The Blue Bottle demonstration, involving the colorful redox cycling of
methylene blue, is often used to introduce and illustrate the scientific
method to younger science students and to study reaction rates and
mechanisms with advanced high school and university students. This paper
describes a greener blue bottle demonstration that reduces the total amount
of material used in the demonstration and improves the safety of the
demonstration by reducing the pH of the reaction from a strongly basic
solution to one with a pH of 3.0. In the revised protocol, the dye cycles
between the oxidized (blue) and reduced (colorless) state in the
presence of atmospheric oxygen (oxidant) and ascorbic acid (vitamin C, reductant). The description also includes a protocol for running the same reaction using consumer products thus, expanding the use and application of
this demonstration outside the traditional chemistry classroom.
Summary prepared May 2005 by Julie A. Haack, Department of Chemistry at the University of Oregon.
Wellman, W. E.; Noble, M. E. J. Chem. Educ., Print 2003, 80, pp 537-540.