Speaker 1: Hey, welcome to Sign Stuff, a production of iHeartRadio. I'm
Speaker 1: More hitch Ham, and today we are answering a really
Speaker 1: hard question, maybe the hardest we've ever tried to answer,
Speaker 1: which is is there anything harder than diamonds? Okay, that
Speaker 1: was a silly pun, but we've all heard the slogans
Speaker 1: the diamond is forever, it's a girl's best friend. But
Speaker 1: it's a diamond? Really that sturdy? Let break if I
Speaker 1: hit it with the hammer? What happens if I stick
Speaker 1: one in the oven? We're going to talk to an
Speaker 1: expert on heart materials and we're going to ask her
Speaker 1: all the tough questions. See I could have said hard,
Speaker 1: but I didn't. Anyways, get ready to quit our ring
Speaker 1: on it as we bling out and find out is
Speaker 1: there anything harder than diamonds? Enjoy? Hey everyone, Today we're
Speaker 1: answering a pretty basic question, which is are diamonds the
Speaker 1: hardest material known to humans? Now, for this episode, I
Speaker 1: interviewed a really cool expert, Professor Jody Bradby, from the
Speaker 1: Australian National University, and I learned a lot of cool
Speaker 1: things about diamonds I didn't know before, Like, for example,
Speaker 1: did you know you can make a diamond out of
Speaker 1: peanut butter. Yeah, this is something scientists actually tested and
Speaker 1: it's true. Okay, I'm gonna let doctor Bradby explain it.
Speaker 2: I'm Professor Jody Bradby. I'm head of a high pressure
Speaker 2: physics group at the Australian National University.
Speaker 1: Great. Now, when you say it's high pressure, is it
Speaker 1: like there's a lot of pressure on everyone working there or.
Speaker 2: There are so many puns. In my fields, we have
Speaker 2: a high stress environment. Yeah, definitely, but we create really
Speaker 2: high pressures to make new materials.
Speaker 1: Oh, very exciting. So today we're trying to answer the
Speaker 1: question is there anything harder than diamonds? So I thought
Speaker 1: we could start having you talked to us just about
Speaker 1: diamonds themselves. What makes diamonds so hard?
Speaker 2: Yeah, So basically diamond consists of carbon atoms. So if
Speaker 2: you arrange the carbon atoms in a particular crystal structure,
Speaker 2: then that's what makes the diamond.
Speaker 1: How do the atoms get into a crystal structure?
Speaker 2: Okay, so you get your carbon atoms, and now we've
Speaker 2: got to do something to trick those carbon atoms to
Speaker 2: form a crystal lattice. So nature uses two things to
Speaker 2: do this. It uses temperature and pressure, so we have
Speaker 2: to have really high pressures and really high temperatures. So
Speaker 2: the pressure forces the carbon atoms close together, and then
Speaker 2: the little electrons in the atoms go, oh dear, we're
Speaker 2: going to have to rearrange and we need to make
Speaker 2: different friends. So they form different bonds, and they form
Speaker 2: what's called a convalent bond.
Speaker 1: So it's just carbon.
Speaker 2: Yes, yes, it's one of the beauties of diamond making.
Speaker 2: There's like carbon everywhere. I think some scientists famously a
Speaker 2: diamond out of peanut butter once just to prove that
Speaker 2: you could do it.
Speaker 1: How do you make a diamond out of peanut butter?
Speaker 2: So they just got a bit of peanut butter and
Speaker 2: squeeze the life out of it. Basically it released a
Speaker 2: lot of other things like hydrogen and things. I think
Speaker 2: it actually broke the system that they were using, but
Speaker 2: they did make like tiny little diamonds, which is a
Speaker 2: really cute experiment.
Speaker 1: Oh wow, was it the chunky or the smooth kine
Speaker 1: or the shiny.
Speaker 3: Code I don't know.
