Turn on the light with the switch. Rotate the lower disk using the handle so as little light as possible gets through both disks. Insert plastic objects between the upper and lower disk. Adjust the position of the lower disk. What do you see? Where do all the colours come from?
Also try Insert the laminated cellophane sheet between the disks. Move and rotate the cellophane. Describe what you see.
Light oscillates in all directions. Polarizer 1. Polarized light oscillate in one direction. Polarizer 2. Polarizer 2 obstructs the light coming from polarizer1.
Fun facts
Light is electromagnetic waves. The lamp light oscillates in all directions. The grey disks obstruct all oscillations except those that oscillate in one particular direction. We say that the disks polarize the light. When the polarisation of the two disks are at right angles, they totally obstruct the light. The plastic and the cellophane turns the direction of the polarisation of the light. Different frequencies of the white light are turned differently, thereby giving us the many colours.