WEBVTT - History of Electricity Part One 0:00:04.200 --> 0:00:12.840 Get technology with tech Stuff from how stuff works dot com. 0:00:12.880 --> 0:00:16.160 Hey there, and welcome to tech Stuff. I'm your host, 0:00:16.320 --> 0:00:19.960 Jonathan Strickland. I'm a senior writer for how stuff works 0:00:20.040 --> 0:00:23.560 dot com, and today we're gonna take a look at 0:00:23.600 --> 0:00:27.680 the history of electricity, from the earliest experiments all the 0:00:27.680 --> 0:00:30.760 way up to the formation of today's power grid and 0:00:30.800 --> 0:00:32.920 how it all works. Well, at least in this part, 0:00:32.960 --> 0:00:36.199 we're gonna explore the first section of that history. But 0:00:36.440 --> 0:00:40.080 as it turns out, the history of our experimentation and 0:00:40.640 --> 0:00:45.000 knowledge of electricity is exhaustive and I would really need 0:00:45.040 --> 0:00:47.200 to do more than one episode. So this is part 0:00:47.320 --> 0:00:49.840 one of what is likely to be a two part 0:00:49.840 --> 0:00:54.080 episode about the history of electricity. I'll try to limit 0:00:54.520 --> 0:00:57.640 the number of electricity based puns I will drop in 0:00:57.680 --> 0:00:59.760 this episode, but don't be shocked if you hear a 0:00:59.800 --> 0:01:04.679 few of them. So first, let's define what electricity is, 0:01:05.400 --> 0:01:08.039 or rather, instead of letting me define it, let's use 0:01:08.160 --> 0:01:12.080 Miriam Webster, because that's kind of their job. Electricity is 0:01:12.160 --> 0:01:15.959 a fundamental form of energy, observable in positive and negative forms, 0:01:16.000 --> 0:01:19.680 that occurs naturally as in lightening, or is produced as 0:01:19.720 --> 0:01:22.560 in a generator, and that is expressed in terms of 0:01:22.600 --> 0:01:26.600 the movement and interaction of electrons. That's actually kind of 0:01:27.160 --> 0:01:29.880 a little simplistic. It's talking about the move of electrons. 0:01:29.920 --> 0:01:33.679 It's really more about the move of electric charge and 0:01:33.760 --> 0:01:38.640 not of electrons. Specifically, if you had some other carrier 0:01:39.200 --> 0:01:41.960 that was carrying electric charge, it would be more about 0:01:41.959 --> 0:01:45.559 the movement of that carrier. As it turns out, electrons 0:01:45.600 --> 0:01:49.920 are the naturally occurring negatively charged particles sub atomic particles 0:01:49.960 --> 0:01:55.800 that are concerned, especially with electronics. So it's understandable, but 0:01:55.840 --> 0:01:57.520 I just want to point that out that it's really 0:01:57.560 --> 0:01:59.920 more about electric charge and less about the actual sub 0:02:00.000 --> 0:02:04.440 stomic particles. Uh, don't worry, even though we'll be talking 0:02:04.600 --> 0:02:08.160 a lot about electrons. I promise this show won't be 0:02:08.280 --> 0:02:12.200 too negative. And I'm seriously done with puns for just 0:02:12.240 --> 0:02:15.640 a bit now. To further define electricity, it helps if 0:02:15.639 --> 0:02:18.280 we get some basic ideas established. Now, keep in mind 0:02:18.639 --> 0:02:22.080 these aspects of electricity were not understood for centuries. So 0:02:22.120 --> 0:02:25.480 when I go into the history of electricity, remember that 0:02:25.919 --> 0:02:30.440 for the vast majority of our experience working with and 0:02:30.480 --> 0:02:34.359 trying to understand electricity, we did not have any knowledge 0:02:34.400 --> 0:02:41.639 of the underpinning foundational physics. Right. We were making observations 0:02:41.919 --> 0:02:45.160 and we were even building things that could take advantage 0:02:45.200 --> 0:02:48.360 of this stuff, but we didn't actually understand what it 0:02:48.440 --> 0:02:50.080 was doing or how it was working, which I always 0:02:50.080 --> 0:02:53.480 find really fascinating, this idea that we can harness something 0:02:53.960 --> 0:02:57.280 without fully understanding what it is and how it works. 0:02:58.040 --> 0:03:00.920 But it's good for us, as in myself and you 0:03:00.960 --> 0:03:03.959 guys the audience, to understand some of these basics before 0:03:04.000 --> 0:03:07.240 we get too far into the discussion. Otherwise I have 0:03:07.320 --> 0:03:11.240 to keep interrupting the history lesson for science lessons, and 0:03:11.240 --> 0:03:14.280 then it gets kind of a little complicated. Some of 0:03:14.280 --> 0:03:16.519 that's gonna happen anyway, but I want to get the 0:03:16.560 --> 0:03:23.720 foundation out of the way. So the most important thing 0:03:23.800 --> 0:03:27.160 to remember here is that we're talking electric charge, and 0:03:27.200 --> 0:03:29.480 we want to make sure we can make sense of this. 0:03:29.639 --> 0:03:32.760 It's time to get current on our terms. So I 0:03:32.800 --> 0:03:36.680 guess that really wasn't the last pun I'll be talking about. 0:03:36.680 --> 0:03:40.360 So electric charge comes in two flavors, positive and negative, 0:03:40.640 --> 0:03:43.640 positive charge and negative charge. You're probably very familiar with 0:03:43.720 --> 0:03:47.240 us on the sub atomic particle level. Pot you know, 0:03:47.320 --> 0:03:50.200 we have we have our our protons those are positively charged. 0:03:50.480 --> 0:03:53.680 We have our electrons, those are negatively charged. Now, opposite 0:03:53.760 --> 0:03:58.560 charges attract one another in circuits. A carrier moves negative 0:03:58.640 --> 0:04:02.720 charges to a source of positive charge. So some sort 0:04:02.880 --> 0:04:07.760 of subatomic particle needs to carry that negative charge throughout 0:04:07.760 --> 0:04:10.000 the circuit until it can get to the source of 0:04:10.040 --> 0:04:14.280 a positive charge. Because negative quote unquote wants to be 0:04:14.400 --> 0:04:17.839 with positive. It doesn't really want anything, it's just that's 0:04:17.880 --> 0:04:22.320 the natural tendency, right these for these two different charges 0:04:22.360 --> 0:04:26.520 to attract one another. Now, in practical terms, the carrier 0:04:26.640 --> 0:04:29.599 is an electron. So that's why we talk about electricity. 0:04:29.600 --> 0:04:33.760 It's when we talk about electronics. Um it's the subatomic 0:04:33.760 --> 0:04:36.640 particle that possesses negative charge. So if we do a 0:04:36.760 --> 0:04:41.200 basic electrostatic experiment where we take a block of wax 0:04:41.600 --> 0:04:43.880 and we rub that block of wax with some wool, 0:04:44.600 --> 0:04:47.560 we will build up an electrostatic charge. So what's happening 0:04:47.600 --> 0:04:51.159 is we are imparting a negative charge to the wax 0:04:52.240 --> 0:04:55.120 and creating a positive charge to the wool. So, in 0:04:55.120 --> 0:04:58.080 practical terms, that means the wax has a surplus of 0:04:58.120 --> 0:05:02.680 electrons and the wool has a efficiency of electrons. Effectively, 0:05:02.720 --> 0:05:05.160 you are rubbing some of the electrons from the wool 0:05:05.320 --> 0:05:07.960 onto the wax. That makes the overall charge of the 0:05:07.960 --> 0:05:10.359 surface of the wax negative. It makes the overall charge 0:05:10.400 --> 0:05:13.400 of the surface of the wool positive. And if we 0:05:13.480 --> 0:05:17.640 create a pathway that electrons can follow from the wax 0:05:18.160 --> 0:05:22.440 to the wool, then electrons will take that pathway, pop 0:05:22.440 --> 0:05:26.039 back over to the wool and sort of repair that 0:05:26.200 --> 0:05:31.760 deficiency where that that deficiency of electrons will be balanced out, 0:05:31.800 --> 0:05:35.560 where electrons will journey back over and rejoin, and they'll 0:05:35.600 --> 0:05:37.839 probably be a big party, you know, or at least 0:05:37.839 --> 0:05:43.760 a subatomic one. And that's that's the basics for electric charge. 0:05:43.920 --> 0:05:47.880 So now we have to build on this foundation. There 0:05:47.920 --> 0:05:51.440 are three other basic concepts that we need to understand, 0:05:51.960 --> 0:05:56.720 and those are voltage, current, and resistance. Now these will 0:05:56.760 --> 0:05:59.680 be important throughout the discussion of electricity, particularly as people 0:05:59.800 --> 0:06:02.920 begin to get a deeper understanding of what was actually 0:06:02.960 --> 0:06:07.359 happening with electricity. Voltage is probably the trickiest one for 0:06:07.400 --> 0:06:11.960 people who aren't inclined toward electronics and electricity. It's all 0:06:12.000 --> 0:06:15.640 about potential energy, specifically the potential energy represented by a 0:06:15.680 --> 0:06:20.599 pair of different electric charges. So voltage is sort of 0:06:20.640 --> 0:06:23.560 like pressure. You can imagine it as a force that 0:06:23.720 --> 0:06:28.000 pushes electrons through a conductor, which is oversimplifying, but it's 0:06:28.040 --> 0:06:30.680 helpful when you imagine it that way. So voltage is 0:06:30.720 --> 0:06:34.240 the pressure in the system. The higher the voltage, the 0:06:34.320 --> 0:06:38.280 greater the pressure, the stronger that push is. A low 0:06:38.400 --> 0:06:41.520 voltage has very little push, while high voltage has a 0:06:41.560 --> 0:06:44.240 whole lot of push, And we need voltage to make 0:06:44.240 --> 0:06:47.800 electronics work. Otherwise nothing is going to cause a current 0:06:47.800 --> 0:06:50.760 to flow through a circuit. You can also kind of 0:06:50.760 --> 0:06:53.479 think of it as like potential energy in