Speaker 1: Yeah, So you can make diamonds out of anything with carbon,
Speaker 1: even peanut butter, which means you can make diamonds in
Speaker 1: a jiff, get it like peanut butter brand No, actually,
Speaker 1: naturally occurring diamonds take a long time. But here's the
Speaker 1: next interesting thing I learned about diamonds. Scientists don't really
Speaker 1: know how long it takes to make them.
Speaker 2: So we famously know that diamonds are formed deep into
Speaker 2: the earth in a kind of a GOLDI lie for
Speaker 2: diamond formation.
Speaker 3: It also takes.
Speaker 2: Potentially billions of years for this process to happen.
Speaker 1: Why does it take a long time?
Speaker 2: Well, that's actually interesting. We don't really know how long
Speaker 2: diamonds take to form deep in the earth. We don't
Speaker 2: know exactly how the process works. It's one of those
Speaker 2: things you do if you read the textbook, it says, yes,
Speaker 2: you need this temperature and this pressure, but we can't
Speaker 2: actually explain the science so that we can't look down
Speaker 2: that deep in the earth and watch what's happening.
Speaker 1: That's right. The actual way in which diamonds form is
Speaker 1: still a mystery. The only reason we think it takes
Speaker 1: a long time is that when we take carbon in
Speaker 1: a lab and squeeze it super hard and make it
Speaker 1: super duper hard, nothing happens. So we assume that it
Speaker 1: must take a long time, maybe billions of years, but
Speaker 1: we're not really sure. Now you might be thinking, wait
Speaker 1: a minute, a joorhe I thought we could make diamonds
Speaker 1: in the lab and in factories, we can make artificial diamonds.
Speaker 1: How do we make those? Well, it turns out that
Speaker 1: to make a diamond in a lab you have to sheath.
Speaker 2: We can play tricks up on the surface of the
Speaker 2: earth where we add metallic catalysts, and that can just
Speaker 2: help the process go a lot faster, and therefore we
Speaker 2: can make it on a time period that you know,
Speaker 2: we don't have to wait around billions of years to
Speaker 2: get your engagement ring. That's where you could create like
Speaker 2: a coke cans worth of diamonds in about an hour.
Speaker 2: And these massive presses and really high temperatures, huge industrial
Speaker 2: process and the diamonds you're talking about here are generally
Speaker 2: in diamonds that you might put them on the top
Speaker 2: of a drill bit, and it did cost about the
Speaker 2: same as a sandwich.
Speaker 1: So we can make diamonds artificially in a lab or
Speaker 1: in a factory, but to get the really natural, pure ones,
Speaker 1: like the ones made inside the earth, you have to
Speaker 1: wait potentially billions of years. And by the way, if
Speaker 1: you're waiting billions of years for an engagement ring, you
Speaker 1: might want to consider either an artificial diamond or a
Speaker 1: new girlfriend or boyfriend. Okay, the next question I had
Speaker 1: for doctor Bradby was what makes diamonds so hard? If
Speaker 1: they're just carbon atoms, what makes them different than a
Speaker 1: lump of coal or graphite, which is what your pencil
Speaker 1: lead is made out of. Both of those things are
Speaker 1: also made of pure carbon, And the answer is that
Speaker 1: it's all about how those carbon atoms are arranged. So
Speaker 1: coal is just carbon. What's the difference between that and diamonds?
Speaker 2: Yeah, excellent question. So that is how we arrange those
Speaker 2: atoms within the structure. So diamond has what we call
Speaker 2: a tetrahedral lattice. That means each carbon atom is attached
Speaker 2: to four of its bodies in a particular structure. It's
Speaker 2: really really and it goes on forever. In this three
Speaker 2: dimensional structure. Coal is basically made of black carbon graphite,
Speaker 2: which is layers of carbon. Now those layers are attached
Speaker 2: to their bodies in three bonds in one sort of plane.
Speaker 2: They're really really strong, but they can move over each
Speaker 2: other really really easily.
