WEBVTT - Special Episode: Electricity 0:00:43.520 --> 0:00:47.080 Hi, I'm Aaron Welsh and this is this podcast will 0:00:47.159 --> 0:00:51.800 kill You. Welcome back, everyone. I'm very excited that you're 0:00:51.880 --> 0:00:55.080 joining me for this latest bonus episode in our mini 0:00:55.120 --> 0:00:57.920 series of bonus episodes that have been coming out for 0:00:57.960 --> 0:01:01.720 the past few months. Jeff as a refresher, I'm putting 0:01:01.720 --> 0:01:05.400 together these bonus episodes as a way to hopefully accomplish 0:01:05.480 --> 0:01:08.760 two things at once. First, I get to explore in 0:01:08.800 --> 0:01:12.080 more detail some aspect of what we covered the previous week, 0:01:12.440 --> 0:01:16.040 helped along by an expert guest, of course, And second, 0:01:16.120 --> 0:01:19.000 I get to then ask that guest all about their 0:01:19.080 --> 0:01:22.600 experiences in their career, what they like about it, how 0:01:22.640 --> 0:01:25.480 the field could be improved, any advice they may have 0:01:25.560 --> 0:01:28.520 for people interested in a career in public health or 0:01:28.560 --> 0:01:33.920 disease research, or science communication, and so much more. It's 0:01:33.959 --> 0:01:37.319 been such a fun journey so far, and I'm especially 0:01:37.360 --> 0:01:41.280 looking forward to this week's episode, which I think may 0:01:41.319 --> 0:01:46.319 be our most electrifying yet. Last week, Aaron and I 0:01:46.400 --> 0:01:50.320 covered lightning strikes, especially what happens to your body if 0:01:50.320 --> 0:01:53.200 you are unfortunate enough to get in between the lightning 0:01:53.240 --> 0:01:55.840 and the ground. And if you haven't listened to that 0:01:55.920 --> 0:01:59.320 episode yet, you should definitely check it out before listening 0:01:59.320 --> 0:02:02.000 to this one, because in it we cover a lot 0:02:02.040 --> 0:02:05.720 of the basics of lightning and some of electricity, and 0:02:05.880 --> 0:02:08.320 I think it'll really help to provide a background for 0:02:08.400 --> 0:02:13.200 what we'll be talking about today, which is more about electricity. 0:02:13.880 --> 0:02:17.720 In our Lightning episode, we talked mostly about well lightning, 0:02:17.840 --> 0:02:21.280 how it forms, the biological impacts of lightning on the body, 0:02:21.600 --> 0:02:24.959 and some differences between getting struck by lightning and getting 0:02:25.000 --> 0:02:28.440 electrocuted through other ways. But what we didn't really get 0:02:28.480 --> 0:02:32.920 into in any great detail was how electricity in general works. 0:02:33.400 --> 0:02:38.119 For example, what is voltage, what is amperage, what's resistance, 0:02:38.760 --> 0:02:41.359 what's the difference between them, and why do they matter 0:02:41.440 --> 0:02:45.400 in understanding electricity, And also some of the other ways 0:02:45.440 --> 0:02:49.000 outside of getting struck by lightning that electricity and biology 0:02:49.040 --> 0:02:52.760 can intersect, like fish species that can generate their own 0:02:52.800 --> 0:02:58.359 electricity for stunning prey, or how modern electrotherapy is done. 0:02:58.400 --> 0:03:00.920 And part of the reason why we didn't cover these 0:03:00.960 --> 0:03:04.240 things on our regular season episode was because we can't 0:03:04.280 --> 0:03:07.519 cover everything. We have to put at least some boundaries 0:03:07.560 --> 0:03:10.320 on how much we can talk about in a single episode. 0:03:10.919 --> 0:03:12.960 But it also comes down to the fact that the 0:03:13.000 --> 0:03:16.920 principles of electricity, they're complicated and they can be difficult 0:03:16.919 --> 0:03:20.800 to understand. And understanding them well enough to be able 0:03:20.840 --> 0:03:23.480 to explain them in an accessible way to someone else. 0:03:24.160 --> 0:03:27.880 Now that takes a whole nother kind of skill, one 0:03:27.880 --> 0:03:31.160 that my guest for this bonus episode has in abundance. 