the form 0:06:53.680 --> 0:06:58.200 of as an analogy of kinetic energy. So let's say 0:06:58.200 --> 0:07:00.760 that you have a level surface pond which you've got 0:07:00.760 --> 0:07:05.159 a two little corrals of marbles. They don't really have 0:07:05.200 --> 0:07:07.680 any potential energy with respect to one another. They're on 0:07:07.720 --> 0:07:10.080 the same level. But let's say you raise one of 0:07:10.120 --> 0:07:11.800 those up, you tilt it, and you raise it up, 0:07:11.800 --> 0:07:14.520 so the corral is still holding the marble's in. But 0:07:14.720 --> 0:07:17.200 now the marbles have potential energy because they're at a 0:07:17.280 --> 0:07:20.880 higher level than the lower marbles. And then let's say 0:07:20.920 --> 0:07:23.960 you were to connect a little slide between the top 0:07:24.040 --> 0:07:26.760 corral and the bottom corral and allow the marbles to 0:07:26.960 --> 0:07:30.240 roll down the hill. Well, this would be sort of 0:07:30.320 --> 0:07:35.960 like a copper wire connecting an area that has a 0:07:36.040 --> 0:07:39.160 surplus of electrons to an area that has a deficiency 0:07:39.200 --> 0:07:45.240 of electrons. It's allowing for the movement of those electrons. Now, 0:07:45.280 --> 0:07:48.600 in the case of voltage, we're really talking about electric 0:07:48.640 --> 0:07:53.280 potential here. We're not talking about kinetic energy or potential 0:07:53.360 --> 0:07:56.640 energy that can be converted into kinetic energy. Is really 0:07:56.640 --> 0:07:59.640 just meant as an analogy. So when we talk about 0:07:59.720 --> 0:08:02.440 volta age, we talk about it with respect of two 0:08:02.480 --> 0:08:06.119 points on a circuit. So a voltage difference between two 0:08:06.120 --> 0:08:09.880 points on a single circuit and their potential difference really 0:08:09.920 --> 0:08:13.400 which we may also call a voltage drop. The potential 0:08:13.400 --> 0:08:17.160 difference between two points is measured in a unit called volts. 0:08:17.640 --> 0:08:20.040 No big surprise there. A volt is the amount of 0:08:20.120 --> 0:08:23.560 energy needed to force an electrical current of one ampier 0:08:24.000 --> 0:08:26.480 more on that in a second, through a resistance of 0:08:26.600 --> 0:08:29.640 one ohm more on that in a second, to at 0:08:29.640 --> 0:08:32.800 a particular temperature. Now, you can have a voltage between 0:08:32.840 --> 0:08:36.439 two points without having any connection between them. So you 0:08:36.480 --> 0:08:38.920 can have a voltage between two things that do not 0:08:39.040 --> 0:08:43.319 have an active pathway between the two. If the distance 0:08:43.520 --> 0:08:50.079 between the two points is decreased, then that electrostatic field 0:08:50.280 --> 0:08:56.479 that the voltage difference creates will intensify. If you increase 0:08:56.600 --> 0:09:01.760 the space between those two points, the electrostatic yield will diminish. 0:09:02.200 --> 0:09:05.880 So distance plays a factor, not just the difference in voltage. 0:09:06.200 --> 0:09:10.320 So that covers voltage. But now let's talk about current. 0:09:11.040 --> 0:09:14.360 So technically the current is a flow of electrical charge, 0:09:14.400 --> 0:09:17.920 and we commonly think of it as the movement of electrons, 0:09:17.960 --> 0:09:20.880 but again that's an oversimplification. You can actually have a 0:09:20.960 --> 0:09:24.200 flow of positive charge and that would still be a current. 0:09:24.840 --> 0:09:27.280 If you add a flow of positive charge, that's technically 0:09:27.280 --> 0:09:30.480 a current. But when we're talking about circuits and electronics, 0:09:30.480 --> 0:09:36.240 were really talking about electrons, not positively charged electrical charges. 0:09:36.840 --> 0:09:39.599 So we tend to simplify it and say it's the 0:09:39.640 --> 0:09:42.000 flow of electrons. Just keep in mind that that is 0:09:42.040 --> 0:09:46.760 an oversimplification, uh, because electrons are the charge carriers of 0:09:46.800 --> 0:09:50.240 negative charge. Now, in a way, you could think of 0:09:50.280 --> 0:09:53.480 it as electrons are the messengers and the electric charge 0:09:53.520 --> 0:09:56.640 they carry is the message, and that's what's really important. 0:09:56.720 --> 0:10:00.400 But in practical terms, we can just so aplify it 0:10:00.440 --> 0:10:05.160 to electrons. We measure current in ampiers, uh, and that 0:10:05.280 --> 0:10:08.400 gives us a sense of the intensity or quantity of 0:10:08.559 --> 0:10:13.840 a charge. So voltage is the force behind moving a charge, 0:10:13.880 --> 0:10:17.720 and amperage tells you how much charge is actually moving. 0:10:18.320 --> 0:10:20.840 And this can help if you start to imagine voltage 0:10:20.880 --> 0:10:24.640 as being a locomotive engine and the amperage as being 0:10:24.720 --> 0:10:28.320 a series of train cars. So a low amperage current 0:10:28.520 --> 0:10:30.320 you might think of as just being two or three 0:10:30.360 --> 0:10:35.040 train cars being pushed by a locomotive engine, but you 0:10:35.120 --> 0:10:38.720 might think of high amperage as being a series of 0:10:38.760 --> 0:10:41.880 train cars like fifteen or twenty being pushed by that 0:10:42.040 --> 0:10:45.679 same locomotive engine. In both cases, the locomotive engine is 0:10:45.720 --> 0:10:49.480 putting out the same amount of force. It's just that 0:10:49.559 --> 0:10:53.640 in one case it's pushing a relatively small number of 0:10:53.679 --> 0:10:56.240 train cars and the other one that's pushing a larger number. 0:10:56.320 --> 0:10:58.240 But the amount of force it's using for both is 0:10:58.280 --> 0:11:03.000 the same. So that's the difference between current and voltage, 0:11:03.440 --> 0:11:08.920 or if you prefer amperage and volts. Uh. Now, current 0:11:09.000 --> 0:11:11.280 will get a bit more confusing when we start talking 0:11:11.320 --> 0:11:14.280 about the direction of flow. And that's thanks to a 0:11:14.360 --> 0:11:17.760 certain founding father of the United States. But I don't 0:11:17.800 --> 0:11:19.920 want to jump ahead. We'll get there when we get there. 0:11:20.360 --> 0:11:23.560 I'll save that for a little bit later in this episode. Finally, 0:11:23.679 --> 0:11:27.000 we have the concept of resistance, and as the name suggests, 0:11:27.000 --> 0:11:29.640 this is the property of a material to resist the 0:11:29.679 --> 0:11:33.200 flow of electric charge. A material with a very high 0:11:33.320 --> 0:11:36.400 resistance is an insulator. It does not allow electric charge 0:11:36.440 --> 0:11:38.400 to pass through it very easily. You would have to 0:11:38.480 --> 0:11:41.280 use a great deal of energy to move an electric 0:11:41.360 --> 0:11:44.520 charge through that kind of material. A material with very 0:11:44.520 --> 0:11:48.079 low resistance is a conductor. It will allow electric charge 0:11:48.120 --> 0:11:52.520 to flow through relatively easily. Now, even conductors have resistance. 0:11:53.440 --> 0:11:57.520 You have to get to very low temperatures, like super 0:11:57.760 --> 0:12:00.960 frozen temperatures almost close to absolute zero to get to 0:12:01.360 --> 0:12:05.200 super conductivity, where you have zero resistance and a conductor 0:12:05.240 --> 0:12:09.240 becomes an ideal or perfect conductor. But at other temperatures 0:12:09.280 --> 0:12:12.560 there's some resistance. You can get around that by making 0:12:12.679 --> 0:12:17.360 a cable thicker. Thin cables have a higher resistance than 0:12:17.400 --> 0:12:21.280 thicker cables. But that's kind of beyond what we're talking 0:12:21.320 --> 0:12:26.600 about here. We measure resistance in Ohms and Ohm. George Home, 0:12:26.760 --> 0:12:30.480 who is a physician who kind of figured all this 0:12:30.520 --> 0:12:34.000 stuff out, uh, developed Ohm's law. Now that tells us 0:12:34.000 --> 0:12:37.440 that voltage is equal to current times resistance, or you 0:12:37.480 --> 0:12:41.080 could say current is equal to voltage divided by resistance, 0:12:41.160 --> 0:12:44.280 or that resistance is equal to voltage divided by current. 0:12:44.760 --> 0:12:49.040 It's this relationship between current, resistance and voltage that is 0:12:49.559 --> 0:12:55.880 inherent in electricity and electronics. Now, those basic concepts are 0:12:55.920 --> 0:12:59.480 the very foundation for all electronics. Now, obviously it gets 0:12:59.480 --> 0:13:02.920 more comp located. Uh, and you can add in all 0:13:02.920 --> 0:13:05.760 sorts of different elements besides that, with like diodes and 0:13:05.760 --> 0:13:07.440 things of that nature. But I just wanted to get 0:13:07.480 --> 0:13:11.600 that covered as the basis for the conversation that follows. 0:13:12.080 --> 0:13:14.880 And now we're going to dive into a history lesson. 0:13:15.600 --> 0:13:21.040 So humans have known about electricity in some form for millennia. 