Get in touch with technology with tech Stuff from stuff works dot com. Hey there, everyone, and welcome to tech Stuff. I'm Jonathan Strickland and I'm Lauren and we have a cool, super cool episode, but it has to be super cool for most applications. We're talking about superconductors today. Now, in order to talk about superconductors, really we thought it was necessary to kind of backtrack and talk about electronics and electricity. Yeah, because to understand why superconductors are so amazing, you first have to have that that basic information about electronics in general. So here's a fundamental problem with electronics, with with any sort of circuitry, with any kind of system. Really, it's not just electronics. That's that's one way we can look at it. But there's this problem where you pour energy into a system and because of things like entropy, the output you get is less than the energy you put in. Now, of course we know we cannot create or destroy energy, correct, Yeah, it's one of those laws of thermodynamics, and if you try and break them, then the thermodynamics police show up. So actually it just means that you cannot break that law. So if you can't break that law, if you pour energy into a system and you're not getting as much output as you're getting input. It's because you're losing energy through some other action. Normally in almost every system that we're really familiar with, that's heat. Right. Heat becomes a byproduct. Energy goes to produce heat, which means that whatever you were trying to do is slightly less effective than what you had intended. So we see this with things like car engines are a great example. You pour in fuel, the engine burns up the fuel and converts that into power, but you don't get as much power out as you're getting energy in from the source of that fuel. So the same sort of thing is true with electronics. And in this case, the thing we talk about when we're talking about losing energy is called resistance. That's the resistance of any particular material to the flow of electricity through that material. So with that basic information there, now we're gonna really dive into the very very basic building blocks of electronics. Yes, because the thing is that superconductors lose no energy to resistance, right, They have no resistance exactly. However, they require extraordinarily cold temperatures like on the magnitude of thirty nine kelvin's which is that's cold. Yeah, when you remember, zero kelvin is zero molecular movement. That's absolute zero. That's that's like if you were to go into the deepest reaches of space and there are no molecules moving around, everything is perfectly still. That's zero. Kelvin is equivalent to negative two and thirty four degrees celsius or negative eighty nine degrees fahrenheit. Right, So that's that's that's pretty cold. But to understand again about resistance, let's let's take this this this tour through the building blocks of electronics. So, now, the early early understanding we had about electricity, uh gave us some ideas that we kind of have to work around these days. Like specifically, the idea of current. Current is a confusing thing for someone who has doesn't understand electricity because it run the direction of current runs counter to the actual flow of electrons. Right when all of these terms were being created, we didn't know as much about sub atomic particles a k a. Much at all anything so so do today. So before we understood anything about electricity, we began to learn things about about charge and the idea of opposite charges attracting one another and like charges repelling one another. Now we could have called electrons positive charge. We could have done that. There's no reason why we would have said all tron's are negatively charged. It's just a word, right, But that was what was considered a negative charge, and then you would have the opposite would obviously be a positive charge. You know, we could have called these left and right, or are up and down or anything really, but banana and oboes. Everyone knows the obo is nature's opposite to the banana. So the the these opposite charges, the negative and the positive, attract one another. Now, if you were to have a negatively charged material and a positively charged material, uh, you know, within the same general area of each other, the potential that separated those opposite electric charges would be called voltage, all right. So that's when someone's talking about voltage, they're talking about this potential that's separating the opposite electric charges, and it's it's the capacity that they would have for doing work if those opposite charges were connected together somehow. So you would have to have something that would allow these charge jes to mix together. So back in the early days of electricity, before we really understood the mechanics of it, you would think that all right, well, all the positively charged particles would leap over to the negative side and the negative charge particles would lead to the positive side until the charges had equalized. Right, And even if you had one material that was more negatively charged than the other material was positively charged, the actual negative charge would also even out eventually, like omosis, it would kind of work itself out, so you would you would end up with a larger amount of material that had a negative charge. It would just be a lower negative charge than the original material you started with. Right. So here we were still thinking about this as these little charged bodies, these charged particles, both of positive and negative zipping across um and you can you can measure voltage by measuring the the two different points. So for example, if you have one on the positive ode and one of the electric node are a negative node rather, you then look at those two contact points. That's where you get your voltage. If you're using the same point of contact and you're checking different other electrodes, uh that same contact though contact you're using for all of them, we usually call the ground right, that's the ground contact. Now, a material that does conduct electricity is called a conductor for that very reason, right convenient and there, and there are some materials that are very good conductors. A lot of the metals, for example, are great conductors. How how conductive material is depends on how easily it's component atoms donate electrons, right right. You need to have these free electrons. Free electrons are this when you have an atom. Obviously