Barber Pole
Safety Warnings
Warning: Chemical Handling
Purpose
A rotating polarizer beneath a cylinder of Karo syrup doped with silver nitrate creates colored bands that appear to spiral upward, demonstrating that light scattered at 90° is polarized. Students see Malus's law in action as different heights cycle through bright and dark with the rotating analyzer.
Figure 1:
The cylinder containing silver nitrate in Karo syrup, illuminated from below in a darkened room. Scattered light from the suspended particles is visible throughout the solution.
Figure 2:
Complete apparatus with the glass cylinder on a ring stand and the clock-motor-driven polarizer assembly (white box) at the base.