WEBVTT - The Basics of Electricity 0:00:04.240 --> 0:00:07.240 Welcome to Tech Stuff, a production of I Heart Radios 0:00:07.320 --> 0:00:14.080 How Stuff Works. Hey there, and welcome to tech Stuff. 0:00:14.080 --> 0:00:16.959 I'm your host, Jonathan Strickland. I'm an executive producer with 0:00:17.000 --> 0:00:19.880 I Heart Radio and I love all things tech and 0:00:20.040 --> 0:00:24.400 in a recent episode, I talked about how scientists, doctors, 0:00:24.520 --> 0:00:28.680 and philosophers had experimented with using the direct application of 0:00:28.840 --> 0:00:33.279 electricity in an effort to treat various medical conditions. In 0:00:33.320 --> 0:00:36.920 this episode, we're going to take a further step back 0:00:37.200 --> 0:00:40.839 to understand the basics behind electricity itself. A lot of 0:00:40.840 --> 0:00:43.680 this is going to be a refresher course from science classes, 0:00:43.800 --> 0:00:47.120 primarily in physics, but it's to cover stuff that often 0:00:47.120 --> 0:00:51.199 confuses people, and I'm including myself in that category. I 0:00:51.280 --> 0:00:54.400 often get confused to the point where I frequently have 0:00:54.520 --> 0:00:58.120 to do a quick refresher. So I'm not a scientist, 0:00:58.160 --> 0:01:00.800 I'm not an electrical engineer. I have to remind myself 0:01:00.800 --> 0:01:04.520 on the basics whenever I talk about electricity. Complicating matters 0:01:05.040 --> 0:01:07.880 is that many text books for younger students in particular, 0:01:07.959 --> 0:01:12.320 frame electricity in ways that can be misleading. They oversimplify 0:01:12.440 --> 0:01:15.600 ideas to the point where they're kind of, you know, wrong, 0:01:16.280 --> 0:01:18.360 and I know I've been guilty of doing the same 0:01:18.400 --> 0:01:21.520 thing on this show. After all, I am a product 0:01:21.560 --> 0:01:24.840 of the educational system that relies on such textbooks, and 0:01:24.920 --> 0:01:28.039 I didn't have a background and electrical engineering. I know 0:01:28.120 --> 0:01:31.480 I have on many occasions described electricity as the flow 0:01:31.520 --> 0:01:36.039 of electrons, and that's not really the case. Now. Electrons 0:01:36.120 --> 0:01:40.400 are charged sub atomic particles. They carry an electric charge. 0:01:40.720 --> 0:01:45.399 But electricity, a vague term at best, isn't about these 0:01:45.480 --> 0:01:49.560 carrier particles. It's more about the electric charge itself. So 0:01:49.680 --> 0:01:53.120 I have to actually unlearn what I had learned to 0:01:53.200 --> 0:01:57.400 talk about this more accurately. So if you're like me, 0:01:58.000 --> 0:01:59.840 then this episode is going to be great for you. 0:02:00.120 --> 0:02:02.920 And if you already know electricity inside and out, you'll 0:02:02.920 --> 0:02:06.480 probably find this episode a little too basic for your liking. 0:02:06.920 --> 0:02:09.440 Or in a worst case scenario, you might hear me 0:02:09.520 --> 0:02:13.240 get something totally wrong. I'm working hard to prevent that, 0:02:13.520 --> 0:02:16.600 but I am human. So if I say something totally wrong, 0:02:17.000 --> 0:02:19.400 feel free to call me out on it, but please 0:02:19.919 --> 0:02:24.600 just be nice about it. I am well intentioned, and 0:02:24.600 --> 0:02:26.240 if I make a mistake, I want to correct it. 0:02:26.680 --> 0:02:30.280 Just don't drag me under the bus for it, all right, 0:02:30.320 --> 0:02:33.079 So Let's assume some of you out there are like 0:02:33.200 --> 0:02:36.880 me and you don't have a background in working with electricity. 0:02:37.320 --> 0:02:40.720 Let's figure out why this is so confusing. I mean, 0:02:40.760 --> 0:02:43.880 we do have different units of measurement all to describe 0:02:44.160 --> 0:02:50.360 various components of electricity and the behavior of electrical phenomena. 0:02:50.600 --> 0:02:53.520 You know, we have whats, we have what hours or 0:02:53.520 --> 0:02:56.520 more frequently, actually, really we have kill a lot hours. 