0:13:21.360 --> 0:13:25.000 Fails of melitas, and I know I mispronouncing that, So 0:13:25.040 --> 0:13:29.200 to all my my Greek historians out there, I deeply apologize, 0:13:29.240 --> 0:13:33.400 but I have little Latin and less Greek. Along with 0:13:33.440 --> 0:13:38.280 my my buddy Shakespeare. Anyway, he had noted that amber, 0:13:38.640 --> 0:13:43.280 the material amber, would attract light materials to its surface 0:13:43.320 --> 0:13:45.600 after being rubbed. So if you rubbed amber with a 0:13:45.640 --> 0:13:48.520 cloth and then held it towards feathers, for example, you 0:13:48.559 --> 0:13:50.520 would notice that feathers would have a tendency to be 0:13:50.640 --> 0:13:55.040 attracted to the amber. Now, later on we would understand 0:13:55.080 --> 0:13:58.400 that this is static electricity, this is building an electrostatic 0:13:58.559 --> 0:14:02.080 charge using amber. But this was more of an observation 0:14:02.120 --> 0:14:06.560 back in those times and and this centuries before uh 0:14:06.600 --> 0:14:11.319 the common era. And in fact, the word electricity comes 0:14:11.360 --> 0:14:13.960 from the Latin electron, which in turn comes from the 0:14:14.040 --> 0:14:19.000 Greek electron, which means amber. So when we talked about electrons, 0:14:19.920 --> 0:14:23.040 that means that's the Greek word for amber. And it's 0:14:23.080 --> 0:14:26.520 because of this initial well not even initial, but this 0:14:26.680 --> 0:14:30.480 early observation. I just thought that was kind of interesting, 0:14:31.640 --> 0:14:37.280 and you would eventually learned that a future engineer. Scientists 0:14:37.920 --> 0:14:43.000 named this whole process electricity in honor of this early observation. 0:14:43.680 --> 0:14:47.080 Now in nineteen thirty six, we're jumping ahead just to 0:14:47.120 --> 0:14:52.360 talk about another discovery about ancient civilizations. There was a 0:14:52.680 --> 0:14:59.240 railroad project that ended up excavating some um some ruins 0:14:59.480 --> 0:15:03.480 southeast to Baghdad, and they revealed what we have commonly 0:15:03.560 --> 0:15:07.760 referred to as the Baghdad batteries. These were vessels that 0:15:07.800 --> 0:15:11.280 appeared to have been designed specifically to generate electricity, at 0:15:11.320 --> 0:15:16.440 least that's one of the hypotheses about these uh, these vessels. 0:15:16.480 --> 0:15:20.560 Some people disagree, but it's a very popular one. Now 0:15:20.600 --> 0:15:23.440 you probably have heard about this in some form of 0:15:23.480 --> 0:15:26.280 another or another. You may have even seen the MythBusters 0:15:26.280 --> 0:15:29.360 episode where they talked about this. The team and MythBusters 0:15:29.360 --> 0:15:32.160 talked about the possible applications for these so called batteries, 0:15:32.200 --> 0:15:35.520 which could include a thing that you would use in 0:15:35.600 --> 0:15:41.360 religious ceremonies where you would have these metal coded vessels 0:15:41.400 --> 0:15:43.760 that if you were to touch them, you would create 0:15:43.920 --> 0:15:46.800 a circuit and you would allow electricity to flow through 0:15:46.840 --> 0:15:49.720 you and that would create a tingling or numbing sensation 0:15:49.760 --> 0:15:53.200 in your hands, thus akin to some sort of mystical 0:15:53.280 --> 0:15:57.000 experience and thus being part of a religious experience. Or 0:15:58.200 --> 0:16:00.600 it could be that it was more of a practical 0:16:01.800 --> 0:16:06.520 approach toward something like electro plating, and I thought that 0:16:06.600 --> 0:16:08.840 was really cool. So let's talk about what electroplating is, 0:16:08.880 --> 0:16:12.400 because otherwise, you know, it doesn't really mean anything to you. 0:16:12.960 --> 0:16:16.680 As the name implies, electroplating involves using electricity to cover 0:16:16.920 --> 0:16:22.320 or plate one material with another material. Typically you are 0:16:22.520 --> 0:16:26.080 plating one type of metal, not necessarily metal, but the 0:16:26.120 --> 0:16:30.280 early version of electro plating was metal, but one type 0:16:30.280 --> 0:16:34.520 of metal with a more precious metal. So the reason 0:16:34.560 --> 0:16:38.239 you might do this is to make really pretty expensive 0:16:38.360 --> 0:16:42.720 looking stuff without using too much of the actual precious material. 0:16:43.520 --> 0:16:46.240 So you might gold plate a copper bowl, for example, 0:16:46.320 --> 0:16:49.440 because you want the gold bowl. Gold is more precious 0:16:49.440 --> 0:16:52.240 than copper, but you don't want to actually have to 0:16:52.280 --> 0:16:54.320 go out and dig as much gold as you would 0:16:54.320 --> 0:16:56.240 need to build a gold bowl, so you want to 0:16:56.240 --> 0:17:00.600 plate the copper bowl with gold. That way, it looks 0:17:00.800 --> 0:17:03.000 exactly the way you wanted to, but you didn't have 0:17:03.080 --> 0:17:05.760 to spend all that time and effort getting all that gold. 0:17:05.760 --> 0:17:08.720 In other words, we can thank the laziness and greed 0:17:08.800 --> 0:17:11.800 of human beings for some of the early advances as 0:17:11.840 --> 0:17:16.800 far as electricity is concerned, So you might want to 0:17:16.880 --> 0:17:19.840 use electroplating to do that. We also use electroplating for 0:17:19.880 --> 0:17:23.960 other purposes, like putting rust resistant coatings onto stuff that 0:17:24.000 --> 0:17:27.159 otherwise would corrode. Uh. You can also use it to 0:17:27.160 --> 0:17:32.280 produce alloys like bronze and brass. But let's go back 0:17:32.280 --> 0:17:35.560 to electroplating. So let's say these ancient people were using 0:17:35.920 --> 0:17:39.359 the so called Bagdad batteries in order to electroplate gold 0:17:39.359 --> 0:17:42.760 onto copper. How would you do this well, First you 0:17:42.800 --> 0:17:45.160 have to make sure that the copper is totally clean, 0:17:45.400 --> 0:17:48.760 because if it has any Schmutz on it, the gold 0:17:48.760 --> 0:17:51.760 will not properly adhere to the copper and it'll flake off. 0:17:52.680 --> 0:17:58.040 So you typically would clean copper this way by dipping 0:17:58.080 --> 0:18:01.600 it in a solution that either is a really powerful 0:18:01.640 --> 0:18:05.159 alkaline solution or a very powerful acidic solution to to 0:18:05.280 --> 0:18:08.440 truly clean it. Once you did that, you would then 0:18:08.600 --> 0:18:12.359 attach a conductor from the battery to the copper that 0:18:12.400 --> 0:18:15.840 you're playing on on electroplating. So if it's a bowl, 0:18:16.119 --> 0:18:18.440 then you would want to make sure that the terminal, 0:18:18.720 --> 0:18:23.680 the proper terminal from the Baghdad battery is in contact 0:18:23.920 --> 0:18:28.160 with that copper bowl. Then you would put that whole thing, 0:18:28.280 --> 0:18:32.600 the copper bowl with the um the terminal into an 0:18:32.640 --> 0:18:36.359 electro light solution, which is in this case a gold 0:18:36.359 --> 0:18:40.239 based electro light, so you have gold particles within the 0:18:40.320 --> 0:18:44.119 electrolyte itself. Now electrolytes, by the way, our materials that 0:18:44.240 --> 0:18:48.240 dissociate into ions when dissolved in a suitable medium and 0:18:48.280 --> 0:18:52.520 become a conductor of electricity. So ions, of course, are 0:18:52.520 --> 0:18:56.320 are our variations of atoms that have a net charge 0:18:56.520 --> 0:18:59.040 on them. They're not neutral. They have either a net 0:18:59.040 --> 0:19:02.159 negative or a net positive charge. So when you do this, 0:19:02.240 --> 0:19:06.520 you've got your gold ions in this electrolyte solution. You 0:19:07.040 --> 0:19:10.919 then put the electrodes together so that not together, but 0:19:11.000 --> 0:19:14.080 within the solution, so that a current can pass through 0:19:15.000 --> 0:19:18.760 the electrodes. Allow the current to go through the electrolight 0:19:18.880 --> 0:19:23.640 into the other terminal or the other electrode, and you've 0:19:23.640 --> 0:19:26.199 got a negative in a positive electrode. So when the 0:19:26.200 --> 0:19:28.879 current passes through the electro light, the electrolyte splits up 0:19:28.880 --> 0:19:31.800 and some of the metal atoms contained within the electrolyte 0:19:31.800 --> 0:19:34.720 are deposited on one of the two electrodes that you 0:19:34.760 --> 0:19:37.720 inserted into the electrolyte. So what's really happening is the 0:19:37.760 --> 0:19:40.600 metal atoms are ions. They hold that charge. They're attracted 0:19:40.640 --> 0:19:43.399 to the electrode that has the opposite charge, and they 0:19:43.440 --> 0:19:47.320 attached to it. So if you have a negatively charged 0:19:47.920 --> 0:19:52.280 terminal and you have positively charged gold ions, that opposite 0:19:52.280 --> 0:19:55.679 attract rule still takes place and the gold will plate 0:19:55.920 --> 0:20:02.200 onto the copper electrode or bowl in this case, and 0:20:02.480 --> 0:20:04.879 then you've got your gold plated copper thing of a 0:20:04.960 --> 0:20:07.920 jig which is kind of cool. Now there's some who 0:20:07.920 --> 0:20:11.160 put forth the hypothesis that perhaps ancient people has made 0:20:11.160 --> 0:20:14.840 other uses of electricity, all the way up to even 0:20:14.880 --> 0:20:20.159 powering lights in ancient Egypt, but most scholars that I 0:20:20.240 --> 0:20:28.119 have consulted dismiss this as unrealistic. I haven't really seen 0:20:28.200 --> 0:20:32.440 much evidence to support this apart from some circumstantial evidence. 