Two polarized disks were put into a grooved holder with their polarization axes lined up, and a bright red light emitting diode (LED) was placed on one side, and a light sensor was placed on the other side. Light intensity was measured as a function of the plastic rotating polarizer angle from 0 to 180 degrees. Science Workshop was used to measure the intensity for every 5-degree rotation (Fig 1).Method 2:The mineral calcite exhibits birefringence (double refraction), and therefore has two different values for its index of refraction. A calcite crystal was placed on top of print and rotated in order to see the difference between the two rays, the ordinary ray and the extraordinary ray. A polarizer was then used to look at the images formed by the calcite.Method 3:In order to determine the stress points in a plastic object, we used a photoelastic effect where we looked at the object through a polarizer. When the plastic was squeezed together, changes in the color occurred, displaying points with greater stress.Method 4:Polarization by reflection from a non-metallic surface was used in this method in order to help distinguish the plane of incidence, and Brewster’s angle. A cardboard disk with a picture on it and a polarizer were placed in the holder, with a piece of black plastic (n=1.491) in between them. Brewster’s angle was determined from tan = n, and =56. We then looked through the polarizer at this angle and were able to determine the polarization direction. We also viewed the reflection of a ceiling light directly above the black plastic in order to determine if it was polarized in this case.Method 5:In order to determine polarization by scattering, a jar was filled with water and dried milk, and then a flashlight was shined directly down into the top of the jar. From the side of the jar, we looked through a polarizer at the scattered light. From this we determined if the light was horizontally polarize...
