Demonstrations

Index of Refraction - Wesson Oil

Code Number :	6A40.30
Disclaimer:	Reprinted by permission of Dick Berg, University of Maryland, for use on this website. The demonstrations contained and referenced herein are listed for the purposes of cataloging and describing physics demonstrations which should be conducted only under the direction of a trained instructional support professional or physicist. These demonstrations are not presented for the purpose of being conducted by persons unconnected to this Facility and/or persons not consulting with or being supervised by the recognized instructional support professional or physicist and his/her staff. The University is responsible only for those demonstrations carried out using its own equipment using established safety and scheduling policies, and bears no responsibility for those choosing to use this source material for their own purposes. All demonstrations described and contained herein are public domain, and can also be found in reference materials in libraries, bookstores, and electronic sources. Further information regarding legal liability in use of demonstrations and labs will be found on the web site Injuries in School/College Laboratories in USA. The University of Iowa Disclaimers: University of Iowa Disclaimer All Rights Reserved..
Condition :	Excellent
Principle :	Refraction and Critical Angles
Area of Study :	Optics
Equipment :	400 ml Beaker, Watch Glass or Test Tube, Wesson Oil, Glycerin, Immersion Oil, Karo Syrup. Trichloroethylene, Anisole, Carbon Tetrachloride.
Procedure :	A popular index of refraction demonstration is to make Pyrex glass disappear by immersion in a liquid with the same index of refraction. Carbon Tetrachloride, Anisole, and Trichloroethylene were used extensively in the past but these are now listed hazardous carcinogens so we try to stay away from them. Immersion oil will also work but it is expensive to get the 200 to 300 ml volume necessary to immerse a test tube. The cheaper modern day alternative is 'Wesson' vegetable oil and Pyrex glass. NOTE: If using a test tube you need to have some of the liquid inside the tube also. Pyrex has an index of refraction of 1.47. The index of refraction for other common liquids are: Clove Oil - 1. 535 Lemon Oil - 1. 481 Neroli Oil - 1.482 Orange Oil - 1.473 Safflower - 1.466 Vegetable Oil (50 degree C) - 1.47 Oil of Wintergreen - 1.536 Glycerin - 1.473 Karo Syrup has an index of refraction close to soft glass for use with stirring rods and glass cylinders. It has been reported that Lexan and Glycerin also work well. However, our testing indicates that Glycerin and soft glass works better than Lexan. Mixing glycerin and water together in different concentrations will work to match most other types of glass. The "Phantom Crystals" are commonly used as a substitute for soil in potted plants. They are able to absorb a large amount of water and keep it from evaporating, and so they are used to keep plants from drying out under stress conditions. The crystals are a mixture of: 25% Hydroxyethel Methacrylate, methacrylic acid, acrylimide copolymer, cross-linked homopolymer for absorption and desorption of water, and 35% silica to stabilize the system.

References

Christopher J. Olney, "Refractive Index of a Liquid as a Function of Temperature," TPT, Vol. 36, # 1, p. 46- 47, (Jan. 1998).

J.M. Dudley and A.M. Kwan, "Snell's Law or Harriot's?," TPT, Vol. 35, # 3, p. 158-159, (March 1997).

William R. Gregg, "An Old Optics Demonstration - Redone More Safety", TPT, Vol. 31, # 1, Jan. 1993, p. 40.

Walter C. Connolly, "The Cheshire Cat", TPT, Vol. 21, # 4, Apr. 1983, p. 263.

Walter C. Connolly, Thomas L. Rokoske, "The Disappearing Dropper", TPT, Vol. 18, # 6, Sept. 1980, p. 467.

Thomas B. Greenslade, Jr., "Index of Refraction by an Updated Pfund's Method", TPT, Vol. 17, # 9, Sept. 1979, p. 394.

"Refractive Index of Liquids", TPT, Vol. 17, # 4, Apr. 1979, p. 258.

Donald K. Day, "A Safe Pyrex 'Vanishing Solution,'" TPT, Vol. 15, # 7, p. 438, (October 1977).

F. J. Wunderlich, D. E. Shaw, M. J. Hones, "Pyrex "Vanishing Solution", TPT, Vol. 15, # 2, Feb. 1977, p. 93.

Donaldl K. Day, "A Safe Pyrex "Vanishing Solution", TPT, Vol. 15, # 7, Oct. 1977, p. 438.

"New Life for an Old Device: The Ring Interferometer", TPT, Vol. 24, # 1, Jan. 1986, p. 52.

K. Hagenbuch and B. Scott, "Comment on the Note "A Simple, Sensitive Method for Measuring the Refractive Index of a Liquid", AJP, Vol. 45, # 10, Oct. 1977, p. 1004.

K. Tennakone, "A Reply to Comment on "A Simple, Sensitive Method for Measuring the Refractive Index of a Liquid", AJP, Vol. 45, # 10, Oct. 1977, p. 1004.

O-215: "Beaker-in-a-Beaker," DICK and RAE Physics Demo Notebook.

O-216: "Crushed Tube Made Whole-Spoof", DICK and RAE Physics Demo Notebook.

"Disappearing Glass," PIRA News, Vol. 8, # 5, April 1994.

"Disappearing Glass Rods," Science Snackbook, p. 40.1 - 40.2.

"Index of Refraction," PIRA Newletter, Vol. 3, # 17, p. 9, 1990.

Paul Doherty, "Hands-On Science In Class and Out," The Exploratorium, p. 12.

Ron Hipschman, "Disappearing Glass Rods," Exploratorium Cookbook II, p. 104.1 - 104.4.

T. D. Rossing, C. J. Chiaverina, # 4, "Disappearing Drinking Glass", Light Science, Physics and Visual Arts, p. 101.

Brian Jones and Matt Fackelman, "Vanishing Rods", Don't Forget the Duct Tape, p. 145 - 148.

"Disappearing Test Tube in Salad Oil," Physics From the Junk Drawer, 3rd Edition, The Science House, North Carolina State University, p. 47.

Mail Questions and Comments to: Dale Stille