Arpita: 0:11 Hey everyone, welcome back to the Smart Tea Podcast, where we talk about the lives of scientists and innovators who shape our world. How are you, Aarati? Aarati: 0:20 I'm doing really well. How are you, Arpita? Arpita: 0:23 I'm good. I feel like we're finally fall. We're finally cozy. What's going on in your life? Aarati: 0:29 Well, my biggest thing this week is that I voted. So I'm feeling very proud of myself for checking that big checkbox off my list. Arpita: 0:38 A plus. Aarati: 0:39 Yes, I just sat down over the weekend read through all the propositions read through what all the candidates were saying and it took me like a good hour or so but I feel well informed. Arpita: 0:51 Oh, there's so much. Aarati: 0:52 Yeah. Arpita: 0:53 Good! Aarati: 0:53 I feel I feel like I made good decisions. I feel smart and I did my civic duty. So i'm very proud of myself. Arpita: 1:01 I love that. Aarati: 1:02 Yeah, how about you? Arpita: 1:04 I have had a busy few weeks at work. And so I think the rest of my life is like a little bit on catch up. Um, but I'm very excited. I'm going backpacking this coming weekend. Um, I'm going to Desolation Wilderness, which I have never been to before, just outside of Tahoe. And I'm super stoked. I feel like this is gonna be like the last little bit of backpacking before it gets really freezing. Um... Aarati: 1:30 Yes. Arpita: 1:30 So... Aarati: 1:31 That sounds really fun. Yeah, that sounds amazing. So you just, Go for a weekend or how does it I've never been backpacking. So I don't know anything about it. Arpita: 1:42 Oh, we gotta rope you in, Aarati. It's really fun. We're just doing one night. Two nights is my limit honestly like two nights is my limit and then I'm... I'm ready to be done. But yeah, we're going on Saturday and then it's about a six mile hike so it's not super super far. So six mile hike and then we'll sleep and then we will just hike back. Aarati: 2:03 Oh nice! Arpita: 2:03 And then come back on Sunday. So it's nothing super, super crazy, but we're going to Lake Aloha, and Logan's planned the whole thing out, and I think it's going to be really, really fun. I'm, I'm really excited. I hope we'll see some fall colors, like up in the Alpine Lake, and yeah. I'm, I'm stoked. I think it'll be like a fun getaway. Aarati: 2:22 Is it just going to be the two of you or do you have friends going? Arpita: 2:26 Yeah, we have some friends going. Um, my sister is coming and it's her birthday weekend. And so this is kind of her birthday backpack. And so that, that's kind of the main impetus for going, but yeah. Aarati: 2:36 I see. That's that's a nice way to celebrate that. I feel like that's unique. It's something different than going to a restaurant and which, yeah, I love doing that too. But, you know... Arpita: 2:46 Yeah, this is I think she's I think she's in both. So, Aarati: 2:48 Yeah, well, of course, of course, you need to do both. I feel like birthdays last all week, really, in general. So, Arpita: 2:55 Yeah, totally. She texted me this morning and she was like, It's Scorpio season, and she's a Scorpio, and I was like, thank you for letting me know. Aarati: 3:02 Me too! Arpita: 3:07 We love Scorpios. Aarati: 3:08 Yes, we're pretty amazing, gotta say. Arpita: 3:12 Yeah, who are we talking about today? I'm really excited. Aarati: 3:15 Today, we are going to be talking about Wilhelm Roentgen, who was the inventor, or discoverer, I should say, of X-rays, and the reason I wanted to do him was actually because my friend's son, um, broke his leg, like last week. Arpita: 3:34 Oh no! Poor baby. I know right after his birthday? Aarati: 3:38 Yeah, right after his birthday. He like fell over broke his leg, but he healed super fast. Like he healed... Arpita: 3:45 Yeah. Aarati: 3:46 He's like putting weight on it within a week. And I was like, Oh my gosh, I didn't even like I didn't realize babies healed that fast. Arpita: 3:53 Yeah, the pediatric fractures are super common and heal super fast. Aarati: 3:58 Yeah! Arpita: 3:59 Yeah, it's actually insane like pediatric injuries are basically not real like they're Aarati: 4:05 I did not realize that. Arpita: 4:06 Like a rubber band. Yeah, they're rubber band for sure. Yeah, just bounce back so quickly. Aarati: 4:11 And she sent me the X-ray of his leg and circled the part where the fracture was and I was like where I don't see it so She's like it's right there. I'm like, no, it's not there's nothing there so But... Arpita: 4:25 I'm glad he's better. Aarati: 4:27 Yeah, he's, he's running around like it never happened. And I'm just like, man! Arpita: 4:32 I feel like for them, they're like honestly pretty stoked to have something cool, like a cast, like they're like, this is actually kind of cool. Like, I wonder if he's old enough for that, but I feel like they're usually so undeterred. Aarati: 4:42 At first I think he was like, what is this thing that you're putting on my leg? It's impeding me. I don't like it But then after a bit I think he kind of like understood like Oh, okay. This is something special because I can't put weight on this leg. So this is something that is going to help me. I think he figured that out. And then I think it also helped that when they took him to daycare and stuff like that, like people will sign his cast and make him feel a little bit special. Yeah. So I think that, I think that helped a bit. So Arpita: 5:14 That's funny. Aarati: 5:15 Yeah. But anyway, that's who we're doing today. We're doing Wilhelm Röntgen, um, or Röntgen. There's a lot of German names in this. Arpita: 5:24 I was gonna say, this sounds aggressively German. Wilhelm. Aarati: 5:28 There's like an umlaut over the O in his name and I'm just like, I do not know. So, I think it's Röntgen or that's the closest I'm gonna get with my very American accent. So. Arpita: 5:39 Great. Sorry, Wilhelm. Aarati: 5:41 Yeah, so he was born on