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Chiming Clock Demonstration Science Project

Clocks have always played an important role in science because the measurement of time has an impact on the phenomena that science observes. This key role has made the improvement of time keeping an important scientific endeavor of it's own. This makes using a modern alarm or chiming clock ideal for a scientific experiment. A clock demonstration that makes an impressive science project demonstration is one that operates using homemade electricity.

Overview and Materials
- This science project demonstration shows how to power an alarm clock without store bought batteries. Instead, the clock is powered from electricity that is generated naturally with the help of potatoes and other items you can find at home or at a local hardware store. In addition to two potatoes, the experiment requires the use of three alligator clips, heavy copper wire, two nails and a low voltage digital alarm clock (1 to 2 volts).
Procedure
- Potatoes are numbered "1" and "2" to distinguish them. Potato 1 is used as the positive terminal (+) on the battery and potato 2 is used as the negative (-) terminal. Next, insert a nail and a copper wire into each potato, ideally as far from the nail as possible. Connect one end of the alligator clip to the wire in potato 1 and the other end of the clip to the positive terminal in the battery compartment. Connect one end of an alligator clip to potato 2 and then the other end of the clip to the negative terminal in the battery compartment. Finally, connect the last alligator clip from potato wire 1 to potato wire 2. The clock should be powered and you can set the alarm.
What's Happening
- The demonstration of the potato-powered chiming clock could not be complete without explaining how it's all possible. Essentially, there is a chemical reaction happening inside of the potato. Zinc in the nail reacts with the copper in the wires. The potato helps channel the spontaneous electron transfer that occurs as a result of the reaction. Those electrons stream along the copper wires, through the alligator clips and into the battery terminals of the clock.
Alternatives
- To add variety to this demonstration, you can swap potatoes with other produce such as lemons, tomatoes and apples, and then make hypotheses on how these changes will effect your results. Using a series of alternatives allows you to examine the unique properties of each element, make measurements and record data on the differences you observe based on the materials used.

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