Help with Light-Refraction Project

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The discussion revolves around a grade 9 science fair project focused on light refraction and the relationship between the density of liquids and their index of refraction. The student is struggling to identify a clear pattern between these two variables and is curious why some low-density substances, like oil, have a higher index of refraction than denser substances, such as water. Participants emphasize the importance of making observations and testing hypotheses rather than assuming relationships based on conjecture. They suggest plotting graphs of density versus index of refraction to identify any correlations and highlight that the relationship is complex, influenced more by molecular structure than density alone. The conversation underscores the need for empirical data to draw valid conclusions in scientific inquiry.
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Hi I am 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 I am 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..
 
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!Live_4Ever! said:
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..
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

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.

AM
 
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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.
 
aaaaaah so hard... and my friends call me a Quantum Physics geeko... :smile:

Thanks for your help guys! :biggrin:
 
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