0:02:56.880 --> 0:03:00.680 We have volts, we have amps, we have ohms. It 0:03:00.680 --> 0:03:03.480 can get a little overwhelming, so I'm gonna do my 0:03:03.520 --> 0:03:06.400 best to try and clear stuff up a bit now. 0:03:07.160 --> 0:03:11.040 In that medical history episode, I talked about Greek philosophers 0:03:11.040 --> 0:03:14.840 who observed the effects of static electricity, what we call 0:03:14.960 --> 0:03:19.120 static electricity, where you build up an electric charge and 0:03:19.160 --> 0:03:22.360 it can be discharged when you come into contact with 0:03:22.400 --> 0:03:26.120 something else, and about how Benjamin Franklin proved that this 0:03:26.240 --> 0:03:29.400 was the same stuff as was found in lightning. But 0:03:29.480 --> 0:03:32.359 I mostly stayed away from the history of detecting and 0:03:32.400 --> 0:03:36.600 measuring electrical phenomena and the terminology that we associate with it. 0:03:36.880 --> 0:03:39.600 So that's really what this episode will end up being about. 0:03:40.160 --> 0:03:43.360 And in that previous episode, I mentioned that Benjamin Franklin 0:03:43.400 --> 0:03:46.840 thought of electricity as a sort of fluid. He was 0:03:46.880 --> 0:03:49.400 not alone in this. It was a prevalent thought at 0:03:49.400 --> 0:03:53.560 the time, and that's probably why he described the movement 0:03:54.000 --> 0:03:59.000 of electricity as current. But the way Franklin described current 0:03:59.080 --> 0:04:02.280 and the way we tiply talk about electricity has caused 0:04:02.320 --> 0:04:07.200 confusion for some folks like me. So I'll explain. Imagine 0:04:07.520 --> 0:04:10.960 you have two pools of water and they're connected by 0:04:11.000 --> 0:04:13.840 a hose. Now imagine that the ground is perfectly level 0:04:14.000 --> 0:04:17.680 between these two pools of water. You would expect the 0:04:17.680 --> 0:04:19.120 water in the hose to be pretty much in a 0:04:19.160 --> 0:04:23.160 state of equilibrium. It would be still. But imagine one 0:04:23.240 --> 0:04:27.360 pool is at a slightly higher elevation than the other. Well, 0:04:27.400 --> 0:04:29.680 then you would expect water to follow the force of 0:04:29.680 --> 0:04:33.240 gravity and flow down through the hose into the other pool. 0:04:33.600 --> 0:04:36.720 You would have a current, and you could think of 0:04:36.760 --> 0:04:40.800 the pool at the higher elevation as being positive, at 0:04:40.880 --> 0:04:43.680 least in terms of elevation. So in that context, you'd 0:04:43.680 --> 0:04:46.720 say that a current of water is flowing from positive 0:04:47.160 --> 0:04:51.560 to negative through the hose. Now I'm oversimplifying a bit, 0:04:51.680 --> 0:04:55.200 but that's kind of what Franklin was thinking. When it 0:04:55.240 --> 0:04:59.600 comes to the fluid. He observed with electricity. He described 0:04:59.640 --> 0:05:02.640 current as moving from positive to negative, and this has 0:05:02.680 --> 0:05:06.080 more to do with the electrostatic experiments he was doing 0:05:06.120 --> 0:05:10.679 and whether or not the surface that he was rubbing with, 0:05:11.000 --> 0:05:15.680 for for example, was the positive or whether it was 0:05:15.720 --> 0:05:18.520 the negative. You also have to remember that Franklin made 0:05:18.520 --> 0:05:22.039 his observations more than a century before we had discovered 0:05:22.040 --> 0:05:25.400 that electrons are even a thing that exists. I have 0:05:25.520 --> 0:05:28.880 often joked that Franklin really messed us all up with 0:05:28.960 --> 0:05:33.120 his description of current going from positive to negative, but 0:05:33.240 --> 0:05:36.080 turns out that's not really true. Now explain why that 0:05:36.240 --> 0:05:39.400 is in just a moment. Now, Later on after Benjamin 0:05:39.440 --> 0:05:43.200 Franklin's time, we would learn more about electricity and we 0:05:43.240 --> 0:05:46.960 began to learn about electric charges and electric potential. We 0:05:47.000 --> 0:05:50.719 began to understand that you can have different magnitudes of 0:05:50.760 --> 0:05:54.360 electric charge and it could be negative, it could be positive, 0:05:54.360 --> 0:05:57.719 and that you can create a connection between different things 0:05:57.760 --> 0:06:01.000 with different electric charges and observe of a flow of 0:06:01.040 --> 0:06:05.239 electric charge or an electric current. This was all stuff 0:06:05.279 --> 0:06:08.520 that we learned over time. And let's think back on 0:06:08.560 --> 0:06:12.760 our two pools connected by a hose analogy. If we 0:06:12.800 --> 0:06:15.719 had two pools that were on level ground and we 0:06:15.800 --> 0:06:19.719 equated that with a conductive pathway in an electrical circuit. 