March 27th, 1845 in a town called Lennep, which was in the Kingdom of Prussia at the time. So now that area is Remschield, Germany, which is just north of Cologne. He was an only child, and his parents were Friedrich Konrad Röntgen, who was a merchant and a cloth manufacturer, and Charlotte Konstanz Frowien, I hope. Anyway, at the time, there was a lot of political unrest in Prussia, so when Wilhelm was three, the family decided to move to the Netherlands, where Charlotte's family was from. As a boy, and even later as an adult, Wilhelm loved roaming around nature, and he also showed a special aptitude for making mechanical devices, so kind of two, I don't know, opposites there a little bit, but I feel like there's a lot of symmetry between him and some of the other people we've talked about. Arpita: 6:48 Yeah. Aarati: 6:48 In terms of loving nature and liking to build things. So after secondary school, his parents encouraged him to pursue higher education. So he enrolled in high school at Utrecht Technical School. And this was several miles away from his home, so he ended up actually living with a family friend, Dr. Jan Wilhelm Gunning, who taught chemistry and pharmacy at the Utrecht University, and Wilhelm was really welcomed into the Gunning family, and it was Dr. Gunning who truly inspired Wilhelm to pursue science. However, Wilhelm was kind of a mixed bag when it came to his classes. He got good grades in math, chemistry, languages, and art, but ironically he scored quote unquote very bad in physics. And if that wasn't bad enough, one day Wilhelm's science career almost ended completely when one of his fellow students drew a caricature of their teacher on the blackboard. And when the teacher saw it, they demanded to know who drew it, and somehow the blame fell on Wilhelm, and Wilhelm refused to give up the name of the person who really drew it, and so he was expelled from high school. Arpita: 8:06 That's funny, at least he's loyal, I guess. Aarati: 8:09 I don't know. I don't know why you would not give up the name of the student. But yeah, he, he was expelled from high school. Arpita: 8:15 Snitches get stitches. Aarati: 8:17 I, apparently. And so now without a high school diploma, he wasn't able to register as a student at the Utrecht University, which was kind of his goal because Dr. Gunning was a professor there and there was like, that was such an inspiration for him. And to further put a nail in that coffin, he failed the entrance exam anyway for the university. So, he was allowed to audit the classes at Utrecht University, but he wasn't allowed to take exams or get any credit. Arpita: 8:50 Okay. Aarati: 8:51 But he was doing that. He was auditing math and science, um, but then a friend of his, Carl Thormann, told him to try the Swiss Polytechnical School in Zurich because they didn't require a high school diploma in order for you to enter college, which I don't understand. Arpita: 9:07 Odd. Aarati: 9:08 Different times, I guess. So Wilhelm was like, that sounds like a good idea, so he went off to Switzerland and he enrolls in the Polytechnical Institute as a mechanical engineering major. And again, here, Wilhelm is not a great student. After his first year, he got a warning that if he kept getting low grades, he wouldn't be allowed to move forward. And he got the same warning after his second year. So he's barely scraping by here. Arpita: 9:33 Why did he register as mechanical engineering? Wasn't he really bad at physics? Aarati: 9:37 Yeah, I don't know, but he liked to build things, I guess. And, Arpita: 9:41 Okay. Okay. I was wondering if there was like a real reason why he did that. I'm like, wasn't, this doesn't seem to be playing to his strengths, I guess, is what I'm trying to say. Aarati: 9:48 It doesn't, and the thing, well the things that I read about him were that he kind of was more into thinking about things in a more abstract way, like theoretical things, but then when it came down to like structure and doing things practically, he wasn't great at that. Arpita: 10:06 Got it. Aarati: 10:07 So, he liked to think about things like kind of in a broad sense, but then he had trouble kind of with details, which again is ironic, we're going to get to that. Yeah. But he worked really, really hard and his professors were very invested in helping him. So by the end of his third year, he was actually doing pretty well in his classes. So he got his diploma and then I guess this was like an option for graduates of the polytechnical school that he was at. So after his undergrad, he was given the option to enroll into a one year PhD program at Zurich University. So again, I'm like, this is unheard of, like, yeah, just go to school for a year and get your PhD. Arpita: 10:49 Yeah, I, I'm confused by the, okay, carry on, carry on. Aarati: 10:52 Yes, but I think it's also that this is like the 1800s, and so physics is like, wow, you discovered a particle? Amazing, you get your PhD and now you're famous, you know? Arpita: 11:05 You get a PhD and you get a PhD. Aarati: 11:07 Exactly. So he does that. He goes to study for his PhD at Zurich University and he goes from studying mechanical engineering to physics, and here he studied under Professor Rudolf Clausius and August Kundt, who, once again, were very dedicated to helping Wilhelm succeed. As a student, Wilhelm was very hardworking, and he was also very introverted, so when he wasn't studying, he had a small group of friends that he would hang out with. He loved going for hikes in the mountains and rowing boats on the lake, so he was not like a party person, he didn't like talking to people a lot, but he enjoyed kind of more quiet, reserved, outdoorsy type activities. He also enjoyed eating at a local inn, where it just so happened the innkeeper's daughter, Anna Bertha Lundwig, or Bertha, Ludwing. Sorry. Anna Bertha Ludwing. Um, I said it like three different