It was Rock Night on Friday night. If you weren't there, you missed another great performance by the staff band with our new lead singer. (I've never been known to be modest) There were a lot of other great performances too. Lots of Physics to look at but I chose this lighting unit at the back. It has a rotating drum with rectangular flat sections of plane mirror on them. The rule for reflection is that the angle of incidence = angle of reflection. The angles are measured to the normal line, an imaginary line sticking out of the surface of the mirror at 90 degrees. As the mirror rotates, the angle of incidence varies which changes the angle if reflection so the reflection of the light moves. Then the light will jump to the next mirror section. Next time I need to look more carefully at what exactly happens when it jumps from one mirror section to the next.
