Lemon battery
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The lemon battery is an experiment proposed as a project in many science textbooks [1]. It consists in sticking two metallic objects of different kind, usually a galvanized nail and a copper coin, in a lemon. These two objects work as electrodes, producing an electrochemical reaction that generates a small amount of electricity. Image:Lemon battery.png
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 light 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 [2]. Any fruit or vegetable containing some acid can be used, but lemons are preferred because of their high content of acid [3] [4].
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.