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Homework Help: Help with Light-Refraction Project

  1. Jan 3, 2005 #1
    Hi Im doing a science fair project (Im in grade 9 just to let u no :biggrin: )on light refraction and to study how the density of different liquids affect light refraction.

    I am having problems with finding a pattern between Index of Refraction and Density, also Im having problem extrapolating a pattern Density and the angle of Refraction

    and also.. Why do some low density substances like oil have a greater index of refraction than higher density substances like water?

    I understand Snell's law completely and stuff like that.... I just have problems on finding a pattern and actually expanding upon the project......any assistance will be very much appreciated..
  2. jcsd
  3. Jan 4, 2005 #2

    Andrew Mason

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    You are learning a very important first lesson in science. One has to make observations and work out an explanation from observed facts. You are doing it the other way around.

    You can start out with a conjecture to test it, but if the facts don't fit the conjecture, it has to be abandoned and you have to try something else until you find the correct relationship or theory.

    You are insisting that there is a relationship between density and index of refraction simply because you think there ought to be one. Look at a list of materials and their index of refraction, such as here: http://hyperphysics.phy-astr.gsu.edu/hbase/tables/indrf.html#c1

    Then plot out some of their densities. You have to find another table such as this one:
    http://www.mcelwee.net/html/densities_of_various_materials.html [Broken]

    Do you see any relationship?

    The relationship between index of refraction and the physical or chemical properties of the medium is very complex. It relates to the way light propagates through a medium and has to do with the atomic or molecular structure of the medium rather than its density.

    Last edited by a moderator: May 1, 2017
  4. Jan 4, 2005 #3
    If you think density is related to refractive index,Just draw a couple of graphs btw densityvs refractive index,density^2 vs refractive index,etc.Once you get a st.line,You know that is the relation btw density and refractive index.
    It might help if you know graphs of some standard functions.
  5. Jan 4, 2005 #4
    aaaaaah so hard... and my friends call me a Quantum Physics geeko... :rofl:

    Thanks for your help guys! :biggrin:
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