with metal. There's gold, steel, lead, and tin. They're all unique, but again, also all metals. So Ava, what inspired this question about how metal is made? I was fidgeting with one of my bracelets that had metal on it one time. And I have multiple bracelets that are like different kinds of metal. They're the same color, but they're slightly different. And I was wondering, how are they made? That's a great source of a question. So you're just looking around and being like, what is this thing? So I'm wondering, how often do you have a question about the world? Is it like all the time? Or is it just once in a while? I say it's pretty constant, like a lot. So what are some other questions that have popped in your head lately that you remember? Well, I remember I was in the car with my dog and I was playing with him with his tennis ball. And I was throwing it up in the air and we were moving forward. But the ball wasn't going backwards, which I thought was kind of weird, but also really cool. That is really cool. And Eva, you sound like you're Albert Einstein, for real. Like one of the smartest people in the world. He wondered that exact same thing. That's so cool. Metal is neat, and we use it for so many things, from jewelry and silverware to giant ships and skyscrapers. It's also used to make wires for electricity. It's in our phones and computers. It's everywhere. And like we said, there's so many kinds of metal, too. Iron, copper, steel. Aluminum, brass, nickel. Gold, silver, bronze. Ah, gold, silver, bronze. Three metals I've never won at the Olympics. Hey, Eva and Molly. Hey, Sandin. Why are you dropping by? Well, I have a quick unpacking question. You see, I found this box mixed in with the other boxes for our library, but it's full of Bs. So it goes with the apiary. But I kind of forgot where we put that. Apiary. An apiary is a fancy name for the place you keep your Bs. We have a hive that helps pollinate our garden. Sandin, that box has B, like the letter B. It's filled with books that start with B. That's why it's in the library pile. Oh, I was wondering why it felt like books, smelled like books, and also sounded like books. Thanks, Molly. Later. Okay, back to metal and your question. How is metal made? The truth is, most metal isn't made here on Earth. We often find metal, or we take metal and mix it with other things to make new kinds of metal. But the raw stuff, the origins of metal, that comes from massive exploding stars. Oh, I want to try that. Massive exploding stars. So cool. Truly. Like most things, the raw materials for metal are made inside really huge stars. Think of them like giant ovens. These massive stars cook up the stuff that makes planets like ours. They do that by smushing tiny things called elements together. This makes new elements. Some are metals. When those big stars die, they explode. That explosion can also make new elements. It also blasts all those new elements into the cosmos. Once all that stuff is floating in space, it can start to clump together and eventually make planets like ours. The plucky little planet we call Earth. So that's how the original metals we found on our planet got made. Thanks, stars. You're welcome. But there's so much more to the story, like strange rocks from space, super hot mud ovens, and an ancient murder mystery. But first, another mystery. It's time for the... Mystery sound. You ready, Ava? Mm-hmm. All right, here it is. Mm-hmm. Mm-hmm. Mm-hmm. Mm-hmm. Mm-hmm. Mm-hmm. Mm-hmm. Mm-hmm. Mm-hmm. Mm-hmm. It kind of sounds like people, like, slapping down a bunch of, like, plastic cups on a table. Ooh, I like that idea. Let's hear it again and see if anything new pops up. Some of it sounds kind of like sneakers on a basketball court, and then other parts of it sound like something banging against, like, the table or, like, the wall or something. I heard, like, a little, I don't know, almost, like, metal sound or something. I have no idea what it is, either. But yeah, it sounded like something banging, and it was kind of like rhythmic. So I'm gonna say... Vellego Minifig came to life and started playing the drums on a soda can that was lying around the house. I think that's reasonable. Yes. I like your answer better. Okay, well, we'll hear it again at the end of the show and get another chance to guess, and hear the answer, so stick around. Keep listening. We've got an episode coming up all about skunks. They're cute little critters with a creative way to keep away dangerous animals. Yeah, they spray a powerful stink. We want to know if you were an animal and needed a super creative way to keep your enemies away, what would you do? Ava, what would your special defense be? Well, if I were an animal, I would probably want to be a head truck so I could roll up and then fall and then roll and crash into people. I love that. It sounds like a very fun defense mechanism, and adorable, too. Well, listeners, tell us your idea for a unique animal protection power, record it and send it to us by going to brainson.org. We also love getting your artwork, questions, and mystery sounds. Again, send them to us at brainson.org. Thanks, cute listening. Ba-ba-ba-ba-ba-ba-ba-ba-ba-brainson. This is Brains On. I'm Molly. And I'm Ava, and we're learning about metals like aluminum and iron, silver, and copper. Copper, my favorite old-timey gangster word for police. Hey, Mark, what's up? I had an