Using a Laser to Measure the Speed of Light

The law of refraction, which is known as Snell's Law, applies to our everyday life. For example, when you answer the door and see your friend's face through the window, you see light that is refracted through the glass. Snell's Law compactly describes what happens to the trajectory of a beam of light as it passes from one medium, for example, air to another, for example, glass. As we apply Snell's Law and the definition of index of refraction in this project, we are able to measure the speed of light in Jello. The beauty of this project also lies in how we can verify one of the most basic laws of optics experimentally by using readily available and inexpensive components.
Note that Snell's Law not only applies to our case of the laser beam passing through air and Jello but also to other examples of how the incident object changes direction as it passes from a faster medium to a slower medium, and vice versa. For example, a marching band walks together in time with the music and take the same length steps. What if the band moves across a grassy football field at an angle, and as each band member crosses the 50 yard line, he suddenly finds the field very muddy and slippery? As a result, he/she steps in time but takes steps that are 20% shorter because of the mud. What happens? Answer: Those who have crossed the 50 yard line are traveling at 80% the speed of those who have not, and the line of band members bends at the 50 yard line, just like light in this experiment. With a little thought, one can even compute the angle at which the line bends (actually the reverse of what we are trying to do in this experiment).