 Hi, I'm Zor. Welcome to Unizor Education. I would like to talk about batteries and generators. This lecture is part of the course called Physics for Teens, presented on Unizor.com. By the way, on the same side, there is a prerequisite course, which is called Math for Teens. Now, we are talking about electricity right now. So, this is just part of this part of the part of the part of the whole course, which is dedicated to electricity and magnetism. If you found this lecture somewhere on YouTube, on some other source of information, I do suggest you to rather watch it from theunizor.com because every lecture on the website has a detailed note for this lecture. It's like a textbook, basically. Plus, all the lectures are presented in certain logical order, so I do recommend you to take the course. And in particular, the course contains many problems which I'm solving, and some problems are given as exams, which you can take. And the site is completely free. There are no advertisements, so no financial strings attached. All right, let's go to the batteries. I would like to start with analogy. Everything in physics is really understood much better if you make some kind of a meaningful analogy. So, analogy which I'm trying to use when talking about batteries and generators, basically the generators of electric energy. And the analogy is the heater or the boiler, whatever, and the radiator when you are heating the room. So, what actually happens is, so this is something which is the source of heat, let's call it a boiler or something. Now, the hot water is generated by this boiler, and it goes to the house to the radiator. This is the radiator. Now, there the hot water gives away its heat, basically, heating the room, and the cold water goes back into the boiler, and this is the flame, and it heats again the water, and the water circulates. So, this generates energy, and this consumes the energy. Now, very, very similar process is happening when you have an electric circuit. So, let's say you have an electric circuit which has the battery, this is the battery, and a resistor. Now, what happens here? Basically, exactly the same thing. The battery somehow, we are not talking about how, but somehow, generates electricity, which means what? It means it separates certain electrons from the corresponding nuclei and sends electrons to a negative terminal, and the positively charged atoms which have lost a certain number of electrons are accumulated on another terminal. So, this is the excess of electrons. This is the deficiency of electrons in atoms. Now, what happens then? Basically, it generates potential energy. Why? Because, obviously, negative and positive charges, the atoms which have plenty of electrons and some free electrons on one side, and the atoms which have a deficiency of electrons on another side, electrons are gravitating or attracted towards the positive terminal because it has lack of electrons. Now, but the battery doesn't let them to connect together. It separates them. That's the purpose of the battery. So, it keeps them apart in as much as, for instance, I took something like a stone from the ground and lifted it up. I gave potential energy. I don't let the stone go down. Now, if there is a circuit, then we are allowing electrons actually to connect to these atoms which lack electrons, which have deficiency of electrons, but not through internal connection within the battery. No, the battery separates them. That's the purpose, but through the other way. And electrons don't have any other choice but to go this way to basically connect with those atoms they were separated from. And meanwhile, as they are moving, they are actually converting the potential energy which the battery has created into kinetic energy of electrons. Now, they are going through this wiring in the same way as the hot water goes through the pipe, then it hits the resistor and the hot water goes into radiator where it actually gives away the heat and what electrons do with the kinetic energy which they have. Well, they are trying to drag through this resistor. Basically, the resistor is resisting, so part of the kinetic energy is wasted and the resistor probably is heated, but we'll talk about this separately. Then, on another end, it goes back here. Great, but battery continues working. So again, it separates them and forces the electrons go and that's how the whole circuit is working all the time. So electrons are separated here through some kind of whatever the mechanism of battery is. For instance, if it's a car battery, then it's some kind of a chemical energy which is contained in this chemical energy because of this chemical reaction results in separation. Whatever this source is, there are many different ways to produce electricity to separate electrons from the atoms. But anyway, battery is functioning and then it goes all around, all around. So that's basically how the mechanism of generating energy, electric energy and consuming is happening. Now, my next topic is what happens if we are using multiple batteries. Basically, there are two major ways of connecting batteries in a series and in a parallel. Now, what happens first in a series? Well, in the series, you have two batteries connected like this. So the negative terminal of one is connected to positive terminal of another and then the negative part of this is connected through all this. I'm sorry, this is positive. So what happens here? Again, let me use the analogy with the heater. What happens if we connect two heaters one after another? This is also a heater. Well, the water, the cold water which is coming here is being heated up to certain temperature. But then it goes to a heater again, which means the temperature will rise even further and then it goes out. Now, the speed of the water actually is exactly the same. We don't change the speed, but we do change the