 Now let's talk about waves on a string. And in particular right now I'm talking about a simulation we're going to be using a lot in class and that I'll be showing you some things in my future videos. Now these simulations are made by a group called PHET, which is out of the University of Colorado. And this particular website here will take you to their basic opening and you can see that they've got a lot of different simulations on a lot of different topics. The one that we're going to be looking at today is Wave on a String. And this URL will take you to sort of the opening page for that. So let's quickly go take a look at that. So here's this opening page. And if you hit the play button here, it actually takes you into the simulation. And this is sort of my opening. Now there's different things I can do with this particular simulation. I want to show you just a couple of things about how to work with it. First of all, if you make any changes and you want to reset it back, you can use this orange button down here to reset back to this state. You can change things over here, such as which type of end do I have. And I like to use the no end a lot. You can specify whether you're going to have a pulse, whether you're going to have manual, which manual means I move it up and it just responds to whatever I have. And if you move something up and you're not sure you like it, clicking restart will take you back to sort of a basic on that. For oscillate, I like to hit the pause button first so that it doesn't start playing until I've had a chance to set my parameters. And your parameters are down here on the bottom. You can set damping, tension, amplitude and frequency. You can also bring up different rulers to help you measure things about what's happening in there. You can also list some sort of reference line that you can move up and down so you can compare your wave to different things. So let me just show you real quick here, starting our oscillation off. It starts my wave moving. Now, damping, which we'll explore later, I often take that down to nothing just so I don't have any. I'll often have a tension that's sort of somewhere in the middle. And let's just keep those for there right now. Now, I can set this in slow motion so I can see a little easier what's happening here. I can pause it at any point and then sort of step it forward one step at a time if I want to see very carefully what's happening. Or I can start it playing again. And again, I can always go back to restart if, for some reason, I want to change something that's been going on. So in this particular case, let's put it in normal, a little bit higher tension, adjust my amplitude. And I'll see a little bit different motion here. So there's just your brief introduction to all of the different possibilities of things that you can do with this particular application. So as a summary, you can use this simulation to explore both wave pulses and oscillating waves. You can adjust parameters such as the amplitude, the frequency, and the wave speed through the tension. We'll look at that more later. And then you can play around with other effects such as damping and reflection. I didn't show you a lot in this one, but we'll take a look at those later.