0:20:32.440 --> 0:20:37.240 Some supporters cite a hieroglyphic relief that shows what to 0:20:37.320 --> 0:20:41.359 our modern eyes appears to be an enormous lightbulb, but 0:20:41.440 --> 0:20:45.640 the accepted interpretation of that hieroglyph seems to be that 0:20:45.800 --> 0:20:48.560 it's a lotus leaf with the figure of a snake 0:20:48.680 --> 0:20:53.000 on it, not a huge ancient lightbulb. Still, it seems 0:20:53.000 --> 0:20:54.880 that there was at least some knowledge of the existence 0:20:54.880 --> 0:20:57.760 of electricity, if not what it actually could do or 0:20:57.800 --> 0:21:01.520 what it was. Now that's a trend that would last 0:21:01.600 --> 0:21:05.200 for centuries. In fact, we were making use of electricity 0:21:05.480 --> 0:21:08.080 well before anyone really knew what was going on with it. 0:21:08.200 --> 0:21:10.560 And again, to me, that is one of the phenomenal 0:21:10.560 --> 0:21:13.160 things about human history is when we come across these 0:21:13.200 --> 0:21:16.679 moments where people have figured out something or how to 0:21:16.800 --> 0:21:20.080 use something without really fully understanding why it is that 0:21:20.119 --> 0:21:23.399 could be dangerous. Clearly, there were plenty of cases of 0:21:23.440 --> 0:21:26.720 that in the nineteen fifties with radiation, where people thought 0:21:27.119 --> 0:21:32.080 that radiation didn't have any particular harmful effects. You might 0:21:32.080 --> 0:21:35.679 have seen things about like using X rays in shoe 0:21:35.680 --> 0:21:38.679 stores so that people could see their feet through the 0:21:38.760 --> 0:21:42.040 shoes that they were trying on. And then only later 0:21:42.280 --> 0:21:45.000 did we realize that X rays are an ionizing form 0:21:45.080 --> 0:21:47.880 of radiation and that we probably should not or definitely 0:21:47.920 --> 0:21:50.840 should not have been doing that. Um same sort of 0:21:50.840 --> 0:21:52.800 thing with electricity. We were putting it to use before 0:21:52.840 --> 0:21:56.440 we ever really understood what was going on there. Uh. 0:21:56.600 --> 0:21:59.320 But of course electricity isn't ionizing radiation, so it does 0:21:59.400 --> 0:22:05.160 have very different effects then radiation does. But what follows 0:22:05.200 --> 0:22:07.920 is a brief history of the developments that unfolded as 0:22:08.040 --> 0:22:11.760 very very smart people figured out what the heck electricity is. 0:22:12.240 --> 0:22:15.200 So in the fifteen hundreds you had an English physician 0:22:15.320 --> 0:22:19.960 and proto scientist named William Gilbert who began to experiment 0:22:20.000 --> 0:22:24.000 with magnets and static electricity. So he used loadstone, which 0:22:24.040 --> 0:22:27.639 is naturally magnetic iron ore, and he published his work 0:22:27.720 --> 0:22:32.840 in sixteen hundred under the title De magnete or a 0:22:32.920 --> 0:22:38.040 de magnet magneti. It's magneto but with a knee. He 0:22:38.119 --> 0:22:43.040 was able to describe magnetism and static electricity as distinct phenomena, 0:22:43.200 --> 0:22:45.440 though he wasn't really sure what was actually causing it. 0:22:45.760 --> 0:22:48.560 His hypothesis was that there was some sort of fluid 0:22:48.960 --> 0:22:52.479 or humor, as in the various humors of the body. 0:22:52.720 --> 0:22:56.520 There was another prevailing physical theory at the time, and 0:22:56.560 --> 0:22:59.720 that this was the cause of attraction with static electricity, 0:22:59.800 --> 0:23:02.000 and that if you rubbed amber, what you were actually 0:23:02.000 --> 0:23:05.159 doing was removing some of that fluid from the amber, 0:23:05.200 --> 0:23:09.239 which created a hole or like a vacuum around it, 0:23:09.320 --> 0:23:12.080 and this is why light objects would become attracted to 0:23:12.119 --> 0:23:16.320 the amber. He called it a fluvium and described it 0:23:16.400 --> 0:23:22.399 as an electric effect. In sixteen sixty an inventor named 0:23:22.400 --> 0:23:26.640 Otto von Gerrika built a machine using a globe made 0:23:26.640 --> 0:23:29.639 of sulfur, and if you rubbed the globe as it turned, 0:23:29.720 --> 0:23:33.080 you could build up a charge, an electrostatic charge, causing 0:23:33.119 --> 0:23:35.639 it to attract small light objects such as feathers or 0:23:35.640 --> 0:23:39.160 scraps of paper. Garrika also observed that his invention would 0:23:39.200 --> 0:23:42.400 cause a spark if you rubbed the globe for long enough. 0:23:42.480 --> 0:23:46.719 You could then touch something metal like a brass knob 0:23:47.080 --> 0:23:51.600 and see a spark fly between the electrostatically charged object 0:23:51.640 --> 0:23:57.000 and the grounded piece of metal. Stephen Gray, another English scientist, 0:23:57.080 --> 0:23:59.960 observed in seventeen twenty nine that some stuff doesn't can 0:24:00.040 --> 0:24:03.200 duct electricity at all. So he thought some materials would 0:24:03.240 --> 0:24:07.200 allow the fluid of electricity to flow through and other 0:24:07.600 --> 0:24:11.920 materials would hamper the flow of this fluid electricity, which 0:24:11.960 --> 0:24:15.000 is sort of true when you get to electrical resistance, 0:24:15.040 --> 0:24:19.320 only we're not talking about a fluid really. Later that century, 0:24:19.520 --> 0:24:25.400 Dutch inventor's Pietr von Musen book and evolved von Kleist 0:24:25.880 --> 0:24:28.960 created what we now call the Layden jar, and there 0:24:28.960 --> 0:24:33.080 are actually two variations on basic Layden jars, which store 0:24:33.200 --> 0:24:37.199 electrostatic charges. They're essentially capacitors, So you build up an 0:24:37.200 --> 0:24:40.000 electric static charge in this thing, and then when you 0:24:41.080 --> 0:24:46.520 touch the the charged component, you allow that electro static 0:24:46.640 --> 0:24:52.040 charge to discharge to spark um. So they release all 0:24:52.080 --> 0:24:56.240 of that charged energy in an instant, unlike a battery, 0:24:56.320 --> 0:25:03.119 which releases UH which which creates the voltage difference and 0:25:03.160 --> 0:25:06.600 allows for electric electric current to flow over time. A 0:25:06.600 --> 0:25:11.800 capacitor releases it in a in a a moment. There 0:25:11.800 --> 0:25:13.800 are two basic versions of the Leyden jar, and the 0:25:13.840 --> 0:25:18.600 first one uses a metal container inside which you have 0:25:18.840 --> 0:25:22.639 a glass vessel nestled inside that metal container, and inside 0:25:22.640 --> 0:25:27.000 the glass vessel you have a second metal container nestled 0:25:27.040 --> 0:25:29.600 inside that. So it's kind of like a sandwich where 0:25:29.600 --> 0:25:33.800 the bread is metal container and the and the meat 0:25:33.880 --> 0:25:38.359 inside is glass. I don't recommend eating that sandwich, it 0:25:38.400 --> 0:25:43.040 would not taste good and probably hurt you, but it 0:25:43.119 --> 0:25:48.040 was that layer metal glass metal, and you would then 0:25:48.160 --> 0:25:50.760 also have a rod of metal that would extend up 0:25:50.760 --> 0:25:55.600 from the base of that interior lining. So imagine like 0:25:55.640 --> 0:26:00.399 a column rising up from that internal metal cup inside 0:26:00.480 --> 0:26:02.679 the glass vessel, which in turn is inside a larger 0:26:02.680 --> 0:26:07.760 metal vessel. The second variation has a metal vessel filled 0:26:07.800 --> 0:26:10.919 with a conductive fluid like water that's got a salt 0:26:10.960 --> 0:26:13.119 dissolved in it. Water on in its own will conduct 0:26:13.160 --> 0:26:16.320 electricity as long as it has some impurities in it, 0:26:16.359 --> 0:26:19.560 but you can make it conduct electricity more effectively by 0:26:19.560 --> 0:26:22.840 adding or doping the water with some of those impurities, 0:26:23.359 --> 0:26:25.160 and it would have a metal rod sticking out from 0:26:25.160 --> 0:26:27.119 the water. Now, both versions would allow you to do 0:26:27.280 --> 0:26:29.520 essentially the same thing, which is store up that electro 0:26:29.520 --> 0:26:32.679 static charge. And you do this by building up an 0:26:32.720 --> 0:26:36.920 electric static charge in something else. So you might take 0:26:36.960 --> 0:26:39.720 some amber, for example, and rub the amber. Then you 0:26:39.760 --> 0:26:43.400 would bring that into contact with that metal bar that's 0:26:43.400 --> 0:26:47.440 extending upward from the jar. That would introduce a charge 0:26:47.560 --> 0:26:52.320 to one plate in this capacity, and that would create 0:26:52.359 --> 0:26:56.040 the opposite charge in the opposing plate. Uh in this 0:26:56.080 --> 0:26:59.240 case that exterior metal casing, you would need to ground 0:26:59.280 --> 0:27:01.520 the outer metal case, which you could just do by 0:27:01.560 --> 0:27:04.800 touching it yourself, or you could run a wire from 0:27:04.960 --> 0:27:08.879 the exterior metal case to the ground or to a 0:27:08.920 --> 0:27:11.720 metal pipe. And when you create a pathway between the 0:27:11.720 --> 0:27:14.480 two plates by touching the charged rod, it creates a 0:27:14.520 --> 0:27:17.280 spark as the charge is able to equalize, and that 0:27:17.320 --> 0:27:20.360 could be a significant shock, depending on how much you've 0:27:20.359 --> 0:27:23.200 built up inside this laden jar, to the point where 0:27:23.280 --> 0:27:27.360 it could really hurt or possibly do serious damage. Both 0:27:27.440 --> 0:27:31.920 Klaised and Moose musten Brook had shocking experiences with the 0:27:32.040 --> 0:27:34.960 respective laden jars, and neither was really sure exactly what 0:27:35.040 --> 0:27:37.360 was happening. Now we've got a lot ward to talk 0:27:37.400 --> 0:27:42.200 about with the early discoveries surrounding electricity. But before we 0:27:42.560 --> 0:27:44.480 get a charge out of all that, let's take a 0:27:44.560 --> 0:27:55.200 quick break to thank our sponsors. All right, we're up 0:27:55.200 --> 0:27:59.800 to seventeen fifty two, and that's when we revisit the 0:28:00.600 --> 0:28:05.000 the great founding father I had mentioned earlier, Benjamin Franklin. 