Electrochemistry   Carl W. Vermeulen, PhD Science-Projects.Com Williamsburg, Virginia science_projects@yahoo.com

The goal of this workshop was to show teachers who they can have their students each actually do exercises in electrolysis, electroplating, making voltaic cells and determining the reduction series of elements. The key word is 'actually' because usually catalog equipment is so expensive that the experiments are at best only demonstrated at the front of the class. This workshop introduces the teachers to extremely inexpensive, yet safe, equipment that is readily available. It is hard to beat a VOLTAIC CELL made from some fruit or vegetable! The set up is simple (shown to the left of the title, above. What is more as is shown, with a few added metals, the reduction potential series can be easily determined.
See: www.science-projects.com/RedoxPot/RedoxPotentials.htm

The plastic drinking cup ELECTROLYSIS device shown at the right is rather self-explanatory, and can be easily made at home. The parts are obtained from RadioShack, grommets from a hardware store, graphite electrodes are extracted from large first-grader pencils. Interesting questions arise when the students do NOT obtain the result of two hydrogens to one oxygen. If the salt is adjusted to more or less concentrated, or away from the halides, more chemistry sneaks in to help answer the puzzled minds of the students.
See: www.science-projects.com/Electrolysis/eLysis.htm

Electroplating is an interesting switch because ordinarily things would go the opposite direction as with the fruit voltaic cell in the first part above. But if we impose an opposite voltage that exceeds that of the voltaic cell, the reaction is driven in the opposite direction - often with the result that a metal is plated out on the negative electrode. Of course, out of sight, this is happening in your rechargable automotive battery when it is charging as lead metal is plating out from the PbSO₄ electrolyte. In practice, often the metal forms as needles that don't adhere well to the electrode and fall to the bottom of the container. So it happens in the figure shown to the left when you try to plate out copper from the colored solution. The copper appears black(!) as it clings to the electrode and bits fall to the bottom. BUT collect some of it and remove it from the solution and - voilà! - it is recognizably golden in color!
See: www.science-projects.com/Electroplating/ePlate.htm

Post-Presentation Comment by Presenter

The most important theoretical part of this presentation runs into a technological glitch: It is very important that you have available voltmeters that can easily detect DC-volts down to 0.05 volts. One's needle voltmeter should have a scale that reads a max of 2 volts. (Most voltmeters have their lowest scale reading to 15 VDC.). Digital voltmeters seem to work best. Needed: a simple qualitative device that would have two LED's on it so that when the wires of connected, the LED closer to the negative source lights up.

Regarding procuring a collection of a dozen or more wires or different elements to plug into one's fruit, this presenter hounded all the commercial desks, and there seems to be no single supply source from which a teacher could buy them. If you are interested, encourage this presenter to search further!