0:06:20.360 --> 0:06:23.120 Let's just say it's a it's a copper wire connecting 0:06:23.400 --> 0:06:27.440 two terminals. Then we would describe that wires having equal 0:06:27.440 --> 0:06:29.919 amounts of potential on either side. There's not a positive 0:06:29.960 --> 0:06:32.840 and a negative terminal, they're both neutral, and in other words, 0:06:32.839 --> 0:06:35.960 there's no difference in electrical potential. There's no difference in 0:06:36.000 --> 0:06:39.799 potential energy, there's no flow of electrical charge, and thus 0:06:40.000 --> 0:06:43.200 no electrical current. In the analogy in which we think 0:06:43.240 --> 0:06:46.240 of one pool being at a higher elevation than the other, 0:06:46.640 --> 0:06:51.160 we would describe the corresponding electrical system as the end 0:06:51.240 --> 0:06:54.440 of the wire representing the elevator pool, elevator pool having 0:06:54.440 --> 0:06:57.680 a higher potential energy or just higher potential, and the 0:06:57.720 --> 0:07:00.760 lower end having a lower potential energy or lower potential, 0:07:00.920 --> 0:07:03.800 And we call this difference an electric potential between the 0:07:03.880 --> 0:07:07.279 high and the low pools as the voltage. So the 0:07:07.320 --> 0:07:11.160 greater the difference between those two points in the analogy, 0:07:11.240 --> 0:07:14.840 the greater difference in an elevation would mean the greater 0:07:15.120 --> 0:07:19.120 the voltage. So if you have one that is one 0:07:19.240 --> 0:07:23.720 terminal that's extremely positively charged and one that's extremely negatively charged, 0:07:23.840 --> 0:07:27.320 you have an extreme voltage. The difference between those two. 0:07:27.720 --> 0:07:32.560 Sticking with the analogy of water, voltage is like water pressure. 0:07:33.000 --> 0:07:36.440 It's kind of how hard the electricity is being pushed 0:07:36.560 --> 0:07:41.800 through the conductive connection between the different terminals. So if 0:07:41.840 --> 0:07:46.840 the electric potential is of great magnitude, you get more pressure. 0:07:47.200 --> 0:07:50.640 It's like a water hose shooting out water at high force, 0:07:50.880 --> 0:07:54.120 like a fire hose connected to a fire hydrant. If 0:07:54.160 --> 0:07:57.400 the electric potential isn't that great, if if the difference 0:07:57.640 --> 0:08:01.280 isn't that great, then the voltage is lower, and in 0:08:01.320 --> 0:08:04.040 our analogy, the water pressure is lower, so water would 0:08:04.080 --> 0:08:06.120 come out and kind of a lazy arc as opposed 0:08:06.160 --> 0:08:10.280 to blasting out at full force. And it helps if 0:08:10.320 --> 0:08:14.480 we remember that opposite charges attract each other and like 0:08:14.840 --> 0:08:19.120 charges repel each other. So if there's a big difference 0:08:19.240 --> 0:08:23.440 in electrical potential between two connected points, the like charges 0:08:23.480 --> 0:08:26.360 are going to want to rush over to the opposite 0:08:26.440 --> 0:08:30.120 charges and get the heck away from the other like charges. 0:08:31.240 --> 0:08:33.800 If you listen to my previous episode, then you heard 0:08:33.800 --> 0:08:37.560 me talk about Alessandro Volta, the man who invented the 0:08:37.600 --> 0:08:40.920 voltaic pile, which was a precursor to the modern battery. 