WEBVTT - How was radiation discovered? 0:00:08.720 --> 0:00:12.280 Hey, Daniel, would you risk your life for science? It 0:00:12.440 --> 0:00:15.880 might depend on the science we're talking about. Would you 0:00:16.000 --> 0:00:19.680 risk getting eaten if you've got to meet Adians for example? Tempting, 0:00:19.800 --> 0:00:23.760 but I'll pass. How about would you risk speghettification if 0:00:23.800 --> 0:00:26.000 you got to see the inside of a black hole? 0:00:26.400 --> 0:00:29.080 You know, I might actually take that trip. Or would 0:00:29.120 --> 0:00:33.239 you risk deadly radiation to understand the nature of matter? Actually, 0:00:33.479 --> 0:00:35.720 I've kind of already done that. One really does a 0:00:35.800 --> 0:00:40.000 large hadron collider generate deadly radiation? It does, But that's 0:00:40.040 --> 0:00:42.880 not how I've been exposed. How have you been exposed 0:00:42.880 --> 0:00:46.640 to radiation? Well, flying the switzerlanded back like a thousand times, 0:00:46.760 --> 0:00:49.320 you get a lot more radiation at high altitude, really 0:00:49.520 --> 0:00:52.400 you have. Every Transatlantic trip is like a chest X ray. 0:00:52.680 --> 0:00:54.920 I thought you said you've been been by a radioactive 0:00:54.960 --> 0:00:59.920 Swiss spider, and I gained that spider's proportional physics, smart 0:01:00.200 --> 0:01:19.880 and chocolate making ability. I am jorhandmade cartoonists and the 0:01:19.880 --> 0:01:24.040 creator of PhD comics. I'm Daniel. I'm a particle physicist, 0:01:24.120 --> 0:01:27.000 and I like to think of myself as radioactive. Are 0:01:27.040 --> 0:01:30.839 you technically radioactive? Are most people radioactive? At some level, 0:01:30.959 --> 0:01:34.080 like bananas are radioactive. Yeah, so you're probably more radioactive 0:01:34.080 --> 0:01:36.560 than most people. But I grew up in Los Almos, 0:01:36.640 --> 0:01:38.640 New Mexico, where we like to say we all glow 0:01:38.680 --> 0:01:44.400 in the dark. Really, I did grow up in Los Almos, 0:01:44.440 --> 0:01:46.440 but we don't actually like to say that. Well, I 0:01:46.440 --> 0:01:48.040 do eat a lot of bananas, and I do have 0:01:48.080 --> 0:01:50.600 a certain glow about me, i'd like to think, but yeah, 0:01:50.640 --> 0:01:53.640 Welcome to our podcast. Daniel and Jorge explain the university 0:01:53.640 --> 0:01:55.960 production of our Heart Radio, in which we shine a 0:01:56.080 --> 0:02:00.000 radioactive glow into all the mysteries of the universe, the big, 0:02:00.240 --> 0:02:03.000 crazy things that are out there tearing the universe apart, 0:02:03.160 --> 0:02:06.000 the powerful forces that are holding it together, the things 0:02:06.080 --> 0:02:09.160 far from home, and the things right here in our backyard. 0:02:09.520 --> 0:02:12.680 All the mysteries of physics revealed and explained to you. 0:02:12.840 --> 0:02:15.920 That's right, we radiate knowledge and give you an X 0:02:16.040 --> 0:02:19.200 ray view of all of the amazing secrets that are 0:02:19.200 --> 0:02:22.040 out there to discover in the universe, and all of 0:02:22.040 --> 0:02:23.840 the secrets that are yet to be discovered. And all 0:02:23.880 --> 0:02:26.600 the while you can stay home and safe, tucked into 0:02:26.600 --> 0:02:29.359 your couch, sipping that mug of tea and learning about 0:02:29.360 --> 0:02:34.720 the universe. No tinfoil hat needed or leadline hats. That's right. 0:02:34.800 --> 0:02:37.680 This counts exactly zero as part of your annual dose 0:02:37.760 --> 0:02:40.519 of radiation, even though you'll be learning all about it. 0:02:40.480 --> 0:02:44.040 It's right. Well, we're technically getting to people through sound waves, 0:02:44.320 --> 0:02:47.480 not light weights or radiation. That's right. But actually radiation 0:02:47.560 --> 0:02:50.760 is sort of any sort of energetic particle or wave. 0:02:50.960 --> 0:02:55.360 So sound is technically speaking a kind of radiation. So 0:02:55.400 --> 0:03:00.040 we are radiating your ears with our voices. What no it, 0:03:00.120 --> 0:03:02.399 I said a limit? Get you like, if I throw 0:03:02.440 --> 0:03:07.600 a baseball, I'm radiating a baseball. Baseballs are radiation, yes, absolutely, Now, 0:03:07.680 --> 0:03:11.480 the technical definition of radiation is sort of weirdly broad. 