Solar Power

- [Narrator] In this video, we're going to talk about solar energy, which is one of the energy sources that allows us to turn on our stereos, charge phone batteries and power other electronic appliances and this source of energy is becoming more and more common these days. People like it because it's renewable and it's something that we'll have as long as the sun is shining. Now, what I have here is a solar panel, solar panel. And what a solar panel does is, it takes energy from the sunlight, I'll call light energy, light energy. And it turns it into electrical energy, in the form of electricity. And the way I like to think of it, we took an idea from plants, which plants came up with leaves a long time ago, to absorb the sunlight and use that energy to create all of the chemicals that it needs to live and grow. But instead of making all of those chemicals, we're actually using it to make electricity. And electricity, you might already know, is what we use to turn on light bulbs or power our refrigerators or watch videos on the Internet and what it is is the flow of these little particles called electrons, through a wire and then through the light bulb, or whatever it is you're trying to turn on. So what a solar panel really does is, it moves these electrons, it causes them to move. So what lets the solar panel do this? Well, a solar panel can do this because it's made of a very special kind of material called a semi-conductor, semi-conductor, semi-conductor. A semi-conductor is something that's kind of in between the two main types of electrical materials that we usually think about. The first kind is just a regular conductor, conductor and a conductor is just something that allows electricity to flow through it. So metal is a conductor, water can also act as a conductor. It's just something that allows electrons to flow through it, and you see this semi, semi means half or part and conductor is just this other word, conductor. So that's where the word semi-conductor comes from and the other type of material is called an insulator. This is something like plastic or wood, finish writing it, insulator. Plastic or wood, and these kinds of materials don't allow electricity to pass through, right? You don't see wires made out of wood. You, in fact, might see wood or plastic or rubber or something used to stop electricity from flowing. A wire is actually surrounded by rubber because rubber will block the electricity from flowing through. So these are the two main types and a semi-conductor is something in between. Now this interesting in between nature of semi-conductors allows us to do a lot of things, really. Really, all of electronics are based on semi-conductors sometimes acting like insulators and sometimes acting like conductors. The computer you're watching this on is made of lots of semi-conductors put together in complicated ways, to turn it into a computer but anyway, going back to semi-conductors in solar panels, one property of a semi-conductor used in a solar panel is that in a dark room, in a dark room, a semi-conductor is going to act like an insulator. It's just going to be a plain insulator, not much going on. But if you put it in a light room or if sun shines on it, if we put sunlight onto this solar panel, it will actually start to act differently. The light will hit the electrons inside of the material and the electrons will absorb some of that energy and start to act differently. So in a light room, the electrons hit by the light will start to act differently. In a light room, it'll actually act more like a conductor and actually, the brighter the light, as long as you don't make it so bright that it damages the solar panel, you'll get more and more of this conductor-like behavior and you'll get more and more electricity out of it. So this difference between how a semi-conductor acts in a dark room and how it acts in a light room or outside in the sunshine, is the main thing that allows solar panels to turn light energy into electricity. So these solar panels sometimes sit right on top of buildings and provide electricity for those buildings and other times, a whole bunch of them are grouped together in a really sunny area and then the electricity is sent out to buildings through wires or power lines. So hopefully that was interesting.