This experiment will help students understand the importance of the critical angle and the index of refraction.
Light enjoys moving freely through substances, but when it leaves the easy to move through air and enters a substance that slows it down, it will refract. Refraction is the bending of light. In this case, the light is bending towards the middle of the gelatin because Jell-O is harder to move through than air. If the light were coming from the Jell-O and going into the air, it would do the opposite.
The angle of the laser with respect to the box is called the incident angle. On the other hand, the angle which the light exits is called the critical angle. They are related through Snell’s law which states that The “n” is the index of refraction, or the difficulty of movement through the substance.