ways now. Anyway, she went by the name Bertha, which I can say. So she worked as a waitress at this inn and he liked to eat there. Um, probably for more reasons than one. So after his year in Zurich, he published his dissertation entitled Study of Gases, which was, you guessed it, a study of behaviors of gases at different temperatures and pressures, and that's like literally all he needed to get his PhD. Arpita: 12:37 Like P= nRT? Like, what are we talking about? Aarati: 12:40 I guess so? I think it was just like, how does this gas behave at this temperature, and what is the pressure at that temperature? And then now if I lower the temperature, what's the pressure? And like Arpita: 12:49 Are you serious? Aarati: 12:50 Like, this is what it sounds like to me. Arpita: 12:53 I think my chemistry homework was harder than that. Aarati: 12:55 I know, it definitely was. So, but he was basically doing a lot of work on like, entropy and thermodynamics types of things. Okay. On the same day he graduated from his PhD, he went to that inn where Bertha worked and he proposed to her. Arpita: 13:11 I also got proposed to the day I defended. Aarati: 13:14 Did you really? Arpita: 13:15 Yeah. Aarati: 13:15 Oh my god, that's so cute. I didn't know that. That's adorable. Arpita: 13:20 It was a long day. Aarati: 13:21 Way to increase your chances when you're really happy. She's in a good mood. Arpita: 13:26 I think that's what happened. It's like how sleep deprived and delirious could she possibly be? Let's increase the chances. Aarati: 13:33 Yeah, exactly. In this case, PhD and he's like,"Great. I'm going to go propose to my girl." So she accepted, but Wilhelm's father did not approve of the marriage first, because Bertha was six years older than Wilhelm was, and she also came from a poor family. So his father said if they got married, he would cut off all his financial support. So Wilhelm was like, Okay, I guess I gotta go get a job then. So around this time, Professor Kundt, who Wilhelm had been working with during his PhD, got an appointment as the chair of physics at the University of Würzburg back in Germany. And Professor Kundt had a really high opinion of Wilhelm, and he appointed him as his assistant in his new lab. So Wilhelm moved back to Germany, while Bertha went to live with Wilhelm's parents for a while so she could learn German cooking and housekeeping skills from Wilhelm's mother. So preparing for married life, basically. Arpita: 14:39 Yeah, cute. Aarati: 14:41 Yeah. And although Wilhelm's father didn't really approve of Bertha, Wilhelm's mom found Bertha to be loving and quote unquote careful, which I took to mean that she paid attention to detail, so. Arpita: 14:55 Oh, those are probably translated, right? So it's probably not careful in English. Aarati: 15:00 Yeah, true. So, I was like, okay, at least Wilhelm's mom likes Bertha. After about two years, in 1872, Wilhelm and Bertha got married at the Röntgen's home. And true to his word, Wilhelm's father cut off his financial support. But at this point, Wilhelm and Bertha were okay living on Wilhelm's salary at the University of Würzburg, so it wasn't much. They weren't, like, super well off, but it was enough to get by. However, the university was very poorly funded, and Professor Kundt and Wilhelm found that it just wasn't very well equipped for setting up a new physics lab. Luckily for them, the Franco German War had just ended in 1871, and France had ceded some land over to Germany, including the city of Strasbourg. Therefore, the University of Strasbourg was being reorganized to become a German institution now. And Professor Kundt was asked to be the chair of physics there. So Kundt went to Strasbourg and Wilhelm went with him. And after a few years, Wilhelm's parents even moved to Strasbourg to be closer to him. So it sounds like they're very, like, close knit family. Here Wilhelm published a few more papers. One was on specific heat of certain gases, one was details about using an air barometer to specifically measure gas pressure, one was on the heat conductivity of crystals, and finally one on the electrical characteristics of quartz. A lot of, a lot of thermo, like a lot of thermodynamics. Arpita: 16:29 Yeah, interesting. Okay. Aarati: 16:30 Yeah. But what's really important to note about this work is, like, none of it was particularly groundbreaking. Most of it was repeating experiments that other people had already done, but he was maybe using, like, a slightly different method. Or he was trying to get the same results and then trying to explain any discrepancies he saw. Arpita: 16:50 Okay. Aarati: 16:51 And so that's a really important point as to the type of scientist he was. He was like spending a lot of time being very precise about his measurements. Um, and so it would take him years to publish a paper, but most of the time it wasn't like, Oh my gosh, this amazing discovery that he's made. Arpita: 17:09 Yeah. Okay. That makes sense. It also does sound like a lot of junior faculty papers, right? It's like you're not doing your most groundbreaking research yet. You're sort of getting your name out there and, you know, either refining protocols or validating results, like making smaller steps as opposed to like your biggest paper. Aarati: 17:30 Yeah, and he also like it was kind of part of his personality to kind of go chase after like the little why is this little thing happening that maybe other scientists had noticed but it wasn't part of their bigger picture so they kind of disregarded it, but he would go and chase down that little detail and be like what's happening there can I explain that one little thing. Arpita: 17:52 Gotcha. Aarati: 17:53 Yeah, he also spent a lot of time trying to find practical evidence for physics theories, but often hit a dead end because the instruments at the time were just not advanced enough to prove or disprove