 All right, I have a chemical reaction here. In the last lecture, I explained that chemical reactions are basically just breaking chemical bonds on one side of the reaction and reforming them on the other side of the reaction. We start out with something on one side and at the end of the chemical reaction, we have something different. That is a chemical reaction. Now, look, I have a, I mean, is everything that I teach you my favorite? I'm pretty sure it is. This is my favorite chemical equation except for the one that goes backwards, which is photosynthesis. This is cellular respiration and it is glucose and I've shown you the chemical formula for glucose and we'll break that down and see what that is saying. Glucose plus oxygen combines to form reacts to form carbon dioxide plus water plus energy. This is how we get energy out of our food. It's this process of cellular respiration. I might as well write that down up here. Cellular respiration. And it is. We get energy, glory days, out of the glucose molecule by breaking it up and reforming it into something else. Chemical reactions, everything on the, I don't know, this is the left side, correct? On the left side of, I don't know because it's not really, it doesn't have to be the left side, on the back end of the arrow, on the, this is the direction we're going. In this case, it's on the left. These are called reactants and on the front side of the arrow, the things that result are the products. Chemical reactions always obey something called the conservation of matter. This is a law that we shall see over and over and over and it's super interesting. This, it's not entirely intuitive. Conservation of matter says, dude, try as you like. You cannot create, you cannot create or destroy matter. And what this means is that in our chemical reaction, if we start with six glucose, I mean, if we start with six carbon atoms in our glucose molecule right here, on the other side, we have to have six carbon atoms. How can we see one? What do you think that means? For each molecule of glucose that goes through cellular respiration, we're gonna end up with six molecules of carbon dioxide that get blown off. Because we put six carbons in, we get six carbons out. That makes sense, doesn't it? If, now, I'm just gonna go ahead and show you, you can convince yourself that this is true. One glucose molecule plus six oxygen molecules will give rise to six carbon dioxide molecules and six water molecules plus energy. And we will talk about how awesome that is in after our first exam. There's something else I wanted to tell you about this. I don't know what else I wanted to tell you. We can reverse chemical reactions. We can't create matter or make more. Maybe that's it, dude. And then our last thing that we're gonna talk about is kinetic energy, which is required. Okay, so that's our link to the last topic in this lecture.