The lemon battery is an experiment proposed as a project in many science textbooks ^*. It consists of inserting two different metallic objects, for example a galvanized nail and a copper coin, into a lemon. These two objects work as electrodes, causing an electrochemical reaction which generates a small amount of electricity.

The aim of this experiment is to show students how batteries work. After the battery is assembled, a multimeter can be used to check the generated voltage. In order for a more visible effect to be produced, the battery can be used to power a LED. Since the produced voltage is typically insufficient to power a standard LED, two or more batteries are connected in series.

Technically, both oxidation and reduction occur. At the anode, zinc is oxidised:

Zn → Zn²⁺ + 2 e^-

At the cathode, hydrogen is reduced:

2H⁺+ 2e^- → H₂

A common alternative to lemons are potatoes Any fruit or vegetable containing some acid can be used, but lemons are preferred because of their higher acidity ^*.

External links

• Lemon Battery, Hila Research Center
• The Lemon Battery Challenge, National Engineers Week
• D.J. Swartling, C. Morgan (1998). Lemon Cells Revisited—The Lemon-Powered Calculator. Journal of Chemical Education, 75 (2), page 181.

See also

• Daniell cell
• electrochemistry
• battery (electricity)
• electrode

Electric batteries | Battery shapes | Disposable batteries | Biology