certain theories. After about a year with Kundt's help and a strong recommendation, Wilhelm was able to get a position as a lecturer in 1875, and then he was offered a full professorship position at the Agricultural Academy of Stuttgart Hohenheim. The move to Stuttgart Hohenheim was a little bit of an emotional one for Wilhelm because although the position came with a pay increase and he was automatically able to become a German citizen because of the position that it was, it also meant that he had to leave behind Professor Kundt who had really taken him under his wing and influenced his work, and it also meant moving away from Strasbourg, away from his friends and family. Also, the housing that they provided at Hohenheim was pretty terrible, and Wilhelm was always complaining about the rats in the place. So, yeah, not good. So, unsurprisingly, after about a year and a half, Professor Kundt wrote a letter saying, Hey, if you want to come back to Strasbourg, I will recommend you to be the new chair of theoretical physics here. And Wilhelm was like, yes, please. And he and Bertha went back to Strasbourg. Arpita: 19:13 Yeah, how do you pass that up? Especially when you're living with rats. Aarati: 19:16 Yeah, I mean, it's like, I will take the pay decrease to go back and live with my friends and family in a non rat infested house. Arpita: 19:25 Yeah, it's a no brainer. Aarati: 19:26 Yeah. So he's bouncing around a lot at this point in his life. Um, after three years at Strasburg, William published 15 papers in physics and was truly becoming a rising star in the field. Because of this, in 1879, he's nominated to be the chair of physics at the University of Giessen. He was even recommended by Hermann von Helmholtz, who is a very famous physicist known today for his work in energy conservation and optics. So he moves to Giessen, he stays there for almost 10 years, and again his parents followed him to live with him there. They, at this point, are very proud of him because he's essentially building his own career without any sort of patron or outside financial support, which I guess was common at the time. Arpita: 20:13 That does make sense. Yeah. Aarati: 20:14 Yeah. Arpita: 20:15 Does the dad come around then? Aarati: 20:18 Um, I think he, the dad is proud of him, but not enough to give him money. Arpita: 20:23 Give him money. Aarati: 20:24 Yeah. But at this point it's like, oh, but he doesn't need it anymore. Arpita: 20:27 It doesn't matter. Aarati: 20:28 He doesn't. Yeah. It doesn't. He, he made his own, he made his own way. Arpita: 20:31 Yeah. Okay. Okay, okay. Aarati: 20:33 At Giessen, both of his parents actually passed away. His mother died a year after he moved there and his father died four years later. They were both buried in Giessen and it was a pretty hard loss for Wilhelm because he really loved his parents, like pretty obviously they were following each other around, you know, Europe. And even ten years later, there's a letter where he wrote to a friend reminiscing about his mother and how he still misses her. Arpita: 20:58 Oh. Aarati: 20:59 Yeah. So. At Giessen, Wilhelm was asked to design a new physics department. The old ones were really cramped and over 30 years old, so he was given a new space to work in. He also taught experimental physics, giving lectures on optics, heat, and electricity. And he published about 20 more papers during this time on a bunch of different things, namely the properties of quartz and also the photophone, which was invented by Alexander Graham Bell. Um, and it was a precursor to the telephone. So the photophone was a way to transmit sound, but using light waves instead of electricity. Arpita: 21:41 Oh, I was going to ask what the photo was, but okay. Aarati: 21:44 Yeah. Yeah, but again, it's worth noting, Wilhelm was really just adding his two cents here. Like Alexander Graham Bell is the one who got the acclaim for that invention of the photophone. And Wilhelm was just like, Oh, also it does this one other little thing that not many people cared about, you know, so he's doing a lot of these types of experiments with gases and pressure changes, thermodynamics, um, and how different types of light waves are absorbed by different materials. And so now we're building up to his big discovery, but we're not quite there yet, but the thorough way in which he conducted his experiments and the quality of his publications gained him a lot of recognition. Hi everyone, Aarati here. I hope you're enjoying the podcast. If so, and you wish someone would tell your science story, I founded a science communications company called Sykom, that's S Y K O M, that can help. Sykom blends creativity with scientific accuracy to create all types of science communications content including explainer videos, slide presentations, science writing, and more. We work with academic researchers, tech companies, non profits, or really any scientist to help simplify your science. Check us out at sykommer. com. That's S Y K O M M E R dot com. Okay, back to the story. In 1888, he was offered the position of a Professor of physics and the director of the new physical institute at the University of Würzburg. So Wilhelm, who is now 43, moves to Würzburg with Bertha. And at this point, Wilhelm and Bertha still did not have any children. And since Bertha was six years older than Wilhelm, and so was approaching 50 years at this point, it was highly unlikely that she was going to be able to conceive. And this was a really big source of pain for both of them, but especially for Bertha because she loved children. Yeah. But in 1887, Bertha's only brother died and left behind a six year old daughter, Josephine. So Wilhelm and Bertha took in Josephine and basically made her like their daughter. And then when she was 21, they legally adopted her. Arpita: 24:08 Aww, that's very cute. Aarati: 24:10 Yeah, so they became