5E40.27 - Potato Clock
This unit is designed to show that a battery may be made from a acidic fluid or fluid matrix and two electrodes of different materials, in this case copper and zinc. These clocks runs on approximately 2 to 3 volts so the unit has two cells connected in series. Usually I use two small beakers filled with Mountain Dew. Insert a copper and zinc electrode into each beaker making sure that electrodes do not touch each other. The clock should start immediately and can then be set to the correct time. The two beakers may be replaced with two potatoes, two lemons, two potted plants, and a host of other possibilities. In the fluid matrix situations ( fruits and plants ) the electrodes may have to be moved to within 1/2 inch of each other to maintain the needed conductivity.
- James Stankevitz, Roy Coleman, "A Curious Clock", TPT, Vol. 23, # 4, Apr. 1985, p. 242 - 244.
- Thomas B. Greenslade Jr., "Student Battery Cell", AJP, Vol. 89, #11, Nov. 2021, p. 1008.
- Jodi and Roy McCullough, "Voltaic Cells with a Two Potato Clock", The Role of Toys in Teaching Physics, p. 4.196.
- Janice VanCleave, "Potato Circuit", Physics for Every Kid - 101 Easy Experiments in Motion, Heat, Light, Machines, and Sound, p. 16 - 17.
- Carl Ahlers, Expose Excite Ignite An Essential To Whizz-Bang Chemistry, Galvanic Cell.
- Daniel J. Swartling and Charlotte Morgan, "Lemon Cells Revisited - The Lemon-Powered Calculator", Journal of Chemical Education, Vol. 75, #2, Feb 1998, p. 181.
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