0:03:11.840 --> 0:03:13.840 Any kind of light, any kind of particle, any kind 0:03:13.840 --> 0:03:18.680 of way that transmits energy is radiation. But practically speaking, 0:03:18.680 --> 0:03:21.639 when we talk about radiation, we mean very high energy 0:03:21.720 --> 0:03:24.400 particles or higher energy waves that are going to deposit 0:03:24.440 --> 0:03:27.960 a significant amount of energy. And so a flashlight or 0:03:28.000 --> 0:03:32.000 this podcast are not typically categorized as radiation, even though technically, 0:03:32.040 --> 0:03:36.440 according to physicists it is. Well it's a very loaded word, 0:03:36.640 --> 0:03:39.640 isn't it. I mean, especially like in the eighties. I 0:03:39.680 --> 0:03:42.040 feel in the nineties, you know, radiation was such a 0:03:42.160 --> 0:03:45.400 negative thing, and nobody wanted radiation and the thing that 0:03:45.480 --> 0:03:48.920 made you sick. Yeah, exactly. Radiation can be pretty dangerous. 0:03:48.920 --> 0:03:52.320 They're basically these little invisible bullets flying through the universe, 0:03:52.440 --> 0:03:54.520 and they can do real damage. They can fly through 0:03:54.560 --> 0:03:57.000 your cells, they can bust up your DNA, they can 0:03:57.120 --> 0:04:00.480 cause you cancer. And so radiation definitely is something to 0:04:00.520 --> 0:04:02.520 think about and worry about. And it's one of these 0:04:02.560 --> 0:04:05.440 things in the world that's not visible to our naked 0:04:05.440 --> 0:04:08.760 eye yet turns out to be pretty important. So it's 0:04:08.760 --> 0:04:10.680 a key that tells us that there's a lot going 0:04:10.720 --> 0:04:13.440 on in the universe that we can't directly see. Yeah, 0:04:13.520 --> 0:04:16.160 So a big question is how do we even discover 0:04:16.640 --> 0:04:19.880 radiation or even come to believe it exists if it 0:04:20.000 --> 0:04:23.119 is in fact invisible. Yeah, it's part of this story 0:04:23.160 --> 0:04:26.080 of peeling back the nature of reality and figuring out 0:04:26.080 --> 0:04:28.360 that the universe has a lot of stuff going on. 0:04:28.839 --> 0:04:31.400 But to me, it's always fascinating to figure out how 0:04:31.440 --> 0:04:34.359 that came to be, how that understanding sort of filtering 0:04:34.400 --> 0:04:37.080 into human minds, because here we are standing on the 0:04:37.120 --> 0:04:40.120 shoulders of giants, understanding all these things about the way 0:04:40.160 --> 0:04:42.919 the world works. But this required a real shift in 0:04:42.960 --> 0:04:46.400 people's understanding of the nature of the universe. So I'm 0:04:46.400 --> 0:04:49.280 always super interested in those moments, like what was it 0:04:49.320 --> 0:04:52.920 to convinced people? What experiments did people do that revealed that, 0:04:53.080 --> 0:04:55.440 because I hope that will help us understand what experiments 0:04:55.440 --> 0:04:58.280 in the future might again change the way we think 0:04:58.320 --> 0:05:02.799 about the universe. Yeah. So usually people assign this discovery 0:05:02.839 --> 0:05:06.840 to Madame Curie and her experiments, but there's actually more 0:05:06.960 --> 0:05:09.520 to the story, right there is she did not, in 0:05:09.600 --> 0:05:13.000 fact discover radiation. She won a couple of Nobel prizes. 0:05:13.160 --> 0:05:15.799 She was quite a genius. She discovered a lot of stuff, 0:05:15.800 --> 0:05:19.000 but you can't give her credit for discovering radiation. It's 0:05:19.040 --> 0:05:22.800 a fascinating story. Well you can't even define it. I mean, sure, 0:05:23.279 --> 0:05:27.280 then nobody discovered radiation or everyone discovered that's right. The 0:05:27.279 --> 0:05:30.000 first little swimming organism that developed an eyeball, I supposed 0:05:30.040 --> 0:05:33.880 discovered radiation when it used photons to guide itself around 0:05:34.000 --> 0:05:36.640 the primordial soup on Earth. I suppose, yeah, right, like 0:05:36.720 --> 0:05:41.200 the first organism to use or detect light. Right, that 0:05:41.400 --> 0:05:44.280 definitely predates humanity. But I think we should focus on 0:05:44.320 --> 0:05:46.960 the kind of radiation we're talking about, which is you know, 0:05:47.120 --> 0:05:50.960 high energy particles or waves that come from like radioactive decay, 0:05:51.080 --> 0:05:53.560 things that are different from the normal kinds of radiation 0:05:53.640 --> 0:05:55.680 we used to live our lives. We're talking about a 0:05:55.800 --> 0:05:59.120 change in how we've understood the universe. Okay, so it's 0:05:59.160 --> 0:06:04.920 a invisible well, potentially dangerous and obviously very scientifically significant. 