Amethyst is a crystal!
MvH/Getty Images
This episode shines a light on crystals, and they’re sparkling right back at us! We’ll zoom way in on a diamond to understand the structure that makes crystals special, and hear about some unexpected crystals, too (hint: chocolate chip cookies contain a few different crystals!). Then, we take a look at how crystals form and get their cool colors. Plus, Marc and Sanden hunt down a hoax about Mesoamerican crystal skulls.
And! A mystery sound and a moment of um: why does sugar taste sweet?
Audio Transcript
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MOLLY BLOOM: Hi, friends. Before we start the show, we have a quick request for our listeners who are 18 and older. We love your help to make the show even better. So whether you've been with us for years or this is your very first episode, we would appreciate you taking a short anonymous survey. We want to hear from our listeners all over the world, and it will help Brains On be a better and stronger show.
So please go to americanpublicmedia.org/survey to complete the survey today. Again, that's americanpublicmedia.org/survey. Thank you so much.
CHILD ANNOUNCER 1: You're listening to Brains On, where we're serious about being curious.
CHILD ANNOUNCER 2: Brains On is supported in part by a grant from the National Science Foundation.
[FOOTSTEPS]
[DOOR SLIDING]
CRYSTAL 1: OK. I'm here. You can get started now.
MOLLY BLOOM: Hi. I'm Molly, and this is Layla.
LAYLA: Hello.
CRYSTAL 1: So nice to meet you. I'm Crystal.
MOLLY BLOOM: Nice to meet you, Crystal. Although I'm a little confused while you're in the studio. We're just about to start taping.
CRYSTAL 1: Then I'm right on time. I thought I was late.
MOLLY BLOOM: I--
CRYSTAL 1: I was so thrilled when I heard that you were doing an episode all about crystals.
LAYLA: Oh, I see. Your name is Crystal.
CRYSTAL 1: You bet it is.
LAYLA: But this is our time to start taping.
[DOOR SLIDING]
CRYSTAL 2: Hi, there. Sorry I'm running a few minutes late. So nice to meet you. I'm Crystal.
CRYSTAL 1: Likewise.
CRYSTAL 2: Oh, how fun.
MOLLY BLOOM: Two crystals.
[KNOCKING]
[DOOR SLIDING]
CRYSTAL 3: Hi. Is this where the crystal taping is.
CRYSTAL 1: Sure is.
CRYSTAL 2: Come on in.
LAYLA: Let me guess, your name is Crystal.
CRYSTAL 3: Oh, wow. How did you know?
CRYSTAL 1: Crystal. This is Crystal.
CRYSTAL 2: Hi.
CRYSTAL 1: And I'm Crystal!
CRYSTAL 3: Such a pleasure.
[KNOCKS]
MOLLY BLOOM: Come on in, Crystal.
[DOOR SLIDING]
CRYSTAL 4: Oh, good. You were expecting me. Sorry I'm late. Hi, everybody.
CRYSTAL 3: Hey, Crystal!
CRYSTAL 2: Hi, Crystal.
MOLLY BLOOM: Crystal, this is Crystal, Crystal, and Crystal.
CRYSTAL 4: What a treat.
[KNOCKING]
[DOOR SLIDING]
CRYSTAL 5: Hi, is this the studio?
LAYLA: It is indeed. Welcome, Crystal.
CRYSTAL 5: Thanks.
CRYSTAL 6: Wait, wait, wait. Hold the door, hold the door. Here I come. Oh, thanks. Hi, I'm--
MOLLY BLOOM AND LAYLA: Crystal.
CRYSTAL 1: Crystal--
ALL: Hi, Crystal.
MOLLY BLOOM: In case you've lost count, we're now at six Crystals.
LAYLA: It's starting to feel really crowded.
[KNOCKS]
CRYSTAL 7: Aunt Crystal?
[DOOR SLIDING]
Is my Aunt Crystal in here?
MOLLY BLOOM: Now we are really off the rails. You might as well come on in and look around.
CRYSTAL 7: Oh, thanks.
MOLLY BLOOM: If your Aunt Crystal isn't in here, we have several possible substitutes.
CRYSTAL 7: Aunt Crystal? Auntie Crystal? Are you in here?
[INTERPOSING VOICES]
LAYLA: Should we tell them this crystals episode isn't about them?
MOLLY BLOOM: Not sure they'll listen. But I do know one surefire way to get the episode started. Play the theme music.
[MUSIC PLAYING]
You're listening to Brains On from APM Studios. I'm Molly Bloom, and my co-host today is Layla from Kalamazoo, Michigan. Hi, Layla.
LAYLA: Hi.
MOLLY BLOOM: And today, we're taking a look at crystals.
LAYLA: But not humans named Crystal.
MOLLY BLOOM: Right. More like the shiny see-through rocks.
LAYLA: Sorry, Crystals.
CRYSTALS: It's-- I totally get it-- no worries-- oh, no problem. It's fine.
MOLLY BLOOM: So Layla, what got you interested in crystals?
LAYLA: Well I just really how shiny they are. And I haven't learned a lot about them in school yet. But I see books about them and I get them in library and stuff. And I just really think they're really cool and pretty.
MOLLY BLOOM: They are, I agree. So is there a color of crystal that you like a lot?
LAYLA: Ooh. I like pink. Pink and purples.
MOLLY BLOOM: So why do you think humans are so fascinated by crystals?
LAYLA: Maybe just because they're shiny and a lot of people like shiny things.
MOLLY BLOOM: I'm always distracted by shiny objects myself.
[TRILLS]
You wrote in with a great question about crystals. Do you remember what it was?
LAYLA: I wondered how crystals form and where did they come from.
MOLLY BLOOM: It's a really wonderful question. And actually, the way crystals are formed is what makes them special and different from ordinary rocks. Crystals are made of atoms. Those are the tiny chemical building blocks that make up everything around us. And in lots of materials, like plastic or concrete, the atoms are just jumbled up. But when something crystallizes, all of its atoms link up in a special order that repeats over and over. Not a jumble at all.
We asked Brains On producer Menaka Wilhelm to look into what makes a crystal a crystal for us. So she'll be here in just a moment.
LAYLA: Oh, while we wait. I should show you this app I use. It's called Crystal Clear. You tell it a material, and it tells you if it's a crystal. Check it out.
[MUSIC PLALYING]
MOLLY BLOOM: Oh, wow. The app has a soundtrack? OK, how about, OK, that purple see-through gemstone, it's called amethyst.
[DINGS]
CRYSTAL CLEAR APP: That's a crystal. Amethyst is actually a purple form of quartz.
LAYLA: And now how about salt?
[DINGS]
CRYSTAL CLEAR APP: That's a crystal. So is sugar. So fun to put those little crystals in and on your food.
MOLLY BLOOM: Let's try something a little more out there. How about amber? That goldeny-clear stone.
[FALSE SOUND]
CRYSTAL CLEAR APP: No. Not a crystal. It is see-through, but it's a fossil. It's atoms don't follow any order or rules.
LAYLA: What about a pearl?
CRYSTAL CLEAR APP: No. Well, kind of. It's stacks of little crystals, so it's not one crystal. It's bunches of crystals.
MOLLY BLOOM: So not all of the stones we put in jewelry are crystals.
LAYLA: And there are crystals and ordinary things, too.
[DINGS]
CRYSTAL CLEAR APP: That's right.
MENAKA WILHELM: Yoo-hoo. Molly? Layla? I'm here to charge up our crystal knowledge. Is someone else here?
LAYLA: Hi, Menaka.
MOLLY BLOOM: We're using this cool app Layla uses to see what's a crystal.
CRYSTAL CLEAR APP: I'm an app.
MENAKA WILHELM: Oh, perfect. Because I brought along two of my favorite crystals. One you might expect--
MOLLY BLOOM: Ooh, a diamond.
[DINGS]
CRYSTAL CLEAR APP: That's a crystal.
MENAKA WILHELM: And one you might not.
LAYLA: A pencil?
[FALSE SOUNDS]
CRYSTAL CLEAR APP: It's lead, it's a crystal.
MENAKA WILHELM: Wow. That app is spot on.
LAYLA: Yeah, but it's probably time to close it for now.
CRYSTAL CLEAR APP: Goodbye.
[MUSIC PLAYING]
MOLLY BLOOM: It's so interesting that all these different looking things can all be crystals.
MENAKA WILHELM: Yeah, it turns out crystals are defined by their insides and not their outside shape or color. I asked Joya Cooley to tell us about crystal insides. She's a chemist at California State University Fullerton.
[? JOYA COOLEY: ?] Yeah, I wish there were some way that we could like zoom in super far so we could see what was going on?
LAYLA: Oh, there is a way, the Zoom Ray!
MOLLY BLOOM: That's right, our patented handy-dandy device that lets us shrink down to any size. We keep it in the studio for exactly this reason.
ZOOM RAY: Zoom, zoom.
MOLLY BLOOM: It's ready.