you have an electron shell or several shells, depending on how how large the atomist and uh, and if you have free electrons that aren't tied down to anything on the outer shells, then that allows electricity to pass more freely because what happens is a new electron comes in. This is oversimplifying, but a new electron comes in and essentially bunks out one of the other electrons in that outer shell, which then will bonk out one further down the line. So if you've got a lot of free electrons, then that allows this this passage to happen fairly easily. And UH, that's what allows you to connect these these differently charged UH materials to equal that out. We call this current. But again, the current is the idea of positively charged particles passing from one material to the other. As we learned later, it's actually electrons that are passing through, not positive charges. But we we consider stuck with that the terminology which means which means that when you say current, you're actually talking about the opposite direction as what the electrons are really going through. So if you're talking about a circuit's current, you are looking at it going positive to negative, when in reality the electrons are going negative positive, basically proving that Benjamin Franklin was not a time traveler, right right, Yeah, there are a lot of jokes on the Internet saying that we have Benjamin Franklin to blame for this misunderstanding. That again is oversimplifying it. Franklin was one of but not the only. Yeah kind of point. Yeah, he was like the mascot for electricity before we knew what we could do with it. Now, current we measure in ampiers or amps and an emperor is the rate of flow of one coolmb of charge in one second past some given point. And so that raises the question, what is a coolmb. It's a whole bunch of charge. Yeah, it's a lot of charge. It's actually quite a bit of charge. But you know, we won't boil. It's not technically important, no, not for not for this discussion, but just know that it's a lot of charge. So if you hear someone talking about a cool lomb, that's a lot of charge. Current of course does have the direction as the flow of positive charges. You can think of positive charge in a way as vacancies holes, positive holes that could accept an electron. Right, because if if you have even if you have a build up of negative particles, if there's no positively charged part if there's no if aren't, if there are no vacancies at another point, then those that charge is just gonna keep building up. It doesn't the electrons and nowhere to right, So that brings us to the concept of an insulator. Now, an insulator is sort of the opposite of a conductor. This is a material that charge cannot flow through those those component atoms at their their electrons just want to stay put. Yeah, yeah, they usually the usually you don't have any free electrons on the outside. They're all uh, they're all bonded together. So that means that an incoming electron has nowhere to go. So with nowhere to go, then this stuff just halts the flow of electricity, and this includes things like air is an insulator. Now, granted, if you were to pour enough energy into air, you could ionize it and then it becomes a conductor. But you have to pour energy into air for that to happen. That's what happens with lightning strikes, that kind of thing. Otherwise it's more commonly it's it's it's all those things you know, like like rubber or glass, exactly exactly. Now we've covered conductors, we've covered insulators. That brings us to semi conductors. Now, this is a term that a lot of people are familiar with because semiconductors we talk about that all the time. We talk about electronics like microprocessors, semiconductor plants, or a silicon wafer. That's what a silicon chip that has a microprocessor on it. So what exactly is a semiconductor, Well, if you're looking at the name, it kind of gives it away. It's a material that can act like a conductor or connect like an insulator. Now, naturally, if you were to just make a if you were to make like a wafer of silicon, it was pure silicon, it would be an insulator. But because those those electrons are all tied up, right, so you can't push more electrons through it. However, if you were to start introducing impurities into the silicon on purpose, this isn't right right right, Yeah, Like I like phosphorus or boron are two typical ones exactly. Then you are doing a process that's called doping, and the semiconductor business that's not a bad thing. You won't get thrown out the Hall of Fame of Semiconductors for doping. In fact, doping is necessary to make a semiconductor work. Now, if you were to dope a semiconductor with uh atoms that have extra electrons, extra being free electrons and that that outer shell, I don't mean that they're actually carrying around more electronic electrons, right, yeah, like phosphorus exactly electrons. Phosphorus has a free electrons, then you would get what it's called in type semiconductor material because it has more negatively charged particles. Now, boron has what we would call vacancies or holes that what electrons could flow into. So if you put boron, if you introduce boron into silicon, it would have availability to accept electrons. A positively charged or P type exactly. And if you were to take both of these types of doping and apply them to one silicon wafer, so that let's just say on the left side you have N type silicon and on the right side of P type silicon, that would allow electrons to flow across in the direction from negative to positive. Correct, correct, And it would prevent the flow of electrons to go from positive to negative because again those negative electrons in the N type silicon will will repel any incoming electrons. This is the basis of a very specific type of electronic component called the diode. Diodes are important. They're kind of a one way street in electronics and uh. And one of the reasons this is in orton is when you have something like alternating current. Alternating current, it's exactly what sounds like. It alternates direction. Remember I was saying before. Current is the flow of positive charge in a circuit. If you have alternating current running through it, then that current is running one way and then the other way, and it alternates at thousands of times per second. We call it hurts. That those cycles per second, So it's usually like twenty hurts, so twenty thousand times a second. It's going pooh back and forth. Now I like that sound effect. Yeah, that's