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Question
Are lemon/fruit, vegetable, and vinegar batteries examples of galvanic/voltaic cells?

Are galvanic cells (with zinc and copper) without a salt bridge an OPEN circuit?  

But don't galvanic cells allow brief flow of electrons without salt bridge?  So doesn't this seem to be a temporary closed circuit?

Thanks

Answer
Hello Elizabeth,

1. According to this website
https://en.wikipedia.org/wiki/Galvanic_cell
"A galvanic cell consists of two half-cells". That would not be true of  lemon/fruit, vegetable, and vinegar batteries. So perhaps it is quibbling, but I guess the answer needs to be no.

2&3. Based on the answer to #1, the answer to #2 would appear to be yes. Galvanic cells without a salt bridge would be 2 unconnected half-cells. But - scroll to the section heading Description and continue scrolling to the 1st bullet below. Look at the last sentence. That supports what you say in your 3rd question. I don't know how long it would be before the "imbalance in charge would stop the reaction". It would depend of course on the size of the load (therefore the current) between the electrodes and the size of the half-cells.

Go to
https://en.wikipedia.org/wiki/Lemon_battery
These batteries do not have a salt bridge, but they don't qualify as galvanic cells. I don't see a need to quibble about semantics, but your teacher may see such a need.

I hope this helps,
Steve  

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Steve Johnson

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I would be delighted to help with questions up through the first year of college Physics. Particularly Electricity, Electronics and Newtonian Mechanics (motion, acceleration etc.). I decline questions on relativity and Atomic Physics. I also could discuss the Space Shuttle and space flight in general.

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I have a BS in Physics and an MS in Electrical Engineering. I am retired now. My professional career was in Electrical Engineering with considerable time spent working with accelerometers, gyroscopes and flight dynamics (Physics related topics) while working on the Space Shuttle. I gave formal classroom lessons to technical co-workers periodically over a several year period.

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BS Physics, North Dakota State University
MS Electrical Engineering, North Dakota State University

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