[? JOYA COOLEY: ?] Oh, how awesome!
MENAKA WILHELM: So let's check out this diamond first.
MOLLY BLOOM: Sure.
MENAKA WILHELM: We'll just zoom on down to the size of an atom.
ZOOM RAY: Zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom.
MENAKA WILHELM: OK, so at this scale, we're smaller than the tip of a needle, smaller than a tardigrade. We're smaller than any of the cells in the human body. We're smaller than bacteria and viruses and way tinier than DNA. We are so tiny that if we walked up to a small-sized grain of sand. It would feel like we were walking up to a really giant shopping mall. And that means we're small enough to see the structure of this diamond, its atoms.
MOLLY BLOOM: Whoa. It never stops being amazing to see the building blocks of the universe up close like this.
LAYLA: Yeah, so I see a bunch of circles all stacked together.
MOLLY BLOOM: Yeah, the diamond has kind of like a 3D honeycomb thing going on.
MENAKA WILHELM: That's a great way to describe it.
[? JOYA COOLEY: ?] All a crystal is is a regular repeating pattern of something.
MENAKA WILHELM: And these atoms are made of a chemical called carbon. They're bonded together in a super organized way.
[? JOYA COOLEY: ?] So you get this really cool 3D structure where it goes up and down, left and right, and front and back basically.
MOLLY BLOOM: She's right. It's the same pattern in all directions.
LAYLA: And it repeats over and over and over again, (ECHOES) over and over again, over and over again, again and again, again and again.
MENAKA WILHELM: If we hop over to our pencil now and check out its lead at the same scale--
ZOOM RAY: Zoom, zoom, zoom, zoom, zoom, zooom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom.
MENAKA WILHELM: This material, the pencil lead, is called graphite.
LAYLA: Whoa, it's made of all carbon atoms, too, just like the diamond.
MENAKA WILHELM: Good eye. But the atoms in pencil lead are arranged in a really different shape than the diamond. Now, the carbon atoms are forming six-sided rings, hexagons!
LAYLA: Oh, they look like on a soccer ball, the shapes that are white.
MOLLY BLOOM: And then those six-sided rings attached side by side to form a flat blanket of hexagons.
[? JOYA COOLEY: ?] Again, it's still carbon, but there isn't really an up and down to it. So that's why graphite is great for pencil lead because it's just got this sheet-like structure. It comes off in sheets when you're writing, so that's actually what happens when you're writing.
MENAKA WILHELM: It's crystal sheets sliding onto your paper every time you use a pencil! But diamonds are also crystals, and they're made of the same atoms as pencil lead. And writing with a diamond would not work.
LAYLA: So just being arranged in a different crystal pattern makes these two really different materials.
MENAKA WILHELM: Yeah, and some crystals also form from multiple kinds of atoms and groups of atoms, too. There are lots of different kinds of crystals, and they're made of all kinds of stuff. But the one thing that they have in common is that they're built with this very organized repeating pattern.
LAYLA: Cool.
MENAKA WILHELM: OK, I think we're ready to zoom back out and talk about how these crystal shapes form.
ZOOM RAY: Zoom, zoom, zoom, zoom, zoom, zoom, zoom.
MENAKA WILHELM: So in a crystal, the atoms are all bonded together in their nice pattern. They're solid, but lots of crystals like quartz, for example, start out as atoms floating in a liquid.
LAYLA: Whoa, like atoms dissolved in water?
MENAKA WILHELM: Yeah, in some cases. Other times, quartz forms from rock that's so hot it's liquid. That's called magma. And when the atoms that make quartz are floating around in a liquid, they're not all bonded together. They're floating free. But if they bump into each other, some of those atoms will stick together. And then more atoms will stick to those atoms, kind of like how when you're making a snowball, more and more snow will stick to the outside of your snowball. And when atoms that form crystals stick together, they bond in an ordered pattern.
[? JOYA COOLEY: ?] They're more stable that way. So it's like they want to be that way.
MENAKA WILHELM: It's kind of like sitting in a chair. Like you could walk up to a chair and sit on the back rest or on one of the arms--
LAYLA: But you might fall over, and then you'd have to find a new place to sit.
MENAKA WILHELM: Right. Your best bet is really just to sit in the butt part of the chair. Some atoms just fit together the way the butts fit in chairs. There are places they can sit together comfortably, and that ends up creating a pattern.
MOLLY BLOOM: OK, so crystals form as atoms bond together in a comfortable chair-butt situation over and over and over.
MENAKA WILHELM: Right, and the way atoms bond together often depends on temperature. For example, if rock juice is really hot, all the atoms inside of it are bouncing around a lot. They're moving too fast to find good ways to bond.
[? JOYA COOLEY: ?] So when they start to cool down, then that's when they can find their buddy and say, OK, I'm really stable if I just sit next to you in this particular arrangement.
MENAKA WILHELM: But there are other ways that crystals form, too. Like if you think about the way that salt crystals form from salt water, salt bits bump into each other and bond as water evaporates into the air. So that's almost like the atoms that make salt are splashing around at a pool party, but the pool is drying up and getting smaller. So the atoms are bumping into each other more. And when they bump into each other, they can bond and form these neat little cubes. And those cubes are salt crystals, and they'll keep bonding into that same structure as long as there are atoms available to bond.
[? JOYA COOLEY: ?] So like a salt crystal would stop growing if it couldn't find another cube to stack on top basically.
MENAKA WILHELM: So the atoms that make crystals often find each other in a mix of other chemicals, but they bond together in these really specific ways. So they form pattern structures.
LAYLA: So organized.
MENAKA WILHELM: I know.
HAPPINESS MONITOR: Brrrring.
[SQUEAK]
Woohoo!
MENAKA WILHELM: Oh, speaking of organized, that's my personal happiness monitor letting me know I have a happiness inducing activity scheduled right now.
MOLLY BLOOM: A happiness inducing activity?
MENAKA WILHELM: Yep. I organize my day around little tasks to make me happier. And wow! My current activity is to eat some great crystals, sugar and chocolate in the form of freshly baked cookies. I'll be right back.
LAYLA: Bring some back, won't you?
ANNOUNCER: Brains on, on, on.
MOLLY BLOOM: Menaka munches on cookies, let's have have our ears munch on the--
[MACHINE SOUNDS]
CHILD: (WHISPERS) Mystery sound.
MOLLY BLOOM: Ready for the mystery sound Layla?
LAYLA: Yes.
MOLLY BLOOM: All right, here it is.
[MEDIUM PITCHED RINGING]
OK, Layla, what are you thinking?
LAYLA: Maybe in like some kind of factory or kind of a car slowing down on its brakes really slowly?
MOLLY BLOOM: Mhm. Mhm. I like both of those thoughts. But we will hear it again. Give you another chance to guess and hear the answer in just a bit.
[MUSIC PLAYING]
LAYLA: When you knock on wood--
MOLLY BLOOM: Or avoid stepping on cracks--
LAYLA: Maybe you kiss a four-leaf clover before a big test?
MOLLY BLOOM: Or you always wear your lucky podcast socks in the studio even if you forgot to wash them? Or maybe that's just me. Anyway, we're doing an episode all about superstitions, and we want to know--
LAYLA: What superstitions do you have?
MOLLY BLOOM: Record yourself telling us and send it to Brains On.org/contact. You can also send a question like this one.
TAMARA: Hi, I'm Tamara, and I'm from Mexico. But right now, I'm living in Ecuador, and my question is why does sugar taste sweet?
LAYLA: We'll answer that question at the end of the show, just after the credits.
MOLLY BLOOM: Don't miss it.
LAYLA: And keep listening.
[MUSIC PLAYING]
MOLLY BLOOM: You're listening to Brains On. I'm Molly.
LAYLA: And I'm Layla.
MENAKA WILHELM: And I'm Maneka with a plateful of warm cookies.
LAYLA: (MUNCHING COOKIES) Mm, so good.
MOLLY BLOOM: Mm, delicious sugar crystals. Mm! You know what these crystals need though?
[POURING LIQUID]
MENAKA WILHELM: Milk?
MOLLY BLOOM: You read my mind.
[GULPING]
Ah.
HAPPINESS MONITOR: Brrring.
[SQUEAK]
Woohoo!
MENAKA WILHELM: Oh, look. It's calculating my new happiness quotient. Wow! Sharing those cookies with you all added 8% more happiness to my day. Self high five.
[CLAP]
Now, where were we?
LAYLA: We were talking about the atoms that make crystals all crystally.
MENAKA WILHELM: Right, but when we typically think of crystals, it's not atoms or even salt or sugar or graphite that we think of.
LAYLA: It's shiny rocks.
MENAKA WILHELM: Shiny rocks, exactly. Crystals like diamonds, for example, are famous for their glistening, shimmery surfaces. In fact, we've gotten some questions about that.
MASON: My name is Mason from Westernville, New York, and my question is where do crystals get their shine?
REN: Hi, my name is Ren from Santa Barbara, California. My question is why are crystals shiny and how do they form?
