Along the lines of the video below, my oldest grandson Archer came up with some very interesting results from his 8^th grade science project: Magic Molly purple potatoes produce more electricity gram-for-gram than Yukon Gold or Red Norland; 10.6 vs 7.9 vs 7.6 millivolts; respectively. All the potatoes came fresh from his family’s garden. He chained 3 potatoes together for each voltage measurement, thus dampening out potato-to-potato variation.

Archer also tested a sweet ‘potato’, which did very poorly on his voltage measurement (5.9 mV)—perhaps not surprisingly, it not actually being a potato.*

Archer had hypothesized that “all of the potatoes will create the same amount of volts because the phosphoric acid in the potatoes that gives them power has no color, and color is the difference between most potatoes; therefore, there shouldn’t be a difference in voltage output.” However, given his sample size being only one per variety of potato, further testing would be needed to disprove his hypothesis with adequate statistical power (e.g., p<0.05).

I advise starting with at least 4 of each potato variety and doing the testing via a randomized plan, that is a proper design of experiment. It would also be interesting to do add other factors, such as boiled versus raw and extend the test out for some days to see if the voltage drops.**

Who knew such an unglamorous vegetable (“starchy tubers”, ha ha) could be so much fun?

* See Carnegie Museum of Natural History’s explanation: Potatoes, Sweet Potatoes, and Yams: What’s the Difference?

** For clues on this, see The Not So Humble Boiled Potato! by Samantha Parker, Museum Educator, National Electronics Museum, 2020.