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Voltmeter values drop w/ time when measuring elec chem cell?

  1. Jul 26, 2015 #1
    I set up a zinc-copper elctrochemical cell by placing both electrodes in lemon juice to test the ability of lemon juice to conduct a current. I used a voltmeter and attached each lead to one of the metal electrodes. What I observed was that the voltage over time given on the voltmeter began to decrease and continued to decrease. I would be grateful if someone could explain what is happening? Thanks so much!
  2. jcsd
  3. Jul 26, 2015 #2


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    2017 Award

    Staff: Mentor

    How long did the process take?
    The voltmeter draws some current and the cell does not run forever.
  4. Jul 27, 2015 #3
    See "electrochemical cell polarization".
    What you see is normal for these home made cells.
  5. Jul 28, 2015 #4


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    These cells work better if you use copper sulfate solution instead of the lemon juice. Careful, it is toxic.
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