MENAKA WILHELM: Well, it's a little different for every crystal. Not all of them are that shiny unless you polish or cut them. So like for that diamond I brought-- which by the way, I'll need that back, Molly-- that's shiny in part because jewelers have cut it to have flat reflective surfaces. And those nice flat reflective surfaces are great at bouncing light back into our eyes, making shine. But also, some of the light goes into the diamond and bounces around inside of it and then comes back out and hits our eyes, and that makes sparkly brilliance. Let's take a moment to stare at that shine and brilliance, shall we?
MOLLY AND LAYLA: Ohh.
HAPPINESS MONIOR: Brrring.
[SQUEAK]
Woohoo!
MENAKA WILHELM: Woo! That made me 2% happier. I'm on a roll. Now, to understand how crystals in nature get their slick shine and cool colors, you'll probably need to ask a geologist, which I did.
MARISA ACOSTA: Yeah, my name is Marisa Acosta, and I am a PhD in Earth Sciences. And I grow crystals in the lab to try and understand how they grow in nature.
MENAKA WILHELM: Marisa is a Researcher at the University of Lausanne in Switzerland. She says that crystals in nature also grow long, flat surfaces that reflect light. And remember how I said that some crystals first start as atoms in a liquid?
MOLLY BLOOM: Oh, yeah, that was right before you went to get your cookies.
MENAKA WILHELM: Right.
MOLLY BLOOM: Well, Marisa says, the slower these bits form into crystals, the bigger the flat surface they grow, and the more shiny and impressive they become.
MARISA ACOSTA: So if you cool the crystal really, really, really slowly, then you have a lot of time for that crystal to push out impurities and to form the most beautiful shape that it can form. But if you grow crystal really, really quickly, then it doesn't have time to form itself into the most beautiful version of itself that it would if it had all the time in the world. And you end up with a lot of poorly formed crystal faces. So they don't have those nice, flat surfaces that glint in the light.
MOLLY BLOOM: Oh, so that's why I am also very slow in the mornings. I am forming into the most beautiful version of myself for that day.
MENAKA WILHELM: Sure.
LAYLA: But what about all the cool colors? Diamonds are usually white, but there are also red crystals, purple crystals, blue ones.
MENAKA WILHELM: Right. Crystals are truly the Skittles of rocks. The cool colors come from minerals in the crystals, and sometimes, even small amounts of a mineral in a crystal can change its color. For instance, you know how we talked about quartz before?
LAYLA: Yeah.
MENAKA WILHELM: Quartz is a classic crystal, and it's just made of two things, silicon and oxygen. Its structure is one silicon atom for every two oxygen atoms. So we call it silicon dioxide, and normally, it's clear. But Marisa says, if a third thing sneaks in, the color changes dramatically.
MARISA ACOSTA: If you have silicon dioxide, and it grows in the presence of iron, then you can incorporate those iron impurities into the crystal lattice in teeny tiny amounts like 50 iron atoms per a million quartz atoms. And you can get this nice purple color. And it changes the way that the crystal reflects and scatters light. And that's responsible for the color change.
LAYLA: Oh, right, purple quartz is called amethyst. I learned that from my app.
[BEEPING]
CRYSTAL CLEAR APP: You're welcome.
MENAKA WILHELM: And sometimes, you have tiny crystals that grow inside of a crystal, and that can change its color, too.
MOLLY BLOOM: Crystals in crystals?
MENAKA WILHELM: Yeah, these are called inclusions. Think of it like those cookies we ate. The cookie part was like the main crystal, and the chocolate chips were the inclusions. So if you have a crystal like quartz, it's clear normally. But if it grows with little chocolate chips of a crystal called hematite inside of it, which is basically rust, then the quartz goes from clear to red. Cool color achieved.
LAYLA: Sweet.
MENAKA WILHELM: Yeah, and one of the coolest things about crystals--
MOLLY BLOOM: Besides being super pretty.
MENAKA WILHELM: Oh, of course, but also everything about a crystal helps tell a story about how it formed. That means its shape, its size, those traces of other elements and the crystals inside of the crystals. They all give us clues. With enough detective work, scientists like Marisa can use a crystal to piece together the very history of our planet itself.
MARISA ACOSTA: From these teeny tiny crystals, I can tell you about something that happened over a million years, 50 million years ago, at super deep down in the Earth, in the mantle maybe, and start to unravel these bigger picture stories of plate tectonics and supercontinent cycles and the formation of the Earth. Those types of things are the things that I'm really interested in using the crystals to figure out.
MOLLY BLOOM: Wow, I guess they are more than just their good looks. Who knew?
[MUSIC PLAYING]
CRYSTAL CLEAR APP: I knew. I love crystals.
MENAKA WILHELM: That is a very chatty app you have there.
LAYLA: I know. I'm actually not sure how to turn it off.
MENAKA WILHELM: Oh, totally fine. Anyway, I just love thinking about all the stories hiding in crystals, ancient history packed inside of a shiny rock.
HAPPINESS MONITOR: Brrrring.
[SQUEAK]
Woohoo!
MENAKA WILHELM: Whoa, contemplating the vast history of the Earth raised my happiness by a whole 12%.
MOLLY BLOOM: Well, thank you for sharing all that with us.
LAYLA: Yeah, thanks.
MENAKA WILHELM: No problem. Now, I got to go. I promised all those human crystals I would show them around Brains On HQ. It's the least I could do since they came all the way over here. Luckily, giving tours also makes me happy.
HAPPINESS MONITOR: Brrrring.
[SQUEAK]
Woohoo!
MENAKA WILHELM: Bye!
[ROBOT SOUNDS]
ROBOT: Brains, brains, brains on.
MOLLY BLOOM: Layla, let's revisit the mystery sound, shall we?
LAYLA: Yes.
MOLLY BLOOM: Here it is one more time.
[MEDIUM PITCHED RINGING]
OK, last time, you were like, maybe squeaky brakes or a factory. Do you have new thoughts about what it might be?
LAYLA: Actually, no because that's all I can think of right now.
MOLLY BLOOM: Just squeaky brakes on the brain. I do know that sound. It does sound a lot like that. Well, let's hear the answer.
MAYA: Hi, I'm Maya from Aliso Viejo, California. That sound was my finger turning on the rim of a crystal glass.
MOLLY BLOOM: Oh.
LAYLA: Oh.
MOLLY BLOOM: Yeah. So do--
LAYLA: That's cool.
MOLLY BLOOM: Can you picture that like the rim of the glass, and you move your finger on it? You get a little bit wet, and it makes that kind of noise?
LAYLA: Yeah, I can picture that.
MOLLY BLOOM: Have you done that before?
LAYLA: Actually, I don't think so.
MOLLY BLOOM: You should try it. It's pretty funny. You got to go at the right speed and have the right amount of liquid on your finger. And depending on how much water is in the glass, it'll make like a higher or lower pitch. But I have something to tell you. It's going to maybe blow your mind. Crystal glasses aren't real crystals. They're just called crystal. So crystals--
LAYLA: Weird.
MOLLY BLOOM: Yeah, isn't that weird? So crystals have atoms that line up in that very orderly pattern. But glass, the atoms are totally unorganized. They're all over the place, not like a crystal at all. And glass isn't even a solid.
LAYLA: Weird.
MOLLY BLOOM: Yeah, it's what's known as an amorphous solid, which means it's somewhere between a solid and a liquid.
LAYLA: That is so cool.
[CRYSTAL GLASS HUMMING]
MENAKA WILHELM: Glass, you look crystal clear, but you're actually hiding lots of cool sciencey secrets. And speaking of secrets, let's see what the Hoax Hunters have unearthed today.
SANDEN TOTTEN: I'm Sanden.
MARC SANCHEZ: And I'm Marc.
SANDEN TOTTEN: And we're back with another edition of--
[MUSIC PLAYING]
SANDEN AND MARC: "Hoax Hunters."
[MUSIC PLAYING]
(SINGING) We like myths, but we hate getting tricked, yeah. We like myths, but we hate getting tricked. We like myths, but we hate getting tricked.
[? SANDEN TOTTEN: ?] (SINGING) We hate getting tricked. No, we don't like it.
MARC SANCHEZ: A hoax is when somebody tricks you into believing something that isn't true.
SANDEN TOTTEN: And today's hoax is all about Mesoamerican crystal skulls.
MARC SANCHEZ: Say that again?
SANDEN TOTTEN: Meso--
[ELECRIC GUITAR]
--american--
[ELECRIC GUITAR]
--crystal--
[ELECRIC GUITAR]
--skulls.
[ELECRIC GUITAR PLAYING]
MARC SANCHEZ: So awesome. Picture the head of a skeleton made out of utterly awe-inducing crystal.
[GASPS]
SANDEN TOTTEN: Whoa. These mysterious crystal skulls ranged from milky white to crystal clear.
MARC SANCHEZ: And ranged from the size of a bead to the size of an actual human head.
