Electrochemistry with Simple Materials to Create Designs and Write Messages

An activity is described in which items found around the home are used in electrochemical experiments to create messages and artistic designs. To do so, a battery is connected to wires fashioned out of aluminum foil. When these wire electrodes are touched to a paper towel soaked in fluids obtained from household cleaners or disinfectants, the resultant redox reactions cause color changes on the paper towel. For example, the reduction of water at a cathode can cause a blue color to develop on a paper towel soaked in foam cleaner that contains thymolphthalein, and oxidation of iodide ions at an anode can produce a black color on a paper towel soaked in decolorized iodine. The experiments are very simple to set up and carry out; produce striking visual results; and relate to concepts in electrochemistry, acid-base chemistry, and thermodynamics. As such, the activity may be tailored for use in settings that range from outreach events to general- and analytical-chemistry courses.