WEBVTT - The Matter of Everything, with Suzie Sheehy 0:00:03.040 --> 0:00:07.040 Welcome to Stuff to Blow Your Mind, a production of iHeartRadio. 0:00:13.240 --> 0:00:16.520 Hello, and welcome to the Stuff to Blow Your Mind podcast. 0:00:16.720 --> 0:00:19.560 My name is Joe McCormick. My regular co host, Robert 0:00:19.640 --> 0:00:21.800 Lamb is not with me today, but he'll be joining 0:00:21.800 --> 0:00:25.160 again next time. Today's episode is going to be an interview. 0:00:25.400 --> 0:00:28.840 This is a conversation I had with the accelerator physicist 0:00:28.920 --> 0:00:33.200 and author Susie Sheehy about her recent book The Matter 0:00:33.360 --> 0:00:38.800 of Everything, How Curiosity, Physics and Improbable Experiments Changed the World. 0:00:39.240 --> 0:00:42.040 Susie's publisher sent us a copy of this book for review, 0:00:42.080 --> 0:00:44.559 and I really loved it. So it's a history of 0:00:44.760 --> 0:00:48.640 modern physics experiments from Runken's cathode ray tube and the 0:00:48.640 --> 0:00:51.199 discovery of X rays all the way up to the 0:00:51.360 --> 0:00:55.240 Large Hadron Collider and beyond. And what makes this book 0:00:55.320 --> 0:00:58.320 really special, in my opinion, is that it focuses not 0:00:58.400 --> 0:01:03.400 just on theoretical advancements, but on the labor of designing 0:01:03.480 --> 0:01:07.959 and building experiments to test those new ideas. And because 0:01:08.000 --> 0:01:12.000 it illuminates so much about the experimental apparatus behind the 0:01:12.040 --> 0:01:15.000 progress of science, I think this book has a lot 0:01:15.040 --> 0:01:18.600 of interesting things to say, not just about the history 0:01:18.600 --> 0:01:21.240 of our quest to understand matter and energy, but about 0:01:21.280 --> 0:01:25.679 epistemology and critical thinking and work to read from her 0:01:25.760 --> 0:01:30.280 author bio. Susie Shehe is a physicist, science communicator and 0:01:30.440 --> 0:01:33.720 academic who divides her time between her research groups at 0:01:33.720 --> 0:01:37.360 the University of Oxford and the University of Melbourne. Her 0:01:37.360 --> 0:01:42.000 research addresses both curiosity driven and applied areas, and is 0:01:42.080 --> 0:01:48.360 currently focused on developing new particle accelerators for applications in medicine. Again, 0:01:48.440 --> 0:01:51.560 the book is called The Matter of Everything and I 0:01:51.560 --> 0:01:53.760 guess that does it. For the introduction, Here is my 0:01:54.120 --> 0:01:59.080 interview with Suzie Shehe. Susi Shehey, Welcome to the podcast. 0:01:59.440 --> 0:02:00.680 Thanks Jen, nice to be here. 0:02:01.120 --> 0:02:04.200 So I wanted to start off talking about how I 0:02:04.240 --> 0:02:06.360 think a lot of the histories of physics that I've 0:02:06.400 --> 0:02:10.680 read focus more on the theoretical side, like what led 0:02:10.720 --> 0:02:14.680 to the insights theoretical physicists had, how they dreamed up 0:02:14.720 --> 0:02:17.600 their models, and things like that. I really loved that 0:02:17.680 --> 0:02:22.640 this book was intensely focused on the experimental component of physics, 0:02:22.680 --> 0:02:26.040 and there was a lot of focus on the details 0:02:26.160 --> 0:02:29.960 of the experiments, how they did it, and understanding experiments 0:02:30.000 --> 0:02:34.720 as human projects operating under constraints. What kind of insights 0:02:34.760 --> 0:02:37.239 do you think are revealed by looking at the history 0:02:37.240 --> 0:02:42.000 of particle physics through the experimental lens, in particular, especially 0:02:42.080 --> 0:02:45.160 things that you might miss if you only talk about 0:02:45.160 --> 0:02:47.320 physics as a sort of history of ideas. 0:02:48.120 --> 0:02:50.799 Yeah, you phrased that so beautifully in there by the way, 0:02:51.080 --> 0:02:55.839 the importance of experiments. So I'm an experimental physicist, right. 