3. Taking Measurements
a. Turn out the room lights. A small light might be useful for seeing the computer keys to type in values and to put the analyzing polarizer on and off. The lights can be on except when taking a measurement.
b. Start recording. Do not click on STOP until all of the procedure steps are completed.
c. Set Brewster’s plastic disk angle to 85 degrees. The square analyzing polarizer should not be in place. Rotate the spectrophotometer arm to about 85 and, while watching the digits display of the Reflected Light Intensity, fine tune the angle to get into the beam. It doesn’t have to be exact, just so that you get enough light.