0:06:05.279 --> 0:06:08.880 But how was radiation discovered? That's a big question, and 0:06:08.920 --> 0:06:11.320 that's the question we're exploring today. So to the end 0:06:11.320 --> 0:06:20.560 the program, we'll be talking about how was radiation discovered? So, 0:06:20.560 --> 0:06:22.839 as usually, we were wondering how many people out there 0:06:22.960 --> 0:06:26.000 knew how radiation was discovered? So thank you to everybody 0:06:26.040 --> 0:06:29.400 who have volunteered their answers to these tricky physics questions 0:06:29.400 --> 0:06:33.000 without referring to any reference materials, Google or Being or 0:06:33.120 --> 0:06:36.039 ask Jeeves. And if you would like to participate in 0:06:36.200 --> 0:06:39.680 future Baseless Speculations for the podcast, please write to us 0:06:39.800 --> 0:06:42.520 two questions at Daniel and Jorge dot com. Maybe that 0:06:42.520 --> 0:06:45.440 should be the name of that website, Daniel Baseless speculation 0:06:45.520 --> 0:06:48.919 dot com. You might get a lot of hits. Yeah, exactly. 0:06:48.920 --> 0:06:51.159 We just pointed to our book every single time we 0:06:51.240 --> 0:06:53.640 have no idea. Dot com is the answer to all 0:06:53.680 --> 0:06:59.720 these questions. Oh, interesting, interesting marketing technique. Lure people in 0:07:00.160 --> 0:07:02.920 with a juicy website and then sell them a book. 0:07:03.080 --> 0:07:05.480 Yeah exactly. I think they call that click bait. So 0:07:05.560 --> 0:07:07.560 think about it for a second. If someone approached you 0:07:07.560 --> 0:07:10.400 and asked you if you knew how radiation was discovered, 0:07:10.680 --> 0:07:13.160 what would you say. Here's what people had to say. 0:07:13.360 --> 0:07:15.200 I have no idea, but I think it has something 0:07:15.200 --> 0:07:17.600 to do with Marie Curry playing around with some kind 0:07:17.600 --> 0:07:20.360 of radioactive substance and like X raying her hand or 0:07:20.400 --> 0:07:24.480 something like that. Radiation was discovered by Madame Cury. I 0:07:24.600 --> 0:07:29.400 just know that was discovered Marie Cury. I believe radiation 0:07:29.560 --> 0:07:32.480 was discovered by Marie Cury. I don't know how she 0:07:32.600 --> 0:07:37.240 did it. She was probably experimenting with what became known 0:07:37.240 --> 0:07:41.920 as radium and saw it glowing. I think radiation was 0:07:42.040 --> 0:07:47.080 discovered in the eighteen hundreds when some radioactive material uranium 0:07:47.960 --> 0:07:50.960 was glowing in the dark or was unusually hot. All right, 0:07:51.120 --> 0:07:53.800 it looks like Marie Curry and the Curys have a 0:07:53.800 --> 0:07:57.520 pretty good policies because most people went to them as 0:07:57.520 --> 0:08:02.040 the discoverers of radiation. Yeah, she definitely ensconced in popular 0:08:02.080 --> 0:08:05.600 culture as somebody deeply associated with radiation. And you know, 0:08:05.680 --> 0:08:08.679 she actually did have a good publicist late in her career. 0:08:08.760 --> 0:08:11.200 She did a whole tour of the United States giving 0:08:11.240 --> 0:08:14.240 talks all about radiation stuff. So she became quite famous 0:08:14.480 --> 0:08:17.920 and associated with radiation. So that has lasted up to 0:08:18.200 --> 0:08:20.840 the present day, almost a hundred years later. Right, Well, 0:08:20.960 --> 0:08:23.440 we don't want to take away anything that she did 0:08:23.560 --> 0:08:26.520 or that the Crease did. It's really more about definition. 