0:03:31.880 --> 0:03:35.000 Doctor Timothy Jorgensen might be a familiar name to you, 0:03:35.480 --> 0:03:39.040 especially if you've listened to our radiation episode before, which 0:03:39.080 --> 0:03:41.960 features a short interview with doctor Jorgenson in which he 0:03:42.080 --> 0:03:46.200 walks us through exactly how radiation works, or maybe you 0:03:46.320 --> 0:03:49.120 read his book Strange Glow, all about the science and 0:03:49.200 --> 0:03:53.800 history of radiation. Well, as it turns out, doctor Jorgenson 0:03:53.880 --> 0:03:58.400 recently wrote another fantastic book called Spark, and this one 0:03:58.560 --> 0:04:02.000 is all about how electricity works, the ways in which 0:04:02.040 --> 0:04:05.680 our understanding of electricity has changed throughout history, what it 0:04:05.720 --> 0:04:08.480 has taught us about biology so far, and what it 0:04:08.520 --> 0:04:12.040 could teach us in the future. So who better to 0:04:12.120 --> 0:04:14.880 bring on to help us gain a better understanding of 0:04:14.920 --> 0:04:18.880 the ins and outs of electricity. In this bonus episode, 0:04:19.080 --> 0:04:22.960 Doctor Jorgenson and I are going to explore amberage versus voltage, 0:04:23.279 --> 0:04:26.880 how the human body uses electricity, some of the modern 0:04:26.920 --> 0:04:31.360 applications of electrotherapy, and so much more. And since doctor 0:04:31.440 --> 0:04:35.159 Jorgenson is such an accomplished science communicator, I wanted to 0:04:35.200 --> 0:04:37.760 take the opportunity to pick his brain on how you 0:04:37.839 --> 0:04:40.560 go about writing a book on such a wide topic 0:04:40.640 --> 0:04:44.000 and still manage to make it fun and accessible, Ways 0:04:44.040 --> 0:04:46.960 in which grad and med school training could incorporate science 0:04:47.000 --> 0:04:51.600 communication and advice for those interested in becoming science communicators. 0:04:52.240 --> 0:04:55.080 I am super excited to dive in. So we're just 0:04:55.120 --> 0:04:57.360 going to take a quick break here and then I'll 0:04:57.440 --> 0:04:59.600 let doctor Jorgenson introduce himself. 0:05:24.040 --> 0:05:27.800 My name is Tim Jorgenson. I'm a professor at Georgetown University. 0:05:28.200 --> 0:05:31.880 I direct a program in health physics, and I am 0:05:32.000 --> 0:05:36.200 i am a professor in radiation medicine and also biochemistry 0:05:36.200 --> 0:05:40.320 and the medical school. And I've written two books that 0:05:40.360 --> 0:05:43.520 are targeted for a general audience. The one is called 0:05:43.720 --> 0:05:47.600 Strange Glow, The Story of Radiation, and then my most 0:05:47.680 --> 0:05:51.960 recent book is Spark The Life of Electricity and Electricity 0:05:52.000 --> 0:05:54.479 of Life. And I'm happy to be here. 0:05:55.400 --> 0:05:57.920 Well, thank you so much for joining me today. I 0:05:57.960 --> 0:06:01.839 am really excited to ask you about of questions about electricity. 0:06:02.240 --> 0:06:04.800 So I loved your latest book, Spark, and I thought 0:06:04.839 --> 0:06:07.880 it was a fascinating and brilliant way to tell the 0:06:07.880 --> 0:06:12.160 story of electricity through this lens of biology. What made 0:06:12.200 --> 0:06:14.520 you want to write this book and how did you 0:06:14.560 --> 0:06:17.040 decide on the format that you use, Like, how did 0:06:17.040 --> 0:06:19.920 you decide what to include or what not to include? 0:06:20.279 --> 0:06:23.760 So this book is an outgrowth of my previous ones. 0:06:23.839 --> 0:06:28.279 So I had written the previous book about radiation, and 0:06:29.360 --> 0:06:33.600 in writing that book, I had included an explanation of radiation, 0:06:34.120 --> 0:06:38.680 but I also had mentioned some things about electricity. Scientists 0:06:38.720 --> 0:06:41.920 who work in radiation have one foot in the electrical 0:06:41.960 --> 0:06:45.320 world and one foot in the radiation world, because the 0:06:45.360 --> 0:06:48.320 two disciplines are connected, and I had mentioned some things 0:06:48.360 --> 0:06:51.640 about electricity in those books. So I got some questions 0:06:51.680 --> 0:06:55.280 about electricity too. So the book was quite successful and 0:06:55.440 --> 0:06:58.719 the publisher was interested in me writing another book. But 0:06:58.760 --> 0:07:01.239 I didn't want to write another radiation book. I thought, 0:07:01.520 --> 0:07:04.760 I've said all I can say about