Audible Sound Controlled Blue Bottle Experiment

Abstract

© 2022 American Chemical Society and Division of Chemical Education, Inc.The formation of chemical patterns is in general difficult to control due to the random diffusive motions of the reacting chemical species in solution. In this paper, we present a new method using audible sound to control the formation of chemical patterns obtained in blue bottle experiments. The waves generated on the surface of the solution by applying audible sound result in the nonuniform dissolution of atmospheric gases such as oxygen at the nodal and antinodal positions. On the basis of this phenomenon, the shapes of the patterns could be tuned according to the characteristics of the applied sound input, such as frequency and amplitude. This is an easy way for students to follow and control redox-responsive and pH-responsive chemical reactions in solution. The experiments involve chemicals that are mostly nontoxic and are easy to demonstrate since they involve common electronic gadgets (e.g., smartphones, Bluetooth speakers, etc.). These experiments provide interesting demonstration activities as well as a new understanding of utilizing audible sound for controlling chemical reactions.