0:02:55.919 --> 0:02:59.280 So one of the things that I observed when I 0:02:59.320 --> 0:03:03.200 sort of start on the journey of writing this book 0:03:04.080 --> 0:03:08.560 was that almost every other comparable book was written by 0:03:08.600 --> 0:03:13.120 a theoretical physicist, And so you'd get these stories where 0:03:13.520 --> 0:03:18.360 you get this wonderful insight of say, either Einstein or 0:03:18.360 --> 0:03:21.880 one of the key theoretical physicists of the age, And 0:03:21.960 --> 0:03:24.840 it was like it was almost like they came to 0:03:24.880 --> 0:03:29.320 these insights purely from their own personal genius, right. And 0:03:29.360 --> 0:03:31.360 this was the story of physics that I was taught 0:03:31.520 --> 0:03:34.520 pretty much when I did at university as well. But 0:03:34.600 --> 0:03:36.760 it was also the story that comes across in these books. 0:03:36.760 --> 0:03:39.120 And I don't know whether this is just like an egotistical, 0:03:39.160 --> 0:03:42.880 aggrandizing thing that people do. Certainly these people are very 0:03:43.000 --> 0:03:46.520 very smart, right, but they're not islands and I think 0:03:46.520 --> 0:03:49.440 that's one of the key insights that you get from 0:03:49.480 --> 0:03:52.160 taking a different approach to looking at the history and 0:03:52.200 --> 0:03:55.920 looking more at the experiments and more at the wider 0:03:56.000 --> 0:04:00.480 view of how physics progresses. And I think any theoretical 0:04:00.480 --> 0:04:03.520 physicists today would all and hopefully also though is historically, 0:04:03.720 --> 0:04:06.440 would admit that, you know, their work is nothing without 0:04:06.440 --> 0:04:08.960 the work of the experimentalists, because at the end of 0:04:08.960 --> 0:04:11.560 the day, physics is a subject which is trying to 0:04:11.600 --> 0:04:16.360 describe the universe, our actual universe, not just some theoretical 0:04:16.440 --> 0:04:19.640 mathematical universe that doesn't really exist. And so the only 0:04:19.800 --> 0:04:23.200 way to meet those two things in the middle is 0:04:23.240 --> 0:04:25.480 through experiment. You have to actually get out there and 0:04:26.960 --> 0:04:31.240 test nature. But that's where a lot of people, i 0:04:31.279 --> 0:04:34.719 think naively think that we just we know what we're 0:04:34.720 --> 0:04:36.680 doing with that that we just we can go out 0:04:36.680 --> 0:04:39.200 there and build an experiment and test or find this thing, 0:04:39.680 --> 0:04:42.560 and that once the theorist predicts it, that it's a 0:04:42.600 --> 0:04:46.000 straightforward journey. So that's I think the next sort of 0:04:46.080 --> 0:04:48.960 key insight there is that it is not a straightforward 0:04:49.040 --> 0:04:53.440 journey to discover and uncover the nature of our universe, 0:04:53.520 --> 0:04:56.440 especially on these tiny scales. That we're looking at that 0:04:56.480 --> 0:04:58.839 are so much smaller than what we can see with 0:04:58.880 --> 0:05:02.520 our own eyes. And so when you delve into that, then, 0:05:02.560 --> 0:05:06.279 as you say, there's this detailed development of how experiments 0:05:06.279 --> 0:05:10.919 actually work, whether that's electronically, whether that's because they require 0:05:11.240 --> 0:05:15.080 two thousand people with different expertise to actually put them together, 0:05:16.040 --> 0:05:19.599 and also just that co development of technology and instrumentation 0:05:20.320 --> 0:05:24.480 along with the development of ideas and insights about the universe, 0:05:24.520 --> 0:05:28.200 and it really is sort of a synergistic development. So 0:05:28.200 --> 0:05:31.400 there's I think a few things there about throwing out 0:05:31.400 --> 0:05:35.480 the lone genius stereotype, managing to recognize how important it 0:05:35.520 --> 0:05:38.480 is that we actually interact in the real world and 0:05:38.520 --> 0:05:42.280 do experiments, and then just the unpredictable nature of doing 0:05:42.279 --> 0:05:44.560 those experiments at all. 0:05:44.600 --> 0:05:47.839 You mentioned in the book that some people think that 0:05:48.279 --> 0:05:52.880 Diract's equation is the most beautiful equation in all physics. 