Speaker 3: They're quite slippery.
Speaker 1: The sheets of graphites are slippery, that's right.
Speaker 3: They slip over each other.
Speaker 2: That's why when you touch coal, it comes off on
Speaker 2: your hand, but if you touch diamond it does not.
Speaker 1: So the secret beween diamond's heartners is a lucky combination
Speaker 1: of two things. The first is that the carbon atoms
Speaker 1: form really strong bonds with each other. If you remember
Speaker 1: from high school chemistry, carbon has four electrons in its
Speaker 1: outer shell, so it forms perfect covalent bonds with itself,
Speaker 1: and these are the strongest types of bonds there are,
Speaker 1: as opposed to ionic bonds, which is what all table
Speaker 1: salt together, for example, or hydrogen bonds, which is what
Speaker 1: holds water molecules to each other. But here's the kicker, though,
Speaker 1: The bonds that carbon forms in diamonds are not the
Speaker 1: strongest kinds of covalent bonds that carbon can make. The
Speaker 1: carbon in graphite actually form stronger bonds what are called
Speaker 1: SP two bonds, which are stronger than SP three bonds,
Speaker 1: which is what carbon uses in diamonds. So technically graphite,
Speaker 1: which is what you use in your pencil to write
Speaker 1: that smears when you rub it against paper, is stronger
Speaker 1: than diamonds. But how is that possible? Well, as doctor
Speaker 1: Bradby said, the carbon in diamonds forms a three D structure.
Speaker 1: Think of it like the scaffolding and a building before
Speaker 1: you put on the walls and floors in it, whereas
Speaker 1: the carbon in graphite forms two D grids or sheets
Speaker 1: which slip past each other and make the graphite crumply.
Speaker 2: So you might have heard of carbon nanotubes. They were
Speaker 2: these sort of wrap around tubes of graphite essentially, and
Speaker 2: they joined up in a big tube and they were
Speaker 2: very very strong, and there were people saying that they
Speaker 2: were going to build elevators to the moon with these
Speaker 2: carbon nano structures because they were so very very strong.
Speaker 2: So that is a very strong bond, but it's only
Speaker 2: one layer, so you can play tricks to try to
Speaker 2: make it kind of three dimensionally strong. But you don't
Speaker 2: need to do that with diamond because its crystal structure
Speaker 2: is already three dimensional strong in all the directions, and
Speaker 2: that's why it's super hard. So nearly all materials that
Speaker 2: are relatively hard have the same properties, have that same
Speaker 2: two things, a really strong bond and a essentially isotropic
Speaker 2: or the same in every direction bonding network.
Speaker 1: It's just that magic combination and only carbon will do that. No,
Speaker 1: there's other materials as well, all right, and that brings
Speaker 1: us to the big question of the episode, which is
Speaker 1: is there anything harder than diamonds? We're going to find
Speaker 1: out and I think the answer will surprise you. Stay
Speaker 1: with us, We'll be right back. Welcome back. All right.
Speaker 1: We talked about how you can make diamonds out of
Speaker 1: peanut butter, how we're not quite sure how diamonds are
Speaker 1: made under the ground, and about the magic sauce that
Speaker 1: makes diamonds so hard. Now the question is how hard
Speaker 1: are they? Are there other materials that are harder? I
Speaker 1: asked our expert, doctor Bradby this question. Okay, so then
Speaker 1: now the question is harder materials that are harder than diamond?
Speaker 1: Or could there be materials harder than diamond? Yes?
Speaker 2: Yes, So this is one of those intriguing scientific questions
Speaker 2: because because when you get out into the literature, there's
Speaker 2: always a little bit of ajibaji discussion around this. So
Speaker 2: you have some groups claiming that they've created this material
Speaker 2: that is theory should be harder than diamond. And this
Speaker 2: is the crux of the things. There's a lot of
Speaker 2: theoretical calculations that might predict a material to be harder
Speaker 2: than diamond.