really close. They were like a very tight family unit. They would go be out in nature all the time, go on hikes. They would take family vacations together. And so overall, life in Würzburg is going pretty great. Arpita: 24:24 Yeah. Aarati: 24:26 Okay. So now we're finally getting to the main event. In the 1890s, scientists all over the world were studying the properties of cathode rays. So we talked about these a little bit. Arpita: 24:38 Yeah. Aarati: 24:38 In the episode on Percy Spencer, the inventor of the microwave oven. So just a quick reminder. A cathode ray is created in a vacuum tube and is made of glass that has a cathode or a negatively charged electrode on one end and an anode the positively charged electrode on the other end and when you send energy through it negatively charged electrons stream off the cathode and move towards the anode. And scientists can actually see this beam of electrons, um, moving through the tube because the vacuum tube is coated in phosphor and it makes the electron beam or cathode ray show up as a green beam of light. So actually, if you see videos of this, it's super cool looking. Arpita: 25:25 Yeah. Aarati: 25:26 But at the time scientists did not know what cathode rays actually were because they didn't even know what electrons were so... Arpita: 25:34 Interesting. Aarati: 25:34 They were just like putting energy through this tube seeing this beam of green light and being like cool. What's that? You know? They didn't know what it was. They had no... they didn't know what properties it had, they didn't know what made it up. And so that's what all these scientists are trying to figure out basically. And there were two physicists in particular, Heinrich Hertz and Philipp Lenard, trying to figure this out, and they made a version of the cathode ray tube that had a window on one end that they covered with different materials to see if the cathode ray could pass through it. So, when they covered the window with gold or silver, the cathode ray got absorbed and couldn't pass through, but it could pass through aluminum foil. So you're sending energy through this tube, it's going from the cathode to the aluminum foil and actually going through the aluminum foil out of the vacuum tube. Arpita: 26:30 And it has to do with the density of aluminum versus the density of gold and silver? Okay. Aarati: 26:35 Yeah. Yeah. But once it did get through the aluminum foil, it would kind of dissipate really fast. It would only survive for about a few centimeters before dying off. So it couldn't exist like the cathode ray couldn't exist for very long outside of the vacuum tube. But now they could actually study like what effects the cathode ray had on different things outside of the vacuum tube. So they were experimenting by holding up different materials in front of the cathode rays and noting that some of them would heat up or fluoresce, but again, that was about the extent of their knowledge. Arpita: 27:11 They were kind of just messing around a little bit. Aarati: 27:13 Yeah. Arpita: 27:14 They're just like, what happens now? Aarati: 27:15 Exactly. Let's point this cathode at something and see what happens. Arpita: 27:19 Okay. Aarati: 27:20 That's exactly what they're doing. So the important one to note is they found that if they held up a screen covered in barium platinocyanide crystals, they would start to fluoresce. Arpita: 27:32 What is that? And where did they get it? Aarati: 27:33 Yeah, so I don't know. Um, they don't know why this happened. It was like one of many things that they were studying and they were just making a note that hey we've got this screen. We covered it in barium platinocyanide crystals for whatever reason and Hey, look, they glow great, you know, like but why do they glow? We don't know. So they're just making a note. Arpita: 27:56 Why do they have? Bario, what is it? Aarati: 27:59 Barium platinocyanide crystals. It was like a list of like many different things. I'm sure there's a physics reason for why they chose that as their short list, but I think they were doing like many different, um, types of materials. And that was just one that will become important to Wilhelm's story. So that's why I'm just mentioning that one, but there were other materials that like either heated up or would fluoresce or whatever that they were also making a note of. So, Wilhelm read about Hertz and Lenard's experiments, and he wanted to replicate them. So, he built his own version of their cathode ray tube with the window and covered it with aluminum foil, just like they had. And then he wrapped the whole tube in black cardboard so no visible light would interfere with his experiments. And on November 8th, 1895, Wilhelm attempted to replicate this particular experiment with the barium platinocyanide crystals. So, he got a screen that was covered in the crystals, he cut off a small piece, and he set the bigger piece aside on his bench. And then he held up the small piece of the screen in front of the cathode rays. And it started to fluoresce, but then he noticed that the larger piece of the screen that he had left lying on the bench a few meters away was also fluorescing and he's like, that's weird because scientists knew that the cathode ray once it left the vacuum tube would die off after a few centimeters and he wasn't even holding up that part of the screen in front of the cathode ray. So Arpita: 29:35 It's like a few meters away. Aarati: 29:36 Yeah. So he's like, huh, something else is causing this fluorescence and it must be some kind of ray that's invisible, but was able to pass through the cardboard that he had covered the cathode ray tube in. So initially Wilhelm like couldn't really believe what he was seeing. So for the next few weeks, he kept his discovery a complete secret. He holed himself up in his lab for weeks trying to find some explanation. Like, he just couldn't