I highly recommend making hollow prisms from thin glass sheets sealed with
epoxy. It's easy. I published an article in the Journal of Chemical
Education that shows an easy way to make them. The article also suggests
some nice experiments to do with the hollow prism
Title: A Liquid Prism for Refractive Index Studies
Author: Edmiston, Michael D.
Publication: Journal of Chemical Education, vol. 78, Issue 11, p.1479
Publication Date: 11/2001
Bibliographic Code: 2001JChEd..78.1479E
If you web-search on Liquid Prism + Edmiston you can find others who have
built prisms as I suggested and used them in various ways. I also have an
earlier publication about using the liquid prism with a spectrometer, and it
also makes some suggestions on making measurements with homemade prisms, but
it does not describe in detail how to make the prisms. The reference for
this earlier article is..
A very safe liquid to use (other than water) is various concentrations of
sugar in water. This is explained in detail in my J Chem Ed article. The
article also explains how to use the hollow prism as a refractometer for
measuring sugar content in soft drinks, fruit juices, syrups, etc.
We make lots of hollow prisms and have a lab for general-education science
students in which they measure the sugar content in soft drinks using the
hollow prism with a laser pointer.
Another liquid that is more hazardous (fumes, and flammability) is toluene.
If it is more hazardous, why use it? Because it has high dispersion. Using
a white-light source, the color spectrum observed with toluene is much more
spread out that the spectrum seen with water and water solutions. This is
caused by the aromatic ring (benzene ring) in toluene. High dispersion
versus low dispersion has been used as a quick test in organic chemistry to
screen for aromatic versus aliphatic compounds. Thus, any aromatic liquid
will show the high dispersion, but toluene is the least expensive, most
readily accessible, and has rather low toxicity compared to others. Do not
use benzene as it is too toxic. Do not put aromatic liquids such as toluene
in a plastic container because many plastics will dissolve in toluene, but
toluene works fine in the hollow glass prisms I describe as long as you
don't leave the liquid in it for hours and hours (in which case it softens
the epoxy).
I have more ideas, but start with my J Chem Ed article, or other people on
the web who have expanded on my J Chem Ed article.
Michael D. Edmiston, Ph.D.
Professor of Chemistry and Physics
Bluffton University
1 University Drive
Bluffton, OH 45817
419.358.3270
edmiston@bluffton.edu