unpacking question. I found this box in the library, but I think it belongs in the A-peary, but I forgot where we put that. Let me guess, does the box say B on it? It does! It's probably another box full of books that start with B. Take it to the library, please. Okay. Oh, by the way, your guest is here. Later. Hey, Molly. Hey, Ava. Hey, it's Dylan Thurris from Atlas Obscura. Glad you made it. Of course, and congratulations on your new place. In fact, I brought you a little headquarters warming gift. What is it? Oh, it's a giant hunk of metal. Really, it could be almost anything. You could use it as a paperweight or a doorstop or a paperweight. So many different uses. Thanks. We invited Dylan here to help us tell the story of how humans learn to work with the amazing stuff we call metal. Dylan recently co-wrote a book called The Atlas Obscura Explorer's Guide to Inventing the World. What's it about? It is an adventure and a journey through a chain of human invention. So it starts with fire and tells you two places that have to do with how humans have used fire, including the cave that has the oldest evidence of fire use ever. And then once you have fire, you can make glass. And once you make glass, you can make lenses. And once you have lenses, you can make telescopes and microscopes. And so it's a journey both around the world to interesting places, but also through the history of technology. Very cool. Totally. So as we just explained, there's been metal on earth since the planet formed, but it was often buried deep in the ground or stuck inside rocks. But early humans found ways to use it and work it or shape it into things. So way back, thousands and thousands of years ago, people would occasionally come across big chunks of things like copper or gold. And they were soft enough to be worked by, say, hitting them with a rock or a hammer or putting them over a fire to just sort of soften them up a little bit. So there's where you start to see some of the earliest examples. And sometimes this is 10,000 years ago, and these are just little beads of copper, for example. Or 7,000 years ago, you find some gold ornaments, kind of jewelry. But there was another way humans would get metal too. And it's pretty epic. Imagine that you are in the desert, the Saharan Desert, and suddenly something comes shooting across the sky and it is bright and there's a loud explosion. And so you go and you investigate, and you might find these pieces of black, heavy stone. And they would feel pretty different from the other rocks in the area. They were very distinct. They were much, much heavier. And these were from iron meteorite. Iron meteorites are basically big chunks of mostly iron. People who found these likely thought they were very special because we see them used in very special ways. For example, buried with the Egyptian king Tutankhamun, there was this beautiful royal dagger that had sort of gold handle and a beautiful golden sheath. And the blade is made from an iron meteorite that had crashed into the planet. So these things were kind of truly considered like a gift from the gods. So early on we got metal from the ground or occasionally it would fall from the sky. Some of the metals were easier to shape than others, like copper. And people were pretty good at shaping copper as far back as 5,000 years ago. We know this thanks to an ancient murder mystery. The story starts in the early 1990s, a little over 30 years ago. Two people were hiking around the Italian Alps. And they happened to pass a glacier and they saw something that actually quite concerned them. They had found a body stuck half protruding out of the ice and it didn't look good. It looked like it had been there a very long time, but they actually called the police because they thought, well, I don't know. You know, maybe there's been something bad has happened here clearly. There's a dead body frozen into this glacier. Well, it turns out that that body was 5,300 years old. But they were right about one thing. There had been a murder. We'll hear what scientists learned from this frozen body in a minute. But first, time to go check the mail. We asked for listener ideas about what rooms we should add to our new headquarters. And we've gotten so many great ideas. Here's one from 11 year old Beebe from Hamilton, Ontario. Beebe writes, hi, I have an idea for the new room in the new headquarters. I thought that you could have a room called the betterinator, a room where you can put something that's boring and turn it into something more fun. Like a shoelace into some noodles or homework into a coloring sheet. Okay, I love this idea. Oh, okay, here's another one from 12 year old Raina in Delhi, India. My name is Raina and my idea for an empty room in the brains on universe is a triple rainbow generator room. Thank you. Triple rainbow generator? Okay, we were thinking of a double rainbow generator. But why do double when you could do triple? Thank you, Raina. So cool. If you all have ideas you'd like to send in, head to brainson.org. We love hearing from you. Want our shows without the ads? Join SmartyPass. You get ad free versions of Smash Boom best. Moment of Unforever Go and brains on. Plus you support shows full of facts, ideas and real science. Go to brainson.org to sign up. Thanks. Brains on, on, on. Okay, we're back. We talked about how humans found metal and learned to shape it into