Speaker 1: Whoa, whoa, whoa, Wait a minute. We can create materials
Speaker 1: or invent materials that don't exist.
Speaker 3: Oh, we do that all the time.
Speaker 2: We can use machine learning techniques and we do these
Speaker 2: things what's called a random property search. So essentially, what
Speaker 2: the modeling people do is they get a whole lot
Speaker 2: of atoms and they put them in a can. Now
Speaker 2: the cans in their computer, but they still call it
Speaker 2: a sample, and they apply various conditions to that sample.
Speaker 2: They might provide a pressure at temperature, they might suddenly
Speaker 2: unload it quickly. They do something to that, and they
Speaker 2: look at what the energy of that system is. And
Speaker 2: if there is a little dip, that means like the
Speaker 2: atoms might be stuck down there. They're all in that
Speaker 2: little configuration. That could indicate that that is a stable structure.
Speaker 2: So then they go, oh, what happened there? And then
Speaker 2: they pull those atoms out at that particular point and
Speaker 2: they look at the structure and they go, oh, this
Speaker 2: is a good structure.
Speaker 1: Uh huh.
Speaker 2: Maybe this is going to be really important in terms
Speaker 2: of a super conducting magnet or it might be really
Speaker 2: really hard.
Speaker 1: Well, this is pretty cool. Scientists can now basically simulate
Speaker 1: nature and basically roll the dice and see if they
Speaker 1: can get atoms to form new kinds of materials that
Speaker 1: maybe we've never seen before. I always thought in movies
Speaker 1: when they mention the fictional material like vibrinium or adamantium
Speaker 1: in the Marvel movies, that it was all made up.
Speaker 1: But there really could be materials out there that can
Speaker 1: do things we can't even imagine right now. Of course,
Speaker 1: though this is all in the computer. The real question is.
Speaker 2: Can we physically create that material, And sometimes the answer
Speaker 2: is no, or can we physically create enough of it
Speaker 2: that we can measure it to actually confirm that it's
Speaker 2: harder than diamond. It's possible, we can never get there physically,
Speaker 2: Like it's just impossible in the terms of pressure, temperature,
Speaker 2: thermodynamics to get to that structure.
Speaker 1: It's impossible to get atoms to make that structure, even
Speaker 1: though it's technically possible. Getting there is a whole different
Speaker 1: thing possible. Yeah.
Speaker 2: Yeah, So there's many, many of these structures proposed. I
Speaker 2: think carbon's got ten or twenty, maybe hundreds of structures
Speaker 2: of carbon that have been proposed to exist.
Speaker 1: Uh huh.
Speaker 2: And this is carbon that's bonded in the same way
Speaker 2: the covalent bond. And we've really only found two that
Speaker 2: we can confirm.
Speaker 1: Okay, there are two materials that scientists think should be
Speaker 1: harder than diamonds. The first one is a material that's
Speaker 1: found in meteorites. Okay, so what are these two materials?
Speaker 3: Okay?
Speaker 2: Some one is a different arrangement which is called Lonsterlight.
Speaker 1: What's it called again, Lonsterlight lines Delight Okay.
Speaker 2: So it's named after Kathleen Lonsdale, who is a carbon
Speaker 2: scientist in the UK. Amazing person, really worth going down
Speaker 2: a rabbit hole with her, and in honor of the
Speaker 2: work that she did in carbon, the lons Light structure
Speaker 2: was named after her.
Speaker 1: So it's also made out of carbon.
Speaker 2: It's made out of carbon. It's also made out of
Speaker 2: convalently bonded carbon. It's also in a continuous three dimension network,
Speaker 2: so it ticks the boxes that we've been talking about.
Speaker 1: Huh.
Speaker 2: But it's got a different structure.
Speaker 3: So the way the.