believe this phenomenon was real. So, he was putting all of these materials in front of the crystal screen, like huge stacks of books and planks of wood, but the crystals kept fluorescing. So, like, whatever was causing the crystals to light up was not only not dying off as soon as it left the vacuum tube, but it was moving through these heavy materials and still causing the crystals to fluoresce. He placed the crystals on a photographic plate so he could take a picture, and then he started checking out what happened to other things. And he was astonished to find that when he put a compass on the photographic plate and took a picture, he could see the needle of the compass even through the metal case when it was closed. Arpita: 30:50 Oh, yeah. I see. Like, it's like an old school, just kind of clamshell situation, and he can see inside of it even when it's closed. Oh, that's cool. Aarati: 30:59 Yeah. So, like, these rays are passing through the metal case and allowing him to see like the inside of it of the compass. Arpita: 31:08 Pretty cool. That would probably blow my mind too. Aarati: 31:10 Yeah. And then he tried his own hand and of course saw the bones his own bones in the photograph that he took. And I think, obviously, initially, this kind of freaked him out, um, like, yeah, so when his wife Bertha kept asking him, like,"What's going on? You're holed up in your lab all day, like you're not coming out." All he would say was that if people knew what he was doing, they, quote, would say Roentgen must have gone out of his mind," basically. Arpita: 31:42 I mean, it's not entirely, you know, out of the realm of possibility. Aarati: 31:47 Yeah, because he, he just couldn't believe that like what he was seeing... he just couldn't fathom that this was a thing So he was like I must be making this up. I must be having some sort of hallucination. I cannot literally be seeing my bones right now. This is insane. Arpita: 32:03 If he was a lady, he would be a witch. So... Aarati: 32:06 Yes. Oh my god. Good point So speaking of um, finally on December 22nd, he brought Bertha into his lab and he turned on the cathode ray placed her hand in front of the photographic plate and took a picture of it and in it. She could clearly see the bones of her own hand and her wedding ring kind of floating around her finger. Arpita: 32:30 That's cool. Yeah. I mean, they make sense. But yeah. Aarati: 32:33 Yeah. So initially creeped out by the image too. And she thought that she was seeing a vision of her own death. Arpita: 32:41 Mmm, I mean, yeah, I get it. Aarati: 32:44 So, this image has now become famous as one of the first radiology images, or Röntgengrams. So, finally now, he's convinced himself he wasn't crazy, that he, what he had found was real. And he published his findings in a paper called On a New Kind of Rays. Since he had no idea what these rays were, he just called them X-rays'cause he couldn't think of a better name for them. Arpita: 33:10 That's so funny. I actually was wondering why they were called X-rays. Aarati: 33:14 Yeah, just it doesn't stand for anything. It's just like X is just unknown. Arpita: 33:19 Like a placeholder like literally solve for x. Oh, interesting. Aarati: 33:23 He was just like, I don't know what they are, so I'm just gonna say X. In the paper, he noted that there were certain things that these X-rays could pass through, like wood, cloth, and soft tissues in humans, but not other things like certain metals and bones. And now we know, actually thanks to one of Wilhelm's own students who followed up on his research, that X-rays are a type of electromagnetic radiation. They're on the opposite end of the spectrum as microwaves. So microwaves, radio waves, and infrared waves have really long wavelengths, longer than we can see with the naked eye. Then we have our very small little window of visible light with all the color wavelengths that we can see. And then the waves get too short for us to see. And that's the ultraviolet range and X-rays fall into that range as well. Arpita: 34:14 And then gamma rays? Aarati: 34:15 Yeah, and gamma rays. Yeah. Arpita: 34:17 Okay. Aarati: 34:17 And since X-rays are so short, between 0. 01 and 10 nanometers, they can pass through a lot of different materials. Arpita: 34:27 Right. Aarati: 34:27 So things that are really dense, or elements that have higher numbers of electrons or like higher, or I guess lower on the periodic table, they can block X-rays from passing through. And so that's why X-rays can pass through our soft tissue, like our muscle and fat and skin because it's less dense. It's made of lower numbered elements like hydrogen and carbon, a lot of water, oxygen, nitrogen, like those elements and X-rays can pass right through, but bones are made of calcium and that's higher up on the periodic table or lower down, I guess, if you're looking, it has a higher number Arpita: 35:06 Higher atomic number. Aarati: 35:07 Yeah. Yeah. And so they don't allow X-rays to go through them. And so they clearly show up. Arpita: 35:13 And so like her wedding band or the sheet of gold. Aarati: 35:16 Yeah, exactly. So when Wilhelm published his findings, initially many physicists were very skeptical and were like, no way this is a thing. But after seeing the images of Bertha's hand and repeating the experiments for themselves, the scientific community was amazed and super excited. They immediately saw what a huge breakthrough this was and Wilhelm became an overnight sensation. He was not super thrilled by this because he was an, he was an introvert and he really hated the attention. Um, he declined numerous interviews with the press, but in January, the German Emperor Wilhelm II invited him to give a demonstration of the X-rays to the court in Berlin. And that's not really an invitation that he could decline. Arpita: 36:03 Sure, that's like a, that's like a volun-told. Aarati: 