radiation. So my 0:07:04.839 --> 0:07:07.880 wife said, well, people seem to be as interested in 0:07:07.880 --> 0:07:11.000 the electrical part as the part of the radiation. Why 0:07:11.000 --> 0:07:14.800 don't you write something about electricity using the same style 0:07:14.920 --> 0:07:18.600 that you did for the radiation stories, and so I've 0:07:18.640 --> 0:07:20.480 thought about that for a while and I thought that 0:07:20.600 --> 0:07:25.040 sounds like a pretty good idea. And the strategy of 0:07:25.080 --> 0:07:27.960 the book is you tell the story a human interest story, 0:07:28.080 --> 0:07:31.680 something that will get people interested in finding out what happens, 0:07:31.840 --> 0:07:33.920 and the story usually something that happens in that story. 0:07:34.000 --> 0:07:37.560 Something technical happens in the story, and you have to 0:07:37.800 --> 0:07:39.960 break the narrative of the story and explain to the 0:07:40.000 --> 0:07:43.400 read the technical thing so they can keep following the story. 0:07:43.400 --> 0:07:45.280 And then you go a little further and then I 0:07:45.360 --> 0:07:48.280 call it the trojan horse strategy. By the end of 0:07:48.280 --> 0:07:52.040 the story, they've learned about Helen of Troy, but they've 0:07:52.040 --> 0:07:55.040 also learned about how to build a wooden horse as well, 0:07:55.240 --> 0:07:58.320 you know. So the idea here is that the person 0:07:58.400 --> 0:08:01.560 will kind of absorb a lot of technical information passively, 0:08:01.800 --> 0:08:04.560 but also they'll remember that technical information because it's in 0:08:04.600 --> 0:08:05.760 the context of a story. 0:08:06.680 --> 0:08:09.280 So there is so much ground that we could cover 0:08:09.400 --> 0:08:12.720 here in our discussion of electricity, and so many different 0:08:12.800 --> 0:08:15.800 aspects that we could focus on. But if we're going 0:08:15.880 --> 0:08:19.520 to talk about even just one area of electricity, it's 0:08:19.560 --> 0:08:23.240 probably best to get a baseline for how electricity actually 0:08:23.320 --> 0:08:26.680 works in our episode last week, Aaron went through the 0:08:26.680 --> 0:08:29.800 basics of how lightning forms. But can we get even 0:08:29.920 --> 0:08:34.080 more general? Can you explain what exactly electricity is and 0:08:34.120 --> 0:08:37.960 what the differences between voltage, ambridge and resistance. 0:08:39.160 --> 0:08:43.120 So electricity as we now know, which was not known 0:08:43.440 --> 0:08:47.640 when it was first discovered, electricity is the flow of electrons. 0:08:48.240 --> 0:08:52.800 Atoms have a nucleus and they have a cloud of 0:08:52.840 --> 0:08:57.120 electrons around them, and some atoms hold on to those 0:08:57.120 --> 0:09:02.560 electrons very tightly, like metals have a very loose grip 0:09:02.679 --> 0:09:05.679 on some of the outer electrons, and so they can 0:09:05.800 --> 0:09:09.679 jump from atom to atom. And when you get a 0:09:09.720 --> 0:09:13.760 flow of these electrons going in a particular direction for 0:09:13.800 --> 0:09:18.079 some reason, that's an electrical current. So some things are 0:09:18.160 --> 0:09:22.280 good at shuffling electrons down to the next guy, and 0:09:22.320 --> 0:09:26.160 those are conductors, like copper wires are good and other 0:09:26.280 --> 0:09:29.360 things like wood and plastic are not so good with 0:09:29.520 --> 0:09:34.959 moving their electrons along, and so those are insulators. And 0:09:35.840 --> 0:09:40.960 rather than just categorize things in terms of insulators and conductors, 0:09:41.240 --> 0:09:45.280 we could think of things as everything has some potential 0:09:45.480 --> 0:09:48.840 to be a conductor, but some are bad conductors and 0:09:48.880 --> 0:09:52.600 some are good conductors. And the reason that they are 0:09:52.720 --> 0:09:55.800 bad is because that they have a property called resistance. 