the sound of electrons just zig zagging. But a lot of our electronics don't run on alternating current. They need to run on direct current. So diodes are a good way of addressing that because they will only allow charge to pass through in one direction. So even if you have an alternating current, then it's going to prevent current from passing through one way and allow it to pass through the other way. That's one of the ways we use to to transform alternating current into direct current. So right, and this problem is why you get those little um, those little boxes on your electric plugs to transform the alternating current coming in through your through your system to be yeah, through through that the pluggy thing, outlets, outlets. It's been a long day, it has, it has. I'm giggling more than usual. We've been in a meeting for a long long time. If you need to know how long. Just a quick aside, check out Josh and Chuck's series Trapped in a Meeting. It's very good. It's very funny, and it's very real. It's it's so real, it's it's it's my video debut. So check that out. That's right. You can see Lauren blocking me for almost every episode. I can just see like either the front of my face or the back of my head and almost every shot. But uh, that's just me complaining. That's fine. So let's move on to we we've we mentioned resistance. Resist is this property that resists the flow of a charge, and it depends on the material of the conductor, uh and the flaws that that conductor might have that create resistance. Uh. The gauge of the conductor, So example, the gauge of wire. So how how much of it there is? Right, The thinner the wire, the greater the resistance in general, So if you're talking about copper wire and you're talking about smaller gauges which are actually larger wires. I don't know why that is. I'm sure someone out there understands why the gauge and size are inversely related aperture related things. There's something out there, I'm sure, and I bet I could have found it out easily if I looked it up. I didn't think too, but I'm sure some of our electronic attrician friends out there know exactly why. Anyway, the larger the diameter of the wire, the lower the resistance. Uh. And the other thing is the temperature of the material itself. In fact, if you lower the temperature of the material, then you can decrease the resistance. That's the varying basis. And and that that that temperature comes in because uh, you know, he heat makes atoms bang around into each other more, which which is part of what causes resistance. And and on the flip side, resistance causes heat. Right, those atoms are starting to bang around. That actually creates heat. It's essentially friction on an atomic level or sub atomic level because you're talking about electrons, but it still creates heat. And that's where you get this loss of energy in your system or loss of output where you're not really losing energy in the sense that you know it's still going somewhere, it's just no longer contained within the system that you have created. Right. So what does Owns law have to do? Right? Ohms law is the relationship between voltage and resistance. All right, So it is explained as voltage equals current times resistance, or because we can switch these around, current equals voltage divided by resistance. So you look at the voltage across whatever the resistor itself is, whether it's a specific component in electronic circuit or the overall circuit or just a wire. And uh, that way, you can if you know the voltage and the current, you can determine what the resistance is. Actually, as long as you know any of those two, you can determine the third because you know what how they relate to one another. UM. Now, on top of all of this, we then have the concept of power. This is that output that you're getting, and power is we measure that in watt's w A T T S and power released into a resistor equals the voltage times the current or voltage squared divided by resistance or current squared multiplied by resistance. The point we're getting to is that these basic concepts of electronics are all very very closely related to one another, and the more we understand about them, the greater potential we have to UH creating new stuff that really takes advantage of Right, it was our eventual understanding of these basic principles that has allowed us to kind of break the physics that that or or twinge the physics them. What happened was we understood things how we we understood how things worked and kind of our normal, under normal room temperature situation. Because because you know, early early people working in electronics, early people early electronics work, they were trying to plug in their xbox. No. No, the people who are working on electricity, very early on, when we were just learning about the principles of electricity and and what it is, how these different elements relate to one another, they didn't necessarily have the capacity to alter things enough to really see like, gosh, what would happen if we super cool super cool that. Yeah, they didn't have the ability to do it early early on, but it wasn't too late when they started to to really experiment with it. But we'll get into that alright. So that is our down and dirty basic electronics coverage there, and now we can actually look at super conductors and explain exactly what they are, how they work, and why they're so amazing. So before we jump into that, let's take a very quick break to thank our sponsor a right back to superconductors. So we've covered conductors, insulators, we've covered semiconductors, we've heard about resistance. What exactly is a superconductor? All right? Technically this is some sort of material that will conduct electricity without resistance below a certain temperature, and you don't want that resistance obviously, because again you have that loss of energy. You wanted to be as efficient as possible. So if you could find a material that does not convert any of that energy into heat and it's all output, then you've just dramatically increased the efficiency of your system. It's about as close to perpetual motion as we can ever expect to get, which is really exciting, you know, for cost purposes and all kinds of all kinds of fun research bits which will get into in a minute sure. And uh. In fact, the according to superconductors dot org, which has a lot of really fun information about superconductors. By the way, UH, scientists call it a quote macroscopic quantum phenomenon in the quote, which is huge literally