Does Light Travel in a Straight Line?
“Hi I’m Steve Jones and I’m going to discuss the idea that light travels in a straight line. Does it travel in a straight line? Well I’ll answer that question immediately. Yes and no. Obviously 200 years ago nobody would have disputed the fact that light appeared to travel in straight lines and except for the occasions when we see things like reflections from a mirror, this is a mirror here so if we see a reflection from a mirror, we can say yes it travels in straight lines there and there but I’m sorry there it doesn’t. So the other is if we have a prism, this is a type of prism, this is solid glass and we get what we call internal reflection so reflection is a process where light doesn’t travel in straight lines, it is reflected and if I look at a lens, again a solid piece of glass, as the light enters it it bends so we can say that it travels in straight lines and here with refraction what we have here is a triangular prism. This is solid glass, this is air and the light bends so no
