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Code Number: 6H30.40
Demo Title: Polarization - Karo Syrup, Depths of Karo
Condition: Excellent
Principle: Circular Polarization & Faraday Rotation
Area of Study: Optics, E & M
Equipment:
Plexiglas Tube Filled with Karo Syrup, Karo Syrup, 38% Transmission Polarizers, and Slide Viewer, Spoked Polarizer Plate.
Procedure:
Karo Syrup will show different colors depending on depth when between crosses Polarizers. This can be done two ways. Pour Karo into a tall container and watch the change or put the large Plexiglas rod into the a container that already contains Karo and watch the colors change as you push the rod into the syrup.
NOTE: Only secondary colors are seen here.
This can be done on the overhead for most cases but for a portable unit you can do this with the slide viewer and some Polaroids.
A cool variation is to place the spoked polarizer plate under the beaker, add some Karo syrup, and then rotate the other polarizer over the beaker.
References:
- Xinyo Wang, Jiasheng Wu, Jiaxuan Wang, Yujie Li, and Wei Zhuang, "Polarization and spin", TPT, Vol. 63, #4, April 2025, p. 303.
- Paul Changnon, "Animated Displays IV: Linear Polarization", TPT, Vol. 31, # 8, Nov. 1993, p. 489 and referenced in Resource Letter TLC-1 Teaching Light and Color, Demonstration Experiments Resource Articles.
- Roland A. Hultsch, "A Demonstration of Optical Activity", TPT, Vol. 20, # 7, Oct. 1982, p. 476.
- George Freier, B. G. Eaton, "Optical Activity Demonstration", AJP, Vol. 43, #8, Aug. 1975, p. 939.
- Wallace A. Hilton, "P-6", Experiments in Optical Physics, p. 77.
- Bill Franklin, "Optically Active Materials", Teaching about Color & Color Vision, 1996, p. 9D-1.
- The Exploratorium, "Rotating Light: Polarized Light Passing Through Sugar Water "Rotates" to Reveal Beautiful Colors", The Magic Wand & Other Exp. in Light & Color, p. 94 - 99.
- W. Bolton, "Optical Rotation", Book 2 - Waves and Particles, Physics Experiments and Projects, 1968, p. 26-27.
- Optical Rotation, Wikipedia, https://en.wikipedia.org/wiki/Optical_rotation.