0:08:41.240 --> 0:08:44.480 He did that back in eighteen hundred. It's from his 0:08:44.600 --> 0:08:48.440 name that we get volts and voltage, and a volt 0:08:48.960 --> 0:08:51.559 is a unit of measurement to describe the difference in 0:08:51.640 --> 0:08:56.000 electric potential between two points. I'll get back to describing 0:08:56.040 --> 0:08:59.920 exactly how we define volts in a second, because unfortunately 0:09:00.480 --> 0:09:03.040 that definition depends upon us knowing what some of this 0:09:03.160 --> 0:09:05.600 other stuff is. First. It doesn't do you much good 0:09:05.640 --> 0:09:08.120 to give a definition if you realize that all the 0:09:08.120 --> 0:09:12.880 other terms in that definition are undefined. Okay, So if 0:09:12.880 --> 0:09:17.600 we assume voltage is pressure water amps, Now, amps are 0:09:17.640 --> 0:09:21.400 a measure of current, or how much electrical charge is 0:09:21.440 --> 0:09:25.320 flowing through a specific point in a circuit per unit 0:09:25.360 --> 0:09:28.400 of time. So let's go back to the water analogy 0:09:28.440 --> 0:09:31.480 and change things up a bit. Imagine that we have 0:09:32.160 --> 0:09:34.720 those sets of pools we've been talking about. We have 0:09:34.800 --> 0:09:37.679 one pool at a higher elevation and one pool at 0:09:37.679 --> 0:09:40.679 a lower elevation. Now let's say that we copy that. 0:09:40.920 --> 0:09:42.840 So now we've got to we've got two pools at 0:09:42.880 --> 0:09:46.640 high elevation, two pools at low elevation. With one of 0:09:46.679 --> 0:09:50.040 the high low sets, we connect the two pools with 0:09:50.240 --> 0:09:53.640 an ordinary garden hose, and with the other set, we 0:09:53.679 --> 0:09:56.559 connect the two with a concrete tube with a much 0:09:56.600 --> 0:10:00.400 greater diameter than the garden hose, more water will be 0:10:00.480 --> 0:10:04.160 able to flow through a given point, Let's say it's 0:10:04.200 --> 0:10:07.880 the midpoint of the concrete tube per unit of time 0:10:08.160 --> 0:10:11.240 than through the midpoint of the garden hose in that 0:10:11.280 --> 0:10:15.720 same unit of time. The concrete tube has a greater capacity, 0:10:15.920 --> 0:10:18.320 The tube can hold more volume, and thus we get 0:10:18.360 --> 0:10:20.280 more water coming out per unit of time than we 0:10:20.320 --> 0:10:23.320 would observe with the hose. Well, with electrical circuits, we 0:10:23.360 --> 0:10:27.040 described the same idea with amps. Amps tell us how 0:10:27.120 --> 0:10:30.280 much electrical charge passes a given point in a circuit 0:10:30.320 --> 0:10:33.240 per unit of time. So voltage is the pressure and 0:10:33.320 --> 0:10:37.120 amps or current is the amount of charge. Multiply those 0:10:37.160 --> 0:10:41.240 two together and you get what's now. Moving back to Franklin, 0:10:41.400 --> 0:10:44.440 we'll get back to Watson a second. He thought of 0:10:44.480 --> 0:10:47.880 electricity as a positive flow, that the direction of current 0:10:48.000 --> 0:10:51.439 was in the direction of an electrical field, and unfortunately 0:10:51.760 --> 0:10:55.600 we would later learn that it's the negatively charged electrons, 0:10:55.640 --> 0:10:59.840 not the positively charged protons, that really move around in 0:10:59.840 --> 0:11:04.600 a typical electric circuit. So if we follow the conventional 0:11:04.760 --> 0:11:08.800 explanation of current. The flow of current is in the 0:11:08.800 --> 0:11:13.040 opposite direction of the flow of electrons. In a circuit 0:11:13.080 --> 0:11:15.680 with a battery, we would see movement described as the 0:11:15.720 --> 0:11:19.760 electrons going from the negative terminal of the battery through 0:11:19.840 --> 0:11:23.240 a circuit doing whatever work was part of that circuit, 0:11:23.440 --> 0:11:26.920 like lighting a lamp or something before journeying to the 0:11:27.040 --> 0:11:30.360 positive terminal of the battery. But we would describe the 0:11:30.440 --> 0:11:33.719 current in that circuit as traveling from the positive end 0:11:33.800 --> 0:11:36.840 of the battery through the circuit until it got to 0:11:36.880 --> 0:11:41.200 the negative end. But what's more important here is not 0:11:41.880 --> 0:11:45.559 the carrier of the electric charge. It's the concept of 0:11:45.600 --> 0:11:49.080 electrical charge itself, not the movement of electrons, which again 0:11:49.120 --> 0:11:53.000 are just the carriers. Electricity ultimately is about the flow 0:11:53.120 --> 0:11:57.480 of electric charge, positive or negative. So in our day 0:11:57.480 --> 0:12:00.200 to day use of electricity, we're talking about of the 0:12:00.240 --> 0:12:03.959 type where electrons flow through circuits, so we typically are 0:12:04.000 --> 0:12:07.679 looking at negatively charged particles moving in a conductive pathway, 0:12:08.080 --> 0:12:11.199 pushing that negative charge in the opposite direction of what 0:12:11.280 --> 0:12:16.080 we would typically call the current. But electricity isn't the 0:12:16.200 --> 0:12:20.080 movement of electrons, even though that's often how it is simplified. 