0:05:52.920 --> 0:05:55.080 I'm sure that people who have a lot of math 0:05:55.120 --> 0:05:58.320 and physics knowledge would consider that subjective, but it made 0:05:58.360 --> 0:06:01.520 me curious about the different ways that instruments within science 0:06:01.560 --> 0:06:05.280 can be perceived not only as useful or accurate, but 0:06:05.400 --> 0:06:09.120 sometimes esthetically beautiful. So I was wondering about the other 0:06:09.200 --> 0:06:11.640 side of that, as an experimentalist, do you have an 0:06:11.680 --> 0:06:16.000 opinion on what is the most beautiful experiment in all 0:06:16.000 --> 0:06:18.960 of physics? Or do you have at least a few candidates? 0:06:19.440 --> 0:06:24.160 Oh, that's nice. Yeah, I think I definitely appreciate the 0:06:24.200 --> 0:06:27.919 beauty of a well designed experiment that can sort of 0:06:28.000 --> 0:06:31.760 cut through all the background noise and find the thing 0:06:31.800 --> 0:06:35.479 that they're looking for. But I'd say I appreciate the 0:06:35.480 --> 0:06:38.640 beauty of an experiment in multiple dimensions though, right, so 0:06:38.680 --> 0:06:42.520 you can. I can appreciate the beauty of an experiment 0:06:42.520 --> 0:06:47.080 which serendipitously found something that it didn't expect, as well 0:06:47.120 --> 0:06:49.679 as appreciating, you know, the sort of really well designed, 0:06:49.839 --> 0:06:53.120 very specific experiment. But now you're putting me on the 0:06:53.120 --> 0:06:55.479 spot if you ask me what my favorite experiment was. 0:06:55.520 --> 0:06:58.159 I mean, in the book, I really focus on twelve 0:06:58.240 --> 0:07:02.440 key experiments that I chose from what could have been thousands, honestly, 0:07:03.880 --> 0:07:08.719 and focused on how those had contributed to our knowledge 0:07:08.760 --> 0:07:11.760 of particle physics over about the last one hundred and 0:07:11.800 --> 0:07:15.840 twenty years. And I think it's easier probably for me 0:07:15.920 --> 0:07:18.400 to choose a favorite from the earlier ones of those 0:07:18.480 --> 0:07:21.160 because they're smaller. It's easier to understand all the different 0:07:21.280 --> 0:07:26.120 parts of the experiment. And so in that sense, in 0:07:26.160 --> 0:07:29.360 a beauty and esthetic appreciation sense, I think I'm going 0:07:29.400 --> 0:07:33.200 to say the cloud chamber. And this was developed in 0:07:33.240 --> 0:07:38.120 the early nineteen hundreds by a physicist named CITR Wilson, 0:07:38.240 --> 0:07:42.320 Charles Wilson, whose first love was actually meteorology, but he 0:07:42.440 --> 0:07:45.000 was working in the Cavender just Labin, Cambridge in the UK, 0:07:45.720 --> 0:07:48.840 alongside all the people doing all the early work in radioactivity, 0:07:48.920 --> 0:07:52.560 so he was very well versed in radioactivity and those ideas. 0:07:53.560 --> 0:07:56.160 But he invented this chamber originally to try and study 0:07:56.200 --> 0:08:00.200 clouds and the interaction of light and electricity in the atmosphere. 0:08:00.720 --> 0:08:04.720 And then he later realized when someone held an X 0:08:04.800 --> 0:08:07.160 ray tube, well, he and a colleague held an X 0:08:07.240 --> 0:08:09.360 ray tube to the side of it, that he could 0:08:09.440 --> 0:08:13.480 see the passage of radiation through this chamber, which had 0:08:13.480 --> 0:08:15.880 a sort of in his case water vapor and nowadays 0:08:15.880 --> 0:08:20.040 we use alcohol vapors, and these little trails would form 0:08:20.080 --> 0:08:24.480 like little tracts of cloud as the radiation went through 0:08:24.520 --> 0:08:27.000 and left a little bit of energy inside the chamber. 0:08:27.560 --> 0:08:30.160 And I find this beautiful because it's really the first 0:08:30.200 --> 0:08:34.480 time as a species that we get to visualize radiation. 