because you're talking about macroscopic But but that's the things that quantum phenomena. We normally think of quantum mechanics quantum phenomena as happening on a subatomic scale, right, so small that even our most powerful light microscope couldn't see it. You'd have to use something like an electron telling microscope it's highly theoretical and and all very tricky. It's really interesting because our laws of physics as we know it start breaking down at that point. But right, but it's really hard to figure out what's going on there because it's so darn tiny. Right, Yeah, it's it's a totally different set of rules than what we're used to on the classic level. And to have something on the macroscopic level that seems to behave under these quantum phenomena is pretty amazing. So exactly what's going on, Well, let's go back a little bit and look at the history of learning about this. Right, so, way back in nineteen eleven, a Dutch physicist whose name I am now going to butcher, And I apologize to anyone out there who is from the Netherlands who's going to WinCE at everything. I say, um, hi k Kummerling on this of Leighton University, and I bet it's Laden University too, as soon as I say it's Laden because Laden jars. But anyway, Uh, this physicist discovered super conductivity, or at least observed it for the first time as far as we know, looking at solid mercury. They he had made a solid mercury wire and cooled it to the temperature of a about four kelvin using liquid helium, and that is about negative four hundred fifty two degrees fahrenheit or negative two hundred sixty nine degrees celsius. And he noticed that when he did this, its resistance suddenly disappeared. Right, So this was interesting. And this is the sort of thing that I thought I always imagined scientists doing there, sitting around the lab and just saying, huh, I got this stuff. I wonder what happens if I do X to it. You know, let's drop the temperature down to almost absolute zero and see if that doesn't anything interesting. Uh. I know it's way more complicated than that, but I like to think that that's what scientists are doing. Yeah, And and what's what was really going on there was that um, the mercury at that temperature underwent a phase transition. UM. But we'll get more into that in a second, right, So then we skip ahead a little bit. That was nineteen eleven and nineteen thirty three some German researchers Walter Meisner, not the famed theater mentor, because I have a lot of my Eisner technique different shiffering Guy Nicer and Robert Oceanfeld discovered that a super conducting material will repel a magnetic field. Now, this is super cool as well. I keep using that I didn't mean to, and I should have caught myself. It's it's really interesting. It's really interesting. If you've ever seen there's lots of videos on YouTube, right of people using magnets and super cooled super conductor material and they can lock the material in a levitating state above the magnet, right. Or sometimes they have a super conducting bass that is super cooled and then they put a magnet on top of it and it seems to just hang in the air. Now, technically, if you if you actually listen to the physicists who talked about this, there's a great Ted talk where a guy demonstrates this eleven. It's will link it on social I mean everyone's seen it, yeah, but we'll we'll link it anyway because it's still fun to watch. Uh. He explains that technically it's not levitation, it's what they call quantum lock. Uh, And so it's a little different from that, but we'll we'll get more into that in a little bit. And then you skip ahead to nineteen seven, when a trio of scientists leon In Cooper, John Bardine, and John Robert Schreefer proposed the first successful model that explained super conductivity. This might be a good time to mention that while we talk about models that explain super connectivity, honestly, scientists are still learning about the properties of super conductors and how they do what they do, and why they operate at certain temperatures better than other temperatures. So while we're describing this stuff, and while we have superconductors in actual use around the world in thousands of different applications, we still don't understand everything about precisely how it's right. And when I say we, I'm not talking about just me and Lauren. I'm talking about super smart people that that's their job. We're still learning. This is one of those things that I always find exciting. It's just, you know, when you know that you don't know everything, that always gives you that kind of tingle to like you want to learn more. So their theory became known as the B. C. S theory, and it earned them the Nobel Prize in Physics in nineteen seventy two. Now we kind of need to sort of talk about what this theory says. Okay, the atoms in a conductive material that have given up electrons are are are then positively charged ions, right right, okay, um, and when electrons are flowing through them, they're attracted to those negative negatively charged electrons. Cool. Right, Cool, that's a really bad word to use this podcast. Okay, already having made three or four times under under usual circumstances, uh, those ions kind of crunching together towards the electrons that are flowing through them would cause resistance, but not in superconductors. And what we kind of did realized until we started getting into quantum mechanics is that that resistance happens because electrons have properties of both particles and waves, right this, This is that duality thing that always got me confused when I got to that point and learning about science was the idea that something can behave as both a wave and a particle. We see this a lot in quantum mechanics, and it's part of the reason why it's such an interesting and counterintuitive field. Absolutely. Yeah. I mean honestly, my brain kind of just goes, well, well, okay, that's that's fine, to be fair. I think a lot of string theorists have that same reaction to their work. I mean, I'm being honest. I've seen interviews where they say, there comes a point where you just have to say, this is how it works, because it's how it works. It always feels a little bit like double think to me. But yeah, So we've got electrons acting like particles and waves, and um, those excited ions that are in the conductive material kind of create counter ripples in this this flowing lake or river of electrons, and and that winds up causing that resistance I see. But in superconductors, the electrons assume a