Microscale Electrolysis Using Coin-Type Lithium Batteries and Filter Paper

An educational experiment illustrates the electrolysis of water and copper chloride to middle school science students. The electrolysis cell is composed of filter paper soaked with Na[subscript 2]SO[subscript 4] or CuCl[subscript 2] aqueous solution sandwiched, along with a sheet of platinum foil, between two coin-type lithium batteries. When the electrolysis is carried out, the electrolysis cell is connected to a current indicator with a light-emitting diode (LED) and to a current-regulating diode (CRD). Because no elaborate components such as an ammeter, dc supply, or Hoffman Cell are needed, the experiment is easy and inexpensive to carry out. In addition, the time needed to obtain the result is less than 5 min and the results are visually clear. The water electrolysis experiment was tried in science classes of ninth grade students, and the responses from the students were positive. (Contains 7 figures.)