0:08:34.640 --> 0:08:37.839 We get to visualize this thing which is otherwise extremely 0:08:39.920 --> 0:08:44.439 abstract and difficult to understand, and now we're seeing its 0:08:44.440 --> 0:08:47.520 effects almost in real time, so you can photograph as 0:08:47.679 --> 0:08:52.280 particles pass through. And then we get and I think 0:08:52.320 --> 0:08:55.000 the beauty comes in because it's this lovely interaction between 0:08:55.000 --> 0:08:58.080 our own capacities as humans and the development of a 0:08:58.120 --> 0:09:00.840 new instrumentation. Because then you can take you can leave 0:09:00.880 --> 0:09:03.800 these chambers up on mountains, so you can take photographs 0:09:03.840 --> 0:09:07.600 of the interactions there, and from that we discover lots 0:09:07.640 --> 0:09:12.720 of new things, including we discover antimatter for the first time. 0:09:13.400 --> 0:09:16.839 So the positron is the opposite version of the electron, 0:09:17.280 --> 0:09:19.560 and when they come together they annihilate. But they can 0:09:19.559 --> 0:09:23.360 also be produced in pairs electron positron pairs. And there 0:09:23.400 --> 0:09:29.120 were positrons detected by a guy called Karl Anderson in 0:09:29.200 --> 0:09:33.600 the US, and he discovered them in his experiments before 0:09:33.720 --> 0:09:36.840 he'd read about Direct's beautiful equation. I'm coming back to 0:09:36.840 --> 0:09:40.160 the equation again now. He actually wasn't aware of Dirac's work, 0:09:40.160 --> 0:09:43.079 which was published in nineteen twenty nine, but in nineteen 0:09:43.240 --> 0:09:46.680 thirty two he'd built this enormous chamber with this huge 0:09:46.679 --> 0:09:48.920 magnet around it and legged it up a mountain and 0:09:49.080 --> 0:09:52.480 discovered this type of anti matter. And I find that 0:09:53.360 --> 0:09:56.920 really beautiful because then he's literally able to use our 0:09:56.960 --> 0:10:01.040 internal sort of track recognition, our pattern finding system, our 0:10:01.080 --> 0:10:04.320 brain to look at the photographs and actually see that 0:10:04.320 --> 0:10:07.400 there's something new there. And there were other particles discovered 0:10:07.440 --> 0:10:09.600 later as well, the new one being a key one, 0:10:09.640 --> 0:10:13.120 which is a heavy version of an electron, and it 0:10:13.200 --> 0:10:16.280 was really the instrument of choice for many many years 0:10:16.280 --> 0:10:19.640 in the field, and it came from a meteorologists. So 0:10:19.800 --> 0:10:21.640 I don't know, there's something in that story for me 0:10:21.679 --> 0:10:24.840 which is just beautiful about how we can use our 0:10:25.000 --> 0:10:30.000 creativity and sort of reuse of ideas in adjacent fields 0:10:30.040 --> 0:10:32.000 to really make amazing discoveries. 0:10:32.559 --> 0:10:35.679 Yeah. I love that example too, And there's a kind 0:10:35.720 --> 0:10:38.480 of beauty and a kind of lightness and elegance to 0:10:38.520 --> 0:10:43.760 it that in a way seems contrasted by other experiments 0:10:43.760 --> 0:10:48.440 you described that are also incredibly important and wonderful stories 0:10:48.480 --> 0:10:52.240 to understand, Like one that stands sort of opposite it 0:10:52.280 --> 0:10:55.280 in my mind is the story of Ernest Lawrence's team 0:10:55.320 --> 0:10:59.240 and their cyclotron and this chapter struck me as interesting 0:10:59.240 --> 0:11:01.880 in part because I think this is the one where 0:11:01.880 --> 0:11:06.440 you illuminate a history of what struck me as interesting. 0:11:06.520 --> 0:11:10.760 Mistakes like you mentioned a faulty reading from an accelerator 0:11:10.800 --> 0:11:13.480 experiment due to I think it was like deuteron coding 0:11:13.480 --> 0:11:16.319 on target elements. Please correct me if I'm getting this wrong. 0:11:16.679 --> 0:11:19.160 And also an incident where they accidentally made the whole 0:11:19.240 --> 0:11:24.079 lab radioactive without realizing it, which interfered with their measurements 0:11:24.080 --> 0:11:27.520 on on a Geiger counter like device. So what is 0:11:27.559 --> 0:11:32.280 the role of error and making a mess in scientific experiments? 0:11:33.200 --> 0:11:35.160 Do you know? I've been thinking about this more since 0:11:35.240 --> 0:11:39.040 writing the book, and I think we don't. I think 0:11:39.040 --> 0:11:41.600 we don't acknowledge the role of error and failure enough 0:11:41.679 --> 0:11:43.480 in science. In fact, we try and cover it up. 0:11:43.559 --> 0:11:46.040 It's a huge there's a huge issue in fact with 0:11:46.400 --> 0:11:49.480 if I failed experiments not being published, and in some fields 0:11:49.520 --> 0:11:53.160 like medicine, that's that's a huge issue. Actually in physics 0:11:53.200 --> 0:11:56.200 it's less of an issue, but it still happens. But 0:11:56.360 --> 0:11:59.920 Ernest Lawrence's example of the cyclotone is a fantastic example 0:12:00.480 --> 0:12:04.720 where by sort of realizing their mistakes and their errors, 0:12:05.000 --> 0:12:08.079 they really made progress in their understanding. So, as you say, 0:12:08.200 --> 0:12:12.680 they developed this particle accelerator, this circular machine, and then 0:12:13.600 --> 0:12:16.440 over time they realized that they're not seeing the results 0:12:16.480 --> 0:12:20.200 that they think they should be seeing because, for example, 0:12:20.240 --> 0:12:23.960 in one situation, basically everything had become radioactive and so 0:12:24.000 --> 0:12:26.160 all of their measurement devices were just picking up all 0:12:26.200 --> 0:12:28.800 the background radiation and not the radiation they were trying 0:12:28.840 --> 0:12:32.280 to look for. But that helped them understand what was 0:12:32.320 --> 0:12:35.160 happening in the machine as it was accelerating, and they 0:12:35.160 --> 0:12:37.439 missed a number of key discoveries that were made by 0:12:37.480 --> 0:12:40.600 other research groups around the world, but they didn't mind 0:12:40.600 --> 0:12:43.880 too much. And Lawrence sort of had this mindset which 0:12:43.920 --> 0:12:47.040 is relevant to the question of errors and failures, which is, 0:12:47.240 --> 0:12:48.920 you know, he sort of would like to say, there's 0:12:48.960 --> 0:12:51.520 research enough for everyone, or there's discovery enough for everyone. 0:12:51.960 --> 0:12:54.320 And so he was this big believer that he was 0:12:54.400 --> 0:12:57.960 quite quite a futurist, I guess because at the start 0:12:58.000 --> 0:13:00.120 of his career he was I think late to in 0:13:00.120 --> 0:13:03.520 his early thirties when he first invented the cyclotron, and 0:13:03.640 --> 0:13:06.720 he invented it because he couldn't see a path of 0:13:06.760 --> 0:13:10.320 the existing technology. To the end of his career even 0:13:10.520 --> 0:13:12.040 you know, he was sort of looking thirty years in 0:13:12.080 --> 0:13:15.400 the future, going, well, these technologies are just they're going 0:13:15.440 --> 0:13:18.040 to be outdated by the time I get to that point, 0:13:18.280 --> 0:13:19.920 so I'm going to have to invent something new to 0:13:19.920 --> 0:13:23.840 give myself, you know, a path of growth through my career. 0:13:24.080 --> 0:13:26.080 And boy did he get it, you know, he really 0:13:26.559 --> 0:13:29.319 The cycloton was an incredible invention and they're still built 0:13:29.360 --> 0:13:33.880 today in hospitals to generate radioisotopes for medical procedures, which 0:13:33.880 --> 0:13:38.200 is very, very useful. But obviously along the way he 0:13:38.280 --> 0:13:41.479 could be perceived at having failed to make key discoveries 0:13:41.880 --> 0:13:45.920 in physics. So I think induced radioactivity was one of 0:13:45.960 --> 0:13:48.520 the ones that he missed actually, and was found by 0:13:48.640 --> 0:13:55.920 Julio and Currie in France. That's Marie Kirey's daughter, arenar Kiri. 0:13:57.640 --> 0:13:59.840 So I've been thinking about this since writing the book, 0:14:00.320 --> 0:14:02.240 and I think I'd like to make the analogy with 0:14:03.679 --> 0:14:06.439 in the arts, right, So, if you have a creative 0:14:06.480 --> 0:14:10.480 practice in the arts, failure is an error. It's just 0:14:10.480 --> 0:14:12.839 an inherent part of it. And it's also very much 0:14:12.880 --> 0:14:16.120 acknowledged that by failing or making an error, you may 0:14:16.280 --> 0:14:18.920 just stumble upon something new, a new way of doing 0:14:18.960 --> 0:14:23.080 something a new invention. I'm even thinking in the culinary world, 0:14:23.120 --> 0:14:26.920 you know. I know of a chef who now runs 0:14:27.120 --> 0:14:30.560 a three Michelin starred restaurant in the UK, and one 0:14:30.600 --> 0:14:33.520 day he accidentally dropped hot coal into a vat of 0:14:33.520 --> 0:14:38.680 cooking oil, and so they later, you know, decided to 0:14:38.680 --> 0:14:40.960 taste it and see how it tasted, and it tastes 0:14:41.000 --> 0:14:43.720 it amazing, and he uses it in his signature dishes 0:14:43.760 --> 0:14:46.840 