NOTE 1: For many in the field, the Kerr cell is an ancient device, little used nowadays. It has been suggested that, after paying just brief attention to this "historical" device, you discuss with your students a liquid crystal display or the effect of photoelasticity. The latter makes use of the fact that many materials under stress show the property of birefringence, and these, when placed between a crossed polarizer and analyzer can produce dramatic affects in what light gets through, just as discussed for the Kerr cell.

NOTE 2: Some instructors in the field prefer to omit the procedures with the Glan polarizer and Wollaston prism and replace them with a simple procedure where students make two polarizers by stretching Saran wrap and then mount the stretched Saran wrap over holes cut in cardboard masks.