Concept

Imagine you’re driving your car down the road on a summer day. You stop paying attention for a few moments, and drive your car into giant wall of orange jello. The jello wall isn’t perpendicular to the road, though, so picture in your head how one corner of your car hits the wall slightly before the rest of it. That side of your bumper that hits the wall first will now be facing more resistance than other side. The striking side slows down slightly, while the other side continues at the same speed. This causes the car to pivot slightly toward a perpendicular angle to the jello wall. In a moment, your entire car will be in the wall of jello, but it will be moving at a slightly different angle.

Now imagine that you finally make it out of jello covered area. The corner of your that originally entered the wall first now exits the wall first. This decreases resistance on that side of the car first, causing it to speed up. The car consequently turns away from that side, restoring the car to the initial angle it was traveling.

This is basically how Snell’s Law works. When light is travelling at an angle into a denser medium, it bends, or refracts, towards the angle perpendicular to the surface of the medium, also known as the normal angle. And when light travels from a dense medium to a less dense medium, light refracts away from the normal angle.



Bibliography