[MUSIC PLAYING]
Some believe these crystal skulls can give you psychic powers.
SANDEN TOTTEN: Others think they came from the lost city of Atlantis.
MARC SANCHEZ: It's even been said they're proof that aliens landed on Earth thousands of years ago.
[MUSIC PLAYING]
SANDEN TOTTEN: Those are some bold claims. Should we be skeptical, Marc?
MARC SANCHEZ: Only if we don't want to get hoaxed, Sanden.
CHOIR: (SINGING) Don't get hoaxed.
[ROARS]
SANDEN TOTTEN: These mysterious crystal skulls first appeared for sale in the 1860s. People claimed they were made by ancient Mayan or Aztec person. At the time, everybody wanted to buy cool artifacts because ancient cultures were hot.
MARC SANCHEZ: Yeah? But so was hoaxing, and totally fake artifacts were popping up everywhere. Private collectors in museums didn't want to get tricked into buying fakes. So they relied on the help of experts to determine which relics were real and which were not.
SANDEN TOTTEN: Enter Eugene Boban, a French antiquarian and Mexico obsessive.
EUGENE BOBAN: Bonjour. I am an ancient artifact expert. I'll tell you what's legit and what's a lie. You can trust me. I have a mustache.
MARC SANCHEZ: Boban sold a huge number of relics including a few crystal skulls.
[MUSIC PLAYING]
One of his goals ended up at the famous jewelry store Tiffany and Company in New York, and it was bought by the British Museum in 1897, where it still lives to this day.
SANDEN TOTTEN: Yet in 1900, just 3 years after the skull was acquired by the British Museum, Boban told a newspaper journalist this--
EUGENE BOBAN: Numbers of so-called rock crystal pre-Columbian skulls have been so adroitly made as almost to defy detection and have been palmed off as genuine upon the experts of some of the principal museums of Europe.
SANDEN TOTTEN: Which basically means--
EUGENE BOBAN: A bunch of those skulls are fakey fakey eggs and bakey.
MARC SANCHEZ: Whoa, whoa, whoa, whoa. Wait, he admitted there were fake crystal skulls out in the world?
SANDEN TOTTEN: Yep.
MARC SANCHEZ: And wasn't he the one who was famous for selling these crystal skulls?
SANDEN TOTTEN: Yep.
MARC SANCHEZ: Hey, British Museum, it looks like--
MAN: (SINGING) You got hoaxed.
MARC SANCHEZ: Boban doesn't seem as trustworthy as he claimed to be.
SANDEN TOTTEN: Yeah, but a lot of the stuff he sold was real. So some museums continued to show off supposedly ancient crystal skulls. Collectors kept buying them, and the stories kept growing.
MARC SANCHEZ: But folks like Dr. Jane Walsh weren't buying it.
SANDEN TOTTEN: She's a specialist in Mesoamerican archeology and ethnohistory at the Smithsonian.
MARC SANCHEZ: And in 1992, the Smithsonian received a package from an anonymous donor containing a 31-pound crystal skull. The donor claimed it was a relic from the Aztec empire. But Dr. Walsh wasn't so sure.
SANDEN TOTTEN: So she took the skull to Margaret Sacks at the British Museum, and they both examined it with an electron microscope. Turns out the marks and cuts in the crystal were clearly made by modern rotary tools, which were not around in ancient times. But were pretty common in 19th century Europe.
MARC SANCHEZ: Psych! Another skull bites the dust.
EUGENE BOBAN: I doff my hoax hat to you, Walsh and Sacks. You're first rate!
[? HOAX HUNTERS: ?] Ho, ho, hoax hunted.
SANDEN TOTTEN: So what did we learn today, Marc?
MARC SANCHEZ: Just because someone claims to be an expert doesn't mean they are.
SANDEN TOTTEN: And if something seems a little fishy, do your research like Dr. Jane Walsh because you might just uncover the truth.
MARC SANCHEZ: That's all for today's episode of--
[MUSIC PLAYING]
(SINGING) Hoax Hunters! Yeah.
[MUSIC PLAYING]
MENAKA WILHELM: And here's the studio.
CRYSTAL: Oh, right, this is where we came first.
CRYSTAL: Good old studio.
CRYSTAL: Glad to be back.
LAYLA: Maneka and the Crystals, you're back.
MENAKA WILHELM: What is that music?
MOLLY BLOOM: Oh, it's Layla's crystal identifying app.
CRYSTAL: A crystal identifying app?
[MACHINE WHOOPS]
CRYSTAL CLEAR APP: Yeah. You're a Crystal.
CRYSTAL: I am. You get me!
CRYSTAL: [GASPS]
How about me?
[MACHINE WHOOPS]
CRYSTAL CLEAR APP: You're a Crystal.
CRYSTAL: Me next! Me next!
CRYSTAL: Oh, me next.
[INTERPOSING VOICES]
CRYSTAL: Oh, pick me. I'm Crystal.
CRYSTAL: Check me.
[MACHINE WHOOPS]
CRYSTAL CLEAR APP: She's a Crystal, another Crystal. That's a Crystal, all Crystal, except Layla and Molly and Maneka. They're not Crystals.
[MACHINE WHOOPS]
MENAKA WILHELM: A crystal spotting app spotting a cluster of chipper Crystals? This is amazing!
HAPPINESS MONITOR: Brrrring!
[SQUEAK]
Woohoo!
MENAKA WILHELM: Oh my gosh. That's a new record on my happiness meter.
CRYSTAL CLEAR APP: Not a crystal.
CRYSTAL: But I'm a Crystal.
[MACHINE WHOOPS]
CRYSTAL CLEAR APP: Yes, you are. You're a Crystal.
CRYSTAL: I'm a Crystal.
CRYSTAL: I'm a Crystal.
CRYSTAL: I'm a Crystal.
[MACHINE WHOOPS]
CRYSTAL CLEAR APP: That's accurate.
CRYSTALS: She's a crystal. She's a Crystal. They're not Crystals.
CRYSTAL: But we're all crystal.
[MACHINE WHOOPS]
CRYSTAL CLEAR APP: Still accurate, and I'm an app.
HAPPINESS MONITOR: Brrrring.
[SQUEAK]
Woohoo!
MENAKA WILHELM: This crystal chaos is such a delight!
HAPPINESS MONITOR: Brrrring.
[SQUEAK]
Woohoo!
[MUSIC PLAYING]
LAYLA: Crystals often form as pretty rocks like quartz, but there are other less flashy crystals, too, like pencil lead and sugar.
MOLLY BLOOM: All crystals are made of atoms in highly ordered patterns.
LAYLA: They bond in those patterns to be the most stable.
MOLLY BLOOM: And the way crystals bond changes their size, shape, and color.
LAYLA: Studying a crystal can tell you the story of how it formed.
MOLLY BLOOM: We've got some quick credits coming up next, butt then we're answering one more question.
TAMARA: Why does sugar taste sweet?
LAYLA: This episode was produced by Maneka Wilhelm, Sanden Totten, and Marc Sanchez, and Molly Bloom.
MOLLY BLOOM: We had engineering help from Alex Simpson. Our executive producer is Beth Perlman, and the executives in charge of APM Studios are Lily Kim, Alex Schaffert, and Joanne Griffith. Special thanks to Billy Eagan, Rachel Margolis, Lexi Pratt, Naomi Bloom, Cathy [? Maresku, ?] Nancy Yang, Vicky Kreckler, and Peter [? Haukus. ?]
LAYLA: Now, before we go, it's time for a moment of um.
[SAYING UM]
TAMARA: Why does sugar taste sweet?
[MUSIC PLAYING]
[? ANA MARIE ROSA: ?] Sugar actually has an OH group on it, which is a special shape on the molecules that make sugar. And that shape interacts with something on your tongue that we call a receptor. And a receptor is made up of two pieces that sit on your tongue. And when that OH group meets that receptor, that receptor tells your brain that something sweet has landed on your tongue.
[MUSIC PLAYING]
I am Ana Marie [INAUDIBLE] Rosa, and I am a scientist who studies taste. Most sugars are made up of small molecules that are either called glucose or fructose, and when we string those molecules together, we get all different kinds of sugars that are different shapes and sizes. But since they all interact with that same receptor on your tongue, we think all of them are sweet.
We also have artificial sugars, sugars that don't come with calories. And since they have those same groups, they sneak in, and they pretend they're sugars. And your brain thinks they're sweet because they have the same groups and interact with that same receptor.
There are animals that don't actually taste sweet. So cats don't respond to sweet because their diet isn't reliant on sugars. We evolved to eat fruits and things that are sweet, and so we look for those things and prefer them. But cats eat meat, and so they don't need sweetness. Not everybody tastes sweet.
[MUSIC PLAYING]
MOLLY BLOOM: Um.
MENAKA WILHELM: Um.
MOLLY BLOOM: Um. There's nothing sweeter than this group of names. It's the Brains Honor Roll. These are the incredible listeners who send us their questions, ideas, mystery sounds, drawings, and high fives.