Speaker 2: Atoms are physically arranged is slightly different. So instead of
Speaker 2: having a repeating box that is a ubique structure. It's
Speaker 2: got a slightly different structure to that, and we call
Speaker 2: it a hexagonal structure. Now that doesn't mean that it's
Speaker 2: sort of arranged in a hexagonal latters. What it means
Speaker 2: is you can create a hexagonal repeating cell within the
Speaker 2: framework of the crystom. It is predicted to be harder
Speaker 2: than diamond.
Speaker 1: Okay, So the first material scientists think could be harder
Speaker 1: than diamonds is called lonstelate, and it's basically a diamond,
Speaker 1: but with its structure tweaked so that overall its grid
Speaker 1: repeats itself in a hexagonal pattern. It actually has been
Speaker 1: found in nature in meteorites that have crashed on Earth.
Speaker 1: Notably who's found in fragments of the Canyon Diablo meteorite,
Speaker 1: which is what made the huge crater at meteor Crater
Speaker 1: landmark in Arizona. It's also been reportedly found in a
Speaker 1: diamond deposit in Kazakhstan. Now, in theory, according to the
Speaker 1: computer simulations, this lancelide should be harder than diamonds.
Speaker 2: But but there's a butt, And usually with all this
Speaker 2: harder than diamond work, there is a butt. And the
Speaker 2: butt is that it is only on one particular poking direction.
Speaker 1: Okay, it's only strong in one direction.
Speaker 2: Yeap, only in one direction, and that is because of
Speaker 2: the way that breaking of bonds, that movement of things,
Speaker 2: how that works.
Speaker 1: What doctor Bradby is saying is that some materials are
Speaker 1: harder or softer depending on which direction you try to
Speaker 1: squeeze them. Sort of like if you had a box
Speaker 1: in front of you and you try to squeeze it
Speaker 1: from top to bottom or from the sides, it might
Speaker 1: feel hard in all of those directions, but if you
Speaker 1: squeeze it at the corners, it might collapse more easily.
Speaker 1: The same thing happens in crystal materials, and in lancelide,
Speaker 1: one of those directions is predicted to be harder than diamonds.
Speaker 1: The reason for that is a little technical, but basically,
Speaker 1: when you press down on a material and it yields
Speaker 1: or it gives, the atoms tend to rearrange themselves a
Speaker 1: little bit. And in lons oflide, because of its tweak
Speaker 1: diamond structure, the crystal has to rearrange itself twice, which
Speaker 1: is what makes it a harder material. Okay, you might
Speaker 1: have noticed that we keep saying loss of lighte might
Speaker 1: be harder than diamonds. You're probably thinking, if we found
Speaker 1: lons of light in meteorites here on Earth, why can't
Speaker 1: we just test it, you know, smash it against diamonds
Speaker 1: and see which one survives. But the problem is that
Speaker 1: lonz of lte has only been found as tiny, little
Speaker 1: microscopic crystals that are too small to put in a
Speaker 1: machine to test, and also no one's quite been able
Speaker 1: to make it in the lab.
Speaker 2: There is definitely a crystal structure called lonster light that
Speaker 2: is definitely different to the cubic structure. But whether the
Speaker 2: diamond can form enough of this material to be perfect
Speaker 2: and be in a bulk like structure, we have never
Speaker 2: been able to successfully make that.
Speaker 1: Yet.
Speaker 2: We've made tiny amounts of the lunsterlite. You could imagine
Speaker 2: a little one centimeter rock of this stuff, but each
Speaker 2: individual crystal is still really small, like it's not a
Speaker 2: perfect single crystal. It would be lovely if we could
Speaker 2: make a perfect single crystal of this material that was
Speaker 2: about a centimeter, because then we could put it in
Speaker 2: all our machines, we could look at it from every
Speaker 2: direction and we could confirm that is, yes, this is
Speaker 2: exactly that structure. And more importantly, we could actually measure
Speaker 2: and see if it was indeed harder than diamond.
