Hasegawa, Harry Lawndale Community Academy

Objectives 1) Students will learn basic facts of polarization 2) Demonstrate some phenomenological activities illustrating interference patterns. 3) Make "take-home" project of the interference pattern. Equipment and Materials Microprojector Clear plastic box Crystals of: Polarizing films sugar Cellophane tape epsom salt Microscope slides salol mica salt Recommended Strategies Review light waves and experiment with polarizing film. Demonstrate the nature of polarized light showing that polarized light travels in a single plane instead of the 360 degree of unpolarized light. Demonstrate the interference pattern of various crystals which are placed between two polarized films on the microprojector. When light passes through a polarized film, the many color rays (or wave lengths) which make up the white light travel at various velocities and break up or interfere with another ray . A wave length or white light is then subtracted and shows the complementary color-- the color that is left when white light is subtracted. This is the interference pattern. Demonstrate light reflecting from a smooth surface such as plastic is polarized. The reflecting light comes to the eye in a single plane. Show that many digital read-outs are also polarized. Have students make a take-home project demonstrating interference patterns by placing a number of small pieces of cellophane tapes randomly on a microscope slide. Then view the slide placed between two polarizing films.
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