[MUSIC PLAYING]
[LISTING HONOR ROLL]
THEME SONG: Brains Honor Roll.
MOLLY BLOOM: Brains On will be back soon with more answers to your questions.
[MACHINE WHOOPS]
CRYSTAL CLEAR APP: That's accurate.
LAYLA: Thanks for listening.
So please go to americanpublicmedia.org/survey to complete the survey today. Again, that's americanpublicmedia.org/survey. Thank you so much.
CHILD ANNOUNCER 1: You're listening to Brains On, where we're serious about being curious.
CHILD ANNOUNCER 2: Brains On is supported in part by a grant from the National Science Foundation.
[FOOTSTEPS]
[DOOR SLIDING]
CRYSTAL 1: OK. I'm here. You can get started now.
MOLLY BLOOM: Hi. I'm Molly, and this is Layla.
LAYLA: Hello.
CRYSTAL 1: So nice to meet you. I'm Crystal.
MOLLY BLOOM: Nice to meet you, Crystal. Although I'm a little confused while you're in the studio. We're just about to start taping.
CRYSTAL 1: Then I'm right on time. I thought I was late.
MOLLY BLOOM: I--
CRYSTAL 1: I was so thrilled when I heard that you were doing an episode all about crystals.
LAYLA: Oh, I see. Your name is Crystal.
CRYSTAL 1: You bet it is.
LAYLA: But this is our time to start taping.
[DOOR SLIDING]
CRYSTAL 2: Hi, there. Sorry I'm running a few minutes late. So nice to meet you. I'm Crystal.
CRYSTAL 1: Likewise.
CRYSTAL 2: Oh, how fun.
MOLLY BLOOM: Two crystals.
[KNOCKING]
[DOOR SLIDING]
CRYSTAL 3: Hi. Is this where the crystal taping is.
CRYSTAL 1: Sure is.
CRYSTAL 2: Come on in.
LAYLA: Let me guess, your name is Crystal.
CRYSTAL 3: Oh, wow. How did you know?
CRYSTAL 1: Crystal. This is Crystal.
CRYSTAL 2: Hi.
CRYSTAL 1: And I'm Crystal!
CRYSTAL 3: Such a pleasure.
[KNOCKS]
MOLLY BLOOM: Come on in, Crystal.
[DOOR SLIDING]
CRYSTAL 4: Oh, good. You were expecting me. Sorry I'm late. Hi, everybody.
CRYSTAL 3: Hey, Crystal!
CRYSTAL 2: Hi, Crystal.
MOLLY BLOOM: Crystal, this is Crystal, Crystal, and Crystal.
CRYSTAL 4: What a treat.
[KNOCKING]
[DOOR SLIDING]
CRYSTAL 5: Hi, is this the studio?
LAYLA: It is indeed. Welcome, Crystal.
CRYSTAL 5: Thanks.
CRYSTAL 6: Wait, wait, wait. Hold the door, hold the door. Here I come. Oh, thanks. Hi, I'm--
MOLLY BLOOM AND LAYLA: Crystal.
CRYSTAL 1: Crystal--
ALL: Hi, Crystal.
MOLLY BLOOM: In case you've lost count, we're now at six Crystals.
LAYLA: It's starting to feel really crowded.
[KNOCKS]
CRYSTAL 7: Aunt Crystal?
[DOOR SLIDING]
Is my Aunt Crystal in here?
MOLLY BLOOM: Now we are really off the rails. You might as well come on in and look around.
CRYSTAL 7: Oh, thanks.
MOLLY BLOOM: If your Aunt Crystal isn't in here, we have several possible substitutes.
CRYSTAL 7: Aunt Crystal? Auntie Crystal? Are you in here?
[INTERPOSING VOICES]
LAYLA: Should we tell them this crystals episode isn't about them?
MOLLY BLOOM: Not sure they'll listen. But I do know one surefire way to get the episode started. Play the theme music.
[MUSIC PLAYING]
You're listening to Brains On from APM Studios. I'm Molly Bloom, and my co-host today is Layla from Kalamazoo, Michigan. Hi, Layla.
LAYLA: Hi.
MOLLY BLOOM: And today, we're taking a look at crystals.
LAYLA: But not humans named Crystal.
MOLLY BLOOM: Right. More like the shiny see-through rocks.
LAYLA: Sorry, Crystals.
CRYSTALS: It's-- I totally get it-- no worries-- oh, no problem. It's fine.
MOLLY BLOOM: So Layla, what got you interested in crystals?
LAYLA: Well I just really how shiny they are. And I haven't learned a lot about them in school yet. But I see books about them and I get them in library and stuff. And I just really think they're really cool and pretty.
MOLLY BLOOM: They are, I agree. So is there a color of crystal that you like a lot?
LAYLA: Ooh. I like pink. Pink and purples.
MOLLY BLOOM: So why do you think humans are so fascinated by crystals?
LAYLA: Maybe just because they're shiny and a lot of people like shiny things.
MOLLY BLOOM: I'm always distracted by shiny objects myself.
[TRILLS]
You wrote in with a great question about crystals. Do you remember what it was?
LAYLA: I wondered how crystals form and where did they come from.
MOLLY BLOOM: It's a really wonderful question. And actually, the way crystals are formed is what makes them special and different from ordinary rocks. Crystals are made of atoms. Those are the tiny chemical building blocks that make up everything around us. And in lots of materials, like plastic or concrete, the atoms are just jumbled up. But when something crystallizes, all of its atoms link up in a special order that repeats over and over. Not a jumble at all.
We asked Brains On producer Menaka Wilhelm to look into what makes a crystal a crystal for us. So she'll be here in just a moment.
LAYLA: Oh, while we wait. I should show you this app I use. It's called Crystal Clear. You tell it a material, and it tells you if it's a crystal. Check it out.
[MUSIC PLALYING]
MOLLY BLOOM: Oh, wow. The app has a soundtrack? OK, how about, OK, that purple see-through gemstone, it's called amethyst.
[DINGS]
CRYSTAL CLEAR APP: That's a crystal. Amethyst is actually a purple form of quartz.
LAYLA: And now how about salt?
[DINGS]
CRYSTAL CLEAR APP: That's a crystal. So is sugar. So fun to put those little crystals in and on your food.
MOLLY BLOOM: Let's try something a little more out there. How about amber? That goldeny-clear stone.
[FALSE SOUND]
CRYSTAL CLEAR APP: No. Not a crystal. It is see-through, but it's a fossil. It's atoms don't follow any order or rules.
LAYLA: What about a pearl?
CRYSTAL CLEAR APP: No. Well, kind of. It's stacks of little crystals, so it's not one crystal. It's bunches of crystals.
MOLLY BLOOM: So not all of the stones we put in jewelry are crystals.
LAYLA: And there are crystals and ordinary things, too.
[DINGS]
CRYSTAL CLEAR APP: That's right.
MENAKA WILHELM: Yoo-hoo. Molly? Layla? I'm here to charge up our crystal knowledge. Is someone else here?
LAYLA: Hi, Menaka.
MOLLY BLOOM: We're using this cool app Layla uses to see what's a crystal.
CRYSTAL CLEAR APP: I'm an app.
MENAKA WILHELM: Oh, perfect. Because I brought along two of my favorite crystals. One you might expect--
MOLLY BLOOM: Ooh, a diamond.
[DINGS]
CRYSTAL CLEAR APP: That's a crystal.
MENAKA WILHELM: And one you might not.
LAYLA: A pencil?
[FALSE SOUNDS]
CRYSTAL CLEAR APP: It's lead, it's a crystal.
MENAKA WILHELM: Wow. That app is spot on.
LAYLA: Yeah, but it's probably time to close it for now.
CRYSTAL CLEAR APP: Goodbye.
[MUSIC PLAYING]
MOLLY BLOOM: It's so interesting that all these different looking things can all be crystals.
MENAKA WILHELM: Yeah, it turns out crystals are defined by their insides and not their outside shape or color. I asked Joya Cooley to tell us about crystal insides. She's a chemist at California State University Fullerton.
[? JOYA COOLEY: ?] Yeah, I wish there were some way that we could like zoom in super far so we could see what was going on?
LAYLA: Oh, there is a way, the Zoom Ray!
MOLLY BLOOM: That's right, our patented handy-dandy device that lets us shrink down to any size. We keep it in the studio for exactly this reason.
ZOOM RAY: Zoom, zoom.
MOLLY BLOOM: It's ready.
[? JOYA COOLEY: ?] Oh, how awesome!
MENAKA WILHELM: So let's check out this diamond first.
MOLLY BLOOM: Sure.
MENAKA WILHELM: We'll just zoom on down to the size of an atom.
ZOOM RAY: Zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom.
