 Alright, first of our gas law videos and it'll be the kinetic theory of matter. The kinetic theory of matter is used to explain the behavior of matter. We look at what the particles in that substance are doing and use that to explain why that substance behaves the way it does. The kinetic theory of matter, the kinetic molecular theory, tells us a few things about the way the particles behave in a gas. First of all, the particles in a gas are in constant random motion. The particles in a gas are in constant random motion, so they never stop. That's the constant part. And the random part refers to the directions in which they're traveling. They're going all over the place. They do travel in straight lines, so they're not really curving or swerving or anything like that. They're going in straight lines. What's random about it is their directions. They're moving all over the place. One particle might be going up while the other one's going down. One might be even left while the other one's moving right. There's no pattern to the direction in which they move. So we can look inside of a gas. We see particles in there. And that one might be moving that way and that one might be moving that way and that one might be moving that way. They're not all going in the same direction. There's no pattern to the motion in those particles. That's the random part. Because that motion is random, they will collide with themselves and the walls of their container. So this little particle here is heading right towards that wall over there and eventually it's going to hit it. These are inanimate objects they don't think. They don't say, whoa, there's a wall coming. Got a turn. They travel in straight lines. So since this particle here is heading towards the wall, it's eventually going to hit it. These two particles are kind of on a collision course with each other. And if they happen to run into each other, they run into each other. Again, they're inanimate objects they don't think. So they can't swerve around each other. They can't get out of each other's way. If they're heading toward each other, they're just going to hit each other. Now when they do hit each other or the walls of the container, they bounce off. So they'll bounce off each other. They'll bounce off the walls. And they do so in what's called an elastic collision. What that means is they don't lose any energy in those collisions. They just bounce off. They don't speed up. They don't slow down. They just bounce off each other and go different directions. They will be traveling in straight lines when they bounce off each other. So again, after it hits the wall, it's going to bounce off the wall and it's going to go in a straight line in some new direction based on the angle at which it hit the wall. When they hit each other, they're going to bounce off each other. They're going to travel in straight lines in a direction based on how that collision occurred, how they ran into each other. Gases are mostly empty space. I'm going to go back to this picture that I drew the gas. I didn't put many particles in there. And I made sure that there was a good bit of distance between those particles because that's the way a gas is. The particles are relatively far apart. There's a lot of empty space in a gas. A lot of room for them to move around. So much so that the particles don't interact with each other. They cannot attract or repel each other. Think of the interaction between particles like the interaction between magnets. Magnets can attract or repel each other, but only if they're close enough to do it. You take two magnets and get them close together. You can feel a strong pull of attraction or repulsion depending on how they line up. But as you pull those magnets apart, that attraction and repulsion gets weaker and weaker until it eventually disappears. These particles in a gas are so far away from each other that there is no attraction or repulsion. The last thing we can say about a gas is their average kinetic energy. The average kinetic energy is just a measurement and an idea of how fast these particles are going. If they're moving faster, if they're moving slow. This average kinetic energy, how fast or slow they're moving, is determined by temperature and nothing else. So the number of particles that are in there won't affect it. The pressure that are under doesn't affect it. The volume, the amount of space they have to move around then doesn't affect it. The only thing that affects how fast a gas particle moves is the temperature of that gas. When temperatures are high, they will move quickly. When temperature is low, they move slowly. Now, this isn't exactly the same as what I gave you as a handout in class. There were six different points in there. I combined some of those points together in here to make it a little more straightforward so that the related topics are together. But that's basically the same thing that I gave you on your little handout in class. It had six points on it. Everything is covered in here. The idea is as we go through these gas laws, we're going to use these ideas to explain the way that law works. So when we talk about Boyle's law, for example, it's the relationship between pressure and volume. It tells you what happens to the pressure of a gas when the volume of the gas changes. Well, we're going to learn how those are related. What happens when you do that manipulation? And then we're going to explain it with this kinetic theory. So it's something you need to be very comfortable with.