0:09:56.400 --> 0:10:01.720 So resistance is the as it means it's resistant to 0:10:01.760 --> 0:10:04.680 the flow of electrons. Now, a lot of people like 0:10:04.800 --> 0:10:07.880 to describe electricity in terms of a flow of water, 0:10:08.600 --> 0:10:12.160 and it's his for historical reasons. People thought that electricity 0:10:13.120 --> 0:10:15.760 was a fluid, and so it made sense to describe 0:10:15.840 --> 0:10:20.000 things as a flow of this invisible fluid. So if 0:10:20.000 --> 0:10:23.040 we wanted to make an analogy with water, and we 0:10:23.120 --> 0:10:28.160 wanted to make that analogy with a garden hose, for example, 0:10:28.559 --> 0:10:32.280 the voltage would be the pressure at the tap. So 0:10:32.360 --> 0:10:36.160 if you have good pressure, you know it when you 0:10:36.240 --> 0:10:39.120 open the tap the water comes out very forcefully. That's 0:10:39.160 --> 0:10:42.079 the voltage. If you have low pressure, the water just 0:10:42.160 --> 0:10:48.120 kind of dribbles out. The amperage is the representation of 0:10:48.240 --> 0:10:51.960 how much water flows out per unit time. So how 0:10:52.000 --> 0:10:54.280 fast you can how many buckets you can fill us 0:10:54.480 --> 0:10:58.640 a minute, that's the amperage. And if you had to 0:10:58.679 --> 0:11:01.520 describe the resistance, you could say that as you turn 0:11:01.559 --> 0:11:04.040 the valve and you start to close it, you start 0:11:04.080 --> 0:11:06.600 making the hole smaller and smaller for the water to 0:11:06.679 --> 0:11:10.160 pass through. You increase the resistance to eventually at the 0:11:10.200 --> 0:11:12.920 point you shut it off. So if you wanted to 0:11:12.960 --> 0:11:17.680 compare electricity to water, I think that's that's a good analogy. 0:11:17.720 --> 0:11:19.839 A water faucet and the flow in the flow of war. 0:11:21.000 --> 0:11:25.000 And so what influences each of these principles of electricity. 0:11:26.160 --> 0:11:31.240 The reason that electricity flows is because there is an 0:11:31.800 --> 0:11:35.520 over abundance of charge. There are more electrons in one 0:11:35.600 --> 0:11:41.559 place than there are in another place, and so the electrons, 0:11:41.679 --> 0:11:44.880 because they're all the same charge, they repel one another 0:11:45.040 --> 0:11:48.520 and they want to spread out. And so if there's 0:11:48.559 --> 0:11:51.200 a place that they can go to where there is 0:11:51.520 --> 0:11:54.120 less of a density of electrons, that's where they will go. 0:11:54.920 --> 0:11:59.240 That's how things start. So, for example, the earliest electricity 0:11:59.240 --> 0:12:04.440 that we knew about was static electricity, and people produced 0:12:04.480 --> 0:12:08.480 static electricity by rubbing two materials together. It started out 0:12:08.559 --> 0:12:12.120 with rubbing amber with wool. So what's happening there is 0:12:12.120 --> 0:12:15.559 when you rub these two things together, the electrons from 0:12:15.600 --> 0:12:18.960 one thing are being scraped off and moving onto the 0:12:19.040 --> 0:12:23.400 other thing. With wool and amber, that transfer is extreme, 0:12:23.920 --> 0:12:27.800 and so now the charge builds up and the electrons 0:12:27.880 --> 0:12:30.920 on the amber will now try to jump to the wool. 0:12:31.040 --> 0:12:33.960 And that's basically what's going on, and it doesn't have 0:12:34.000 --> 0:12:36.439 to be amber and wool. Amber was hard to find 0:12:36.480 --> 0:12:39.200 and expensive, so people found out that if you rub 0:12:39.320 --> 0:12:42.840 glass with silk you got the same thing, and so 0:12:42.960 --> 0:12:46.760 the first generators of electricity were simply to make a 0:12:46.880 --> 0:12:51.560 glass sphere with a crank on it attached a silk 0:12:51.720 --> 0:12:54.559 pad so that it rubbed, turn it as fast as 0:12:54.559 --> 0:12:57.760 you could, and then bleed the electricity off of the glass. 0:12:58.160 --> 0:13:01.240 The first generator of electricity really stick at electricity machines 0:13:01.240 --> 0:13:03.120 that work just by rubbing things together. 0:13:04.440 --> 0:13:07.920 So you mentioned that there are bad conductors and good conductors. 0:13:08.200 --> 0:13:12.640 What makes something a good or bad conductor? Like why? 0:13:12.760 --> 0:13:16.400 Like why is would a bad conductor versus copper wire? 0:13:17.440 --> 0:13:20.120 So most of the good conductors are metals, and it 0:13:20.200 --> 0:13:24.360 has to do with how available the electrons are to move. 0:13:24.840 --> 0:13:27.160 So the electrons that are closer to the center are 0:13:27.240 --> 0:13:30.440 very tightly bound. But if they have a cloud of 0:13:30.440 --> 0:13:35.679 electrons and some in the outermost shell, they're only weakly attached. 