nearly identical speed and direction, forming a kind of single organized wave that resists that disruption from the ions I see. So instead of having let's let's let's put this on a macro scale. And keep in mind that whenever you change anything from the quantum scale to the macro scale and you're using an analogy, it's imperfect to say the right. And this is also an extreme oversimplification that I'm presenting to you. So, but let's imagine that you have a room full of people, and you have one doorway leading out of the room, and someone walks into the room and says free cake and then leaves, and then everyone just tries to rush the door. All right, Well, the fact that people could only fit through the door a few at a time, but everyone's trying to get through there, that kind of represents resistance in a way. Now, let's say that someone comes in and says, uh, free cake, but there's plenty for everyone, so just come in in the same order that you, you know, walked into the room, and everyone obeys the rules and they all just smoothly exit. That's kind of the idea of superconductors. You've created this experience where everything's happening in a very uh, very ordered, controlled right. Yeah. Yeah, it's sort of like if all those people were members of a dance troupe and they just kind of fell into line and danced quietly out. In fact, that as analogy I've seen several times when looking at superconductors. Now, the BCS theory that we had mentioned explains that the electrons travel in ever changing Cooper pairs, named after leon In Cooper, one of the three of that ps, and that, uh so you have that leading electron. The pairs have a leading electron in a following electron they're both going down this pathway. Keeping in mind, electrons do repel one another. Yeah, so which is where that where the ever changing comes in. They kind of swap around a whole bunch, right. So you've got this pair going down, swappings places occasionally. Uh. And the positively charged ions start to be attracted to that leading electron, which means that you have a growing positive charge, which starts pulling that second electron even harder. That creates this increased pressure if you will of poll really right, it's pulling those electrons even harder than it normally would because the positive charges growing and all of this, all of these different opposing forces essentially end up canceling each other out so that you don't end up with resistance, right, And this this is opposite to the way that resistance normally works, which is so cool, not cool, so interesting. Now, keep in mind this was the first working model of super conductivity, and uh, then future study would end up kind of tweaking this and changing our understanding a little bit. Uh. In fact, in nineteen sixty two, we then had Brian D. Josephson who predicted that electrical current would flow between two superconducting materials even if they were separated by non superconductors or even insulators. Now, that prediction that he made was later on confirmed and he earned the Nobel Prize in Physics in nineteen seventy three, so one year after the BCS team won the Nobel Prize in Physics. So clearly superconductor's big important thing in physics from the fifties through the seventies and up through to today. Oh sure, sure, what more research conducted in the eighties would change the field all over again. But we will talk more about that in a moment. Yeah, yeah, we have to. We have to then discuss the different major types of superconductors, and uh, they're different ways you can divide them up, but the most common way is to refer to them as type one and type two, which not that helpful upon the surface to list actually define these Type one superconductors, Uh, made out of pure metal, right, So you get this pure toll material, whatever the metal is, and then you have to cool it to a point where the metal exhibits zero electrical resistivity and perfect dia magnetism. Alright, so we're talking now about any particular metal. It doesn't matter which one it is. The temperature will will vary depending upon the actual metal you're using, right, So lead is different from copper, that kind of thing. But they all have this they have they all have this specific critical temperature, right, and most of them are pretty cold, so you have to use something really really cold to cool them, like liquid helium, which is hard to get. It's it's very it's expensive, yes, and there's not that much left of it. I mean, in the grand scheme of things, we don't we don't have enough helium for all the stuff we would like to do with helium. For one thing, they're all those children's parties and you think I'm joking, but I'm not. Helium is actually being used in those helium balloons that you see. But you can go out and I there are scientists who say it's a real shame that we're using helium to entertain children when we could be using it to run m R I machines or a super collider or one of a thousand other devices. So so that's one of the downsides of the type one superconductors is that they do need to be cool to these very very low temperatures, and if they go above that temperature, the superconductivity is broken. You can get it back by cooling it back down again, but the actual properties it exhibits as a superconductor go away if the temperature goes over whatever it's critical temperature is for being a superconductor. Another thing that will cause the breakdown of the superconductive state is if you subject it to what's called a critical magnetic field. Right, So remember we we talked about diet magnetism. This means that magnetic fields cannot penetrate this superconductor metal while it's in the superconductor state, so you can't make It's what allows a superconductor to kind of uh float above a magnet, although with type one superconductors that always tends to be wobbly. If you've ever seen a demonstration of this, the whatever the materials is going to be kind of kind of spinning and end and shaking. It doesn't hold it doesn't hold a position very well. It does tend to wobble quite a bit. But uh, if you were to introduce a magnetic field that is stronger than what that superconductor can yeah, yeah, the expel really because it's expelling magnetic field. But yeah, if it's too strong a magnetic field, it again will break down that superconducting state and it will just become a regular conductor as opposed to a superconductor. So you have to maintain its critical temperature and make sure it is not subjected to a magnetic field above