With Refraction You Get

Well, for B Block... nothing, since they had their quiz after we went over their lenses and refraction lab. But, for everyone else, we looked at total internal reflection (the basis of fiber optics) and dispersion (the basis of rainbow formation). For total internal reflection, you should know the basic definition and its relationship to the critical angle. You should also be able to calculate the critical angle for a pair of substances using Snell's Law. We looked at some examples of total internal reflection, starting with a man-mad example (fibers from a cheap fiber-optic Christmas-tree thingie) and then moved on to a natural example (ulexite or television stone).

Attention then turned to dispersion and its consequences. With a material with a high index of refraction, the separation of light due to different paths of travel for different wavelengths is a well-loved phenomenon. In the atmosphere, light has to rely on a second event - total internal reflection - to have enough travel time in the rain drop to show good separation of colors. We looked at some variations of rainbows, such as double rainbows and lunar rainbows, but folks should have a solid idea of how a single rainbow forms and how prisms disperse light.

Tomorrow, we start interference and diffraction - the last two behaviors of light we'll study - before moving on to electricity.