0:13:36.440 --> 0:13:40.040 And if these atoms are right next to each other, 0:13:40.120 --> 0:13:43.240 as they are in metal, they're set in a almost 0:13:43.320 --> 0:13:47.080 like a krystin lattice form. It's very easy for these 0:13:47.120 --> 0:13:50.480 electrons to just move to their next neighbor, and so 0:13:50.880 --> 0:13:54.320 electrons can just flow, particularly if they're being pushed by 0:13:54.640 --> 0:13:57.760 excess charge on one end, they'll just push down and 0:13:57.840 --> 0:14:00.559 the charge will just move to the other end. Things 0:14:00.640 --> 0:14:04.680 like plastics they don't have these weekly held electrons. Most 0:14:04.679 --> 0:14:07.880 of their bonds are covalent bonds that are not involving 0:14:07.920 --> 0:14:11.520 these weekly charged electrons, and so they tend not to 0:14:11.559 --> 0:14:12.599 conduct electricity. 0:14:13.760 --> 0:14:17.200 Can you walk me through the difference between direct current 0:14:17.360 --> 0:14:20.560 and alternating current and what are some of the practical 0:14:20.600 --> 0:14:23.880 implications of the difference between the two and how are 0:14:23.920 --> 0:14:25.480 they used in different settings. 0:14:26.720 --> 0:14:30.720 The story of alternating current and direct current is a 0:14:30.800 --> 0:14:35.600 very interesting one because it involved a war between Edison 0:14:35.960 --> 0:14:39.640 and Westinghouse about which type of current was going to 0:14:39.640 --> 0:14:43.960 be the standard for the United States for power transmission. 0:14:44.080 --> 0:14:48.200 As most people know, Westinghouse won that war, and all 0:14:48.240 --> 0:14:51.120 of our current are household current. Now is alternating current, 0:14:51.200 --> 0:14:54.640 So what is it? So? Direct current is when the 0:14:54.680 --> 0:14:59.760 electrons are moving in one direction only, and in alternating current, 0:15:00.040 --> 0:15:02.800 they move in one direction and then they move back 0:15:02.800 --> 0:15:05.400 in the other direction, and they do this very fast, 0:15:05.880 --> 0:15:09.080 sixty times a second, and they're both electric currents, but 0:15:09.240 --> 0:15:13.440 they have some advantages. The alternating current has a tremendous 0:15:13.560 --> 0:15:19.560 advantage in terms of being able to transmit power great distances, 0:15:20.120 --> 0:15:24.040 and the reason for that, the simple explanation is that 0:15:24.800 --> 0:15:29.080 the easiest way to transmit power great distances is at 0:15:29.160 --> 0:15:34.160 high voltage. You can transmit both types of power, direct 0:15:34.200 --> 0:15:36.840 current and alternating current at high voltage. And when I 0:15:36.840 --> 0:15:39.320 say the best way, that the way that loses the 0:15:39.440 --> 0:15:42.320 least energy to heat. You don't want to produce a 0:15:42.400 --> 0:15:45.680 lot of heat. All that heat is just wasted energy. 0:15:46.200 --> 0:15:49.320 So you do it at high voltage because the only 0:15:49.400 --> 0:15:52.160 other alternative low voltage. You have to push it with 0:15:52.280 --> 0:15:55.000 so much amperage, and amperage is what drives the heat. 0:15:55.840 --> 0:15:58.960 You can do both of them. Both types of current 0:15:59.240 --> 0:16:02.160 can go at high voltage. The problem was at Edison's 0:16:02.200 --> 0:16:05.360 time was that you don't want to bring high voltage 0:16:05.400 --> 0:16:09.280 into the house. Nothing in your house can use this high, 0:16:09.440 --> 0:16:12.840 very high voltage. It has to be stepped down. And 0:16:12.920 --> 0:16:16.640 there was a way to step down alternating current at 0:16:16.680 --> 0:16:20.760 the point of use with local transformers, but there was 0:16:21.000 --> 0:16:24.440 no way at that time to step down direct current. 