that critical limit. All right. So that's Type one superconductors, which then raises the question, what is a Type too superconductor. Now, these are made up of alloys, uh, and they have a much more complex diamagnetic feature to them. Right, They're not They're not as simple as type one. They actually have two thresholds for critical magnetic fields. All right. So if it's if the magnetic field is below the primary threshold, the type two uh superconductor acts more or less like a type one. So in other words, if you super cool this down to below that that threshold, it will behave just like it would be just as if it were a Type one superconductor. Now, um, if if that magnetic field goes above that threshold but still is below the second threshold, you then have a superconductor entering into what is called a vortex state, which to me just sounds like it's some sort of science fiction ee like pulled through the portal into another dimension. But that's not exactly what's happening. It's it's pretty science fiction. It's what's what's going on here is that um uh currents or or whirlpools of of superconducting material will flow around spots of normal material. So you have these islands of conducting material and these vortices of super conducting materials. So within the same substance, some of it is acting like a superconductor, some of it's acting like a conductor. And this creates really interesting properties that will that will cover in a secure right, So that's what really makes it different. Now, granted, if you were to again increase that magnetic field so that it goes above that second threshold, the superconductivity properties breakdown down, so and and and you do have to cool down the type two superconductors. Although there's been some amazing work fairly recently, and that that that eighties stuff that I was talking about, right, that will that will cover in a minute, that really kind of give us some hope for future applications. Um But before we get into all of that, I think it's important we take another quick break and thank our other sponsored. All right, so we talked a little bit earlier about this levitating effect that you can see with superconductors. It's not really levitating. It's called quantum lock or flux pinning, right, And this has to do with that vortex state that we mentioned a second ago. Right. This is for type two, specifically Type one superconductors can do this too, but as we said, they're very unsteady. But type two, if you keep it within that critical uh boundary between those two thresholds we talked about, where it's above the type one threshold but below the type two threshold, you can have this quantum lock where you can put a magnet above a superconducting base or a super super cooled superconductor over a magnet and lock it into a position where it's seemingly just floating. Really it is floating above the magnet or no, for the magnets, floating above the superconductor. However you've had it arranged. And that and that that Ted talk that we mentioned from from two thousand eleven that probably you've seen a call that that was calling it quantum levitation. You know, it's it's the dude just just pushed a magnet around and it kind of float in a circle when it was what he had was he had a I think he had a big circular bang. Yeah, it was exactly like a doughnut in the sense that had a band of magnetic material that runs in a circle. But was it was just a band. It wasn't a disk or anything. It was a band of this magnetic material. So, yeah, like a donut. And then had this super cooled super conducting material that he put He put it in place above the band, so it's not touching the band at all, it's floating above it. And he could actually change the orientation of the superconductor so it could be flat, or he could tilt it so suddenly it was at a forty five degree tilt, and then he could just give it a little push and it would float around the circle of this magnetic band, just floating as though it were on a track and but not touching anything. Right, So there's there's no real apart for air resistance. There's no real force acting against it. So in other words, it's about as close to perpetual motion as you can get. It would just keep going around and around and around until the air resistance finally would make it stop, and he even demonstrates that, uh, it is completely independent of gravity as well. If you were to turn the whole thing upside down, which which is pretty awesome. Uh, it then floats underneath the band. But again, you can change the orientation of the superconducting material. And it's it's kind of a mind blowing video. It's it's really terrific. Uh. And what's what's going on in it is that UM so as superconductors UM cool down, they increasingly expel magnetic fields. And when you when you get a type two superconductor into that vortex state, UM electrons can can form these kind of eddy currents that produce a counter field. Yeah, it's kind of crazy. And and so you've got this, you've got this expelling of fields out from the super conducting material. You also have the norm the quote unquote normal islands of material in there that are attracted to whatever the magnet is UM. And so it's the balance of those two that make that type to superconductor stable as opposed to the type ones that are all wobbly. UM. There's there's also been you might remember background the year two thousand, Uh, some some people got a whole lot of attention for levitating a frog, and you know, water and hazelnuts and all kinds of fun stuff. It was along the same principles and and works because although technically, you know what we think of things like water in organic tissue like frogs is being non magnetic um, they will exhibit a very weak repulsive effect when placed in a very strong magnetic field. I know that I can be repulsed by frogs quite easily. However, if you want to have a fun experiment with frogs and magnetism, you take a frog and you go up to your little sister and you rub it against her hair and then you run. It doesn't actually do anything scientific, but it can be quite amusing. Now over how stuff works. We have articles that cover all sorts of stuff, and we even have one on superconductors. And there was one particular section of the article I wanted to quote that was that was just very effective. Right. This comes straight from our article on superconductors. Superconductors boast more than zero resistance. They also offer extremely high current carrying density, exceptionally low resistance and