0:08:26.600 --> 0:08:28.960 I think I think she discovered a particular type of 0:08:29.080 --> 0:08:33.400 radiation or I guess we'll get into that, but generally speaking, 0:08:33.440 --> 0:08:36.760 it kind of seems like radiation maybe is a broader 0:08:36.840 --> 0:08:39.600 concept than most people assume it is. There's definitely that, 0:08:39.679 --> 0:08:43.120 and she made important contributions and discovered particular kinds of 0:08:43.200 --> 0:08:46.480 radioactive elopments. Will dig into that, but you're right, radiation 0:08:46.559 --> 0:08:48.920 is a sort of a broader set of things. Radiation 0:08:48.960 --> 0:08:53.199 is not just uranium decays and shoots out deadly particles. 0:08:53.440 --> 0:08:56.560 There's a broader set of things. We consider radiation not 0:08:56.720 --> 0:09:00.640 just ordinary light. But it starts, for example, with X rays, 0:09:00.679 --> 0:09:04.040 Like X rays are just high energy photons, but we 0:09:04.120 --> 0:09:08.120 consider them radiation. Yeah, I guess you're saying earlier that 0:09:08.400 --> 0:09:12.000 any light is considered radiation. Even sound is considered radiation, 0:09:12.440 --> 0:09:15.120 even like heat, I guess heat is radiation. Yeah, exactly, 0:09:15.120 --> 0:09:17.400 you radiate heat. You run a lap and you get 0:09:17.400 --> 0:09:20.040 really hot, you are radiating heat out into the universe. 0:09:20.320 --> 0:09:23.200 And everything in the universe that has a temperature gives 0:09:23.240 --> 0:09:27.160 off heat, and so everything in the universe is radiating constantly. 0:09:27.280 --> 0:09:30.000 Radiation is everywhere. But that's sort of again the sort 0:09:30.000 --> 0:09:33.320 of technical physical term for it. When we talk about radiation, 0:09:33.559 --> 0:09:36.480 we think about sort of damaging radiation, radiation that's long 0:09:36.520 --> 0:09:39.600 been invisible to us and reveals something different about how 0:09:39.600 --> 0:09:42.360 the world works. And it was really crucial in understanding 0:09:42.400 --> 0:09:44.680 things like the nature of the atom and the deep 0:09:44.679 --> 0:09:47.360 structure of matter. Right, Well, we knew about light for 0:09:47.400 --> 0:09:49.520 a long time. I mean, it's it's kind of in 0:09:49.559 --> 0:09:52.440 the Bible, Daniel, that they'll be light. It was like 0:09:52.480 --> 0:09:55.040 the first thing is that a reference book. I wasn't 0:09:55.040 --> 0:09:59.520 familiar with that, you know, God at all. I think 0:09:59.520 --> 0:10:02.480 there's some rata for that one. It's probably the most 0:10:02.559 --> 0:10:06.160 impact factor of wall puplications in the history of man. Yeah, 0:10:06.200 --> 0:10:08.400 I submitted something, but it got rejected by the referees. 0:10:09.080 --> 0:10:12.040 So I mean of course, we've known about light for 0:10:12.080 --> 0:10:14.560 a long time, So I guess when when do you 0:10:14.640 --> 0:10:18.360 draw the line as us having discovered radiation, Like, is 0:10:18.400 --> 0:10:21.200 it x rays? Is that the first kind of you know, 0:10:21.600 --> 0:10:25.120 powerful kind of radiation invisible that we've discovered. Yeah, I 0:10:25.120 --> 0:10:27.839 think the discovery of X rays really marked the turning point. 0:10:28.240 --> 0:10:30.280 It's the time we discovered that there are ways to 0:10:30.440 --> 0:10:34.480 transmit energy or other kinds of light that are different 0:10:34.520 --> 0:10:36.679 from the kind of visible light we were familiar with. 0:10:37.000 --> 0:10:39.040 And this specifically was a kind of light that we 0:10:39.080 --> 0:10:42.800 saw could sort of pass through walls and pass through barriers, 0:10:43.120 --> 0:10:45.640 and so it really was doing something different from the 0:10:45.679 --> 0:10:48.040 kind of visible light we were familiar with. And that's 0:10:48.040 --> 0:10:50.640 exactly how it was discovered. I see, like, if you're 0:10:50.640 --> 0:10:52.960 shine a flashlight, it gets blocked by the wall. But 0:10:53.000 --> 0:10:55.920 if you shine an X ray tube at at a wall, 0:10:55.960 --> 0:10:57.720 it will go right through. It will go through most 0:10:57.760 --> 0:10:59.680 of it. Yeah, exactly. And that's why we call it, 0:10:59.720 --> 0:11:02.719 you know, X raying something because X rays passed through 0:11:02.760 --> 0:11:05.200 the soft tissue of your body, but not your