0:28:05.119 --> 0:28:09.600 That's when we got the legendary experiments that Franklin conducted um. 0:28:09.640 --> 0:28:13.000 He was friends with a scientist named Peter Collinson over 0:28:13.040 --> 0:28:18.400 in Europe, and Collinson had sent Franklin and electricity tube. Franklin, 0:28:18.480 --> 0:28:21.280 like his predecessors, thought electricity was a type of fluid, 0:28:21.600 --> 0:28:26.320 and he hypothesized that lightning itself was an electric spark, 0:28:26.600 --> 0:28:29.280 very much like the kind a latent jar could produce 0:28:29.440 --> 0:28:32.800 if you built up enough of an electrostatic charge, and 0:28:32.960 --> 0:28:36.720 thus charged forces would cause a lightning strike. And he 0:28:36.880 --> 0:28:40.760 further hypothesized that you could use a metal rod to 0:28:41.040 --> 0:28:44.680 draw lightning to a specific location, which could end up 0:28:45.000 --> 0:28:48.680 saving structures from being struck by lightning. So if you 0:28:48.720 --> 0:28:50.320 had a house and it got hit by lightning back 0:28:50.360 --> 0:28:54.080 in those days, your house would very much be damaged, 0:28:54.120 --> 0:28:56.600 possibly burned down as a result. So he thought, well, 0:28:56.640 --> 0:28:59.840 maybe you could draw lightning away using long metal rods. 0:28:59.840 --> 0:29:03.240 But problem was he couldn't build a metal rod tall 0:29:03.400 --> 0:29:06.680 enough to dwarf the structures. He thought that he was 0:29:06.680 --> 0:29:09.160 gonna have to build something that could almost reach the 0:29:09.160 --> 0:29:13.120 skies themselves, which made it too big of a challenge. 0:29:14.160 --> 0:29:17.160 Uh So he came up with this idea of using 0:29:17.200 --> 0:29:23.400 a kite instead. Meanwhile, over in France, Thomas Francois d'allebard 0:29:23.760 --> 0:29:26.760 decided to put Franklin's ideas to the test. He actually 0:29:26.800 --> 0:29:30.280 constructed a large metal pole to try and conduct electricity 0:29:30.320 --> 0:29:33.200 and declared that Franklin was absolutely right that in fact, 0:29:33.360 --> 0:29:37.240 that metal rod does draw lightning. But this news didn't 0:29:37.280 --> 0:29:40.640 travel back to America that fast. I mean, it took 0:29:40.640 --> 0:29:43.320 a really long time for information to go from one 0:29:43.320 --> 0:29:48.320 place to another, so Franklin was unaware that his hypothesis 0:29:48.320 --> 0:29:53.000 had proven correct. So that same year, Franklin reportedly conducted 0:29:53.040 --> 0:29:56.959 his experiment using a silk kite with a key tied 0:29:57.240 --> 0:30:01.640 to the silk kite down to the string, and as 0:30:01.720 --> 0:30:04.400 legend goes, he flew the kite up during a thunderstorm 0:30:04.480 --> 0:30:07.240 until the key drew lightning to it, and then used 0:30:07.400 --> 0:30:11.200 that key to charge a laden jar. So the electric 0:30:11.280 --> 0:30:14.120 charge and the key was then transferred to a laden jar, 0:30:14.200 --> 0:30:18.400 which again holds electrostatic charge. Now, I say reportedly because 0:30:18.480 --> 0:30:22.520 Franklin's writings never outright said that that was what happened. 0:30:22.560 --> 0:30:27.200 He never specifically said that he himself had performed the experiment. Now, 0:30:27.200 --> 0:30:29.520 he did say that he did a simplified version of 0:30:29.560 --> 0:30:32.120 this plan and that it happened in Philadelphia, But it's 0:30:32.200 --> 0:30:34.560 unclear who was actually flying the kite at the time. 0:30:35.040 --> 0:30:38.600 And according to modern scientists, if Franklin had conducted the 0:30:38.640 --> 0:30:42.440 experiment as it has generally been reported, Franklin would have 0:30:42.480 --> 0:30:46.640 been toasted. He would have been fried scientifically speaking. So 0:30:46.720 --> 0:30:52.000 the general theory about this not scientific theory, but you know, 0:30:52.040 --> 0:30:54.600 the general idea of what actually happened was that Franklin, 0:30:55.200 --> 0:30:58.160 if he conducted the experiment at all, was able to 0:30:58.200 --> 0:31:01.320 pick up an electrostatic charge by flying the kite near 0:31:01.360 --> 0:31:04.680 a storm, but that the kite was never directly struck 0:31:04.720 --> 0:31:07.480 by lightning. It just rather picked up a charge by 0:31:07.520 --> 0:31:12.520 being lightning adjacent. I guess you could say, all quibbling aside. 0:31:12.560 --> 0:31:14.719 By this time, it became established that lightning was in 0:31:14.760 --> 0:31:19.040 fact a really big spark. Therefore, part of this concept 0:31:19.080 --> 0:31:22.720 of electricity. Franklin made practical use out of this knowledge 0:31:22.760 --> 0:31:25.240 by inventing the lightning rod. Now, the purpose of a 0:31:25.320 --> 0:31:27.520 lightning rod is to attract a bolt of lightning to 0:31:27.600 --> 0:31:31.320 the rod and then channel the electricity down to the ground. 0:31:32.280 --> 0:31:35.920 Uh This spares structures from being hit by lightning and 0:31:35.960 --> 0:31:38.880 thus being damaged. So your lightning rod typically has a 0:31:38.880 --> 0:31:41.880 metal cable that extends down from the rod and then 0:31:42.560 --> 0:31:46.160 is bury. It has like a conductive steak as well 0:31:46.200 --> 0:31:49.080 that's buried in the ground and that channels the the 0:31:49.800 --> 0:31:53.280 the current from the lightning down into the ground. Or 0:31:53.280 --> 0:31:56.600 really it just gives the current a different direction to travel, honestly, 0:31:56.880 --> 0:31:59.320 but if you look at lightning, current goes from the 0:31:59.320 --> 0:32:01.920 ground up to the sky. It doesn't matter. The point 0:32:01.960 --> 0:32:03.600 being that he was able to figure out a way 0:32:03.680 --> 0:32:08.480 of sparing houses by using lightning rods. So he also 0:32:08.600 --> 0:32:12.320 established something about electricity that vexes folks when they're first 0:32:12.520 --> 0:32:17.360 learning about it. Franklin established electricity is having two natures. 0:32:17.360 --> 0:32:21.479 He called it the resinous electricity, which he viewed as 0:32:21.520 --> 0:32:24.360 a dip in the electric fluid from the normal amount 0:32:24.480 --> 0:32:27.000 and thus negative. So this is where the charge is 0:32:27.040 --> 0:32:30.520 flowing too. This would be akin to that idea of 0:32:30.520 --> 0:32:33.240 a vacuum. You have a lack of something a hole, 0:32:33.920 --> 0:32:37.160 and thus something else goes to fill the whole. Then 0:32:37.200 --> 0:32:40.560 there was what he called vitreous electricity, which was an 0:32:40.560 --> 0:32:44.880 excess of electric fluid and thus a positive amount. So 0:32:44.960 --> 0:32:49.640 Franklin said, the movement of electricity goes from positive to negative. 0:32:50.320 --> 0:32:54.120 You have an overabundance of this electric fluid, and it 0:32:54.160 --> 0:32:57.440 moves to where you have a deficiency of electric fluid. 0:32:58.000 --> 0:33:03.080 So the this is somewhat confusing if you're looking at 0:33:03.120 --> 0:33:08.160 the scientific description of what's happening with your basic electric circuit, 0:33:08.560 --> 0:33:12.640 where you're having negatively charged particles, that is, electrons go 0:33:12.920 --> 0:33:15.080 from an area of high concentration to an area of 0:33:15.120 --> 0:33:19.680 low concentration. It's the it's going from negative to positive, 0:33:20.040 --> 0:33:22.560 not positive to negative. But it's because you're looking at 0:33:22.600 --> 0:33:25.440 two different definitions of what is positive and what is negative. 0:33:25.840 --> 0:33:29.440 That's where the real confusion lies. Uh So, when we 0:33:29.520 --> 0:33:34.000 talk about electronics and we talk about electron flow and 0:33:34.040 --> 0:33:37.680 we're looking at it purely from a charge perspective, we're 0:33:37.720 --> 0:33:43.160 looking at negative particles moving towards a positive side. But 0:33:43.240 --> 0:33:45.360 let's make it even more confusing than that. There are 0:33:45.360 --> 0:33:48.920 really two major ways to illustrate charge flow in circuits. 0:33:49.840 --> 0:33:52.720 One of them is called conventional flow notation, which is 0:33:52.760 --> 0:33:56.560 the way electrical engineers tend to describe electrical flow, and 0:33:56.640 --> 0:34:02.600 this follows Franklin's approach. It goes from positive to negative, 0:34:02.680 --> 0:34:05.480 so electricity flows from the positive terminal to the negative 0:34:05.560 --> 0:34:10.759 terminal because we're talking about the surplus of electrons to 0:34:10.880 --> 0:34:13.880 the deficiency of electrons. We're not talking about the the 0:34:13.920 --> 0:34:17.480 electric charge, we're talking about the number. There's more electrons 0:34:17.520 --> 0:34:21.120 over here than they're over there, so that's why this 0:34:21.160 --> 0:34:23.880 is gonna be the positive terminal with more electrons and 0:34:23.920 --> 0:34:26.719 the negative terminal has fewer electrons because we're talking about 0:34:26.719 --> 0:34:32.279 surplus and deficiency. But there's also electron flow notation now 0:34:32.320 --> 0:34:35.440 that one looks at the actual charges, not the numbers. 