lemon battery

This experiment does not work as currently desribed. A single lemon battery cannot light an incandescent bulb. Four lemon batteries wired in series, however, can light a red LED.

Apparatus

A large lemon
A strip of zinc
A strip of copper
A low voltage mes bulb (torch bulb) rated at 1.5 V
Insulated copper wire with crocodile clips soldered onto the end.

Method

Assemble the apparatus as in the diagram on the right. Push the pieces of metal firmly into the lemon to act as electrodes. They must not touch one another. Clip the crocodile clips onto the electrodes and wire them to a bulb. Provided the bulb is sufficiently low voltage it will light. A battery powered digital clock sometimes works where a bulb will not because bulbs draw larger currents than digital displays. This cell provides about 1V. If a large voltage is required they can be connected together in series. Connect the copper electrode of one cell to the zinc electrode of another cell.

How it Works

At the Anode

Both oxidation and reduction occur. A lemon cell is more complicated than a simple cell. Zinc is oxidised

Zn --> Zn²⁺ + 2 e^-

Hydrogen is reduced

2H⁺+ 2e^- --> H₂

At the Cathode

Hydrogen is also reduced at this electrode.

2H⁺+ 2b[electron|e]^- --> H₂

Lemon Battery

Apparatus

Method

How it Works

At the Anode

At the Cathode

See Also