high frequencies, very low signal dispersion, and high magnetic field sensitivity. They exclude externally applied magnetic fields exhibit unusual quantum behaviors and are capable of near light speed signal transmission. This combination of factors effectively rewrites the rules for electromagnetic industries and suggests numerous possible innovations, including improved electric power transmission, generation and storage, smaller, more powerful magnets for motors, cutting edge medical equipment, improved microwave components for communications and military applications, vastly boosted sensors, and using magnetic fields to contain charged particles. So that's that's you know, we're going to talk a little bit more about some of the applications, but the potential is phenomenal. Yeah. And and thank you to Nicholas Jervis or Gurbius, depending on how you pronounce that, for for writing that excellent little bit for that article on superconductivity for us. Yes, yes, it's a great read. I do recommend it. Uh. And there are lots of different substances that can exhibit superconductivity. Uh. Some of them were you know, the pure substances we talked about. The metallic elements can do this if you cool them to the correct temperature. Uh, some of them, some of them that are not metals can exhibit superconductivity Uranium, yeah, or selenium or s l con if you if you lower the temperature enough you have to pressure. Yeah, that's they don't. If it's at just a normal one atmosphere pressure, you can't get it cold enough to do that. But if you increase the pressures, uh, then that the combination of the pressure and the temperature will have them exhibit this superconductive property, and then that you have hot superconductors. All right, this is that recent, more recent research that was begun in the eighties, and so so tell us, tell us what hot superconductors do. Okay, So you know, we've talked about the idea of cold fusion, the idea of having a fusion reactor that could operate at temperatures that are much lower than what we would expect a fusion reactor to to perform at. Right. A hot superconductor is kind of the opposite idea. And while we don't know if cold fusion will ever really work, we do know that hot superconductors are a thing. But when we say hot, we're talking relative terms. It's still very, very very cold. It's still cold enough to kill you if you were to be exposed to it, but it's not so cold as to require liquid helium to cool it. Um. So this was something that that lots of different people were working on throughout the years. Uh and you know, just sort of experimenting with different combinations and materials. Again, getting back to that scientist in the lab saying, Huh, I wonder what would happen if we did this to this. Uh. That that first one was I believe it was discovered by IBM researchers. They they presented a a superconductor of barium lanthum, lanthanum and copper oxide um and and it could achieve zero resistance at thirty five kelvin r what minus two hundred and thirty eight celsius and minus three and nine seven fahrenheit. Wow, Lauren does some wicked math in her head. Yeah. And so instead of using liquid helium, that meant that you could use liquid nitrogen, which is much more plentiful and inexpensive, right, yes, you can, you know, compare to liquid helium. Liquid nitrogen we're lousy with it, right yeah. Yeah, and you can pick it up at the supermarket if you really. The point being that it is much it really lowered the bar for what you could make a superconductor out of, which meant that suddenly you could use them for a lot more applications. You know, before only the most well funded applications could ever afford any sort of superconductor material because everything we had needed to be cooled down so far that you had to have liquid helium to do it. And there are there are plenty of places out there that are using that kind of material, like the Large Hadron Collider, for example, uses superconductors and it's and it's electronics in order for it to increase the speed of proton beams so that they can collide at massive, massive speeds and create a situation that looks like a tiny micro cosmic version of the Big Bang or shortly amediate following the Big Bang. I guess I should say the world record for the hottest quote unquote superconductor was a four, and that it was at thirty eight calvin, which is only a mirror negative on five celsius and negative two eleven fahrenheit. Right, so again still really cold to us, but downright bal me because yeah, it's like a it's like a vacation in the tropics, really, And they were using thallium doped mercuric cuperate which was comprised of the following elements. So this is what you have on your shopping list if you want to make one of these, it's not easy and most of these things are poisonous mercury which is poisonous, thallium which is also poisonous, barium, calcium, copper, and oxygen. It's not something that you can actually go and put together on your own. I wouldn't recommend trying fairly. No, No, Now, your average science lab is not gonna be able to produce that kind of super conductor. But then we can talk a little bit about what we would use this stuff for once being used already, how it's being already used. Yeah, m R I I think is the probably most common that that's magnetic resonance imaging. Yes, so MR eyes are used to look at soft tissues, right, because X rays are very good at looking at things like like your skeleton, but they don't they don't pick up soft tissue very well. M R i's, however, are very good at looking at soft tissue, so they became very important in the field of medicine. And super conductors are a great component for m r I machines, as Jonathan mentioned a moment ago, super colliders such as the Large Hadron collider YEP, and there, of course there are more than just that. That's just probably the most famous one that people have heard about recently. Magnetic levitation trains mag lev trains. There's a couple of examples of these, mostly out in Japan, where the idea is to use the super conductors along a track, so you super cool them and create this uh, this this quantum lock phenomena, and then there are magnets on the actual train that can allow it to levitate above the track, thus allowing it to move without that friction that would normally cause the train to be less efficient and uh and allow it to move it on a high speed um without with a relative minimum of energy input, right right uh. And of course you could also make a train the other way