it would be nice to have a way to switch off the partially reflected ray in the "Bending light" simulation. Most of my students don't need to know about it. Recently I was in a school and used the simulation very briefly to illustrate refraction in a waves revision class, and was very surprised when one student put the ray in on the test they were revising for - it's good that they know about it, and would see it if they do the experiment, but it would be better if I could control it so I can explain what it is at an appropriate point.
oliver-phet
commented
5 years ago