36:07 Yes, exactly. So Wilhelm went, he gave his demonstration, and he talked about the potential military applications X-rays could have, and the emperor was highly impressed and gave him the Prussian Order of the Crown, second class. The next day, Wilhelm gave his only public lecture ever on X-rays. When he entered the auditorium, he was shocked to see that it was fully packed, with students even sitting on the stairs between the aisles. Yeah, he's like, what are all these people doing here? They gave him a standing ovation when he entered, which visibly moved him. After his lecture, people began calling the rays Roentgen rays. However, as we know, the original name of X-rays kind of ended up sticking. He also refused to pursue any patents associated with X-rays because he firmly believed that this kind of technology should be freely accessible for the good of all people. So. That was nice. Uh, when he made his discovery, the implications for healthcare was obviously one of the biggest things people were excited about. And as a result, Wilhelm was awarded an honorary doctorate of medicine from the University of Würzburg. He and Philipp Lenard also jointly received the Rumford Medal for Astounding Achievement in Physics from the British Royal Society in 1896. And I think that brings up the point for a lot of people that Lenard had been very close to discovering X-rays and had probably even kind of noticed the same phenomenon that Wilhelm did, but just didn't follow up on it. Like just again, like that was what Wilhelm was doing. Arpita: 37:50 He's really focused on the details. Yeah. That's super interesting that like, yeah. Cause like so many people were messing with it, that he was actually the one to be like, Wait, there's something else here. Yeah, interesting. Aarati: 38:01 There's something else happening here. And so some people called it lucky because like, so like you were saying, so many people were messing around with cathode rays and it was just luck that he stumbled on this. But one of his students later pointed out that it really was because of his nature of him following up on every single little detail and asking why that... Arpita: 38:21 yeah. Aarati: 38:21 ...he discovered X-rays. Arpita: 38:23 I mean, so much of this, I mean, I don't like to call it luck, but it kind of is a little bit of right place, right time, so he's in the right situation where he has the material to explore this, and it has not quite been discovered yet, and so, you know, there is a mix of, you know, you need all the ingredients to make it happen, but I wouldn't say that he just like stumbled into it. You know, he was looking. I think there are some things where it's like totally a mistake. Like someone made a mistake and then this resulted in it. I don't think this is that. Aarati: 38:52 Yeah, no, because I think there was a lot of people were like, Oh, well, you know, this other scientist should have gotten the credit or this other scientist really just like saw this phenomenon first. Like they, they, noticed something first that now we know is probably caused by X-rays and they were the first ones to make this observation that like this thing is glowing. Arpita: 39:13 That's different. Aarati: 39:14 But they didn't follow it up, you know, and that's why they didn't make the discovery first. Arpita: 39:20 That's not a discovery, but yeah, no, I agree. Aarati: 39:22 So following his discovery, the Bavarian government asked him to chair the physics department at the University of Munich. And again, this is kind of like a volun-told situation, like you were saying, like the government is saying, hey, you need to go to the University of Munich. So Wilhelm and Bertha moved to Munich, but they weren't happy at all about leaving Würzburg. They miss their friends and colleagues and the calm, friendly atmosphere. And in comparison, they found Munich and its people to be kind of stuffy, and they had a really hard time getting along with anyone. Arpita: 39:54 That's so funny, because they're all German, and I'm like, you guys are all stuffy, so. Aarati: 40:00 I mean, to me, it kind of sounded more like they were very outdoorsy, and like, kind of like this calm, laid back kind of country living, and now they're moving into a city, and they're just like, surrounded by all these like fast paced kind of high society people, and he just wasn't that type of person. So, despite his new fame, he rejected the offer to join the class of nobility in Munich, which annoyed a lot of the noble people because they felt like he was snubbing them. So, Just not good at making friends, this guy. But he really just was not into the attention, like he did not, he did not want to be part of the upper class, he did not want, you know, all of that. But this brings us to 1901, which is the inaugural year of the Nobel Prizes. So although Wilhelm had discovered X-rays five years ago at this point, It's value to society was so obvious that there was really no question within the Nobel Prize committee as to who was going to win the Nobel Prize in physics. So when Wilhelm heard the news that he had won, he was thrilled. He traveled to Stockholm where he received the prize and 150, 000 Swedish kronor, which is equivalent to about$900, 000 today. Arpita: 41:19 Damn. Aarati: 41:19 Yeah, But he didn't keep any of it. He donated it all to the University of Würzburg for their continued research. Arpita: 41:27 Wow. Aarati: 41:28 Yeah. Wilhelm stayed at the University of Munich until 1920. Unfortunately, the years had not been kind to him and Bertha. So, during World War I, people were asked to give up their gold and jewelry for the war effort, and Wilhelm was very patriotic, and so he gave what he had, including the gold Rumford medal that he had won with Lenard. Arpita: 41:51 Oh, yeah. Aarati: 41:52 But he did hang on to his Nobel Prize medal. He wasn't giving