0:12:20.559 --> 0:12:23.760 It's really the movement of the charge itself we need 0:12:23.840 --> 0:12:26.800 to be concerned with. And if you have a flow 0:12:26.800 --> 0:12:29.840 of protons, you would still have a flow of charge, 0:12:29.920 --> 0:12:33.600 and thus you would still have electricity. So a particle accelerator, 0:12:33.679 --> 0:12:38.280 for example, the accelerates a beam of protons is creating 0:12:38.320 --> 0:12:41.439 a flow of electricity. Electrons are not even involved in that. 0:12:41.559 --> 0:12:44.720 It's the movement of positively charged particles. You're getting a 0:12:44.800 --> 0:12:48.720 movement of a positive charge that is technically electricity. So 0:12:48.840 --> 0:12:51.720 again we need to kind of divorce ourselves from the 0:12:51.800 --> 0:12:56.840 idea of electrons and think more about electrical charge. The 0:12:56.880 --> 0:12:59.679 electrons happen to be the carriers of that, but that's 0:13:00.120 --> 0:13:03.520 as far as their importance is concerned from this perspective. 0:13:04.080 --> 0:13:06.800 They get important again once we start talking about quantum effects, 0:13:06.880 --> 0:13:10.000 but that's a discussion for a different time. So I 0:13:10.080 --> 0:13:13.800 say all this in order to exonerate Benjamin Franklin a 0:13:13.840 --> 0:13:16.040 little bit. I give him a hard time, but it's 0:13:16.120 --> 0:13:19.920 largely because the way we harness electricity for most of 0:13:19.960 --> 0:13:22.800 the stuff we do means that we have an apparent 0:13:23.000 --> 0:13:26.440 contradiction in the sense of the flow of electrons and 0:13:26.440 --> 0:13:29.000 the flow of current. But to be fair, our lay 0:13:29.080 --> 0:13:32.040 understanding of electricity is based on a lot of misconceptions. 0:13:32.040 --> 0:13:34.040 In general, we focus a bit too much on those 0:13:34.080 --> 0:13:37.240 carrier particles and not the larger concept of electric charge. 0:13:37.520 --> 0:13:41.480 Another misconception has to do with the wires in a circuit. 0:13:42.000 --> 0:13:52.920 I'll explain more after we take a short break. Okay, 0:13:52.960 --> 0:13:58.199 so let's get another misconception out of the way. Many 0:13:58.280 --> 0:14:02.600 people take that analogy of water pipes or hoses or 0:14:02.640 --> 0:14:06.880 tubes as being a literal one to one with electricity, 0:14:07.000 --> 0:14:09.640 and thus the wires in a circuit they think of 0:14:09.800 --> 0:14:14.240 as empty conduits through which electrons can travel like. They're 0:14:14.280 --> 0:14:17.560 imagining the wires as being these hollow tubes, and electrons 0:14:17.559 --> 0:14:20.440 are just shooting down the tubes. They're coming out of 0:14:20.440 --> 0:14:23.720 the battery or out of the wall if you have 0:14:23.800 --> 0:14:26.640 something plugged in, shooting down the tube and getting to 0:14:26.640 --> 0:14:28.840 the other end. But if we think about that for 0:14:28.880 --> 0:14:32.120 even a moment, we realize that cannot possibly be true, 0:14:32.160 --> 0:14:35.240 because the wires themselves are made up of atoms, and 0:14:35.440 --> 0:14:39.640 atoms have electrons. So it's more like a tube or 0:14:39.680 --> 0:14:42.720 a hose or whatever that is already packed with water 0:14:43.040 --> 0:14:45.720 before you connected to the two pools. And even that 0:14:45.840 --> 0:14:49.680 is not a perfect analogy. So let's talk about conductivity. 0:14:49.800 --> 0:14:53.400 Some types of atoms have electrons in their outer energy 0:14:53.480 --> 0:14:58.000 levels that are more lucy goosey. If you have a 0:14:58.080 --> 0:15:01.400 single copper atom, then you've got a nucleus that contains 0:15:01.400 --> 0:15:05.920 twenty nine protons and thirty five neutrons. Now we're talking 0:15:05.920 --> 0:15:09.800 about a basic neutral copper atom, meaning the positive and 0:15:09.840 --> 0:15:13.880 negative charges cancel each other out. So we have twenty 0:15:13.960 --> 0:15:17.400 nine electrons paired up with that nucleus that has twenty 0:15:17.480 --> 0:15:22.360 nine protons. Electrons orbit the nucleus, but not in the 0:15:22.400 --> 0:15:26.640 same way that planets orbit stars or moons orbit planets. 