Seeing the light: Using chemiluminescence to demonstrate chemical fundamentals

The term "chemiluminescence" was first coined by Eilhardt Weidemann in 1888, and refers to the emission of light from a chemical reaction. In its simplest form it can be represented by: A + B Æ [I]* Æ products + light [I]* is an excited state intermediate formed from the reaction of reactants A and B. This attractive phenomenon has been used frequently as a demonstration in teaching classes, and there are a number of "recipes" available in the literature and on the World Wide Web. As part of the CSIRO Student Research Scheme for 1999, a secondary school student (RC) spent time in the laboratories at Deakin University, Geelong, investigating the suitability of a number of chemiluminescence demonstrations based on the luminol reaction which available on the World Wide Web. The particular aim was to find a reaction suitable for use in secondary schools. In this paper we compare and evaluate these luminol chemiluminescence demonstrations, and propose simple adaptations of the demonstrations to demonstrate basic chemical fundamentals.