stuff. And now we're here with Dylan Thuris from Atlas Obscura. He's telling the story of the universe from Atlas Obscura. He is telling the story of a dead body found frozen in a glacier. Dylan, please tell us what scientists learned from this body and what did they think happened? So over 5,000 years ago, there was this guy. This guy, we don't know his real name, but we call him Otsi the Iceman. And he was walking along this glacier and he had all his stuff with him. He had stuff for making a fire. He had different kinds of tools with him. And one of the things he was carrying was this beautiful little axe. Small axe with a copper axe head. Unfortunately, Otsi was being followed because he was quickly shot through with an arrow. It went into his back and pierced his heart. And he wandered, it seems as if he sort of didn't kill him right away. He wandered around for a moment and then seems to have passed out, hit his head, and there he lay for 5,000 years and then was shortly thereafter frozen into this glacier. He froze pretty quickly and his body and all his stuff stayed frozen all that time. Which means his special axe was pretty much the same when they found him as it was 5,000 years ago. And what this axe tells us is that even 5,300 years ago, this hunter-gatherer was carrying an axe where the copper head was made through smelting. Smelting is a way of heating up certain rocks to sort of melt out the metal trapped inside of them. The copper had been made actually far away in southern Italy and melted into this axe head shape, probably cast actually in a little form. Casting is when you pour really hot metal into a shape so the metal cools and hardens into that shape. Kind of like if you poured melted chocolate into a tin shape like a bunny. The chocolate would harden when it cooled and then you'd have a chocolate shape like a bunny. That's what scientists think the people who made this axe did with the copper metal. But you know, they didn't use a bunny shape, they used an axe shape. Right. This was just a very fancy, rare kind of axe to be walking around with all the way back then. So to this day, we don't know who killed Otsi, we don't know why they killed him necessarily, but we know a lot of other things about him. We know what kind of tools he used. And we can also tell that there was this sophisticated network of people making metal tools and smelting copper even 5,300 years ago, all across Italy. So even 5,000 years ago, humans had learned you could heat up rocks to remove the metal trapped inside. That's called smelting. That means they didn't just have to find large chunks of metal to make stuff with, they could find rocks infused with metal too. Smelting copper was all well and good, but for humans to really do amazing things with metal, they'd need stronger metal. Because copper could break pretty easily. So humans found ways to make stronger and stronger types of metal. Like if you mix copper and tin, you get bronze. Which is stronger than copper, but still not as strong as iron or steel. What's kind of so cool and so interesting is people were so obsessed with figuring out, okay, how do we make even better metal? How do we make harder metal? That around the world, independently, many different groups seem to have figured out how to make iron and then later steel along the way. This seemed to happen in the Middle East and Sub-Saharan Africa, in India and China. All of them figured out their own ways of making harder metal. One of my favorite stories of this happens in Tanzania with a group called the Haya, like 2,000 years ago potentially. The Haya people would build something called a kiln. It was made from the mud of a termite mound. A kiln is a special oven usually used for making pottery. And a termite mound is a very tall cone of dirt that termites live in. It's a picture in Ant Hill, but about as tall as a giraffe and made of mud. That's what the Haya people were using to make these kilns. Because the mud from a termite mound is actually very, very good at reflecting heat. And they figure out not only can they build this kiln, they start to say, okay, we're gonna put little holes in the side of the kiln so it can suck air into it and that can make the fire even hotter. And we're gonna preheat it. We're gonna put a bunch of stuff into it so that the kiln gets really, really, really, really hot before we even do the thing we wanna do. And they also figure out, hey, you know what? If we add either some wood or better yet, these reeds that we have everywhere and we burn them, they form this kind of charcoal, this kind of ash, and that seems to add something into this metal, into this iron that makes the metal even stronger. What they were making was steel. Steel is iron mixed with carbon. Charcoal is full of carbon. And steel is full of strength. In fact, it is so strong that once humans master making it, they rebuild the world using it. But that's a story for next time. Dylan will be back with that chapter next week. Thanks for all this info, Dylan. Of course, I can't wait. I'll see you then. A brain's eye. Hey, Sandin, another unpacking question. Worse, we have an unpacking emergency, Molly, and I really need your help. What happened? Well, you know that box that Mark found? The one labeled with a bee? Yeah, what about it? Well, it turns out that one was meant for the apiary. It was filled with actual bees. And so