Speaker 1: I see, but we can't because the sample that you
Speaker 1: have created is really small.
Speaker 2: And of course then we get to the thorny question
Speaker 2: of what do you poke it with? Because at the
Speaker 2: moment all our pokey tools are made of diamond.
Speaker 3: Of course, So this is a.
Speaker 2: Problem I pose to every first year class that I think,
Speaker 2: I am trying to measure something harder than diamond, but
Speaker 2: the only thing I have to measure with is diamond.
Speaker 3: If you want to come and talk.
Speaker 2: To me about the solution to this, please how work.
Speaker 3: In my lab?
Speaker 1: All right, when we come back, we're going to learn
Speaker 1: about another material scientist think might be harder than diamonds.
Speaker 1: And then we're going to talk about two things that
Speaker 1: are definitely harder than diamonds. Don't go anywhere. You're listening
Speaker 1: to sign stuff, Welcome back. So then this long slight
Speaker 1: would be stronger, but only in certain directions. In the
Speaker 1: other directions, it wouldn't be stronger than diamond.
Speaker 3: Correct, Ye?
Speaker 1: Now, is that the only one that we know about
Speaker 1: that might be harder?
Speaker 2: No, there's another few. So there is more on nitri
Speaker 2: that you can get a cubic structure of that or
Speaker 2: hexagonal structure.
Speaker 1: Okay, so that one's not just pure carbon atoms. It's different.
Speaker 2: No, it's got nitrogen in it as well, so it's hydrogen, helium,
Speaker 2: lithium boron. So we're still talking about a low atomic number.
Speaker 3: And this does.
Speaker 2: Seem to be the case that all the harder elements
Speaker 2: are low atomic numbers. They're high up there on the
Speaker 2: periodic table.
Speaker 1: You might not remember this from high school chemistry. I
Speaker 1: certainly didn't, but atoms high on the periodic table are
Speaker 1: smaller and lighter, and it means that electrons are closer
Speaker 1: to their nuclei, which means the bonds they form with
Speaker 1: other atoms are shorter, which makes them stronger. It's also
Speaker 1: no coincidence that boron and nitrogen, the main components of
Speaker 1: or nitrite, are just to the rate and just to
Speaker 1: the left of carbon in the periodic table, so they're
Speaker 1: kind of the closest you can get to a carbon bond.
Speaker 1: But now the question is is this boron nitride harder
Speaker 1: than diamonds?
Speaker 2: That's also predicted to be a super hard material, perhaps
Speaker 2: harder than diamond, but it's not really, I'm not convinced.
Speaker 3: Put it that way.
Speaker 1: Okay, So why are you not convinced?
Speaker 2: Because I am an experimental scientist and one of the
Speaker 2: sayings in my lab is nice story, Now show.
Speaker 1: Me the data. So there's no data for this material
Speaker 1: not convincing no meaning like people have made it, but
Speaker 1: they haven't tested it. What does it mean?
Speaker 2: Yes, well, if you test it using a diamond and
Speaker 2: you poke it, if you're approaching the hardness of the
Speaker 2: diamond and you push them together, you can imagine that
Speaker 2: there's going to be some sort of giving in the
Speaker 2: tip in the diamond.
Speaker 3: As well as the sample.
Speaker 2: And currently that's not accounted for in many of the measurements.
Speaker 1: But the diamond makes a whole a divid in the
Speaker 1: boron like yeah.
Speaker 2: Yeah, I mean the diamond can make a divot in
Speaker 2: other diamond. But that doesn't mean that diamond is harder
Speaker 2: than the tip diamond.
Speaker 1: H What is it? Because if it is harder that
Speaker 1: it's hard to tell.
Speaker 2: Yeah, I would say the evidence that it's harder has
Speaker 2: not been compelling.
Speaker 1: So what would it take to convince you if we
Speaker 1: switched it?
