6H50.20 - Polarization - Tyndall Experiment

See paragraph one in the procedure section.
Code Number:
6H50.20
Demo Title:
Polarization - Tyndall Experiment
Condition:
Excellent
Principle:
Polarization of Light, Rayleigh Effect
Area of Study:
Optics, E & M
Equipment:
Laser, Silver Nitrate Solution, Large Florence Flasks, Polarizing Plate, Pine-Sol, Non-Dairy Creamer or Milk, Stirring Rod.
Procedure:

Rayleigh Effect: Fill a large Florence flask with filtered water. Aim a laser down the neck of the flask as shown.  A polarizing filter should be placed between the laser and the flask unless you are using a polarized laser.  Add a few drops of fresh silver nitrate and look into the side of the flask and as moving 360 degrees around the flask observe the scattered, polarized light. The silver nitrate must be made fresh just before the demonstration as it starts to combine with minerals in the water over time. The polarized light intensity as you go around the flask may be measured with a light meter.

Pine-sol or powered non-dairy creamer will work in place of the Silver Nitrate, and are more environmentally friendly.  However, they do produce a more complicated scattering pattern because of their larger particle size.  

In the file with the laser manuals there is a Metrologic Laser Handbook and Catalog which has 101 uses for a laser described in it including this demo.

References:
  • Craig F. Bohren and Alistair B. Fraser,  "Colors of the Sky",  TPT, Vol. 23, # 5, p. 267, May 1985. 
  • Samuel Derman, "Light Pipes, Hydrostatics, Surface Tension and a Milk Carton", TPT, Vol. 22, # 1, Jan. 1984, p. 42.
  • B. G. Eaton and John B. Johnston,  "More About Light Scattering Demonstrations",  AJP, p. 184, Vol. 53, No. 2, February 1985.
  • Jearl Walker, "6.113, Ouzo Effect", The Flying Circus of Physics Ed. 2, p. 288.
  • O-040:  "Simulated Sunset",  DICK and RAE Physics Demo Notebook.
  • T. Kallard, "Scattering of Light and Polarization", Exploring Laser Light, p. 97.
  • Robert A. Egler, "Interstellar Medium and Stellar Reddening", PIRA Newsletter, May 1991.
  • Robert Ehrlich,  "Polarization of Scattered Light",  Turning the World Inside Out.
  • Joey Green, "Underwater Blue Light Beam", The Mad Scientist Handbook, Vol. 2, p. 101.
  • Borislaw Bilash II, “Colloids Exhibiting the Tyndall Effect“, A Demo A Day – A Year of Physical Science Demonstrations, p. 171.

Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.