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Chemical Education Today
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Letters
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Take Care When Using That Pointer
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Jorge G. Ibanez
Centro Mexicano de Quimica en Microescala, Departamento de Ciencias, Universidad Iberoamericana, Prolongacion Paseo de la Reforma 880, Delegacion Alvaro Obregon, 01210 Mexico, D.F., Mexico
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January 2003 Vol. 80 No. 1 p. 30
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| Full Text |
In the experimental procedure of the Tested Demonstration, “The Use
of an Inexpensive Laser Pointer To Perform Qualitative and Semiquantitative Laser
Refractometry” (1), the authors give the following
warning: “Avoid looking directly at the laser beam.” This warning
is insufficient.
A year ago I was working in the lab trying to test for the presence of CO2 by
bubbling a gas mixture supposedly containing this gas into limewater. Since the
precipitate produced was extremely scarce (it looked more like a colloidal suspension),
I thought of using a laser pointer to take advantage of the Tyndall effect and
thus visualize it. I was using a conical-bottom vial (Ace Glass) and a commercial
laser pointer. After using the laser for this purpose for a few minutes, and even
though I never looked at it directly, I realized that perhaps the reflections
and refractions from the vial had somewhat hurt my vision. For the next few days,
I was very often seeing large “white spots” and this so worried me
that I went to see an ophthalmologist. After careful examination, he said that
nothing of consequence had happened to my vision. Unfortunately, my retina became
very sensitive to bright light for several months. I have recovered, but I wanted
to warn users of laser pointers for purposes such as those mentioned above, that
in spite of not looking directly at the laser light, some side effects may derive
from inadvertent reflections and refractions at glassy or other materials.
Literature Cited
- Neder, A. F.; García, E.; Viana, L. N. J.
Chem. Educ. 2001, 78, 1481–1483.
See Tested Demonstrations Editor's Reply
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| More Information |
 Citation
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Ibanez, Jorge G. J. Chem. Educ. 2003 80 30.
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 Keywords
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Demonstrations; Laboratory Equipment / Apparatus; Laboratory Instruction; Lasers / Laser Spectroscopy; Liquids; Qualitative Analysis
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 History
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Created:
Last Updated: |
December 5, 2002
February 28, 2005
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