Speaker 2: If somebody made an indented tip from oron nitride and
Speaker 2: use that to indented diamonds surface. And there was just
Speaker 2: an indent in the diamond surface. And we looked at
Speaker 2: the tip before and after, and we analyzed it, and
Speaker 2: we looked down with an electron microscope, and we saw
Speaker 2: that there was no defects in that tip.
Speaker 3: That might be a.
Speaker 1: Pretty good proof, meaning the tip didn't crack when it
Speaker 1: hit the diamond. Where hasn't anyone done that?
Speaker 3: That's a good question. I don't know.
Speaker 2: I strongly suspect that it wouldn't actually turn out that way.
Speaker 1: So we come once again to the edge of scientific knowledge.
Speaker 1: This is the hard line literally between what we know
Speaker 1: and what we don't know. We have two pretty good
Speaker 1: contenders for materials that could be harder than diamonds, but
Speaker 1: we're not sure, either because they're hard to make or
Speaker 1: because it's hard to test hardness. I mean, if someone
Speaker 1: gave you a block of something and told you it
Speaker 1: was the hardest thing in the universe, how would you
Speaker 1: check it? Could you tell exactly how hard it was?
Speaker 1: What will you use to check it? So, whether lanzolite
Speaker 1: and boron nitrite are harder than diamonds, the answer is
Speaker 1: stay tuned. The crown for hardest material on Earth still
Speaker 1: belongs to diamonds, or does it. I told you I
Speaker 1: learned a lot of interesting things about diamonds from director Bradby,
Speaker 1: and one of the things I learned was how fragile
Speaker 1: that crown is. There are several things that can knock
Speaker 1: that grown off if you just put a little effort
Speaker 1: into it. The first is that it turns out that
Speaker 1: diamonds have a soft spot, or at least a soft direction.
Speaker 2: And I sort of said a little bit that the
Speaker 2: diamond is isotropic, the same in all directions, but not
Speaker 2: quite isotropic. In some directions. It's slightly stronger than others,
Speaker 2: not much, but we can definitely see that.
Speaker 1: So if it has weaker directions, does that mean you
Speaker 1: can break it?
Speaker 3: Diamonds very easy to break.
Speaker 2: Actually, if you get a diamond and you tap it
Speaker 2: on a particular axis, uh huh, then you can get
Speaker 2: it to fracture. Uh.
Speaker 1: Well, that's how the sheep diamonds.
Speaker 3: That's right.
Speaker 2: When you start off you we'd probably fracture them and
Speaker 2: then you would polish them with diamond paste.
Speaker 1: So diamond is not strong in all directions.
Speaker 2: Uh yeah, Well, if you push it measuring the hardness.
Speaker 2: It's strong, but if you you give it a sharp tap,
Speaker 2: then you could get like a stress wave that would
Speaker 2: go through and fracture it. So it's actually it's not
Speaker 2: really brittle obviously, But if you hit diamond with a hammer, yeah,
Speaker 2: you're going to break it.
Speaker 1: Oh really, But I've seen YouTube videos where people try
Speaker 1: to hit diamonds with a hammer and it doesn't crack.
Speaker 2: Well, maybe they have to hit it along a particular axis.
Speaker 1: See once again, you can't believe everything you see on YouTube. Okay,
Speaker 1: the second thing I learned about diamonds that make them
Speaker 1: less impressive is that on the surface of planet Earth,
Speaker 1: diamonds are only meta stable, which means the shiny crystal
Speaker 1: structure that makes diamonds so pretty it's not absolutely hop
Speaker 1: Carbon atoms want to be arranged. Graphite is.
Speaker 2: Yeah, so we have this concept of what is the
Speaker 2: most stable structure at particular points in a pressure temperature region,
Speaker 2: and where we are here on Earth, the lowest energy
Speaker 2: material for carbon.
Speaker 3: Is this graphitic structure.
Speaker 1: Okay, so if.
Speaker 2: We had a bunch of diamond in our can and
Speaker 2: we heated it, it would.