in a three Michelin starred restaurant now. And I love 0:14:46.920 --> 0:14:50.960 those stories of where errors lead you to new things 0:14:50.960 --> 0:14:53.880 and new ideas. And I do think in science we 0:14:54.280 --> 0:14:56.280 shy away a little bit from that, or we like 0:14:56.320 --> 0:14:58.040 to sort of cover it up and then we publish 0:14:58.040 --> 0:15:00.760 a paper that says the story was a linear one. 0:15:00.760 --> 0:15:04.400 And you know, we made all these discoveries, and in 0:15:04.520 --> 0:15:07.800 digging into the history of these experiments, which were so 0:15:07.920 --> 0:15:12.760 critical in understanding particle physics, I did discover that there 0:15:12.840 --> 0:15:17.040 was probably more failure than even I expected. And as 0:15:17.080 --> 0:15:20.560 an experimentalist myself, I've just come to accept that I 0:15:20.600 --> 0:15:23.160 often don't fully know what I'm doing because no one 0:15:23.200 --> 0:15:26.360 has ever tried to do it before, and that sometimes 0:15:26.400 --> 0:15:28.240 I'm going to try things and they're going to fail. 0:15:28.400 --> 0:15:31.680 And there's a constant process in my lab with my 0:15:31.720 --> 0:15:35.320 students and staff of sort of openly talking about this 0:15:35.640 --> 0:15:37.880 right in it, you know, being candid about it and 0:15:38.160 --> 0:15:40.080 sort of being like that's all right, you know, like 0:15:40.520 --> 0:15:42.880 it's okay that it failed. You didn't know what you 0:15:42.880 --> 0:15:46.360 were doing, because nobody knew what they were doing. But 0:15:46.480 --> 0:15:49.800 for example, you know, you might consider an earlier experiment 0:15:49.840 --> 0:15:52.520 in the book by William Rodkin, who discovered X rays, 0:15:52.960 --> 0:15:56.200 and he discovered them because a sort of painted fluorescent 0:15:56.240 --> 0:16:00.560 screen across his lab was glowing when he had a tube, 0:16:00.920 --> 0:16:04.960 a cathoedray tube in his lab, and he noticed the 0:16:04.960 --> 0:16:07.880 glow and he decided to investigate it. Now, we often 0:16:07.920 --> 0:16:11.960 refer to that as serendipitous, but depending on your perspective, 0:16:12.040 --> 0:16:13.840 you might consider it to be an error. You know, 0:16:13.880 --> 0:16:17.520 you probably shouldn't have had the wrong detector, you know, 0:16:17.800 --> 0:16:21.360 sort of out in the lab at the time. The 0:16:21.400 --> 0:16:23.640 other person that comes to mind is Robert Millican, who 0:16:23.680 --> 0:16:28.280 did twelve years worth of experiments trying to measure what's 0:16:28.320 --> 0:16:31.360 called the photoelectric effect, which is the electrical current that 0:16:31.400 --> 0:16:35.920 flows when you shine light on particular metals. And this 0:16:35.960 --> 0:16:38.760 is an interesting one where along the ways, the early 0:16:38.800 --> 0:16:42.520 phases of quantum mechanics had come around, and Einstein in 0:16:42.560 --> 0:16:45.560 particular had come out with this equation which predicted what 0:16:45.600 --> 0:16:48.680 should happen when you shine this light onto different metals. 0:16:48.920 --> 0:16:54.040 And the upshot of Einstein's theory was really abhorrent to 0:16:54.520 --> 0:16:58.320 the experimentalist. To Robert Millican, he called it the reckless hypothesis. 0:16:58.480 --> 0:17:03.080 And that's because this hype office has implied that light 0:17:03.160 --> 0:17:05.879 would be acting more like a particle than like a 0:17:05.920 --> 0:17:09.199 wave in this experiment. And so he set out to 0:17:09.200 --> 0:17:12.439 prove Einstein wrong, spent twelve years in the lab trying 0:17:12.440 --> 0:17:14.800 to do it, and all he did was pre Einstein 0:17:14.920 --> 0:17:17.840 right to a better precision than anyone had before. So again, 0:17:17.920 --> 0:17:21.080 you might think, and he even thought that he was failing, right. 