MENAKA WILHELM: OK, so at this scale, we're smaller than the tip of a needle, smaller than a tardigrade. We're smaller than any of the cells in the human body. We're smaller than bacteria and viruses and way tinier than DNA. We are so tiny that if we walked up to a small-sized grain of sand. It would feel like we were walking up to a really giant shopping mall. And that means we're small enough to see the structure of this diamond, its atoms.
MOLLY BLOOM: Whoa. It never stops being amazing to see the building blocks of the universe up close like this.
LAYLA: Yeah, so I see a bunch of circles all stacked together.
MOLLY BLOOM: Yeah, the diamond has kind of like a 3D honeycomb thing going on.
MENAKA WILHELM: That's a great way to describe it.
[? JOYA COOLEY: ?] All a crystal is is a regular repeating pattern of something.
MENAKA WILHELM: And these atoms are made of a chemical called carbon. They're bonded together in a super organized way.
[? JOYA COOLEY: ?] So you get this really cool 3D structure where it goes up and down, left and right, and front and back basically.
MOLLY BLOOM: She's right. It's the same pattern in all directions.
LAYLA: And it repeats over and over and over again, (ECHOES) over and over again, over and over again, again and again, again and again.
MENAKA WILHELM: If we hop over to our pencil now and check out its lead at the same scale--
ZOOM RAY: Zoom, zoom, zoom, zoom, zoom, zooom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom, zoom.
MENAKA WILHELM: This material, the pencil lead, is called graphite.
LAYLA: Whoa, it's made of all carbon atoms, too, just like the diamond.
MENAKA WILHELM: Good eye. But the atoms in pencil lead are arranged in a really different shape than the diamond. Now, the carbon atoms are forming six-sided rings, hexagons!
LAYLA: Oh, they look like on a soccer ball, the shapes that are white.
MOLLY BLOOM: And then those six-sided rings attached side by side to form a flat blanket of hexagons.
[? JOYA COOLEY: ?] Again, it's still carbon, but there isn't really an up and down to it. So that's why graphite is great for pencil lead because it's just got this sheet-like structure. It comes off in sheets when you're writing, so that's actually what happens when you're writing.
MENAKA WILHELM: It's crystal sheets sliding onto your paper every time you use a pencil! But diamonds are also crystals, and they're made of the same atoms as pencil lead. And writing with a diamond would not work.
LAYLA: So just being arranged in a different crystal pattern makes these two really different materials.
MENAKA WILHELM: Yeah, and some crystals also form from multiple kinds of atoms and groups of atoms, too. There are lots of different kinds of crystals, and they're made of all kinds of stuff. But the one thing that they have in common is that they're built with this very organized repeating pattern.
LAYLA: Cool.
MENAKA WILHELM: OK, I think we're ready to zoom back out and talk about how these crystal shapes form.
ZOOM RAY: Zoom, zoom, zoom, zoom, zoom, zoom, zoom.
MENAKA WILHELM: So in a crystal, the atoms are all bonded together in their nice pattern. They're solid, but lots of crystals like quartz, for example, start out as atoms floating in a liquid.
LAYLA: Whoa, like atoms dissolved in water?
MENAKA WILHELM: Yeah, in some cases. Other times, quartz forms from rock that's so hot it's liquid. That's called magma. And when the atoms that make quartz are floating around in a liquid, they're not all bonded together. They're floating free. But if they bump into each other, some of those atoms will stick together. And then more atoms will stick to those atoms, kind of like how when you're making a snowball, more and more snow will stick to the outside of your snowball. And when atoms that form crystals stick together, they bond in an ordered pattern.
[? JOYA COOLEY: ?] They're more stable that way. So it's like they want to be that way.
MENAKA WILHELM: It's kind of like sitting in a chair. Like you could walk up to a chair and sit on the back rest or on one of the arms--
LAYLA: But you might fall over, and then you'd have to find a new place to sit.
MENAKA WILHELM: Right. Your best bet is really just to sit in the butt part of the chair. Some atoms just fit together the way the butts fit in chairs. There are places they can sit together comfortably, and that ends up creating a pattern.
MOLLY BLOOM: OK, so crystals form as atoms bond together in a comfortable chair-butt situation over and over and over.
MENAKA WILHELM: Right, and the way atoms bond together often depends on temperature. For example, if rock juice is really hot, all the atoms inside of it are bouncing around a lot. They're moving too fast to find good ways to bond.
[? JOYA COOLEY: ?] So when they start to cool down, then that's when they can find their buddy and say, OK, I'm really stable if I just sit next to you in this particular arrangement.
MENAKA WILHELM: But there are other ways that crystals form, too. Like if you think about the way that salt crystals form from salt water, salt bits bump into each other and bond as water evaporates into the air. So that's almost like the atoms that make salt are splashing around at a pool party, but the pool is drying up and getting smaller. So the atoms are bumping into each other more. And when they bump into each other, they can bond and form these neat little cubes. And those cubes are salt crystals, and they'll keep bonding into that same structure as long as there are atoms available to bond.
[? JOYA COOLEY: ?] So like a salt crystal would stop growing if it couldn't find another cube to stack on top basically.
MENAKA WILHELM: So the atoms that make crystals often find each other in a mix of other chemicals, but they bond together in these really specific ways. So they form pattern structures.
LAYLA: So organized.
MENAKA WILHELM: I know.
HAPPINESS MONITOR: Brrrring.
[SQUEAK]
Woohoo!
MENAKA WILHELM: Oh, speaking of organized, that's my personal happiness monitor letting me know I have a happiness inducing activity scheduled right now.
MOLLY BLOOM: A happiness inducing activity?
MENAKA WILHELM: Yep. I organize my day around little tasks to make me happier. And wow! My current activity is to eat some great crystals, sugar and chocolate in the form of freshly baked cookies. I'll be right back.
LAYLA: Bring some back, won't you?
ANNOUNCER: Brains on, on, on.
MOLLY BLOOM: Menaka munches on cookies, let's have have our ears munch on the--
[MACHINE SOUNDS]
CHILD: (WHISPERS) Mystery sound.
MOLLY BLOOM: Ready for the mystery sound Layla?
LAYLA: Yes.
MOLLY BLOOM: All right, here it is.
[MEDIUM PITCHED RINGING]
OK, Layla, what are you thinking?
LAYLA: Maybe in like some kind of factory or kind of a car slowing down on its brakes really slowly?
MOLLY BLOOM: Mhm. Mhm. I like both of those thoughts. But we will hear it again. Give you another chance to guess and hear the answer in just a bit.
[MUSIC PLAYING]
LAYLA: When you knock on wood--
MOLLY BLOOM: Or avoid stepping on cracks--
LAYLA: Maybe you kiss a four-leaf clover before a big test?
MOLLY BLOOM: Or you always wear your lucky podcast socks in the studio even if you forgot to wash them? Or maybe that's just me. Anyway, we're doing an episode all about superstitions, and we want to know--
LAYLA: What superstitions do you have?
MOLLY BLOOM: Record yourself telling us and send it to Brains On.org/contact. You can also send a question like this one.
TAMARA: Hi, I'm Tamara, and I'm from Mexico. But right now, I'm living in Ecuador, and my question is why does sugar taste sweet?
LAYLA: We'll answer that question at the end of the show, just after the credits.
MOLLY BLOOM: Don't miss it.
LAYLA: And keep listening.
[MUSIC PLAYING]
MOLLY BLOOM: You're listening to Brains On. I'm Molly.
LAYLA: And I'm Layla.
MENAKA WILHELM: And I'm Maneka with a plateful of warm cookies.
LAYLA: (MUNCHING COOKIES) Mm, so good.
MOLLY BLOOM: Mm, delicious sugar crystals. Mm! You know what these crystals need though?
[POURING LIQUID]
MENAKA WILHELM: Milk?
MOLLY BLOOM: You read my mind.
[GULPING]
Ah.
HAPPINESS MONITOR: Brrring.
[SQUEAK]
Woohoo!
MENAKA WILHELM: Oh, look. It's calculating my new happiness quotient. Wow! Sharing those cookies with you all added 8% more happiness to my day. Self high five.
[CLAP]
Now, where were we?
LAYLA: We were talking about the atoms that make crystals all crystally.
MENAKA WILHELM: Right, but when we typically think of crystals, it's not atoms or even salt or sugar or graphite that we think of.
LAYLA: It's shiny rocks.
MENAKA WILHELM: Shiny rocks, exactly. Crystals like diamonds, for example, are famous for their glistening, shimmery surfaces. In fact, we've gotten some questions about that.
MASON: My name is Mason from Westernville, New York, and my question is where do crystals get their shine?
REN: Hi, my name is Ren from Santa Barbara, California. My question is why are crystals shiny and how do they form?
MENAKA WILHELM: Well, it's a little different for every crystal. Not all of them are that shiny unless you polish or cut them. So like for that diamond I brought-- which by the way, I'll need that back, Molly-- that's shiny in part because jewelers have cut it to have flat reflective surfaces. And those nice flat reflective surfaces are great at bouncing light back into our eyes, making shine. But also, some of the light goes into the diamond and bounces around inside of it and then comes back out and hits our eyes, and that makes sparkly brilliance. Let's take a moment to stare at that shine and brilliance, shall we?