0:16:25.400 --> 0:16:28.200 So if you wanted to use direct current in your house, 0:16:28.440 --> 0:16:32.200 it had to be transmitted at low voltage, and that 0:16:32.440 --> 0:16:35.480 caused a lot of problems, and it was not possible 0:16:35.520 --> 0:16:38.040 to transmit it more than a mile that way. But 0:16:38.240 --> 0:16:41.840 if you used alternating current, you could transmit it at 0:16:41.920 --> 0:16:45.640 high voltage very efficiently and then drop it down to 0:16:45.840 --> 0:16:48.960 appropriate voltage for household use when it got to its location. 0:16:49.440 --> 0:16:51.800 So this is what the basis of the war was, 0:16:52.000 --> 0:16:56.880 and so it lives with us to this day. Interestingly enough, 0:16:56.920 --> 0:17:00.560 in the nineteen forties, I believe someone invented away to 0:17:00.600 --> 0:17:03.600 step down direct current, and so if the issue it 0:17:03.640 --> 0:17:06.200 wouldn't be such a big issue today, but we live 0:17:06.280 --> 0:17:08.959 with the legacy of the technology of that period. 0:17:10.200 --> 0:17:15.800 How do these principles of electricity, amperage, voltage, resistance, and 0:17:16.119 --> 0:17:18.840 the type of current, how do those things relate to 0:17:18.960 --> 0:17:24.000 the overall risk of injury or the severity of injury 0:17:24.080 --> 0:17:27.280 for humans if someone comes into contact with electricity. 0:17:28.520 --> 0:17:34.000 To oversimplify things, voltage is what causes the pain. If 0:17:34.040 --> 0:17:37.600 you want to make a fence electric fence to keep 0:17:37.640 --> 0:17:41.240 a bear out of your yard, you want something that 0:17:41.320 --> 0:17:45.800 has very high voltage but very low amperage. It's the 0:17:46.000 --> 0:17:52.199 amperage that kills, not the voltage so things like tasers 0:17:52.840 --> 0:17:57.760 and electric fences, and even static electricity shocks that you 0:17:57.800 --> 0:18:00.680 get by rubbing your feet on the carpet. This can 0:18:00.720 --> 0:18:03.880 be like fifty thousand volts and you feel it. Why 0:18:03.920 --> 0:18:08.200 don't you ever die from a carpet shock Because even 0:18:08.240 --> 0:18:12.280 though the voltage is very high, the amperage is very low, 0:18:13.040 --> 0:18:17.560 so you need amperage to kill. You can even make 0:18:17.600 --> 0:18:23.520 electricity less damaging by interrupting the current flow interrupting the amperage, 0:18:23.840 --> 0:18:27.560 and that's how it works on an electric fence. Okay, 0:18:27.640 --> 0:18:33.159 so alternating versus direct current danger The truth is that 0:18:33.840 --> 0:18:39.000 they're both equally dangerous, and they're different enough that and 0:18:39.160 --> 0:18:44.600 all else being equal, comparison isn't possible, But it doesn't 0:18:44.640 --> 0:18:49.479 really make much difference because they're both dangerous and they 0:18:49.480 --> 0:18:51.880 should both be respected equally. 0:18:53.160 --> 0:18:56.440 So in our discussion so far, and also in last 0:18:56.440 --> 0:19:00.600 week's episode, we've largely been talking about electricity in general, 0:19:00.840 --> 0:19:04.400 or what happens when someone comes into contact with electricity. 0:19:04.960 --> 0:19:07.280 But now I want to shift to talking about some 0:19:07.400 --> 0:19:11.280 of the ways that humans and other animals interact with electricity. 0:19:12.160 --> 0:19:15.360 So how does the human body use electricity? 0:19:15.800 --> 0:19:18.920 The chief use of electricity in the body is to 0:19:18.960 --> 0:19:23.920 operate the nervous system. And in Spark, what I tried 0:19:23.960 --> 0:19:29.919 to show is that neuroscience and electrical science developed together. 0:19:30.800 --> 0:19:36.000 The first ways of detecting electricity were feeling it, you know, 0:19:36.240 --> 0:19:41.000 getting shocks like from amber, or getting it to have 0:19:41.119 --> 0:19:44.479 some effect on a living thing. And frog legs were very, 0:19:44.600 --> 0:19:48.040 very popular. If you touch something and the frog leg moved, 0:19:48.920 --> 0:19:52.560 then you knew that it had electricity in it. It's 0:19:52.600 --> 0:19:55.879 because the electricity has the ability to stimulate muscles and 0:19:56.000 --> 0:19:59.880 nerves that it causes that kind of movement. So during 0:20:00.160 --> 0:20:03.880 course of history, people used the effects on the body, 0:20:04.040 --> 0:20:09.640 either animals or human bodies to measure and detect electricity, 0:20:10.280 --> 0:20:14.240 and likewise people use electricity to figure out what was 0:20:14.280 --> 0:20:18.280 going on in the human body. So these two sciences 0:20:18.760 --> 0:20:21.600 kind of leap frog over one another, and when there 0:20:21.720 --> 0:20:26.919 was an advance in electricity, it allowed further advances in neuroscience. 