Speaker 3: Transform to graphite. Because it's like, if.
Speaker 2: You give me a chance I'm going to lower my
Speaker 2: free energy and form down into this really comfy where
Speaker 2: I want to be phase. So this is the concept
Speaker 2: of meta stability.
Speaker 1: Yeah. So basically, if you stick a diamond in the oven,
Speaker 1: eventually it'll turn to graphite. And again, graphite is what's
Speaker 1: in every pencil on planet Earth. And if there's oxygen
Speaker 1: in the air at around eight hundred and fifty degrees
Speaker 1: celsius or about fifteen hundred degrees fahrenheit, diamond will actually
Speaker 1: spontaneously combust or burn. They'll turn to CO two and
Speaker 1: graphite ashes. So diamonds are only the as materials we
Speaker 1: currently know about in a very limited situation, which is
Speaker 1: on the surface of planet Earth. If you go somewhere
Speaker 1: else it could be a different story. Ah. So like
Speaker 1: if we lived then Venus, where it's nine hundred degrees fahrenheit,
Speaker 1: a diamond armor would not help me.
Speaker 3: It would not help you. Do not get the diamond arbor.
Speaker 1: You'd be better off with a steel armer.
Speaker 2: A nine hundred degrees steel is probably having problems as well,
Speaker 2: getting a bit soft. At that point, what would I
Speaker 2: get Maybe a ceramic Yeah, you know, you could still
Speaker 2: use carbon, but you could change the way the atoms
Speaker 2: are bonded. Maybe you'd use something like a disordered black
Speaker 2: carbon called glassy carbon that is stable up to about
Speaker 2: three thousand degrees. See ah, and it would be light.
Speaker 1: Okay, tell me about this material again.
Speaker 2: So glassy carbon is the black form of carbon, so
Speaker 2: growfitique like but instead of sheets, it's like we got
Speaker 2: all the paper and we scrunched them into a big
Speaker 2: ball and they're all into linked so they're really stuck.
Speaker 2: We call it glassy because it's kind of disordered.
Speaker 1: Uh huh.
Speaker 2: But it's incredibly stable because it's all stuck like that.
Speaker 2: We use them as crucible, so we put things in
Speaker 2: them when we want to heat them up in a
Speaker 2: furnace to say three thousand degrees, and it's super resilient
Speaker 2: to deformation as well. Like I've shoved it in a
Speaker 2: diamond anvil cell and squeezed it and it just stays
Speaker 2: like that up into really really high pressures. It's a
Speaker 2: crazy material.
Speaker 3: It'd be a great.
Speaker 1: Armor on venus because your diamond armor at that point,
Speaker 1: but would evaporate.
Speaker 2: Yeah, that would evaporate, but your glassy carbon would still
Speaker 2: be there. It'd be nice and light because it's made
Speaker 2: of carbon ha ha, Yeah, you'd be fine.
Speaker 1: All right, Well we did it. We found something that
Speaker 1: is definitely harder than diamonds on venus. If you're a
Speaker 1: girl on Venus, you just find yourself a new best friend.
Speaker 1: And hey, look we made it all the way to
Speaker 1: the end without another dad pun proof. I have to
Speaker 1: say it wasn't easy. In fact, was pretty hard. Thanks
Speaker 1: for joining us. See you next time you've been listening
Speaker 1: to Science Stuff. Production of iHeartRadio written and produced by
Speaker 1: me or Hey Cham, edited by Rose Seguda, executive producer
Speaker 1: Jerry Rowland, and audio engineer and mixer Kasey Pegram and
Speaker 1: you can follow me on social media to search for
Speaker 1: PhD comics and the name of your favorite platform. Be
Speaker 1: sure to subscribe to Sign Stuff on the iHeartRadio app,
Speaker 1: Apple Podcasts, or wherever you get your podcasts, and please
Speaker 1: tell your friends we'll be back next Wednesday with another episode.