MOLLY AND LAYLA: Ohh.
HAPPINESS MONIOR: Brrring.
[SQUEAK]
Woohoo!
MENAKA WILHELM: Woo! That made me 2% happier. I'm on a roll. Now, to understand how crystals in nature get their slick shine and cool colors, you'll probably need to ask a geologist, which I did.
MARISA ACOSTA: Yeah, my name is Marisa Acosta, and I am a PhD in Earth Sciences. And I grow crystals in the lab to try and understand how they grow in nature.
MENAKA WILHELM: Marisa is a Researcher at the University of Lausanne in Switzerland. She says that crystals in nature also grow long, flat surfaces that reflect light. And remember how I said that some crystals first start as atoms in a liquid?
MOLLY BLOOM: Oh, yeah, that was right before you went to get your cookies.
MENAKA WILHELM: Right.
MOLLY BLOOM: Well, Marisa says, the slower these bits form into crystals, the bigger the flat surface they grow, and the more shiny and impressive they become.
MARISA ACOSTA: So if you cool the crystal really, really, really slowly, then you have a lot of time for that crystal to push out impurities and to form the most beautiful shape that it can form. But if you grow crystal really, really quickly, then it doesn't have time to form itself into the most beautiful version of itself that it would if it had all the time in the world. And you end up with a lot of poorly formed crystal faces. So they don't have those nice, flat surfaces that glint in the light.
MOLLY BLOOM: Oh, so that's why I am also very slow in the mornings. I am forming into the most beautiful version of myself for that day.
MENAKA WILHELM: Sure.
LAYLA: But what about all the cool colors? Diamonds are usually white, but there are also red crystals, purple crystals, blue ones.
MENAKA WILHELM: Right. Crystals are truly the Skittles of rocks. The cool colors come from minerals in the crystals, and sometimes, even small amounts of a mineral in a crystal can change its color. For instance, you know how we talked about quartz before?
LAYLA: Yeah.
MENAKA WILHELM: Quartz is a classic crystal, and it's just made of two things, silicon and oxygen. Its structure is one silicon atom for every two oxygen atoms. So we call it silicon dioxide, and normally, it's clear. But Marisa says, if a third thing sneaks in, the color changes dramatically.
MARISA ACOSTA: If you have silicon dioxide, and it grows in the presence of iron, then you can incorporate those iron impurities into the crystal lattice in teeny tiny amounts like 50 iron atoms per a million quartz atoms. And you can get this nice purple color. And it changes the way that the crystal reflects and scatters light. And that's responsible for the color change.
LAYLA: Oh, right, purple quartz is called amethyst. I learned that from my app.
[BEEPING]
CRYSTAL CLEAR APP: You're welcome.
MENAKA WILHELM: And sometimes, you have tiny crystals that grow inside of a crystal, and that can change its color, too.
MOLLY BLOOM: Crystals in crystals?
MENAKA WILHELM: Yeah, these are called inclusions. Think of it like those cookies we ate. The cookie part was like the main crystal, and the chocolate chips were the inclusions. So if you have a crystal like quartz, it's clear normally. But if it grows with little chocolate chips of a crystal called hematite inside of it, which is basically rust, then the quartz goes from clear to red. Cool color achieved.
LAYLA: Sweet.
MENAKA WILHELM: Yeah, and one of the coolest things about crystals--
MOLLY BLOOM: Besides being super pretty.
MENAKA WILHELM: Oh, of course, but also everything about a crystal helps tell a story about how it formed. That means its shape, its size, those traces of other elements and the crystals inside of the crystals. They all give us clues. With enough detective work, scientists like Marisa can use a crystal to piece together the very history of our planet itself.
MARISA ACOSTA: From these teeny tiny crystals, I can tell you about something that happened over a million years, 50 million years ago, at super deep down in the Earth, in the mantle maybe, and start to unravel these bigger picture stories of plate tectonics and supercontinent cycles and the formation of the Earth. Those types of things are the things that I'm really interested in using the crystals to figure out.
MOLLY BLOOM: Wow, I guess they are more than just their good looks. Who knew?
[MUSIC PLAYING]
CRYSTAL CLEAR APP: I knew. I love crystals.
MENAKA WILHELM: That is a very chatty app you have there.
LAYLA: I know. I'm actually not sure how to turn it off.
MENAKA WILHELM: Oh, totally fine. Anyway, I just love thinking about all the stories hiding in crystals, ancient history packed inside of a shiny rock.
HAPPINESS MONITOR: Brrrring.
[SQUEAK]
Woohoo!
MENAKA WILHELM: Whoa, contemplating the vast history of the Earth raised my happiness by a whole 12%.
MOLLY BLOOM: Well, thank you for sharing all that with us.
LAYLA: Yeah, thanks.
MENAKA WILHELM: No problem. Now, I got to go. I promised all those human crystals I would show them around Brains On HQ. It's the least I could do since they came all the way over here. Luckily, giving tours also makes me happy.
HAPPINESS MONITOR: Brrrring.
[SQUEAK]
Woohoo!
MENAKA WILHELM: Bye!
[ROBOT SOUNDS]
ROBOT: Brains, brains, brains on.
MOLLY BLOOM: Layla, let's revisit the mystery sound, shall we?
LAYLA: Yes.
MOLLY BLOOM: Here it is one more time.
[MEDIUM PITCHED RINGING]
OK, last time, you were like, maybe squeaky brakes or a factory. Do you have new thoughts about what it might be?
LAYLA: Actually, no because that's all I can think of right now.
MOLLY BLOOM: Just squeaky brakes on the brain. I do know that sound. It does sound a lot like that. Well, let's hear the answer.
MAYA: Hi, I'm Maya from Aliso Viejo, California. That sound was my finger turning on the rim of a crystal glass.
MOLLY BLOOM: Oh.
LAYLA: Oh.
MOLLY BLOOM: Yeah. So do--
LAYLA: That's cool.
MOLLY BLOOM: Can you picture that like the rim of the glass, and you move your finger on it? You get a little bit wet, and it makes that kind of noise?
LAYLA: Yeah, I can picture that.
MOLLY BLOOM: Have you done that before?
LAYLA: Actually, I don't think so.
MOLLY BLOOM: You should try it. It's pretty funny. You got to go at the right speed and have the right amount of liquid on your finger. And depending on how much water is in the glass, it'll make like a higher or lower pitch. But I have something to tell you. It's going to maybe blow your mind. Crystal glasses aren't real crystals. They're just called crystal. So crystals--
LAYLA: Weird.
MOLLY BLOOM: Yeah, isn't that weird? So crystals have atoms that line up in that very orderly pattern. But glass, the atoms are totally unorganized. They're all over the place, not like a crystal at all. And glass isn't even a solid.
LAYLA: Weird.
MOLLY BLOOM: Yeah, it's what's known as an amorphous solid, which means it's somewhere between a solid and a liquid.
LAYLA: That is so cool.
[CRYSTAL GLASS HUMMING]
MENAKA WILHELM: Glass, you look crystal clear, but you're actually hiding lots of cool sciencey secrets. And speaking of secrets, let's see what the Hoax Hunters have unearthed today.
SANDEN TOTTEN: I'm Sanden.
MARC SANCHEZ: And I'm Marc.
SANDEN TOTTEN: And we're back with another edition of--
[MUSIC PLAYING]
SANDEN AND MARC: "Hoax Hunters."
[MUSIC PLAYING]
(SINGING) We like myths, but we hate getting tricked, yeah. We like myths, but we hate getting tricked. We like myths, but we hate getting tricked.
[? SANDEN TOTTEN: ?] (SINGING) We hate getting tricked. No, we don't like it.
MARC SANCHEZ: A hoax is when somebody tricks you into believing something that isn't true.
SANDEN TOTTEN: And today's hoax is all about Mesoamerican crystal skulls.
MARC SANCHEZ: Say that again?
SANDEN TOTTEN: Meso--
[ELECRIC GUITAR]
--american--
[ELECRIC GUITAR]
--crystal--
[ELECRIC GUITAR]
--skulls.
[ELECRIC GUITAR PLAYING]
MARC SANCHEZ: So awesome. Picture the head of a skeleton made out of utterly awe-inducing crystal.
[GASPS]
SANDEN TOTTEN: Whoa. These mysterious crystal skulls ranged from milky white to crystal clear.
MARC SANCHEZ: And ranged from the size of a bead to the size of an actual human head.
[MUSIC PLAYING]
Some believe these crystal skulls can give you psychic powers.
SANDEN TOTTEN: Others think they came from the lost city of Atlantis.
MARC SANCHEZ: It's even been said they're proof that aliens landed on Earth thousands of years ago.
[MUSIC PLAYING]
SANDEN TOTTEN: Those are some bold claims. Should we be skeptical, Marc?