0:15:27.320 --> 0:15:31.680 The electrons inhabit various orbitals, which in turn are in 0:15:31.720 --> 0:15:35.000 what we would call subshells, which are in shells around 0:15:35.000 --> 0:15:37.040 the nucleus. Now I'm not going to dive into all 0:15:37.080 --> 0:15:38.840 of that, because I'm sure most of you have a 0:15:38.880 --> 0:15:42.120 general handle on it. But the twenty nine electrons and 0:15:42.160 --> 0:15:46.000 copper add up to a point where one electron is 0:15:46.120 --> 0:15:49.840 left orbiting the outermost shell. There's no room for that 0:15:49.920 --> 0:15:53.040 last electron in any of the lower shells closer to 0:15:53.080 --> 0:15:57.120 the nucleus, so this electron is pushed out to the 0:15:57.160 --> 0:16:02.080 next lowest energy shell, and it's they're all by its lonesome. 0:16:02.800 --> 0:16:06.040 That means that electron is easier to push around than 0:16:06.080 --> 0:16:10.480 the ones that are locked in packed closer to the nucleus. 0:16:11.000 --> 0:16:14.760 So when you lump a bunch of copper atoms together, 0:16:15.000 --> 0:16:17.320 like that was just one copper atom, right, If we 0:16:17.400 --> 0:16:20.520 put a bunch of copper atoms together and we've got 0:16:20.560 --> 0:16:23.880 something like a copper wire that's made up of trillions 0:16:24.040 --> 0:16:26.760 of these atoms, you end up with a mass of 0:16:26.840 --> 0:16:30.920 copper atoms that all have these single free electrons, and 0:16:30.960 --> 0:16:34.520 you can almost think of those electrons as moving around 0:16:34.720 --> 0:16:37.760 the mass of copper atoms as opposed to being tied 0:16:37.800 --> 0:16:41.920 down to a single copper nucleus. If you then connect 0:16:41.920 --> 0:16:44.480 the wire into a circuit in which you have a 0:16:44.520 --> 0:16:48.320 battery or some sort of generator or something, that battery 0:16:48.400 --> 0:16:51.720 or generator acts as a pump that can push those 0:16:51.760 --> 0:16:56.360 free electrons around. The negative terminal has a charge that 0:16:56.400 --> 0:17:01.360 pushes against those electrons because remember like charge repels like, 0:17:02.240 --> 0:17:06.920 so each of those electrons has its own negative charge 0:17:06.960 --> 0:17:09.879 and pushes further down the path of the circuit. And 0:17:09.920 --> 0:17:12.480 since since the other end of the battery has a 0:17:12.520 --> 0:17:17.440 positive terminal, the negative charges get attracted to the positive side. 0:17:17.800 --> 0:17:21.280 It's not that electrons are shooting out of a battery 0:17:21.600 --> 0:17:24.840 down a pipe, doing some work, and then going into 0:17:24.880 --> 0:17:27.480 the other end of the battery. Is that the charge 0:17:27.800 --> 0:17:31.199 of the battery is pushing through this pathway and the 0:17:31.240 --> 0:17:36.040 electrons carry that charge. Likewise, the electrons are not moving 0:17:36.080 --> 0:17:38.439 at the speed of light. I know I've been guilty 0:17:38.520 --> 0:17:42.159 of saying that before too, but that's not correct. The 0:17:42.200 --> 0:17:45.280 electrons move much more slowly than the speed of light. 0:17:45.920 --> 0:17:48.640 You could even say the charge moves more slowly than that. 0:17:48.800 --> 0:17:52.200 But within the circuit, the charge is moving throughout all 0:17:52.320 --> 0:17:56.400 parts of the circuit at the same time. It's not 0:17:56.520 --> 0:17:59.560 like one electron moves and then the next one and 0:17:59.560 --> 0:18:02.800 then the next one. It's like they're all moving together 0:18:03.040 --> 0:18:06.000 in in lock step. And so you have this entire 0:18:06.119 --> 0:18:08.359 circuit that all goes into motion at the same time. 0:18:08.960 --> 0:18:14.320 And to us that means that we see practically instantaneous results. 