0:20:27.200 --> 0:20:29.600 And when there was an advance in neuroscience, it told 0:20:29.680 --> 0:20:33.680 us more about electricity. And this is basically the understanding 0:20:33.920 --> 0:20:36.800 to this day. It comes right up to the point 0:20:36.840 --> 0:20:42.320 now where we're implanting computer chips in brains to stimulate 0:20:42.400 --> 0:20:46.159 different electrically stimulate different areas of the brains in an 0:20:46.200 --> 0:20:52.240 attempt to cure diseases or power artificial limbs with thoughts. 0:20:52.280 --> 0:20:54.400 And so we've come to the point where we now 0:20:54.440 --> 0:20:59.920 have brain machine interfaces that convert electrical signals into neural 0:21:00.080 --> 0:21:04.800 logical signals and vice versa and so uh. And that 0:21:04.880 --> 0:21:07.760 has all been aided by knowledge about electricity, but also 0:21:07.800 --> 0:21:12.720 knowledge about computers, and also an exploitation of the fact 0:21:12.880 --> 0:21:16.520 that our nervous system works kind of like a computer 0:21:16.600 --> 0:21:20.439 and that it sends binary signals. So when you shock 0:21:20.520 --> 0:21:23.840 a nerve, the amount that it's shocked doesn't go up 0:21:23.960 --> 0:21:27.320 and slowly down. It sends out a bunch of signals 0:21:27.320 --> 0:21:31.639 called action potentials or what are commonly known among neuroscience 0:21:31.760 --> 0:21:35.760 as spikes. And so if it wants a bigger signal, 0:21:35.800 --> 0:21:39.439 it sends more spikes, which is very analogous to what 0:21:39.480 --> 0:21:42.760 a computer does with its binary language. You know, it's 0:21:42.840 --> 0:21:45.840 on or off. Nerves are like sending signals, are not 0:21:45.960 --> 0:21:48.159 on or off, on and off, And so this is 0:21:48.240 --> 0:21:52.520 conducive to these two systems being merged together through these 0:21:52.920 --> 0:21:56.680 brain machine interfaces that actually work both ways. You can 0:21:56.960 --> 0:22:02.120 write information from the computer now into the activating particular cells, 0:22:02.480 --> 0:22:05.600 and the same interface can pick up electrical signals from 0:22:05.600 --> 0:22:08.359 those cells and tell the computer what the brain is doing. 0:22:08.800 --> 0:22:12.640 So this is something that started out with shocking yourself 0:22:12.800 --> 0:22:16.720 with static electricity and frog legs and read up to 0:22:16.760 --> 0:22:20.040 this day, we're looking at brain machine interfaces and how 0:22:20.040 --> 0:22:22.680 they can be used to alleviate disease and pain and suffering. 0:22:23.760 --> 0:22:25.720 I want to talk a little bit more about some 0:22:25.840 --> 0:22:30.719 of these modern applications of electrotherapy. What do we know 0:22:30.840 --> 0:22:34.760 about why or how these modern therapies are effective in 0:22:34.800 --> 0:22:39.439 treating things like epilepsy, certain types of depression, and Parkinson's disease. 0:22:40.840 --> 0:22:46.639 So deep brain stimulation is used primarily for the Parkinson's disease. 0:22:47.000 --> 0:22:51.880 Parkinson's disease is a disease where people have tremors in 0:22:51.920 --> 0:22:55.720 their hands or legs, and these can be quite severe, 0:22:56.440 --> 0:23:00.680 and there was a surgery that partially relieved for people. 