0:17:21.240 --> 0:17:24.520 He thought he was failing as an experimentalist. He was 0:17:24.560 --> 0:17:26.240 really struggling with He had to build all his own 0:17:26.240 --> 0:17:29.560 equipment from scratch. And then at the end of twelve 0:17:29.640 --> 0:17:32.520 years he sort of comes out with this result, which 0:17:32.560 --> 0:17:36.040 I think even when he published it he still didn't 0:17:36.040 --> 0:17:38.000 fully believe, but he was able to sort of say, well, 0:17:38.040 --> 0:17:42.280 it is consistent with Einstein's prediction. And then later on 0:17:42.480 --> 0:17:45.080 about another ten years later, he was awarded the Nobel 0:17:45.119 --> 0:17:47.960 Prize for that and another famous experiment that he did 0:17:48.000 --> 0:17:52.560 about the charge on the electron, and he changes his tune. 0:17:52.560 --> 0:17:55.400 And I found this fascinating that, you know, this very 0:17:55.440 --> 0:17:59.480 fallible nature of the experimentalist, of sort of thinking one 0:17:59.480 --> 0:18:01.959 thing is going to happen and holding this bias that 0:18:02.080 --> 0:18:05.240 you know, no, nature can't possibly work that way. It's ridiculous. 0:18:05.280 --> 0:18:08.960 It's you know, preposterous that a particle could be a wave. 0:18:09.160 --> 0:18:10.919 You know, sorry, a light could be a wave and 0:18:10.960 --> 0:18:14.320 a particle. And then he gets through his Nobel Prize 0:18:14.680 --> 0:18:18.920 speech or lecture and then he's saying, you know, however, 0:18:18.960 --> 0:18:22.760 many years ago when when I set out to demonstrate 0:18:22.840 --> 0:18:29.320 Einstein's photoelectric theory, so so he's making out like him 0:18:29.400 --> 0:18:32.840 meant to do it all along, and I was I 0:18:32.960 --> 0:18:36.440 was shocked. I was like, did someone transcribe that incorrectly? 0:18:36.600 --> 0:18:41.320 I don't think so. And so so it turns out that, 0:18:41.760 --> 0:18:44.320 you know, I think his bias against it was what 0:18:45.520 --> 0:18:50.080 it gave him this force, this will power to persist 0:18:50.080 --> 0:18:52.399 at his experiment for twelve years because he was just 0:18:52.480 --> 0:18:54.560 like emotionally he was just like, this cannot be right, 0:18:54.600 --> 0:18:58.240 this cannot be right, and you know, you would you 0:18:58.280 --> 0:19:02.240 would say that he if I in that enterprise because 0:19:02.760 --> 0:19:07.399 he was wrong and Enstein was right. But this is 0:19:07.760 --> 0:19:09.679 I think this is how science progresses, and it's an 0:19:09.720 --> 0:19:13.200 important part of how science progresses is that, yes, we're 0:19:13.200 --> 0:19:16.000 all human, we're all you know, we're coming with our biases, 0:19:16.040 --> 0:19:19.360 we're very fallible. But isn't it amazing that we can then, 0:19:20.040 --> 0:19:24.159 you know, use the scientific process and apply, you know, 0:19:24.240 --> 0:19:26.800 as sort of apply things to that process to try 0:19:26.800 --> 0:19:30.800 and UnBias ourselves from the results and come out with 0:19:31.760 --> 0:19:35.359 the knowledge that is, you know, sort of accurate, regardless 0:19:35.359 --> 0:19:37.120 of the fact that you didn't believe it going into 0:19:37.160 --> 0:19:38.960 doing the experiment. I think, I think that's actually a 0:19:39.000 --> 0:19:40.720 pretty amazing thing that we can do. 0:19:41.119 --> 0:19:55.560 And like the culture of experiment is the constraint on that. Yes, yeah, well, 0:19:55.560 --> 0:19:59.639 regarding ideas that are wrong but persistent. One of my 0:19:59.640 --> 0:20:04.160 favorite characters in the book is Ernest Rutherford, And there's 0:20:04.160 --> 0:20:07.679 a part where you quote Ernest Rutherford saying that he 0:20:07.760 --> 0:20:10.080 was originally brought up to think of the atom as 0:20:10.680 --> 0:20:13.480 I think the quote is a nice hard fellow red 0:20:13.560 --> 0:20:17.879 or gray in color according to your taste, and that 0:20:17.960 --> 0:20:20.200 struck me as very funny. But then you also mentioned 0:20:20.240 --> 0:20:25.119 in a footnote that even many physicists, still, despite knowing better, 0:20:25.720 --> 0:20:29.480 think of sub atomic particles and atoms as little balls. 