that one up. Arpita: 41:57 Good for him. Yeah. Aarati: 41:58 Yeah. Arpita: 41:58 Yeah. Aarati: 42:00 But when Germany lost the war, all of his war bonds lost most of their value. And then as the years passed, inflation made most of his savings lose value as well. So towards the end of his life, he was basically living in poverty. Arpita: 42:14 Wow, that's crazy. Aarati: 42:15 I know. I was like, I find that so sad. But at the same time, I was like, well, you're the one who decided not to patent it. You're the one who gave away like almost a million dollars. In 1919, Bertha died at the age of 80 after a long battle with kidney and respiratory problems. Her death, of course, was very sad for Wilhelm, and without her he became even more introverted and reclusive. He retired from the University of Munich and burned most of his letters and notes, including many of the papers from around the time when he first discovered X-rays. Arpita: 42:51 Interesting. Why? Aarati: 42:52 I know. To me, that raised the same question. I was like, I feel like at least three or four times now we've heard of scientists burning their notes and burning their research. Arpita: 43:02 Yeah, why? Like, what's the thought process? Like, they just don't want anyone to find? Aarati: 43:06 I wasn't sure. Arpita: 43:07 I guess the most interesting thing about it is like how 180 we are now where I just feel like my first like step into even like chem lab was like write everything down like everything that you do down and like keeping lab notebooks is like a religion and so I'm just curious like that wasn't that long ago it was like early 1900 so it's like What, like what changed in such a short amount of time that people were burning their notes to then being like, we're going to keep religious notes. I don't know. I just like a philosophy thing that I'm curious about. Aarati: 43:42 Yeah, I don't really understand his thought process because, like, unlike John B. Watson, who we talked about a couple episodes ago, like, he burned his notes, I think, because he was kind of ashamed of what he had researched in terms of child psychology and things like that, which I understood that. But this, I was like, I don't know why you're burning your notes. And I think a lot of historians were kind of upset about that, too, because there's a lot that we don't actually know about his discovery and X-rays because it's gone now, you know, so, Arpita: 44:12 But like for no real reason. Yeah, that's yeah, Aarati: 44:16 It is. It is weird. He spent his final few years visiting the few friends he had left in 1921. He suffered from internal bleeding, which his doctor said was due to hemorrhoids, but Wilhelm figured that he really actually had intestinal cancer. Um, I think he could just tell by the way he felt and things. So he died at his home on February 10th, 1923 at the age of 78. And he was given what basically amounted to a royal funeral, like members of the former royal family were present, as well as several prominent members of the scientific and physics communities. He was cremated and his ashes were buried next to Bertha's and his parents in Giessen. So today, X-rays are still used everywhere, obviously, um, most obviously we use them for medical procedures to identify broken bones, tumors, and other types of injuries in the body. They are also used for security purposes to screen like bags at the airport and at different concerts and events. William Röntgen is also still remembered today, not just by the scientific community but the world in general. There are several streets. Named after him, and there's a plaque on the house where he lived as a PhD student in Zurich, as well as a memorial in Geissen that is kind of an abstract version of X-rays passing through a huge stone. It's pretty cool. Arpita: 45:48 That's really cool. Aarati: 45:49 Yeah. There's even a mountain peak in Antarctica named Röntgen Peak after him. Arpita: 45:55 Wow. Really? That's so random. Why? Aarati: 45:57 Yeah. I don't know. Maybe because he was outdoorsy. He loved hiking and adventuring, I guess. Yeah, he was like a very avid mountain climber, so. In 2004, element 111 on the periodic table was named Roentgenium, Roentgenium, yeah. Arpita: 46:16 Those get weird. I feel like after a certain atomic number, they get weird. Real weird, like, like people just start using their names and I'm like, Aarati: 46:22 Yeah, people just started like I know there's like Einsteinium and there's Nobelium. Um, or something. There's like a whole bunch of different ones. So, but I have to say like the original IUPAC name that was given to element 111 was like, Unununium It's like, U N U N U N I U M. And I was like, who? Arpita: 46:43 Who's in charge of this? I have feedback. Yeah. Aarati: 46:46 I'm like, Roentgenium is much better. Thank you for changing that. Arpita: 46:50 Yeah. Aarati: 46:50 Yeah. And finally, November 8th, which is the day that Wilhelm first noticed that the barium platinocyanide crystals in his lab were fluorescing, is now celebrated as World Radiology Day. And I thought that was super cool personally, because November 8th also happens to be my birthday. So, yeah, back to those fellow Scorpios. Arpita: 47:17 Scorpios! Aarati: 47:17 Yeah. So, yeah, that's his story. Arpita: 47:19 I loved it. Great story. That's so fun. I like that story a lot. Aarati: 47:25 Yeah, I thought it was super fun. Super cool. Arpita: 47:30 Thanks for listening. If you have a suggestion for a story we should cover or thoughts you want to share about an episode, reach out to us at smartteapodcast. com. You can follow us on Instagram and Twitter@smartteapodcast and listen to us on Spotify, Apple Podcasts, or wherever you get your podcasts. And leave us a rating or comment. It really helps us grow. Special thanks to our editor, James Fixx. New episodes are released every other Wednesday. See you next time!