This is an audio file detailing how light rays get kinks. The audio is as follows: "Have you ever observed what happens when you stick a pencil in a glass of water, and then look at it from different directions? This picture shows you that the pencil . . .

Here you have another principal ray diagram, just like the one we constructed on the previous page, only this one is interactive. You can click on the object and drag it, and observe what happens to the image. Notice that, as we saw on the previous pa . . .

On this slide, you see a schematic of a principal ray diagram. By identifying two sets of similar triangles, we will be able to derive the thin lens equation. Let's first define the variables: i is the image distance, and o the object distance; f is t . . .

This interactive animation allows you to explore Snell's law by shining a laser from air into a different medium, which can be either water or glass. Move the laser to change the angle of incidence, and observe how the refracted beam changes direction . . .

Not all mirrors are flat, of course. Now we want to consider two special cases of mirrors, both of which are pieces of a shiny sphere. Convex spherical mirrors are the outside of a reflecting sphere (or a part of it), and concave spherical mirrors are . . .

This interactive animation demonstrates how the focal length of a lens changes with its thickness. Like in the previous slide, the lens is shown from the side, and light rays are coming in from the left. Click on the arrows on the lens and pull to mak . . .

This interactive animation is very similar to the one with the convex lens you have used before. Here, too, you can click on the object and drag it to different positions, so you can observe what happens to the image. But now, you are able to move the . . .

We have seen in the last video that a convex lens indeed makes an image of our object, the little lit arrow. But how exactly is this image formed? This animation shows you that light rays are going off in all directions from every point of the object. . . .

In this interactive animation, you can explore how the lens of the eye adjusts its thickness. This allows you to see an object in focus as it is moved to different distances from the lens. Drag the object to another position and observe how the lens c . . .

This is a simulation for chemical kinetics and equilibrium including a simulation modeling the dependence of a one-way reaction as an introduction, a simulation showing chemical kinetics conversions, and a simulation showing chemical equilibrium conve . . .