How do light sticks work?


Vocabulary
chemiluminescence*
excited state*
fluorescent*
When the stick is flexed, a glass ampule inside the stick breaks. This results in the mixing and reaction of an organic oxalate (R-O-CO-CO-O-R', where the Rs stand for organic groups) and hydrogen peroxide, H2O2. The reaction that produces a product in an 'excited' state. The product loses energy to relax back down to its ground state by dumping energy to a fluorescent dye molecule present in the stick. The dye releases the energy as brilliantly colored light.

Lightsticks are often used to demonstrate the effect of temperature on chemical reaction rates. They glow more brightly when immersed in hot water and dim in ice water.

References

"The Effects of Temperature on Lightsticks", J. Chem. Educ. 76, 40A (1999).

Related Links

Chemiluminescence Home Page ( Thomas G. Chasteen, Sam Houston State University)
Chemiluminescence is production of light by chemical reaction. This page offers a Quicktime animation of a chemiluminescent reaction, a list of Web resources about chemiluminescence, and bibliographies on chemiluminescence and bioluminescence.
http://www.shsu.edu/~chm_tgc/chemilumdir/chemiluminescence2.html (5/23/99)

Author: Fred Senese senese@antoine.frostburg.edu


General Chemistry Online! How do light sticks work?

Copyright © 1997-2005 by Fred Senese
Comments & questions to fsenese@frostburg.edu
Last Revised 07/31/07.URL: http://antoine.frostburg.edu/chem/senese/101/consumer/faq/print-lightstick.shtml