bones, 0:11:05.480 --> 0:11:08.560 and so they reveal what's going on inside. And so 0:11:08.760 --> 0:11:11.120 radiation is interesting because they can do these things in 0:11:11.240 --> 0:11:14.440 visible light can't do. But also because it has this power, 0:11:14.679 --> 0:11:17.720 it penetrates and so it reveals what's the inside, all right, 0:11:17.760 --> 0:11:19.760 So then how do we discover X rays? So X 0:11:19.880 --> 0:11:24.280 rays discovered by this guy Runken. And this guy was 0:11:24.280 --> 0:11:26.520 a character. I think you'd like this. He actually was 0:11:26.640 --> 0:11:29.440 kicked out of high school as a student because he 0:11:29.559 --> 0:11:32.200 drew a caricature of one of his teachers, which is 0:11:32.240 --> 0:11:35.240 not very flattering, and so he's sort of a physicist 0:11:35.440 --> 0:11:38.400 and a cartoonist. I almost got exposed from my school 0:11:38.440 --> 0:11:41.199 for the exact same reason, actually exactly. I didn't this 0:11:41.280 --> 0:11:44.640 caricature one teacher, I did all of them. Well then 0:11:44.679 --> 0:11:47.600 maybe there's a Nobel prize in your future. Yeah, stay tuned. 0:11:48.360 --> 0:11:50.559 But he was doing experiments at the time with these 0:11:50.559 --> 0:11:53.679 things called Crooks tubes. We talked about these before because 0:11:53.679 --> 0:11:56.800 they were how electrons were discovered. They're basically just these 0:11:56.840 --> 0:12:00.160 glass tubes that are mostly have vacuum in them. You 0:12:00.160 --> 0:12:02.880 have an anode and a cathode with voltage across them, 0:12:02.920 --> 0:12:05.320 and so you pull electrons off. People have seen these 0:12:05.320 --> 0:12:08.640 seeing before and you get these beams, these glowing beams 0:12:08.679 --> 0:12:11.840 inside that look really cool because the electrons were like 0:12:12.120 --> 0:12:14.959 knocking off atoms and ionizing them, and people were doing 0:12:15.000 --> 0:12:17.240 lots of experiments with them trying to understand what they were. 0:12:17.480 --> 0:12:20.480 And again J. J. Thompson used them to discover the electrons. 0:12:21.000 --> 0:12:24.160 But Runkin was really interested in whether or not the 0:12:24.320 --> 0:12:27.960 rays that were being produced inside these tubes could pass 0:12:28.080 --> 0:12:30.200 through the glass. He was curious to see what they 0:12:30.200 --> 0:12:34.680 could get through. But these rays were originally electrons, like 0:12:34.679 --> 0:12:37.360 like a stream of electrons or or were they light? 0:12:37.640 --> 0:12:39.760 These were a stream of electrons and that's what J. J. 0:12:39.840 --> 0:12:42.840 Thompson discovered. But the glow that you saw that was 0:12:42.960 --> 0:12:45.760 visible light. And so the electrons would knock into a 0:12:45.800 --> 0:12:49.199 few atoms inside the tube, ionized them, they would give 0:12:49.240 --> 0:12:51.000 off some light, and then they would decay back to 0:12:51.040 --> 0:12:53.920 their ground state. So what people were sort of ooing 0:12:53.960 --> 0:12:57.680 and aweing over, we're seeing a beam of electrons exciting 0:12:57.720 --> 0:13:00.840 the gas inside the tube. Okay, but just clear the 0:13:00.840 --> 0:13:03.480 the X ray is not the electrons and X rays 0:13:03.559 --> 0:13:05.480 is a light beam, right, that's right. The X ray 0:13:05.600 --> 0:13:07.719 is not an electron electron as a particle, and X 0:13:07.880 --> 0:13:10.040 ray is a piece of light. Right, It's a photon 0:13:10.160 --> 0:13:13.120 of a specific energy. But this is what Runkin started 0:13:13.160 --> 0:13:15.360 with He started with these tubes and he was playing 0:13:15.360 --> 0:13:18.640 around with them, and he accidentally discovered that they also 0:13:18.800 --> 0:13:22.760 generate X rays, like along with the electrons or when 0:13:22.760 --> 0:13:25.520 the electrons hit stuff. So the electrons, one of the 0:13:25.520 --> 0:13:27.240 things they do is they generate a glow that you 0:13:27.240 --> 0:13:30.079 can see with your naked eye, but they also sometimes 0:13:30.120 --> 0:13:32.360 generate X rays, and we can get into the whole 0:13:32.360 --> 0:13:35.760 details of exactly how that happens, how they're accelerated and radios. 