Add to ORKGThis is an audio file detailing how light rays get kinks. The audio is as follows: "Have you ever observed what happens when you stick a pencil in a glass of water, and then look at it from different directions? This picture shows you that the pencil doesn't seem to be straight any more, it looks like it has a kink! What does this mean? Shining a laser beam, for instance from a laser pointer, onto a bowl of water can give us a clue: the light beam does not continue straight at the border between air and water, it has a kink! The phenomenon is called refraction: a light ray bends when it goes from air into water, or vice versa, or from glass into air, or vice versa ??? generally, when it goes from one medium into another. When we use optical...