-1
$\begingroup$

The second picture are potatoes wired in parallel. I understand that the potato is the medium for a chemical reaction between the copper and zinc. That aside, would wire and in soil potato plant continue to grow replenishing the medium(nutrients and water) regardless of having a current in the potato?

Or

Will the plant react to the physical damage or be depleted of nutrients/water needed to weakening the current or plant?

Maybe the current can be intermittent to allow the plant to recover? Can the current be low enough not inhibit plant growth?

I would ask chemistry if I was interested how a potato clock works, but I am more interested in the plant health and connections.

enter image description here

enter image description here

I have seen many potato experiments online but none where the potato plant was intact in the soil producing power.

$\endgroup$
  • 1
    $\begingroup$ I don't understand why you think the battery's energy comes from the potato. The potato is just a medium for transport of one electrode's atoms (ions actually) to the other. $\endgroup$ – Jim Young Jan 8 '18 at 4:14
  • $\begingroup$ So you have questions about the ionic conductivity of dirt? I think you need to clarify what your question really is. $\endgroup$ – Jim Young Jan 8 '18 at 22:19
3
+50
$\begingroup$

Yes, the potato clock will work when still in the ground, but it won't work any better than a potato removed from the ground.

Potato batteries are awesome and cool projects, but they often convey the wrong concept. The energy produced from a potato battery is not from the substance, nutrients, or sugars of the potato, but rather via the galvanic action of the two metals inserted into the potato.

The simple counter to this mental model is to point out that you can make a battery out of salt water, which clearly doesn't have any organic, energetic molecules in it. However, I'll talk a bit more about what's actually causing this effect and why it doesn't work in the way you imagine it might.

Copper-zinc voltaic cell

The above image is an example of a "potato battery" made without the potato. Identical setup and the energy obtained is identical given everything else the same.

Potato power- er, metal power?

This experiment is supposed to demonstrate the concept of an electrochemical cell. Electrochemical cells obtain their energy from the reduction-oxidation reactions that happen between two metals with different reduction potentials. When two metals - such as copper and zinc - are placed in a medium that permits the exchange of electrons and ions, an electrical gradient is produced as electrons move from one metal to the other and ions move the other direction. This gradient can then be captured and used to do work such as powering a lightbulb or an AI.

In the potato powered example, the power comes from zinc and copper. If you want a more powerful battery, use more zinc and more copper- not a bigger potato. If that is not good enough, try replacing the zinc with something like lithium- this is what we've done with modern, rechargeable batteries.

In truth, the potato battery would be better described as a normal battery that just happens to be inserted into a potato. You'll make a better battery if you use copper pennies and aluminum foil in vinegar.

I do not mean to shoot down your idea, and I am glad you are looking into renewable energy sources- but you may be better served by a class on electricity and batteries than by asking questions on biology.SE!

EDIT: I would assume that the electrical potential of this kind would also kill the plant, given that you're essentially electrocuting it. However, I was unable to find any information on the resistance of potato plants to electrocution.

$\endgroup$
  • $\begingroup$ @Muze I think you're still misunderstanding what happens here. The only thing doing the work is the strips of metal, which aren't alive. The potato could be alive, dead, or something in between- it's irrelevant to the chemistry. Batteries eventually stop working because the electrical potential is "used up", not because they run out of nutrients or life force. Your live potato battery would likewise need to be serviced, with new metals inserted regularly. $\endgroup$ – Dubukay Jan 13 '18 at 2:34
  • $\begingroup$ I'll direct you to this website: thenakedscientists.com/articles/questions/… and this article: ncbi.nlm.nih.gov/pmc/articles/PMC2141166 both of which may provide information for you $\endgroup$ – Dubukay Jan 13 '18 at 2:35
  • $\begingroup$ While that edit does indeed clarify the essence of your question, it’s not the medium that needs to be sustained to keep the battery functional. It’s the electrochemical gradient created by the metals that needs to be sustained, and that’s independent of the medium. $\endgroup$ – Dubukay Jan 13 '18 at 2:40
  • $\begingroup$ your answer is very good I don't know why I asked a dup. if you edit it. I'll up vote it $\endgroup$ – Muze Jun 20 at 14:13
3
$\begingroup$

Placing copper on one side of the potato and zinc on the other will not "suck the energy out of the potato".

the energy in the potato NEVER gets converted into electricity. The metals do all the work, just using the potato as a wet sponge.

Now, it would probably kill the potato though, because of all the ions that are there that shouldn't be there (zn and cu), the ~1 volt current screwing up the electrochemical gradients, etc.

So, yes, it would probably die, but not because anything gets stolen from the potato and it starves. Just because the voltage would interfere with cell functions.

The only real way to know is to experiment on a living plant though

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.