6H30.10: Three Polaroids on the Overhead

Description: A continuation of 6H30.10 (Polaroids on the Overhead), this demonstraion shows what happens when
a third polaroid is placed inbetween the first two. If the first two were oriented so that almost no light was passing through,
and the third was put inbetween at a 45 angle, some light will pass through. This is counter intutive for most students.

Equipment: Demonstration Procedure:
  1. Have the two polarizers on the overhead arranged so that little to no light is passing through.
  2. Insert a third polarizer in between the two at a 45 angle. Note that it actually makes it lighter.
  3. Most students have the misconception that even less light would go through.