iv.Now we are going to flip everything upside down. Change the lower box to air by moving the index of refraction to 1.00 (air) and the upper box to water by changing its index of refraction to 1.33 (water). It is possible that you lose the refracted ray - if so, don't panic, just move the laser back and forth until it appears. Look at your incident ray, your refracted ray, and the normal line. When going from a more dense to a less dense medium, which way is the ray of light bent? v. Finally, move the laser back and forth. Somewhere around a 45o angle, the refracted ray will disappear. Try to explain why we no longer see the refracted ray. This phenomenon, where 100% of the light is kept inside the denser medium is called total internal refraction (or sometimes, total internal reflection) and is the basis behind the idea of fiber optics. Cool video showing this on You Tube will help you answer the question if you are having trouble only the first 2 minutes are needed. DO NOT CLOSE THIS SIMULATION, YOU NEED IT OPEN FOR THE NEXT PAGE