0:20:30.800 --> 0:20:34.359 How do you visualize sub atomic particles or do you 0:20:34.440 --> 0:20:36.879 at all? And is there a better way we should 0:20:36.920 --> 0:20:41.520 try to picture this scale of matter in the mind's 0:20:41.520 --> 0:20:43.359 eye or is it pointless to even try? 0:20:44.680 --> 0:20:48.480 So? I'm going to sheepishly admit that, like all the 0:20:48.520 --> 0:20:51.600 other physicists I've asked, we don't want to admit it. 0:20:51.920 --> 0:20:54.280 But because the first time we were ever introduced to 0:20:54.320 --> 0:20:58.520 the concept of Adams and particles, they were little hard spares. 0:21:00.080 --> 0:21:03.359 When you say protons and neutrons and electrons and the 0:21:03.400 --> 0:21:06.679 atom I have. I have a terrible picture in my 0:21:06.760 --> 0:21:09.960 head that's I know is completely wrong, and yet it persists. 0:21:11.000 --> 0:21:13.320 You know, I have this this, Yeah, I have little 0:21:13.320 --> 0:21:17.080 hard spheres in my mind, just like Rutherford did. And 0:21:17.680 --> 0:21:19.880 I mean this is a This is a huge disservice 0:21:19.920 --> 0:21:23.840 that we do ourselves, I think, by persisting to describe 0:21:23.840 --> 0:21:27.520 in this way. But here's here's a I think a 0:21:27.640 --> 0:21:29.920 key point about the models that we have in our heads. 0:21:29.920 --> 0:21:31.720 And I will answer the question about how better to 0:21:31.800 --> 0:21:35.159 visualize it in a moment. Physics and all the natural 0:21:35.160 --> 0:21:39.520 sciences really are sciences of different scales, and all the 0:21:39.520 --> 0:21:41.199 models that we have and all the theories that we 0:21:41.280 --> 0:21:44.719 have apply on different scales. So if you're a chemist 0:21:44.840 --> 0:21:48.800 or a biologist, it's well, other than some realms of chemistry, 0:21:49.359 --> 0:21:53.159 it's probably okay for you to visualize atoms and particles 0:21:53.200 --> 0:21:57.720 as little hard spheres because the models that predict the 0:21:57.760 --> 0:22:00.280 behavior which you're interested in on the scale that you're 0:22:00.320 --> 0:22:03.280 interested in, which is now more much more macroscopic than microscopic. 0:22:05.000 --> 0:22:07.560 You know, it works perfectly fine, it can sort of 0:22:07.560 --> 0:22:12.760 approximate it. And quantum mechanics, though, is obviously the science. 0:22:12.800 --> 0:22:15.320 When we get down to that very very small level 0:22:16.280 --> 0:22:19.080 and we've realized that it no longer works in the 0:22:19.119 --> 0:22:22.560 same analogous way to say billiard balls on a billiard table, 0:22:23.080 --> 0:22:26.080 and it works in a very different way. Everything is 0:22:26.160 --> 0:22:30.480 much more probabilistic. Nothing is as certain. We can't know 0:22:30.600 --> 0:22:34.000 things like the position and the momentum at the same 0:22:34.040 --> 0:22:39.439 time precisely, so everything becomes a little fuzzier. If I 0:22:39.480 --> 0:22:42.919 were to try and encourage you to properly visualize an atom. 0:22:43.520 --> 0:22:47.359 First of all, you know, the central nucleus of an 0:22:47.400 --> 0:22:51.000 atom is extremely dense and extremely small compared to the 0:22:51.040 --> 0:22:54.439 outer side of the atom. And Rutherford had another beautiful 0:22:54.560 --> 0:22:59.160 analogy for this, which is that if the electrons which 0:22:59.200 --> 0:23:01.960 now you're considering in your head, the electrons to be 0:23:02.040 --> 0:23:04.880 kind of a wave or a sphere or a sort 0:23:04.880 --> 0:23:07.240 of much more, you know, much less like a little 0:23:07.280 --> 0:23:13.920 hard dot and much more like a probability cloud, that 0:23:14.200 --> 0:23:18.439 cloud would be at the walls of a cathedral. And 0:23:18.480 --> 0:23:20.560 if that was the size of a cathedral, then the 0:23:20.680 --> 0:23:22.840 nucleus in the center would be the size of a 0:23:22.880 --> 0:23:26.480 fly or a pee in the middle of the cathedral. So, 0:23:26.640 --> 0:23:29.920 first of all, the scales inside the atom are very 0:23:29.920 --> 0:23:32.800 different to the pictures that we look at when we're 0:23:32.840 --> 0:23:35.880 taught this kind of science, because you just can't fit 0:23:35.920 --> 0:23:38.200 those scales on a page and have them be sensible, right, 0:23:38.240 --> 0:23:41.000 so we condense everything down. So, first of all, for 0:23:41.080 --> 0:23:44.040 most of us, the scales of what things look like 0:23:44.080 --> 0:23:46.800