MARC SANCHEZ: Only if we don't want to get hoaxed, Sanden.
CHOIR: (SINGING) Don't get hoaxed.
[ROARS]
SANDEN TOTTEN: These mysterious crystal skulls first appeared for sale in the 1860s. People claimed they were made by ancient Mayan or Aztec person. At the time, everybody wanted to buy cool artifacts because ancient cultures were hot.
MARC SANCHEZ: Yeah? But so was hoaxing, and totally fake artifacts were popping up everywhere. Private collectors in museums didn't want to get tricked into buying fakes. So they relied on the help of experts to determine which relics were real and which were not.
SANDEN TOTTEN: Enter Eugene Boban, a French antiquarian and Mexico obsessive.
EUGENE BOBAN: Bonjour. I am an ancient artifact expert. I'll tell you what's legit and what's a lie. You can trust me. I have a mustache.
MARC SANCHEZ: Boban sold a huge number of relics including a few crystal skulls.
[MUSIC PLAYING]
One of his goals ended up at the famous jewelry store Tiffany and Company in New York, and it was bought by the British Museum in 1897, where it still lives to this day.
SANDEN TOTTEN: Yet in 1900, just 3 years after the skull was acquired by the British Museum, Boban told a newspaper journalist this--
EUGENE BOBAN: Numbers of so-called rock crystal pre-Columbian skulls have been so adroitly made as almost to defy detection and have been palmed off as genuine upon the experts of some of the principal museums of Europe.
SANDEN TOTTEN: Which basically means--
EUGENE BOBAN: A bunch of those skulls are fakey fakey eggs and bakey.
MARC SANCHEZ: Whoa, whoa, whoa, whoa. Wait, he admitted there were fake crystal skulls out in the world?
SANDEN TOTTEN: Yep.
MARC SANCHEZ: And wasn't he the one who was famous for selling these crystal skulls?
SANDEN TOTTEN: Yep.
MARC SANCHEZ: Hey, British Museum, it looks like--
MAN: (SINGING) You got hoaxed.
MARC SANCHEZ: Boban doesn't seem as trustworthy as he claimed to be.
SANDEN TOTTEN: Yeah, but a lot of the stuff he sold was real. So some museums continued to show off supposedly ancient crystal skulls. Collectors kept buying them, and the stories kept growing.
MARC SANCHEZ: But folks like Dr. Jane Walsh weren't buying it.
SANDEN TOTTEN: She's a specialist in Mesoamerican archeology and ethnohistory at the Smithsonian.
MARC SANCHEZ: And in 1992, the Smithsonian received a package from an anonymous donor containing a 31-pound crystal skull. The donor claimed it was a relic from the Aztec empire. But Dr. Walsh wasn't so sure.
SANDEN TOTTEN: So she took the skull to Margaret Sacks at the British Museum, and they both examined it with an electron microscope. Turns out the marks and cuts in the crystal were clearly made by modern rotary tools, which were not around in ancient times. But were pretty common in 19th century Europe.
MARC SANCHEZ: Psych! Another skull bites the dust.
EUGENE BOBAN: I doff my hoax hat to you, Walsh and Sacks. You're first rate!
[? HOAX HUNTERS: ?] Ho, ho, hoax hunted.
SANDEN TOTTEN: So what did we learn today, Marc?
MARC SANCHEZ: Just because someone claims to be an expert doesn't mean they are.
SANDEN TOTTEN: And if something seems a little fishy, do your research like Dr. Jane Walsh because you might just uncover the truth.
MARC SANCHEZ: That's all for today's episode of--
[MUSIC PLAYING]
(SINGING) Hoax Hunters! Yeah.
[MUSIC PLAYING]
MENAKA WILHELM: And here's the studio.
CRYSTAL: Oh, right, this is where we came first.
CRYSTAL: Good old studio.
CRYSTAL: Glad to be back.
LAYLA: Maneka and the Crystals, you're back.
MENAKA WILHELM: What is that music?
MOLLY BLOOM: Oh, it's Layla's crystal identifying app.
CRYSTAL: A crystal identifying app?
[MACHINE WHOOPS]
CRYSTAL CLEAR APP: Yeah. You're a Crystal.
CRYSTAL: I am. You get me!
CRYSTAL: [GASPS]
How about me?
[MACHINE WHOOPS]
CRYSTAL CLEAR APP: You're a Crystal.
CRYSTAL: Me next! Me next!
CRYSTAL: Oh, me next.
[INTERPOSING VOICES]
CRYSTAL: Oh, pick me. I'm Crystal.
CRYSTAL: Check me.
[MACHINE WHOOPS]
CRYSTAL CLEAR APP: She's a Crystal, another Crystal. That's a Crystal, all Crystal, except Layla and Molly and Maneka. They're not Crystals.
[MACHINE WHOOPS]
MENAKA WILHELM: A crystal spotting app spotting a cluster of chipper Crystals? This is amazing!
HAPPINESS MONITOR: Brrrring!
[SQUEAK]
Woohoo!
MENAKA WILHELM: Oh my gosh. That's a new record on my happiness meter.
CRYSTAL CLEAR APP: Not a crystal.
CRYSTAL: But I'm a Crystal.
[MACHINE WHOOPS]
CRYSTAL CLEAR APP: Yes, you are. You're a Crystal.
CRYSTAL: I'm a Crystal.
CRYSTAL: I'm a Crystal.
CRYSTAL: I'm a Crystal.
[MACHINE WHOOPS]
CRYSTAL CLEAR APP: That's accurate.
CRYSTALS: She's a crystal. She's a Crystal. They're not Crystals.
CRYSTAL: But we're all crystal.
[MACHINE WHOOPS]
CRYSTAL CLEAR APP: Still accurate, and I'm an app.
HAPPINESS MONITOR: Brrrring.
[SQUEAK]
Woohoo!
MENAKA WILHELM: This crystal chaos is such a delight!
HAPPINESS MONITOR: Brrrring.
[SQUEAK]
Woohoo!
[MUSIC PLAYING]
LAYLA: Crystals often form as pretty rocks like quartz, but there are other less flashy crystals, too, like pencil lead and sugar.
MOLLY BLOOM: All crystals are made of atoms in highly ordered patterns.
LAYLA: They bond in those patterns to be the most stable.
MOLLY BLOOM: And the way crystals bond changes their size, shape, and color.
LAYLA: Studying a crystal can tell you the story of how it formed.
MOLLY BLOOM: We've got some quick credits coming up next, butt then we're answering one more question.
TAMARA: Why does sugar taste sweet?
LAYLA: This episode was produced by Maneka Wilhelm, Sanden Totten, and Marc Sanchez, and Molly Bloom.
MOLLY BLOOM: We had engineering help from Alex Simpson. Our executive producer is Beth Perlman, and the executives in charge of APM Studios are Lily Kim, Alex Schaffert, and Joanne Griffith. Special thanks to Billy Eagan, Rachel Margolis, Lexi Pratt, Naomi Bloom, Cathy [? Maresku, ?] Nancy Yang, Vicky Kreckler, and Peter [? Haukus. ?]
LAYLA: Now, before we go, it's time for a moment of um.
[SAYING UM]
TAMARA: Why does sugar taste sweet?
[MUSIC PLAYING]
[? ANA MARIE ROSA: ?] Sugar actually has an OH group on it, which is a special shape on the molecules that make sugar. And that shape interacts with something on your tongue that we call a receptor. And a receptor is made up of two pieces that sit on your tongue. And when that OH group meets that receptor, that receptor tells your brain that something sweet has landed on your tongue.
[MUSIC PLAYING]
I am Ana Marie [INAUDIBLE] Rosa, and I am a scientist who studies taste. Most sugars are made up of small molecules that are either called glucose or fructose, and when we string those molecules together, we get all different kinds of sugars that are different shapes and sizes. But since they all interact with that same receptor on your tongue, we think all of them are sweet.
We also have artificial sugars, sugars that don't come with calories. And since they have those same groups, they sneak in, and they pretend they're sugars. And your brain thinks they're sweet because they have the same groups and interact with that same receptor.
There are animals that don't actually taste sweet. So cats don't respond to sweet because their diet isn't reliant on sugars. We evolved to eat fruits and things that are sweet, and so we look for those things and prefer them. But cats eat meat, and so they don't need sweetness. Not everybody tastes sweet.
[MUSIC PLAYING]
MOLLY BLOOM: Um.
MENAKA WILHELM: Um.
MOLLY BLOOM: Um. There's nothing sweeter than this group of names. It's the Brains Honor Roll. These are the incredible listeners who send us their questions, ideas, mystery sounds, drawings, and high fives.
[MUSIC PLAYING]
[LISTING HONOR ROLL]
THEME SONG: Brains Honor Roll.
MOLLY BLOOM: Brains On will be back soon with more answers to your questions.
[MACHINE WHOOPS]
CRYSTAL CLEAR APP: That's accurate.
LAYLA: Thanks for listening.
Transcription services provided by 3Play Media.