around, where the superconductors are on the train and the magnets are in the track. In fact, I think Japan might have examples of both. I wrote an article years and years ago for Discovery News about it, but frankly I honestly can't remember at this point. But other things, we could use it for nuclear magnetic resonance spectroscopy. That's that that that's just very useful in a pharmaceutical pharmaceutical research. It catches yeah, biotechnology, etcetera, etcetera. And they're they're looking forward to uh to maybe trying to use this in more efficient forms of energy storage or energy capture like wind turbines, right, also just other electric generators in general, so that you don't lose as much of that electricity that you've generated through heat. So again that's one of those things. You know, if we can make power systems more efficient where more of the power we are, more of the electricity we're generating, gets to wherever it needs to be to do work, then that's a win for everybody. It means that you have to consume fewer resources because you don't have to worry about losing you know, x amount of the energy you're trying to produce as heat. Right. Also on the on the quantum level, this could be very useful for things like quantum computers because it's it's working on that tiny quantum scale. Yeah, quantum computers. There's always a super cooling element with quantum computers as well. In order to make them work, we've talked about quantum computers in previous episodes, but I have a feeling we're going to need to do a full episode on quantum computers to really explain what the concept is and how they work, because again, it gets pretty I guess Einstein would call it spooky. I guess I guess he would ump speaking of spooky a quantum entanglement. Superconductors are used to create quantum entanglement, ah so, which is again a very important component in things like the quantum cryptography. Now you have a note here that I've read I see in front of me. I wanted to mention that this is not anti gravity, um, you know it is. You are. You are canceling out a magnetic field, right, but it's not like you have created some way like you can't turn us switch. Everyone floats off the floor exactly. Yeah, and we're we're not we're not counteracting gravitons. We still don't really know how gravity actually works. I mean, wait, we obviously see uh, the effect of it, right, we don't see the actual mechanism. Yeah. Back was a Russian physicist whose name I'm not even going to attempt right now. Um, but but he he claimed to have successfully tested this device that would shield an object from gravity. UM. It involved levitating a a superconducting disc above m magnet and UM, no one, no one in the past couple of decades has figured out how has has been able to replicate this experiment. So that's not that's not what we're talking about, right right. And then, of course the other note I was going to mention was the one about people thought that we somehow reverse engineered superconductors from alien spacecraft. Yeah, because you know what Area fifty one they were. They were holding all those that that that alien space craft, and so they were You wrote that, and I wrote that whole article Area fifty one, and I don't remember any alien spacecraft being in there. No. This is again why those conspiracy theories where people thought that perhaps humans are not ingenious or inventive enough to have come up with this on our own now greted. Since we already talked about how the first experiments with super conductivity date back to nineteen eleven, I think we can be safe to say that it's not the Area fifty one reverse engineering nonsense. Sure, However, I mean, you know it's I do see the connections since we started really up pushing pushing the technology off the ground in the nineteen fifties and nine and nine seven being the year that um oh, the Roswell incident. Of the Roswell incident. Also keep in mind that Roswell an Area fifty one are not remotely close clearly connected. So I this is where Jonathan says, ladies and gentlemen, humans are amazingly smart and amazingly creative, and we come up with some amazing accidents. Yeah, there's sometimes we find out we find stuff that we weren't even looking for, but it becomes really important. And I don't I personally, whenever I think of these reverse engineering stories, it really to me is just downplaying how how brilliant people can be. And that kind of gets me a little upset because I've met folks who are truly geniuses at specific fields and uh, and you know, I think it's an insult to them to say that, Oh, obviously no person could have thought this up. It's too magical. It must have come from somewhere else. Also, reverse engineering isn't really easier necessary. I mean, yeah, because you have to figure out how it works in the first place. And then it's not like you don't. You don't, just know it doesn't involve using a Mac computer to upload of virus to a mothership. Boy, we could do a full episode on just uh, that would be fun to do. Sometimes do a tech stuff episode where we just pick a science fiction film and pick apart all the technical and accuracies in that film. And we could do that occasionally, just once in a while. Let us know. Let us know how you guys feel about that, because that could either be incredibly tiresome or really fun and I'm not entirely sure which one. If you guys, If you guys do think that would be a fun idea, let us know, and I go ahead and propose it. Independent Stay could be the first film that we tackle. That would be a fun one, But we don't have to obviously. If you all think no, that's lane, well that stuff, you should now do it. So, guys, thank you so much for tuning in. This has been a really fun podcast to to really dive into something really interesting and and still mysterious. We're still learning about it. I can't wait to learn more about this and see how we use it in the future. I expect that this is going to be one of those transformative scientific developments that really makes the future an exciting time to live in, which is good because I don't have any choice in the matter. So if you have any suggestions for future episodes of tech Stuff, let us know. Send us an email that addresses tech Stuff at Discovery dot com, or drop us a note On our social media. You can find us on Facebook and Twitter. We have the handle text stuff hs W and Lauren and I will talk to you again really soon for more on this and thousands of other topics, because it how stuff works. Dot Com