0:34:35.920 --> 0:34:38.520 So in that case, the negative terminal is where the 0:34:38.520 --> 0:34:42.320 electrons are and it flows to the positive terminal. Both 0:34:42.680 --> 0:34:46.200 illustrations can describe the exact same circuit, but they're going 0:34:46.239 --> 0:34:50.160 to show a difference in what is positive and negative terminals, 0:34:50.480 --> 0:34:54.120 and so it can get really confusing. Uh. Engineers tend 0:34:54.160 --> 0:34:57.120 to use that conventional flow notation. Professional scientists tend to 0:34:57.160 --> 0:35:01.800 prefer the electron flow notation, and thus we're all left 0:35:01.840 --> 0:35:04.840 scratching our heads. All that being said, an enlightened person 0:35:04.920 --> 0:35:08.160 might argue that Franklin's description is perfectly suitable if we 0:35:08.200 --> 0:35:11.320 look at other examples of electric charge moving across an area, 0:35:11.360 --> 0:35:15.360 Because yes, in wires, we're talking about those negatively charged electrons, 0:35:15.360 --> 0:35:19.040 but in other substances you might talk about protons or 0:35:19.200 --> 0:35:23.080 positively charged ions moving due to a difference in charge. 0:35:23.560 --> 0:35:27.520 And because you have these positively charged ions or even 0:35:27.520 --> 0:35:30.520 sub atomic particles and their movement can also be described 0:35:30.560 --> 0:35:35.080 as electricity. It it's perfectly valid. It's just not what 0:35:35.200 --> 0:35:39.080 we see with electronic circuits. So there's that. Still a 0:35:39.080 --> 0:35:41.480 lot of folks bemoan the fact that Franklin's decision to 0:35:41.560 --> 0:35:44.640 name things as he did was kind of based on 0:35:44.680 --> 0:35:47.640 a whim and it made things more complicated as we 0:35:47.760 --> 0:35:50.480 learned more later on. But honestly, there was no way 0:35:50.480 --> 0:35:52.760 for him to know at the time. It's not really 0:35:52.800 --> 0:35:56.960 his fault. It just kind of turned out that way. Anyway, 0:35:57.000 --> 0:35:59.880 back to the timeline, since we won't learn about electrons 0:36:00.080 --> 0:36:03.879 or a couple of hundred years after Benjamin Franklin's work 0:36:03.960 --> 0:36:07.840 with lightning, we should just go back to what people 0:36:07.840 --> 0:36:10.880 were experimenting with and learning about. So a few decades 0:36:10.920 --> 0:36:14.520 after Franklin's experiments, there was a guy named Charles Augustine 0:36:14.600 --> 0:36:18.880 de Colombe who made some significant contributions to our understanding 0:36:18.920 --> 0:36:23.719 of electricity. He published multiple papers on the subjects of 0:36:23.760 --> 0:36:28.160 electricity and magnetism between seventeen eighty five and seventeen ninety one, 0:36:28.200 --> 0:36:30.120 and he had done a lot of work leading up 0:36:30.160 --> 0:36:34.600 to those publications. Among his discoveries was the relationship between 0:36:34.600 --> 0:36:39.239 the strength of opposite charges and that distance between them. 0:36:39.280 --> 0:36:42.520 He developed what we now call Coulomb's law. Now, this 0:36:42.600 --> 0:36:45.840 law states the electrical or magnetic force depends upon the 0:36:45.920 --> 0:36:48.920 strength and nature of the charges of the two objects 0:36:49.400 --> 0:36:52.640 and the distance between those two objects. So, if you 0:36:52.680 --> 0:36:57.360 have two similarly charged objects, like two positives, they repel 0:36:57.480 --> 0:37:02.640 one another with a non contact force. To opposite charged 0:37:02.760 --> 0:37:05.600 objects a negative and a positive will attract one another 0:37:05.920 --> 0:37:10.719 with a non contact force. These forces are vector quantities, 0:37:10.760 --> 0:37:13.600 which means they have both a magnitude and a direction, 0:37:14.040 --> 0:37:16.880 and the distance between the two objects affects the amount 0:37:16.920 --> 0:37:19.560 of force. The closer the objects are to one another, 0:37:19.920 --> 0:37:23.879 the greater the force is between them, or in other words, 0:37:23.920 --> 0:37:27.360 that the magnitude of the electrosthetic force of attraction between 0:37:27.360 --> 0:37:31.319 two point charges is directly proportional to the product of 0:37:31.360 --> 0:37:34.960 the magnitudes of charges and inversely proportional to the square 0:37:35.040 --> 0:37:39.920 of the distance between them. That's the technical description of 0:37:39.960 --> 0:37:42.960 Coulomb's law. There's also a constant that you have to 0:37:43.080 --> 0:37:46.120 use when you're working with equations using Coulomb's law, but 0:37:46.280 --> 0:37:49.520 we don't need to really dive into that, the point 0:37:49.560 --> 0:37:53.960 being that he realized that distance definitely plays a factor 0:37:54.160 --> 0:37:57.160 with these other forces that we still didn't fully understand 0:37:57.200 --> 0:38:02.120 at that point. Then you have Alessandro Volta, from whom 0:38:02.120 --> 0:38:05.320 we get the word volt He was an Italian physicist 0:38:05.400 --> 0:38:08.279 who became interested in the study of electricity. Now we 0:38:08.560 --> 0:38:11.720 normally credit Volta with the invention of the electric battery, 0:38:11.960 --> 0:38:15.560 those Baghdad batteries set aside. He began by building on 0:38:15.600 --> 0:38:19.600 the work of another physicist named Johann Carl Vilk, who 0:38:19.680 --> 0:38:23.640 had invented the electro forests. The electro forest was a 0:38:23.680 --> 0:38:27.160 simple capacitive generator that could build up an electrostatic charge 0:38:27.160 --> 0:38:31.520 for use and experiments. So all these scientists really wanted 0:38:31.560 --> 0:38:33.719 to study electricity. But to do that you had to 0:38:33.719 --> 0:38:37.000 build up these electrostatic charges so that when you discharge them, 0:38:37.040 --> 0:38:39.399 you had something to study. So this was a guy 0:38:39.440 --> 0:38:42.080 who had developed the electro forests as a way of 0:38:42.120 --> 0:38:48.720 making that easier to do. Um Volta's buddy Luigi Galvani 0:38:48.800 --> 0:38:51.920 had observed something really unusual himself. He noted that when 0:38:51.920 --> 0:38:55.160 he used two different types of metal to make contact 0:38:55.160 --> 0:38:58.200 with the muscle of a frog, an electric current would 0:38:58.239 --> 0:39:00.840 pass between the two, and so he thought the source 0:39:00.880 --> 0:39:03.239 of the electricity was from the frog itself, and he 0:39:03.320 --> 0:39:07.440 called it animal electricity. Volta disagreed, saying that the frog 0:39:07.520 --> 0:39:10.480 was just a conductor, not the generator, and so he 0:39:10.520 --> 0:39:14.040 was calling it metallic electricity. And this was a big 0:39:14.080 --> 0:39:19.240 debate in circles at the time. So in Volta began 0:39:19.280 --> 0:39:23.200 to experiment on metals used, often using his own tongue 0:39:23.800 --> 0:39:26.200 as the laboratory. He would put two different discs of 0:39:26.239 --> 0:39:28.279 metal on his tongue and feel the tingling on his 0:39:28.360 --> 0:39:31.839 tongue and say, yep, there's there's an electric current passing there. 0:39:33.239 --> 0:39:34.920 But he could also use other stuff as well, and 0:39:34.960 --> 0:39:37.279 he was able to observe that in fact, it was 0:39:37.320 --> 0:39:41.839 the metals that were important, not the creature. This also 0:39:41.880 --> 0:39:45.080 inspired Volta to look into electricity further, which culminated with 0:39:45.120 --> 0:39:48.399 the design of the first real battery as far as 0:39:48.560 --> 0:39:52.000 modern science is concerned. It was an eighteen hundred that 0:39:52.120 --> 0:39:57.719 Volta invented the voltaic pile, also known as the voltaic column. 0:39:58.120 --> 0:40:01.920 This battery consisted of alternating layers of zinc and silver, 0:40:02.480 --> 0:40:06.360 or of alternating layers of copper and pewter, with layers 0:40:06.400 --> 0:40:09.560 of paper or cloth soaked in a salt solution in 0:40:09.640 --> 0:40:13.319 between the different metal disks. This arrangement could create a 0:40:13.360 --> 0:40:16.760 steady electric current that didn't need recharging like a Leyden 0:40:16.880 --> 0:40:20.280 jar did, so this was a great solution for engineers 0:40:20.280 --> 0:40:23.040 and scientists who wanted to be able to work with electricity, 0:40:23.120 --> 0:40:25.719 but didn't want to have to stop every time they 0:40:25.920 --> 0:40:29.399 discharged Leyden jar to build up another electrostatic charge. This 0:40:29.520 --> 0:40:32.959 was a a steady source, so it was a huge boon. 0:40:33.400 --> 0:40:36.200 Although he didn't really have any other practical applications for 0:40:36.239 --> 0:40:41.800 electricity just yet. But six weeks after Volta published his findings, 0:40:42.320 --> 0:40:47.640 English scientists William Nicholson and Anthony Carlyle experimented with a 0:40:47.719 --> 0:40:51.520 voltaic pile and electrodes placed in water, and the electric 0:40:51.560 --> 0:40:54.279 current that passed through the water caused the water to 0:40:54.400 --> 0:40:59.560 decompose into hydrogen and oxygen, breaking the molecules of water 0:40:59.680 --> 0:41:03.640 apart art. And this is a process that we call electrolysis, 0:41:03.680 --> 0:41:06.520 specifically with water, but with other things as well, using 0:41:06.560 --> 0:41:11.320 electrical electrical charges to break those molecular bonds. By eighteen 0:41:11.360 --> 0:41:16.400 o two, William Crookshank had designed the first electric battery 0:41:16.480 --> 0:41:19.400 for mass production, using copper and zinc in a wooden 0:41:19.480 --> 0:41:23.520 box filled with an electrolyte of brine and sealed to 0:41:23.640 --> 0:41:27.000 prevent leaking. So a big think of a big wooden 0:41:27.080 --> 0:41:30.600 battery akin to something like a car battery would be 0:41:30.719 --> 0:41:34.920 like this today. So Volta died in eighty seven, and 0:41:34.960 --> 0:41:37.800 it was an eighty one that the scientific community decided 0:41:37.840 --> 0:41:42.279 to name the unit of electromotive force the vault, after him, 0:41:42.760 --> 0:41:44.600 so he was. He did not live to see his 0:41:44.719 --> 0:41:49.520 name used to describe electromotive force, but he certainly was 0:41:49.600 --> 0:41:52.919 the inspiration for it, and other inventors and scientists would 0:41:52.960 --> 0:41:56.920 improve upon Volta's design, including chemist John F. Daniel and 0:41:57.040 --> 0:42:01.080 later a physician from France named Gaston p Ande, who 0:42:01.120 --> 0:42:06.080 designed the first rechargeable lead acid battery. So Plante's design 0:42:06.239 --> 0:42:08.920 is the basis for modern lead acid batteries today, like 0:42:08.960 --> 0:42:12.120 the kind you would find in internal combustion engine vehicles. 