0:13:35.760 --> 0:13:39.040 But sometimes they generate visible light in our spectrum, and 0:13:39.120 --> 0:13:42.120 sometimes they generate photons that are higher energy, and these 0:13:42.160 --> 0:13:44.840 are X rays. So he was interested in understanding, like 0:13:45.280 --> 0:13:47.760 what is this thing generating? Can it pass through the 0:13:47.800 --> 0:13:50.320 glass walls of the tube. So what he did was 0:13:50.320 --> 0:13:53.880 he built a big black box, like a light proof box. 0:13:54.440 --> 0:13:57.240 And his idea was, I'm gonna put this box around 0:13:57.360 --> 0:14:00.200 my tube. I'm gonna see what light is show mind, 0:14:00.240 --> 0:14:03.320 and the inside of the box from this tube, so 0:14:03.360 --> 0:14:05.439 I can see sort of like you know what, light 0:14:05.520 --> 0:14:07.760 comes out of the tube and hits the side of 0:14:07.800 --> 0:14:11.600 the box. So I guess he wanted to know. He 0:14:11.600 --> 0:14:13.800 thought he was trapping the light that was coming from 0:14:13.800 --> 0:14:16.800 the Catherine tube, but actually he saw that the light 0:14:16.920 --> 0:14:19.560 kind of leaked outside of it. Yeah, exactly, he turned 0:14:19.600 --> 0:14:21.680 off the lights in his laboratory just to sort of 0:14:21.720 --> 0:14:23.680 like get things warmed up, and he was going to 0:14:23.800 --> 0:14:26.000 look inside the box to see if he could see 0:14:26.040 --> 0:14:29.000 like light on the inside walls of the box. But 0:14:29.120 --> 0:14:31.520 before he did that, he noticed that he saw this 0:14:31.680 --> 0:14:35.640 weird light outside the box on the wall of his laboratory, 0:14:35.800 --> 0:14:38.040 and he was like, what's that over there? And it 0:14:38.040 --> 0:14:40.280 turns out he had a special sort of screen over 0:14:40.320 --> 0:14:43.240 there just happened to be in the right location that 0:14:43.280 --> 0:14:46.600 can receive X rays and glows when it hits X rays, 0:14:47.040 --> 0:14:49.560 And so he discovered that the light doesn't just go 0:14:49.680 --> 0:14:53.000 through the glass. It also went through his box all 0:14:53.000 --> 0:14:54.560 the way out to the side of his lab and 0:14:54.640 --> 0:14:57.320 hit this special screen. So it was quite by accident 0:14:57.360 --> 0:15:00.760 that he discovered these X rays. Whoa was a special 0:15:00.800 --> 0:15:03.200 screen that he just had that that seems like such 0:15:03.200 --> 0:15:06.960 an accidental discovery. It's totally an accidental discovery. And it's 0:15:06.960 --> 0:15:10.520 a special screen covered with a material that phosphoresces, so 0:15:10.560 --> 0:15:13.400 it absorbs photons at one wavelength and then it gives 0:15:13.400 --> 0:15:16.240 off photons at a different wavelength. So it's a wavelength 0:15:16.320 --> 0:15:18.800 shifting effect. And this is the kind of thing we 0:15:18.840 --> 0:15:20.840 do all the time in physics these days. We absorb 0:15:21.080 --> 0:15:23.560 photons of one thing and it give off photons of 0:15:23.600 --> 0:15:26.360 another color. So he happened to have a screen covered 0:15:26.360 --> 0:15:29.880 in this material. It was a barrio phosphorescent material that 0:15:29.920 --> 0:15:32.720 could absorb X rays and glow in the visible light. 0:15:33.080 --> 0:15:35.520 And he was like, what's that over there, and did 0:15:35.520 --> 0:15:38.120 a bunch of experiments, and he discovered that it could 0:15:38.160 --> 0:15:40.640 pass through his box, and it could pass through lots 0:15:40.680 --> 0:15:43.400 of other things, but that it wouldn't pass through metal, 0:15:43.480 --> 0:15:46.600 for example. Now, was this the first time that, you know, 0:15:46.760 --> 0:15:50.320 humans kind of got the idea that light can go 0:15:50.560 --> 0:15:53.200 through things, or did we already kind of know that 0:15:53.240 --> 0:15:56.000 there are things in nature that can go through things? Now, 0:15:56.000 --> 0:15:58.080 this is the first time we understood that light could 0:15:58.080 --> 0:16:00.920 pass through something that we thought was the wise solid. 