Hello I'm trying to come up with a solid Lab to use for my chapter on Waves and Optics. I am considering having it center on refraction. Here is the problem: All labs I create for my class must avoid being a set of instructions for the student to perform. The must always be set up as a discovery where the experiment itself is not known and must be constructed by the student themselves. As a result, the questions they are given to start with are usually open ended (some labs end up being constructions, such as bridge building or Rube Goldberg devices, but that is not what i want to do here). The issue is that Snell's law is not something one can simply happen upon, so to simply ask them to try and construct and experiment to determine the relationships involved in refracted light would be not within their scope. I'm wondering if anybody had any ideas as to how to approach a good lab that still requires the students to devise their own experiment to solve a particular problem. Thanks in advance.