Who Invented the Potato Clock?

In these environmentally-conscious times, everyone’s been looking towards developing alternative sources of energy, from solar power to geothermal energy. On a much smaller scale, it has been proven that energy can also be drawn from the most unlikely of sources: a potato.


The Potato Clock was invented in 1983 by one William A. Borst. The impetus for this unassuming but clever gadget started rather innocently, when Borst was assisting his stepdaughter on a science project. He was reminded of a physics demonstration that he had witnessed in high school, in which a battery was created by affixing 2 metal prods into a potato. Borst thought of replicating that experiment, but with the addition of an electric-powered device which could run on the small charge of energy that the potato battery would generate.

Borst settled on a digital clock, but he realized that it would require a greater amount of energy than just one potato battery can generate in order to function. So to amplify the charge to be delivered to the clock, he decided to connect 2 potatoes in sequence. The move proved conclusive, and he was indeed able to power a digital clock by drawing electricity from a couple of potatoes.


A further experiment was then made to find out how long the potato-powered clock would operate. The time-duration test was conducted in an auto-repair shop that Borst had co-owned at the time. A customer happened to walk into the shop and asked about the curious device that was being tested. As it turns out, the customer was working for the local newspaper, which would then run an article about Borst’s invention. Eventually, word about the potato clock would spread, and what started as a modest school project caught national attention.

The Skilcraft Corporation later purchased the rights to the clock and currently manufactures it as the Two Potato Clock. While Borst himself never profited from his creation, he did enjoy the recognition that it had brought him. And the potato clock remains an easy and favorite science fair project to this day.

In order to make one’s very own potato clock, one would need 2 baking potatoes, 2 galvanized nails, 2 short-length copper wires, 3 jumper wires (each with alligator clips on both ends), and a low-voltage (1.5-2 volts) LED clock. Make sure that the clock’s batteries have been removed. For the first step, a nail is inserted into each of the potatoes. Then, each of the 2 copper wires is inserted into a corresponding potato, making sure that they are placed as far away as possible from where the nails are positioned.

Using an alligator clip, the copper wire inserted into one of the potatoes (which we shall label Potato 1) is connected to the clock’s positive terminal (+). The second alligator clip is then used to connect the copper wire of the other potato (Potato 2) into the clock’s negative terminal (-). Finally, the last alligator clip is used to connect Potato 1’s nail to Potato 2’s copper wire. All that is left is to set the clock, and one should have a fully-functioning potato clock of their very own.