MadSci Network: Physics
Query:

Re: relation between refractive index and viscosity

Date: Sat Feb 16 14:06:38 2002
Posted By: Allan Harvey, Chemical Engineer
Area of science: Physics
ID: 1012891872.Ph
Message:

The short answer is "no."

To consider whether there would be a relation between two physical 
properties, you have to think about the physical mechanisms involved.  The 
refractive index relates to the interaction of light with the electrons in 
a substance -- the more electrons (and the more polarizable the electrons) 
the higher the refractive index.  The viscosity is the resistance to 
shearing force, and has to do with the interactions between molecules as 
they move past one another.  These mechanisms are not related in any 
significant way.

If you restricted yourself to a specific class of compounds, you might be 
able to find a correlation.  For example, for the n-alkanes, the viscosity 
increases for bigger chains (because there is more opportunity for them to 
interact as they are moving past each other) and the refractive index also 
increases slightly (because the density of electrons is a little higher).  
So, for this very restricted class, you could correlate one property 
against the other, but it would only be valid for that class of comounds 
and would have no physical significance.  You could do the same thing with 
any pair of properties; the two you picked are actually about as 
*un*related as any pair I can think of.

Allan Harvey, steamdoc@aol.com
"Don't blame the government for what I say, or vice-versa."


Current Queue | Current Queue for Physics | Physics archives

Try the links in the MadSci Library for more information on Physics.



MadSci Home | Information | Search | Random Knowledge Generator | MadSci Archives | Mad Library | MAD Labs | MAD FAQs | Ask a ? | Join Us! | Help Support MadSci


MadSci Network, webadmin@www.madsci.org
© 1995-2002. All rights reserved.