0:16:01.440 --> 0:16:04.040 And famously, the first X ray picture he ever took 0:16:04.320 --> 0:16:06.960 was of his wife's hand, and you could see her 0:16:07.000 --> 0:16:09.640 hand with its wedding ring on it, and he showed 0:16:09.640 --> 0:16:11.040 it to her and he thought, this is gonna be 0:16:11.040 --> 0:16:13.800 so romantic and awesome. She was actually really creeped out, 0:16:14.040 --> 0:16:16.160 and she thought oh my gosh, I've seen my own death, 0:16:16.400 --> 0:16:19.200 because she'd seemed like her own skeleton inside her hand. 0:16:19.800 --> 0:16:22.040 And I think it really changed the way people felt 0:16:22.080 --> 0:16:25.800 about like the solidity of stuff. Right, you think of 0:16:25.840 --> 0:16:29.400 yourself as solid and opaque, but you're not. You're transparent 0:16:29.640 --> 0:16:32.640 in some wavelengths of light, in your opaque in other 0:16:32.720 --> 0:16:35.920 wavelengths of light. So then from that they they invented 0:16:36.240 --> 0:16:38.920 X rays, you know, for medical purposes. Yeah, things happened 0:16:39.000 --> 0:16:42.760 really fast because people very quickly understood how powerful this was. 0:16:42.800 --> 0:16:44.960 Like you could see broken bones inside the body, or 0:16:45.000 --> 0:16:47.680 you could see if you're tiled, it's swallowed something metal, 0:16:48.080 --> 0:16:50.640 and so just seeing inside the body without having to 0:16:50.720 --> 0:16:54.720 cut it open was immediately and enormously powerful. And within 0:16:54.760 --> 0:16:57.680 a year people were using it in hospitals. And it 0:16:57.720 --> 0:17:00.120 wasn't hard to make X rays, like Crookes tubes were 0:17:00.000 --> 0:17:02.720 a thing that already existed, and so the technology sort 0:17:02.760 --> 0:17:05.560 of was all around. It just took the right combination 0:17:05.640 --> 0:17:07.399 of knowing what to do and how to do it. 0:17:08.200 --> 0:17:11.159 And he went on to win the first Nobel Prize 0:17:11.160 --> 0:17:14.120 in physics just a few years later. Really the first one, 0:17:14.960 --> 0:17:17.760 the first one, yeah, exactly, and you know it sort 0:17:17.800 --> 0:17:20.240 of satisfies all the requirements. It teaches you something deep 0:17:20.280 --> 0:17:23.240 about the universe and also made a very big impact 0:17:23.320 --> 0:17:26.520 on humanity. Wo and it sounds like it was really 0:17:26.520 --> 0:17:31.080 more about discovering the screen is a combination. You have 0:17:31.160 --> 0:17:32.919 to have the radiation and you have to have a 0:17:32.960 --> 0:17:36.280 screen that can receive it. Right, X rays are invisible 0:17:36.320 --> 0:17:38.399 to us, and so if they can just fly through 0:17:38.400 --> 0:17:40.480 the universe and fly through a wall to see them, 0:17:40.680 --> 0:17:42.600 you have to put something in their path that they 0:17:42.640 --> 0:17:46.600 will interact with and that transform that information into something 0:17:46.840 --> 0:17:50.800 your eyeballs can see. All right, Well, that's X ray radiation, 0:17:50.960 --> 0:17:53.880 which is light radiation. But I guess the more popular 0:17:53.960 --> 0:17:56.919 kind of radiation, or at least in people's consciousness, is 0:17:57.040 --> 0:18:00.560 particle radiation. And that's where the curies come in. And 0:18:00.600 --> 0:18:03.520 so let's get into that kind of radiation. But first, 0:18:03.600 --> 0:18:18.560 let's take a quick break. All right, we're talking about 0:18:19.280 --> 0:18:22.800 radiation and how it was discovered and how you should 0:18:22.880 --> 0:18:26.280 probably wear sunscreen when you're outside and near particle colliders? 0:18:26.359 --> 0:18:31.119 Would that help Daniel and near physicists? Probably because they 0:18:31.160 --> 0:18:34.159 they're so shiny and beaming. Well, they just had to 0:18:34.160 --> 0:18:37.399 do these crazy experiments which sometimes you know, do damage 0:18:37.440 --> 0:18:40.280 their own help. All right, Well, I guess we talked 0:18:40.280 --> 0:18:42.680 about X ray radiation, which which is really just light 0:18:43.000 --> 0:18:46.640 at higher frequencies that can pass through things, and some 0:18:46.640 --> 0:18:51.000 people associate that with radiation. But maybe the more common 0:18:51.000 --> 0:18:53.760 type of radiation that people think of is kind of 