Making a potato clock seems to be a very popular home project at the moment. Instructions on how to make a potato clock of your own are provided below.
I’m fascinated by clocks of all types. I think because the sound of clocks was always in the background when I was growing up. My German grandparents had a beautifully carved cuckoo clock, my English grandparents had a grandfather clock which chimed every quarter hour, my own parents had a mantel clock that had pride of place over the fire and I slept soundly every night soothed by the steady ticking of my bedside alarm clock.
My children now check the time on their mobile phones or in the bottom corner of the PC screen. I love the sight and sound of clocks in public places - Big Ben’s chimes are another fond memory.
Anyway, back to making a potato clock - here are the instructions.
How and why does a Potato Clock work?
The potatoes actually form an electrochemical battery, also known as an electrochemical cell. Basically, the electrochemical cell converts chemical energy to electric energy by a spontaneous electron transfer.
In the particular case of the potato, the zinc in the galvanised nail reacts with the copper wire, with the potato acting as a buffer between the zinc ions and the copper ions.
If the zinc and copper ions touched within the potato they would react but only generate heat. The role of the potato is to keep them apart, so the electron transfer has to take place via the copper wires of the circuit, which channels the electron flow i.e. electricity into the clock.
Supplies Required for the Potato Clock
- two potatoes
- two common galvanized nails
- three pairs of alligator clips connected to one another with wire
- two short pieces of heavy copper wire
- a simple low-voltage LED clock unit that functions from the power of a 1 to 2 volt, button-type battery
Potato Clock Assembly Steps
- Open the LCD clock battery compartment and remove the battery.
(Note that there is a positive (+) and a negative (-) terminal point where the battery was installed.) - Insert one galvanised nail into each of the potatoes.
- Insert one of the short pieces of heavy copper wire into each potato, locating it as far from the nail as possible.
- Use one alligator clipto connect the copper wire inserted in one potato to the positive terminal in the clock unit.
- Use one alligator clip to link the galvanised nail in the other potato to the negative terminal in the clock unit.
- Use the final alligator clip to link the spare galvanised nail in the one potato to the spare copper wire in the other potato.
- Set the clock and you’ve finished.












