Lemon Cells Revisited - The Lemon-Powered Calculator

In the course of doing chemical demonstrations at several grade schools and demonstrations in freshman chemistry lecture we have found that students relate most to experiments that involve common everyday items found in the home. While teaching electrochemistry to our freshman classes we wanted to demonstrate the principles of a voltaic cell using items that students could easily obtain or relate to.

The use of dissimilar metal strips and a lemon to create a voltaic cell is well known and even portrayed in a current freshman chemistry text. We were unable to reproduce a previously published version of the lemon battery. We decided to search for items that could be used in a small to medium sized classroom that would work reliably and repeatably. Using copper and zinc or copper and magnesium as electrodes, the items found to work reliably are various LEDs, various piezoelectric buzzers, an LCD desk clock, and a TI-30 calculator.