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Low Cost, High Index of Refraction?

  1. Jun 7, 2012 #1
    I have my introductory physics students determine the index of refraction of various solids using fairly conventional methods (lining up pins or determining critical angle). I think this experiment would be more interesting if I could vary it more. I would like to find a substance with the following properties:

    * Inexpensive
    * Safe
    * Transparent to most visible wavelengths
    * An index of refraction outside the range of 1.4 to 1.7 (almost all glasses and clear plastics seem to be in this range)

    I've considered using big ice cubes (n = 1.31). Jello is about 1.38, so it's not much of a change. Cubic zirconia is over 2, but I can't find slabs of that.

    Ideas?
     
  2. jcsd
  3. Jun 7, 2012 #2

    Drakkith

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    Water is 1.333. Or did you only need a solid?
     
  4. Jun 7, 2012 #3

    Vanadium 50

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    Lead fluoride is 1.8. Lead tungstate is 2.3. Bismuth Germanium Oxide is 2.15. In the other direction, aerogel is close to 1 (but not so easy to handle).
     
  5. Jun 8, 2012 #4

    Andy Resnick

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    Interesting problem- transparent solids have a very narrow range of refractive index. Can you use liquids at all? Cargille has a nice range of fluids:

    http://www.cargille.com/opticalintro.shtml

    Another option may be gels- not to be too crude, but Astroglide and Purell may work.
     
  6. Jun 8, 2012 #5

    Vanadium 50

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    I think that's more a property of the definition of index than anything else. I could equally well have said " transparent solids have a huge range of light travel speeds: the variation is over a range 100,000 miles per second".
     
  7. Jun 8, 2012 #6

    Drakkith

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    While true, I don't see any problem with saying it like Andy did. It is referring to the index of refraction and the scale we use for it, not the speed of light. (Obviously the two are related, but you get my point I hope)
     
  8. Jun 8, 2012 #7

    Vanadium 50

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    Right, but my point is that the "narrow range" is a property of the variable we use to express it in. In other, equivalent expressions, its not so narrow.
     
  9. Jun 8, 2012 #8

    Andy Resnick

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    Whatever.... slow day?
     
  10. Jun 8, 2012 #9

    Vanadium 50

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    You got it...watching my code slowly compile. Slllooowly.
     
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