0:18:53.800 --> 0:18:56.880 the dangerous kind, I guess, the nuclear kind, and that's 0:18:57.000 --> 0:18:59.680 more like particle radiation. Yeah, and X rays, of course 0:18:59.720 --> 0:19:02.840 also dangerous. They can deposit a lot of energy in 0:19:02.920 --> 0:19:05.960 your skin, and they can cause cancer and UV radiation 0:19:06.000 --> 0:19:08.840 all that stuff, So it's definitely dangerous. But particle radiation 0:19:09.040 --> 0:19:11.720 also very dangerous and more famous because I think of 0:19:11.760 --> 0:19:16.040 the radioactive decays involved in nuclear physics, for example. But 0:19:16.359 --> 0:19:21.280 particle radiation was discovered pretty soon after particles were discovered. Remember, 0:19:21.280 --> 0:19:25.119 the whole idea of a particle didn't really exist until J. J. 0:19:25.200 --> 0:19:28.720 Thompson discovered the electron in the late eighteen hundreds. You know, 0:19:28.800 --> 0:19:31.880 this notion that everything was made out of tiny little bits, 0:19:31.880 --> 0:19:34.359 and we could find those things and we could associate 0:19:34.600 --> 0:19:37.320 like a tiny dot in space with mass and with 0:19:37.359 --> 0:19:40.840 other quantities. This is a whole new idea in physics 0:19:41.080 --> 0:19:43.159 at the time. It's not something which had existed for 0:19:43.200 --> 0:19:45.600 a long time right before, Like light was just like 0:19:45.640 --> 0:19:48.760 a beam, right, like pure energy kind of. Yeah, the 0:19:48.800 --> 0:19:51.600 wave properties of light were dominant, and people thought about 0:19:51.760 --> 0:19:54.960 light as a wave. They thought about matter and waves existing. 0:19:55.280 --> 0:19:57.040 But the whole idea that things were made out of 0:19:57.040 --> 0:19:59.680 tiny particles, or that these tiny particles could fly through 0:19:59.720 --> 0:20:04.000 space invisibly and hurt you, for example, this was brand new, 0:20:04.280 --> 0:20:07.080 but it was discovered pretty soon after the electron was 0:20:07.119 --> 0:20:11.320 discovered again in the late eighteen hundreds, like the next year. Yeah, 0:20:11.359 --> 0:20:14.000 and it was spurred by the discovery of X rays. 0:20:14.040 --> 0:20:16.240 Like everybody in the world was very excited about the 0:20:16.280 --> 0:20:18.920 X ray discovery made a huge wave in the world 0:20:18.920 --> 0:20:27.760 of physics. Pun definitely intended and I thought it was unintentional. No, 0:20:28.040 --> 0:20:30.480 And this bit about the screen that you latched onto. 0:20:30.600 --> 0:20:33.680 This guy Beck Carrell, he also was really excited about that. 0:20:33.880 --> 0:20:37.199 He thought it's really cool for something to absorb energy 0:20:37.240 --> 0:20:40.400 in one wavelength and emit in another. To absorb one 0:20:40.480 --> 0:20:43.080 kind of energy and emit another kind of thing. It's 0:20:43.119 --> 0:20:46.439 called luminescence. And he thought he was really exciting and 0:20:46.480 --> 0:20:48.879 he wanted to follow up in this and make also 0:20:49.000 --> 0:20:52.040 some kind of crazy discovery and he came from a 0:20:52.080 --> 0:20:55.040 long line of physicists people have been studying this sort 0:20:55.080 --> 0:20:58.159 of kind of thing of generation of heat and energy. 0:20:58.680 --> 0:21:01.240 So he did a series of experiments with uranium crystals 0:21:01.359 --> 0:21:04.159 and he was the first to discover particle radiation. So 0:21:04.200 --> 0:21:07.800 he actually came well before the curies. So interesting. Well, 0:21:07.840 --> 0:21:11.120 apparently his father was also a physicist and a radiation 0:21:11.160 --> 0:21:14.360 physicist too. That's right. He actually came from several generations 0:21:14.359 --> 0:21:16.639 of physicists and they all had the same job. They 0:21:16.680 --> 0:21:19.040 all had like the same chair in the head of 0:21:19.080 --> 0:21:21.879 the natural science department in Paris, and so it was 0:21:21.920 --> 0:21:25.320 sort of like a hereditary position almost. He's like a 0:21:25.440 --> 0:21:28.600 legacy physicist in France. So his father looked into radiation, 0:21:28.640 --> 0:21:31.080 but he didn't discover it. His father also had been 0:21:31.080 --> 0:21:35.600