0:42:12.960 --> 0:42:16.840 That has its roots back in the early, well early 0:42:16.880 --> 0:42:20.920 to mid nineteenth century. It's kind of incredible. Later on 0:42:20.960 --> 0:42:23.360 you would see other improvements with battery technology. Might as 0:42:23.400 --> 0:42:25.920 well stick with that for right now. That would include 0:42:25.960 --> 0:42:29.360 the nickel cadmium battery, which was first designed by Valdemar 0:42:29.520 --> 0:42:34.320 Jongner from Sweden in eight and the nickel iron battery 0:42:34.680 --> 0:42:39.000 designed by Thomas Edison, or at least Thomas Edison's team 0:42:39.080 --> 0:42:43.640 of engineers and scientists. There's always a caveat whenever you 0:42:43.680 --> 0:42:46.680 say Thomas Edison's invention, because he had a whole lot 0:42:46.680 --> 0:42:50.000 of people working for him who were busy research in 0:42:50.719 --> 0:42:54.399 developing all sorts of different technologies, and Edison's name gets 0:42:54.440 --> 0:42:56.600 attached to a lot of it. Edison himself was a 0:42:56.600 --> 0:43:01.120 brilliant guy, uh but he larged. He was brilliant in 0:43:01.360 --> 0:43:05.600 bringing people to work on these cool ideas, um sometimes 0:43:05.680 --> 0:43:08.920 contributing to him directly. Sometimes he wasn't, but he was 0:43:09.120 --> 0:43:13.920 providing the space for that kind of work to happen anyway. 0:43:14.560 --> 0:43:17.880 He helped develop the first nickel iron battery in nineteen 0:43:17.960 --> 0:43:21.360 o one. But I've talked a lot about batteries, so 0:43:21.680 --> 0:43:24.320 what I'll do in the next section is talk about 0:43:24.360 --> 0:43:27.359 other developments in electricity. But before I jump into that, 0:43:27.680 --> 0:43:37.279 let's take another quick break to thank our sponsor. So 0:43:37.520 --> 0:43:43.759 one of Volta's contemporaries was Andre Marie Ampere. We talked 0:43:43.800 --> 0:43:48.600 about amps and amperage. It comes from Ampaire, so his 0:43:48.719 --> 0:43:52.640 name also serves as a type of scientific unit, basically 0:43:52.719 --> 0:43:57.120 one describing current as opposed to voltage. And Pierre noted 0:43:57.160 --> 0:43:59.880 in eighteen twenty that a wire carrying an electric cur 0:44:00.280 --> 0:44:03.440 was sometimes attracted to and other times repelled by other 0:44:03.520 --> 0:44:07.360 such wires. So he was starting to notice this magnetic 0:44:07.400 --> 0:44:13.080 attraction along current carrying wires, and in eighteen thirty one, 0:44:13.120 --> 0:44:17.040 another fellow, Michael Faraday, explored this idea further, and he 0:44:17.120 --> 0:44:21.560 discovered that if he revolved a copper disc inside a 0:44:21.680 --> 0:44:26.279 strong magnetic field, it would generate an electric current inside 0:44:26.360 --> 0:44:30.040 the copper disk. Faraday and a guy named Humphrey Davy 0:44:30.120 --> 0:44:34.080 would later build an early electric generator using this discovery. 0:44:34.120 --> 0:44:37.240 The generator consisted of a coil of copper that would 0:44:37.239 --> 0:44:40.920 be moved past a magnet. And this is the very 0:44:41.239 --> 0:44:45.640 very rough basic idea for electric generators today. Moving a 0:44:45.640 --> 0:44:48.920 conductor through a magnetic field induces electricity to flow through 0:44:48.920 --> 0:44:53.200 the conductor. That's the simplified version. Now more specifically, the 0:44:53.280 --> 0:44:57.480 greatest current flows through a conductor when the conductor is 0:44:57.520 --> 0:45:01.239 moving through the most lines of magnetic flux at it 0:45:01.360 --> 0:45:06.200 the fastest rate. So magnetic flux is a magnetic field 0:45:06.280 --> 0:45:11.320 passing through a surface. You've probably seen illustrations of magnetic fields. 0:45:11.920 --> 0:45:15.319 Imagine a bar magnet. It's just a simple rectangle. You 0:45:15.360 --> 0:45:17.719 have a north pole of the bar magnet and a 0:45:17.719 --> 0:45:20.840 south pole of the bar magnet. You would draw lines 0:45:20.880 --> 0:45:25.399 extending outward from the north pole. These lines would start 0:45:25.400 --> 0:45:29.560 to loop back down towards the south pole in ever 0:45:29.680 --> 0:45:34.800 increasing but less strong uh magnetic lines that go further 0:45:34.880 --> 0:45:37.560 out until you get a couple that don't even loop 0:45:37.600 --> 0:45:39.720 back down to the south pole. They just go outward. 0:45:40.840 --> 0:45:44.200 So lines extend out from the north pole and go 0:45:44.400 --> 0:45:47.839 into the south pole, and you designate this by drawing 0:45:47.920 --> 0:45:52.000 little arrows on the lines to show the direction of this. 0:45:52.160 --> 0:45:57.640 The vector quality of this at the south pole you've 0:45:57.680 --> 0:46:00.360 got all those incoming lines, including a couple from apparently 0:46:00.440 --> 0:46:04.800 external sources. When you look at the illustrations of magnetic fields, 0:46:04.800 --> 0:46:08.240 so if you move a conductor through these magnetic fields, 0:46:08.280 --> 0:46:11.760 it sort of breaks those lines. It moves through those 0:46:11.800 --> 0:46:16.120 those lines of magnetic force um and you do it quickly, 0:46:16.719 --> 0:46:20.440 current will flow through the conductor. It induces current to flow, 0:46:21.480 --> 0:46:24.600 and the most current will flow when the conductor moves 0:46:24.640 --> 0:46:28.319 through the ninety degree perpendicular plane with respect to the 0:46:28.360 --> 0:46:32.560 magnetic field. So again, if you've got let's imagine that 0:46:32.560 --> 0:46:36.680 the conductor is a a square. We've got a square 0:46:36.680 --> 0:46:39.960 of copper. It's it's not solid copper. It's just a 0:46:40.840 --> 0:46:43.920 copper wire that's been shaped in the form of a square. 0:46:44.440 --> 0:46:46.560 It's got two prongs at the base of it that 0:46:46.680 --> 0:46:49.719 go down to where there's a crank. So I can 0:46:49.760 --> 0:46:53.440 turn the crank and this will rotate the square. Right now, 0:46:53.480 --> 0:46:56.080 let's say to either side of the square, I put 0:46:56.120 --> 0:46:59.800 two very powerful magnets. One of them has the north 0:47:00.000 --> 0:47:03.520 goal facing into the gap. The other one has its 0:47:03.680 --> 0:47:07.000 south pole facing into the gap. The squares in the 0:47:07.080 --> 0:47:11.360 center in between these two magnets. When I turned the 0:47:11.360 --> 0:47:15.920 square so that it is perpendicular to the magnetic field 0:47:16.080 --> 0:47:20.080 extending out from these magnets. That is the moment when 0:47:20.080 --> 0:47:22.640 it's going to have the most current flowing through the 0:47:22.640 --> 0:47:25.040 square as it as it moves. It has to be 0:47:25.120 --> 0:47:29.000 moving for this to really work. When you get it 0:47:29.080 --> 0:47:33.720 parallel with the magnetic fields, you will have the least 0:47:33.880 --> 0:47:36.920 amount of current. In fact, you have no current at 0:47:36.960 --> 0:47:40.200 all flowing through it at that moment. If you keep 0:47:40.280 --> 0:47:43.560 it turning, then you will be able to generate current 0:47:44.440 --> 0:47:50.480 h fairly consistently. It does actually pulse, it's not it's 0:47:50.520 --> 0:47:52.920 not steady. If you were to measure it out, you 0:47:52.920 --> 0:47:54.960 would actually see it pulsing. And only does it pulse, 0:47:55.719 --> 0:48:01.040 the direction of current will change. Uh, so it's actually 0:48:01.160 --> 0:48:04.880 alternating current. But we'll talk about that again in a 0:48:04.920 --> 0:48:07.560 little bit more a little bit later to really get 0:48:07.600 --> 0:48:10.920 into alternating current. Because in eighteen thirty two there was 0:48:10.960 --> 0:48:15.719 a French inventor named Pixie p I x I I M. 0:48:16.080 --> 0:48:22.360 Hippolyte Pixie or Hippolyta if you prefer, But he built 0:48:22.360 --> 0:48:25.640 an electrical generator based off of Faraday's discoveries that was 0:48:25.719 --> 0:48:28.480 very similar to what I just described. Had these permanent 0:48:28.520 --> 0:48:32.600 magnets that had a rotating