Find and remove the battery from the clock. Take note of the postitive (+) and negative (-) terminals on the battery, Kidzworld advises.
Insert one nail toward the end of each potato. Bluffton University suggests using bright, shiny nails.
Insert copper wire into the other end of each potato, keeping the wire as far away from the nail as possible.
Connect the copper wire from one potato to the positive (+) terminal using an alligator wire clip.
Connect the nail from the other potato to the clock's negative (-) terminal using another alligator clip.
Use the third alligator clip to connect the unused nail from one potato to the unused copper wire in the other potato.
Set your clock; it should be running.