0:18:14.640 --> 0:18:16.800 So if you flip on a light switch to an 0:18:16.840 --> 0:18:21.320 incandescent lamp, the light comes on immediately, it doesn't delay. 0:18:21.440 --> 0:18:24.480 That's why. It's because all of those electrons in the 0:18:24.520 --> 0:18:27.040 circuit are moving at the same time, so the effect 0:18:27.960 --> 0:18:30.560 is that it's moving at the speed of light. But 0:18:30.600 --> 0:18:34.359 in reality, what's actually happening is the electrons as a 0:18:34.400 --> 0:18:38.119 whole in this circuit are all moving together. So a 0:18:38.200 --> 0:18:41.800 battery connected to a circuit is not really a source 0:18:41.800 --> 0:18:44.560 of electrons. It's a source of energy. It's providing the 0:18:44.680 --> 0:18:48.800 energy or the pressure to move that charge through the circuit. 0:18:49.080 --> 0:18:53.240 It's the source of voltage. An electrochemical reaction in the 0:18:53.240 --> 0:18:57.200 battery acts as an internal circuit to create this voltage, 0:18:57.359 --> 0:19:00.560 which manifests as a difference in electrical potential shold between 0:19:00.560 --> 0:19:04.280 the positive and the negative terminals on the battery. Connecting 0:19:04.320 --> 0:19:06.960 that battery to a circuit is what gives the energy 0:19:07.040 --> 0:19:11.359 necessary to move this charge through the circuit and to 0:19:11.520 --> 0:19:13.920 do whatever work it is you need to do along 0:19:13.960 --> 0:19:16.840 the way, such as lighting up that light bulb. Within 0:19:16.880 --> 0:19:20.959 a battery, you've got an exothermic reaction that is working 0:19:21.080 --> 0:19:24.880 against the electric field. So it's kind of like pushing 0:19:24.960 --> 0:19:28.440 a boulder uphill. The force of gravity in that case 0:19:28.720 --> 0:19:31.159 would be working against you and you have to overcome it. 0:19:31.680 --> 0:19:35.120 You have to exert effort to work against the force 0:19:35.160 --> 0:19:38.280 of gravity to push the boulder up the hill. A 0:19:38.280 --> 0:19:41.760 battery likewise is exerting effort in the form of this 0:19:41.880 --> 0:19:46.800 exothermic reaction. The external circuit, that is, the larger circuit 0:19:46.920 --> 0:19:50.760 that you connect to the battery, is following the natural 0:19:51.000 --> 0:19:55.080 energy field. It isn't working uphill. It's got a high 0:19:55.119 --> 0:19:57.879 potential terminal and a low potential terminal, and the current 0:19:57.920 --> 0:20:00.920 flows according to the direct and of high to low 0:20:01.600 --> 0:20:04.560 as Franklin described, The actual electrons are going in the 0:20:04.560 --> 0:20:08.840 opposite direction. As the charge moves through the circuit, it 0:20:08.960 --> 0:20:14.040 encounters energy transforming devices. These would be things like light bulbs, 0:20:14.119 --> 0:20:16.280 heating elements, pretty much, you know, anything that you would 0:20:16.280 --> 0:20:19.800 connect to a circuit. At those points, some of the 0:20:19.800 --> 0:20:24.640 electrical potential energy of the charge gets transformed into some 0:20:24.680 --> 0:20:27.879 other form of energy, light, heat, whatever. The loss of 0:20:27.920 --> 0:20:30.720 electrical potential in a circuit after passing through one of 0:20:30.760 --> 0:20:34.800 these elements is often called a voltage drop. Now going 0:20:34.840 --> 0:20:38.399 to the water analogy again, imagine that you have a 0:20:38.440 --> 0:20:41.920 pool of water. You have a ramp set up above 0:20:42.359 --> 0:20:45.960 that pool of water, like maybe it's like a water slide, 0:20:46.320 --> 0:20:48.960 and the water slide is not turned on, uh, and 0:20:49.040 --> 0:20:51.560 it's smacked aub in the middle of the pool. You're 0:20:51.600 --> 0:20:53.359 also in the middle of the pool, and you grab 0:20:53.359 --> 0:20:56.160 a bucket and you fill it up with water from 0:20:56.240 --> 0:20:59.560 the pool. You lift the bucket up over your head 0:20:59.560 --> 0:21:01.960 to the top of the slide, and you tip the 0:21:02.040 --> 0:21:05.640 bucket out so that the water hits the slide, goes 0:21:05.680 --> 0:21:09.640 down the slide off the other end back into the pool. Well, 0:21:09.680 --> 0:21:13.120 you've just taken water from an area of low potential 0:21:13.240 --> 0:21:16.560 