temperature. Now, what happens in this particular case? Well, this battery separates electrons which are accumulated on this terminal from the atoms which lack electrons on this one. Now, so this is the terminal with axis of electrons. Now, it goes to this. And what happens here with these electrons? Well, this battery separates its own electrons from its own atoms. Plus there are some other electrons which are coming here. So they're pushed also towards, it's like heat. This heating mechanism actually is transmitting the hot water even to a higher temperature. And this particular battery, it already has a certain number of electrons and it adds its own. So these electrons are going through this particular terminal of the battery and goes here. So both electrons from here and electrons from here are accumulated here. So we have more electrons, so to speak. So the result is that more electrons are accumulated on this side than if you have only one battery. So two batteries produce more electrons at the same time. And what happens with these electrons? Well, since you have already separated certain atoms and you're separated even further, you have a greater difference in electric potential on these two poles. So when you are connecting batteries in series, you are basically adding the potential which is created by one battery to potential which is created by another battery. So the difference in potentials becomes greater. That's the voltage. So the voltage is added. So this is the voltage of one battery, this is the voltage of another battery and they are added together. So on these terminals you have the sum of two voltages. That's exactly what happens when you have some kind of a toy which has, okay, insert six batteries. Now how are they inserted? Usually the battery, if you look at this, it has two poles, one and another. And whenever you're inserting them, you usually insert it this way. And this is connected. And this is connected. So you see what happens? This is, it looks parallel, but actually it's a series connection because you see the positive is connected to negative, negative connected to positive, positive connected to negative. And this is output and this is the same thing. So they are geometrically parallel but electrically from the circuit standpoint they are connected sequentially. So it's a series. And that's why if you have let's say 1.5 voltage, let's say it's a AA battery, you have four batteries, then you have what? Six volt as a result. Now what happens if you are connecting parallel? Well that's a different story. Parallel connection is this. Actually I can put it this way. This is the parallel connection. Of two boilers. So what happens? Well they are working basically with certain, in a certain regime, reducing certain amount of heat. But we don't need twice as much heat in a room. So what we are usually doing, we are reducing the flame here and flame here. So they are working longer. They are wasting their, whatever the time it's allotted for them to work before they break. We are prolonging this time. They are working in a lower regime producing the same amount of heat. But this one is producing only half of the heat and this one producing is also half of the heat. Now what happens if we have batteries? Well with batteries we have again similar story. We have these two batteries connected parallel to each other. So what happens here? We need certain amount of electricity here. This is a consumer of electricity. Now we need certain amount of energy. But now we have two sources of energy. So what happens here? If this is a battery and if one battery for instance lasts let's say an hour, then we need only that amount of energy. So basically both batteries can last longer. They will work probably two hours together. Because we are consuming half of the energy from one and half of the energy from another. So if there is certain amount of chemical energy in the battery, let's say we are not recharging them. Just a battery, a regular battery. So we are getting this energy, we are getting only half of the energy from this battery, half of the energy from this battery. So both batteries together will last longer. But the voltage is exactly the same. Because the difference in potential is exactly the same. Whatever this battery develops, let's say 1.5V, if it's a AA battery, and this one if we connect positive to positive, so all positive are connected or all negative are connected. What happens? We will still get 1.5V. However, four batteries will last four times as long, approximately, as one battery. They provide the same 1.5V, but again the amount of energy will be now distributed among four of them. So basically that's the most important part of this lecture. What happens if we are connecting batteries parallel or in series? In case of a series, their voltage is added. In case of a parallel, we are not really increasing the voltage, but we are decreasing the amount of energy we are taking from one particular battery because we are spreading this amount of energy among four of them or five of them or whatever, six of them. And so they last longer basically. So that's the most important part which I wanted to talk about today. It's not very important actually from the theory, but you have to really understand what happens when you are, let's say, put two batteries into a remote control for the television. You're putting them one and another with different sides, not like this one, the picture before that. Okay, that's it for today, and I do recommend you to read the description, the notes for this lecture, which is presented on Unizord.com. And then we will continue for the next lecture. I promise I will have some very interesting problems to solve. So certain problems I will solve like a lecture, and certain problems will be presented as an exam to this particular topic. Okay, so good luck. Thank you.