conductor, that would um actually 0:48:32.680 --> 0:48:35.120 really had a spinning magnet and a steady conductor. But 0:48:35.239 --> 0:48:39.040 same same principle. Right, you've got a spinning magnet and 0:48:39.080 --> 0:48:42.400 a steady conductor. You could rearrange that as a spinning 0:48:42.400 --> 0:48:46.640 conductor in a steady magnet. Doesn't really matter. He found 0:48:46.640 --> 0:48:49.480 that the current direction changed each time the north pole 0:48:49.520 --> 0:48:52.400 passed over the coil after the south pole had passed 0:48:52.400 --> 0:48:55.840 over the coil. And this was an early alternating current generator, 0:48:55.960 --> 0:48:59.120 but there was no real use for alternating current at 0:48:59.120 --> 0:49:02.440 that time, so and Here advised Pixie to design a 0:49:02.520 --> 0:49:06.960 generator with a device known as a commutator. Commutators are 0:49:07.000 --> 0:49:11.400 meant to change alternating current to direct current. So the 0:49:11.400 --> 0:49:15.080 difference between alternating current and direct current is alternating current 0:49:15.280 --> 0:49:19.600 changes the direction of the current. So you have electrons 0:49:19.640 --> 0:49:23.160 flowing through a circuit in one direction, and then they 0:49:23.160 --> 0:49:28.280 will reverse and flow into the other direction with alternating current, 0:49:28.520 --> 0:49:33.600 and they do this many times every second. Then you 0:49:33.719 --> 0:49:37.280 have direct current, where the direction of flow is always 0:49:37.320 --> 0:49:41.040 the same. It goes from if you're doing the conventional 0:49:41.080 --> 0:49:43.880 flow diagram, it goes from the positive terminal to the 0:49:43.920 --> 0:49:48.000 negative terminal and it's never gonna change. It's always gonna 0:49:48.000 --> 0:49:51.719 follow that batteries give off direct current. Power plants that 0:49:51.840 --> 0:49:54.040 use a C generators give off a C current. And 0:49:54.040 --> 0:49:57.000 I'll talk more about that in part two. But why 0:49:57.040 --> 0:50:00.160 do generators create alternating current? And how do commutators work? Well, 0:50:00.200 --> 0:50:03.239 remember that example I just gave. You've got this square 0:50:03.400 --> 0:50:09.320 rotating conductor copper wire. It's in between the two magnets. Uh. 0:50:09.480 --> 0:50:12.440 Let's say that you've got your square position between the 0:50:12.440 --> 0:50:14.160 south pole of one magnet the north pole of the 0:50:14.239 --> 0:50:16.640 other magnet. And at the moment you're holding the square 0:50:16.640 --> 0:50:20.120 steady between the two magnets, and you put put a 0:50:20.160 --> 0:50:23.760 piece of blue tape on the side that's facing magnet 0:50:23.920 --> 0:50:26.600 number one, which has the south pole facing into the gap, 0:50:26.960 --> 0:50:29.480 and you put a piece of red tape on the 0:50:29.640 --> 0:50:32.719 side facing magnet two, which is the north pole of 0:50:32.760 --> 0:50:35.279 the other magnet. And then you rotate the square so 0:50:35.320 --> 0:50:40.239 that it moves down or back with respect to magnet one, 0:50:40.320 --> 0:50:43.960 and up or forward with respect to magnet two. So 0:50:44.160 --> 0:50:46.520 if you're staring at this, you see that blue tape 0:50:46.520 --> 0:50:50.440 start to move down. Let's say that we've got this 0:50:50.800 --> 0:50:56.040 horizontally aligned. It appears to move down with respect to 0:50:56.080 --> 0:50:58.960 the magnets. The red tape moves up with respect to 0:50:59.000 --> 0:51:01.759 the magnets, and as it does, this induces current to 0:51:01.800 --> 0:51:04.760 flow in one direction in the copper wire. But once 0:51:04.840 --> 0:51:08.520 the square hits that parallel position with the magnetic fields 0:51:09.280 --> 0:51:12.600 and then continues its turn, the side that was going 0:51:12.680 --> 0:51:15.200 up is now going down through a magnetic field, and 0:51:15.239 --> 0:51:17.319 the side that was going down through a magnetic field 0:51:17.360 --> 0:51:19.840 is now going up through a magnetic field. So the 0:51:19.840 --> 0:51:22.879 red tape takes this turn starts moving downward. The red 0:51:22.920 --> 0:51:25.120 blue tape is making its turn and moving upward, and 0:51:25.200 --> 0:51:28.320 at that moment, when the conductor breaks that parallel plane, 0:51:29.160 --> 0:51:33.520 the current reverses direction. Turning the conductor quickly will induce 0:51:33.560 --> 0:51:36.600 more current to flow and increase the number of cycles 0:51:36.640 --> 0:51:40.960 the current flow reverses per given unit of time. Now, 0:51:41.000 --> 0:51:43.600 as I said, this is alternating current, but the early 0:51:43.640 --> 0:51:46.640 experiments for the day, they really needed direct current, not 0:51:46.760 --> 0:51:49.040 alternating current, which means you have to find a way 0:51:49.040 --> 0:51:51.800 to make the current flow stable in a single direction, 0:51:52.120 --> 0:51:55.560 and that's where a commutator comes in. A simple commutator 0:51:55.680 --> 0:51:59.000 is a split ring where the two sides of the 0:51:59.080 --> 0:52:02.319 ring are made up of conductive material, but they're insulated 0:52:02.400 --> 0:52:06.800 from each other with an insulating material in between them. 0:52:06.880 --> 0:52:11.040 So imagine a ring that has one tiny sliver cut 0:52:11.040 --> 0:52:13.840 out of the ring, so it's like two halves of 0:52:13.880 --> 0:52:16.840 a ring, and then you have an insulator in between 0:52:16.880 --> 0:52:21.799 the two halves. On either side of this uh split ring, 0:52:22.280 --> 0:52:26.000 you have elements that we call brushes. These are just 0:52:26.360 --> 0:52:31.439 conductive materials that are stationary contacts. They make contact with 0:52:31.520 --> 0:52:36.400 this rotating split ring. So as the conductor turns, so 0:52:36.520 --> 0:52:38.840 does the split ring. And while the direction of current 0:52:38.960 --> 0:52:42.080 changes within the conductor, the nature of the split ring 0:52:42.160 --> 0:52:45.600 makes the flow of current and the overall circuit unidirectional. 0:52:46.200 --> 0:52:48.879 Now I realized this is really difficult to visualize without help, 0:52:48.960 --> 0:52:51.880 so I actually recommend that you go look up videos 0:52:51.920 --> 0:52:55.600 about d C generators to get a better idea of 0:52:55.640 --> 0:52:59.040 what I'm talking about. Because a DC generator, and it's 0:52:59.200 --> 0:53:02.680 most basic level, is really an a C generator with 0:53:02.719 --> 0:53:06.440 a commutator attached to it. The important thing note is 0:53:06.480 --> 0:53:09.680 that the basic generator makes al dre and current and 0:53:09.719 --> 0:53:13.880 the commutator makes it into direct current. Now, at this stage, 0:53:13.920 --> 0:53:17.799 electricity was still something scientists and engineers would experiment with 0:53:18.040 --> 0:53:21.200 they still didn't have any real practical uses for electricity 0:53:21.320 --> 0:53:23.399 right now, not on a massive scale at any rate. 0:53:24.160 --> 0:53:27.280 But over the course of the nineteenth century, it became 0:53:27.320 --> 0:53:31.520 clear that electricity had the potential. It's another electricity pun 0:53:31.600 --> 0:53:34.800 for you to change the world. So in our next episode, 0:53:35.040 --> 0:53:37.960 we're gonna look at the discovery of the actual electron, 0:53:38.160 --> 0:53:40.959 which happened at the very tail end of the nineteenth century. 0:53:41.040 --> 0:53:44.200 We'll talk about the atomic physics involved in electricity. We'll 0:53:44.239 --> 0:53:47.399 also talk about d C versus a C as far 0:53:47.440 --> 0:53:51.240 as the current wars were concerned, and Edison versus Tesla 0:53:51.560 --> 0:53:55.480 and why Edison versus Tesla is really an oversimplification of 0:53:55.560 --> 0:53:59.080 that actual battle. And we'll talk about the rise of 0:53:59.080 --> 0:54:01.440 power grids and the various methods that we use to 0:54:01.640 --> 0:54:06.160 actually generate electricity, from coal plants to nuclear reactors. In 0:54:06.200 --> 0:54:08.680 the meantime, if you guys have any suggestions for future 0:54:08.680 --> 0:54:11.120 episodes of tech Stuff, I recommend you get in touch 0:54:11.160 --> 0:54:15.319 with me. My email address is text stuff at how 0:54:15.400 --> 0:54:17.840 stuff Works dot com, or you can drop me a 0:54:17.880 --> 0:54:21.120 line on Twitter or Facebook. The handle for the show 0:54:21.120 --> 0:54:24.040 at both of those is text Stuff H s W. 0:54:24.920 --> 0:54:27.879 As always, I'm happy to hear any suggestions you might have, 0:54:27.920 --> 0:54:30.200 whether it's a topic for a show or a guest 0:54:30.239 --> 0:54:32.279 I should have on the show, Get in touch with 0:54:32.280 --> 0:54:34.800 me and let me know. Also, remember you can watch 0:54:34.840 --> 0:54:38.960 me record these things live on Twitch. Just go to 0:54:39.040 --> 0:54:42.000 twitch dot tv slash tech stuff to see the schedule. 0:54:42.640 --> 0:54:44.560 And I hope I will see you guys in there 0:54:44.600 --> 0:54:46.640 because it's a fun time and you get to talk 0:54:46.680 --> 0:54:50.800 to me a lot while I record these things. And meanwhile, 0:54:51.000 --> 0:54:59.719 I'll talk to you guys again really soon. For more 0:54:59.719 --> 0:55:02.040 on us and thousands of other topics is at how 0:55:02.120 --> 0:55:12.840 stuff works dot com.