0:23:00.760 --> 0:23:03.840 There's there's a part of the brain deep in the brain, 0:23:04.440 --> 0:23:09.679 and physicians found that if you ablated you you removed 0:23:10.280 --> 0:23:14.280 one half one side of this brain part that you 0:23:14.280 --> 0:23:17.160 could relieve the tremors on the other side of the body. 0:23:18.040 --> 0:23:21.119 So you couldn't do both sides of the body because 0:23:21.160 --> 0:23:24.800 you couldn't eliminate the organ entirely because that would cause 0:23:24.840 --> 0:23:27.760 all kinds of other problems. But they could give people 0:23:27.800 --> 0:23:30.320 relief on at least one part side of their body 0:23:30.720 --> 0:23:36.240 using this technique. And they were using electric probes during 0:23:36.280 --> 0:23:41.720 the surgery to try to stimulate and find this particular 0:23:42.280 --> 0:23:45.680 tissue that they were going to cut out, and when 0:23:45.680 --> 0:23:48.919 they used the probe, they found out that using the 0:23:49.000 --> 0:23:53.639 probe alone eliminated the tremors. So the next thought was, 0:23:53.800 --> 0:23:57.000 maybe we don't have to cut this out. Maybe we 0:23:57.040 --> 0:24:01.720 can just stimulate it and eliminate the tremors by permanently 0:24:02.000 --> 0:24:04.920 planting an electrode in it, And that way we could 0:24:04.920 --> 0:24:08.320 control how much electricity, we control how much much we're 0:24:08.359 --> 0:24:10.719 going to reduce the tremors, and we can remove it 0:24:10.800 --> 0:24:13.800 in the future if it presents a problem and the 0:24:13.840 --> 0:24:18.000 patient is no worse for wear. So electrical stimulation for 0:24:18.040 --> 0:24:22.520 a treatment of Parkinson's with these deep brain stimulation became 0:24:23.119 --> 0:24:26.280 a panacea basically, and now that there are many, many 0:24:26.320 --> 0:24:29.280 people who are benefiting from this and it definitely works. 0:24:29.359 --> 0:24:32.280 The person had tremors and now they don't have trembers. 0:24:32.720 --> 0:24:36.639 Exactly why it works is up to debate, but it 0:24:36.800 --> 0:24:44.000 definitely works. And there are other similar stories for treating depression, 0:24:44.040 --> 0:24:48.439 for example with electric convulsive therapy that also works, and 0:24:48.520 --> 0:24:51.679 so we more and more diseases are being treated. Now 0:24:51.760 --> 0:24:54.880 epilepsy is being treated with electrodes on the vagus nerve, 0:24:55.280 --> 0:24:58.159 and these things work. Then they've been shown to be 0:24:58.240 --> 0:25:02.360 worked by randomized clinical trial, but we don't really know exactly. 0:25:02.359 --> 0:25:04.679 There are many theories, and we're getting closer and closer 0:25:04.680 --> 0:25:06.960 to a better understanding of how the nervous system works 0:25:06.960 --> 0:25:11.239 by using these these therapies, but nobody really understands how 0:25:11.640 --> 0:25:12.000 they work. 0:25:13.560 --> 0:25:16.280 Like you said in your book, electricity has taught us 0:25:16.520 --> 0:25:19.919 so much about how the human body works, and in 0:25:19.960 --> 0:25:23.440 a similar way, several animals have revealed a great deal 0:25:23.560 --> 0:25:27.520 about how electricity works. For example, one of my favorite 0:25:27.560 --> 0:25:33.160 stories of electricity involves Volta finding inspiration in the torpedo 0:25:33.240 --> 0:25:36.480 fish to design this first true battery, which is a 0:25:36.520 --> 0:25:39.119 story that I told in the episode last week. But 0:25:39.200 --> 0:25:43.000 what I didn't go into was how exactly these fish 0:25:43.160 --> 0:25:46.400 generate electricity. So would you mind walking us through that? 0:25:47.720 --> 0:25:52.400 So these fish generate electricity very similar to the way 0:25:52.680 --> 0:25:58.359 are neurons do and as opposed to rubbing things and 0:25:58.400 --> 0:26:03.000 getting static electricity that way, or in a battery, you 0:26:03.000 --> 0:26:08.480 have an electrochemical reaction that's generating the electricity In a neuron, 0:26:09.320 --> 0:26:11.760 neurons do it a little differently. What they do is 0:26:11.800 --> 0:26:17.480 they take charged ions. Ions are molecules that in solution 0:26:17.840 --> 0:26:22.800 that are either positively negatively charged. What neurons do is 0:26:22.920 --> 0:26:28.000 they are able to pump these ions from inside to outside. 0:26:28.680 --> 0:26:33.760 What they do is they produce a charge differential between 0:26:34.000 --> 0:26:38.480 the inside and the outside by pumping ions in probably 0:26:38.640 --> 0:26:41.800 positively charge ion ins and pumping them out. And what 0:26:41.840 --> 0:26:45.280