A potato battery is an electrochemical battery, An electrochemical cell is a cell in which energy is converted to electric energy
The potato and the zinc in the nail reacts with the copper wire. The potato acts as a sort of buffer between the zinc ions
and the copper ions. The zinc and copper ions would still react if they touched within the potato but they would only generate heat. Since the potato keeps them apart, the transfer has to take place over the copper wires of the circuit it transfers energy into the clock. this gives you potato power.
The potato and the zinc in the nail reacts with the copper wire. The potato acts as a sort of buffer between the zinc ions
and the copper ions. The zinc and copper ions would still react if they touched within the potato but they would only generate heat. Since the potato keeps them apart, the transfer has to take place over the copper wires of the circuit it transfers energy into the clock. this gives you potato power.