energy in this case, kinetic energy, and you moved it 0:21:17.119 --> 0:21:20.800 using work to an area of high potential energy. The 0:21:20.840 --> 0:21:23.520 water then flows down the ramp till it gets the end. 0:21:24.000 --> 0:21:26.439 And maybe you even put a water wheel at the 0:21:26.480 --> 0:21:29.560 base of this slide, so when the water hits the 0:21:29.560 --> 0:21:34.359 water wheel, it actually provides the work necessary to turn 0:21:35.200 --> 0:21:38.959 the wheel and you get the wheel turning. You have 0:21:39.080 --> 0:21:44.280 this display of mechanical energy from the water. So that's 0:21:44.480 --> 0:21:48.159 kind of what you would see with a battery in 0:21:48.200 --> 0:21:52.960 a circuit. In this example, you are fulfilling the same 0:21:52.960 --> 0:21:57.720 purpose of a battery. You are lifting some water using 0:21:57.760 --> 0:22:00.520 work from an area of low potential to an area 0:22:00.520 --> 0:22:04.120 of high potential. The battery is doing this but with 0:22:04.840 --> 0:22:10.000 electrical potential, not with you know, physical stuff. Okay, now 0:22:10.000 --> 0:22:13.280 it's time to define an actual vault. I alluded to 0:22:13.359 --> 0:22:17.520 this in the first segment of this podcast. We've got voltage, 0:22:17.600 --> 0:22:21.520 which is this difference in electrical potential between two points. 0:22:21.880 --> 0:22:24.960 And we understand that creating a conductive path between an 0:22:25.000 --> 0:22:28.160 area of high electrical potential and one of low electrical 0:22:28.160 --> 0:22:31.280 potential allows for the flow of current. So how do 0:22:31.359 --> 0:22:34.639 we define a vault. Well, there's actually a couple of ways. 0:22:35.280 --> 0:22:38.439 One is to say that one volt is equivalent to 0:22:38.480 --> 0:22:42.719 the energy consumption of one jewel per electric charge of 0:22:42.760 --> 0:22:47.080 one coolomb. But that just raises more questions, doesn't it. 0:22:47.400 --> 0:22:50.320 The dictionary definition of a jewel is a unit of 0:22:50.359 --> 0:22:53.520 work or energy equal to the work done by a 0:22:53.640 --> 0:22:57.440 force of one Newton acting through a distance of one meter, 0:22:58.160 --> 0:23:00.679 and a Newton is a unit of force. One Newton 0:23:00.880 --> 0:23:03.680 is the force required to impart an acceleration of one 0:23:03.760 --> 0:23:06.680 meter per second per second to a mass of one 0:23:06.800 --> 0:23:10.960 kim okay, So a jewel is the energy required to 0:23:11.000 --> 0:23:14.399 produce a Newton's worth of force through a distance of 0:23:14.440 --> 0:23:18.040 one meter. What's a coulomb. A coulomb is a unit 0:23:18.080 --> 0:23:21.439 of electrical charge equal to the quantity of a current 0:23:21.680 --> 0:23:26.240 of one ampier in one second. It's named after Charles 0:23:26.240 --> 0:23:30.840 Augustine de Coulomb, who in the late seventeen hundreds developed 0:23:30.840 --> 0:23:34.920 a description of the force that interacts between electrical charges. 0:23:35.440 --> 0:23:38.280 He had determined that like charges repel each other and 0:23:38.320 --> 0:23:41.160 that opposite charges attract each other, and his work led 0:23:41.200 --> 0:23:44.720 to further discoveries that the force of this repulsion or 0:23:44.760 --> 0:23:49.200 attraction is proportional to the products of the electrical charges 0:23:49.800 --> 0:23:54.040 and inversely proportional to the square of the distance between 0:23:54.119 --> 0:23:56.720 those two charges. And this is what we now call 0:23:56.800 --> 0:24:01.040 Coulomb's law and another way to define volt That was 0:24:01.080 --> 0:24:03.919 one way, but here's the other one. It's equivalent to 0:24:04.080 --> 0:24:09.120 one amp of current times the resistance of one ohm. 0:24:09.160 --> 0:24:11.719 And oh my goodness, looks like we're gonna have yet 0:24:11.760 --> 0:24:13.960 another thing to talk about here. And while you might 0:24:14.040 --> 0:24:17.359 hear that resistance is useless, I'm here to tell you 0:24:17.400 --> 0:24:21.560 it's pretty important in the case of circuitry. So I 0:24:21.640 --> 0:24:24.560 talked about how copper is a good conductor because of 0:24:24.600 --> 0:24:28.080