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Potato battery, how does it work?

  1. Jan 22, 2013 #1
    Hi just made a potato battery, using a cupper coin and zink nails (not connected in any way, just pit in a nail and 3 inches appart a penny), I was just wondering what is the chemistry/physics theory here?

    Potatoes contain phosphoric acid

    Is it the acid in potatoes that oxidize the 2 metals? or id it the standard electrode potential?

    Electrode potential for Zn
    Zn(+2) + 2e ---> Zn(s) = -0,76 V (so it want's to be oxidized and should reduce Cu (+2) to Cu (s) because Cupper has a positive electrode potential.

    But does the acid oxidize both metals in the first place?
  2. jcsd
  3. Jan 22, 2013 #2


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    Staff: Mentor

  4. Jan 27, 2013 #3
    Using a potato is just one of infinity of choices. Any electrolyte should work given it does not pasivate the surface of the metals.
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