when we opened it in the library, all the bees flew out. Oh, wow, that's not good. Were the bees super angry? Did they sting, Mark? And now you need to know where the anti-sting cream is? Oh, no, no, no, no, no. The bees are actually super happy in the library, but they don't want to leave now. And the bees are building a new hive there and making honey in the books, ruining all the pages. So you need the bee suit and the hive moving equipment so you can get them back to the garden? No, no, no, the bees are actually very respectful of the books. In fact, they love reading. We started a book club together. So what's the problem? We don't know what to read next. Molly, I need you to recommend a book. Quick. I'm on it. Do you think they like historical nonfiction or are they more of a sci-fi fantasy type? You know what? I'll go talk to them. Have they read Hamlet? They might really like the to be or not to be line. Or, oh, you could read Butte the Pooh. No, actually, Pooh tries to steal honey if they may. Not like that. There are lots of kinds of metals, from copper and gold to iron and steel. Humans have been using metals for thousands of years. Some of it they found in the ground. And some of it fell from the sky. Some metals are soft enough that you can shape them by banging them with rocks. But other metals need a lot of heat to make them soft enough to work with. Humans around the world found different ways to do that. And it helped them make stronger and stronger metals. That's it for this episode of Brains On. This episode was written by Sandin Totten. It was edited by Molly Bloom and Sound Designed and mixed by Mark Sanchez. Our website was built by Ken Taborsky at Code of the North at codeofthenorth.com. Special thanks go out to Sharice Pedrick, Max the Dog, Sophia and Mila, and John Aguila. Brains On is an independent podcast. Our show depends on your support. Help the show grow by going to BrainsOn.org and sign up for SmartyPass. That's our ad-free feed, where you get discounts on merch and live events. Plus, hangs with Sandin Mark and me. Get good stuff for supporting good podcasts. Exactly, sign up today at BrainsOn.org. Now, before we go, let's take one more pass at that mystery sound. So, Eva, what do you think this time? I don't really know. Maybe like a rock and like scissors or like something sharp like banging against each other? Ooh, I like that. And last time you thought it was basketball players, maybe, or something? Yeah. Let's hear the answer. I'm learning from private sensory island and the sound you just heard was me practicing my tap dancing. Have you tap danced before, Eva? No, but sometimes I like put on sneakers or shoes and try to. Nice. Yeah, you know what? You were not that far off because you were like people's feet banging. Absolutely, that's what happens in tap dancing. And they have like little metal pieces on the bottom of their shoes. That's why it makes that sound. And you were like metal or rock or something banging around. So definitely partial credit. Now it's time for the brains on our roll. These are the incredible kids who keep the show going with their questions, ideas, mystery sounds, drawings, and high fives. Freya from Granville, Michigan. Alexandra from Denver. Saren from Brighton, England. Cecily from Essex, UK. Annie Gus and Lucy from Norman, Oklahoma. Greta from Cologne, Minnesota. Aurora from Honolulu. Valeria from Linwood, California. Corbin from Bowdoin, Maine. Isla from Coventry, United Kingdom. Colette from Cary, North Carolina. Elizabeth from Newton, Massachusetts. Melani, Callie, and Luke from Ann Arbor, Michigan. Jack and Claire from San Luis Obispo, California. Tate from Charlotte, North Carolina. George from Stanford, Connecticut. Arya from Massachusetts. Luke from West Springfield, Massachusetts. George from Danvers, Massachusetts. Lennon from Dublin, Ohio. Cormac from Washington, DC. George from Chicago. Austin from Brooklyn, New York. Lila from Waterloo, Ontario. Lyle from North Charleston, South Carolina. Carver from Olympia, Washington. Amalia, Cassetta, and Juliana from Bellevue, Washington. Mason from Newcastle, Australia. Dakota from Yuma, Arizona. Quinn from Columbia, Illinois. Ronan from Rockville Center, New York. Lucas from Niverville, Manitoba. Navia from Redmond, Washington. Anya from Vancouver. Juno from Spokane, Washington. Coco from Montreal. Finley from Alcedina, California. Nora from Dobbsbury, New York. Korra from Seattle. Maddie and Edith from Walnut Creek, California. Hannah from Toronto. Art from Cincinnati. Holden from Pittsburgh, California. Sibyl from San Francisco. Sam from Monroeville, Pennsylvania. Luar from Denver. Hutch and Leiden from Austin, Texas. Della from Haddon Heights, New Jersey. Kahira and Dublin from Parker, Colorado. Elliot and Oliver from Oakville, Ontario. Libby from Flat Rock, North Carolina. Sammy from Hongju, China. Liam and Graham from Memphis, Tennessee. Alana from Moorsville, North Carolina. Ananya and Mira from Cary, North Carolina. Agi from Milan, Tennessee. Dean from Oregon. Thomas and Ryan from Tarle Sound, Massachusetts. Arisa from Kuala Lumpur. Gabby from Tucson. Lucas and Chloe from Tampa, Florida. Christian and Arya from Kobaccon, Ontario. And Louis from Auckland, New Zealand. Rains on the wall. High-five. Tune in next week for more answers to your questions. Where we'll learn more about metal. Thanks for listening.