PURPOSE: To demonstrate two ways to change the polarization of light.

DESCRIPTION: Light from a goose neck lamp passes through two polaroids to the observer. Crossing the polaroids stops light from reaching the observer. Inserting a third polaroid at an angle between the two crossed polaroids allows light to pass (above left). That light can be stopped by rotating one of the other polaroids, demonstrating the component of a component of the vector electric field. Inserting a sheet of wax paper between the crossed polaroids causes a large amount of random depolarization due to multiple scattering (above right). Rotating either of the originally crossed polaroids cannot stop the light, demonstrating that the depolarization by scattering is not a coherent process.

SUGGESTIONS:

REFERENCES: (PIRA unknown.)

EQUIPMENT: Bright point source with mounted crossed polaroids, extra polaroid, wax paper.

SETUP TIME: 5 min.