Baked potatoes, mashed potatoes, French fries and homemade clocks, what do they have in common? They all start with potatoes! That’s right, potatoes don’t just provide you with energy when you eat them, thy will also power a clock. This is an easy, at-home science project that will demonstrate how we can supply our energy needs in ways other than just flipping the switch on the wall. Potato clocks are fun and easy to assemble, but first you’ll need to gather some basic supplies.
2 large clean potatoes, or 2 halves of a large potato.
2 galvanized nails (zinc)
2 copper nails or wires
3 jumper wires (with alligator clips on each end)
A Battery operated LCD clock (gray display with black numbers, like a cheap watch, normally taking just one 1.5V battery)
The nails, copper nails, or copper wire, can be found at most hardware stores. Most hardware stores also carry jumper wires with alligator clips, but if yours doesn’t they can also be found at electronics stores. If you are having trouble finding supplies, JM Cremps carries the complete Potato Clock Kit along with other science projects for kids.
First, assemble the items you need, and then let’s get started!
Step 1:Separate the two potatoes. Each potato works as a “galvanic cell,” releasing electrical energy through chemical reactions. Call one potato A (or 1), and the other potato B (or 2).
Step 2: Place one galvanized nail in each potato.
Step 3: Place one copper nail or wire piece into each potato ensuring that the nails don’t touch.
Step 4: Remove the battery compartment lid from the clock.
Step 5: Connect the first jumper wire from the copper nail or wire of potato A to the positive terminal of the clock.
Step 6: Connect the second jumper wire from the galvanized nail of potato B to the negative terminal of the clock, denoted by the symbol “-“.
Step 7: Connect the third jumper wire to the galvanized nail of potato A.
Step 8: Check the clock.
Click here to see the animated version of these instructions.