I saw a video recently that seemed to show a fire being started from a potato, salt, toothpaste, a couple of wires, and what appears to be cotton.

A video showing this is HERE. To summarize, it looks like they:

  • cut a potato in half
  • cut a rounded out hollow in one half and filled it with a mixture of salt and toothpaste
  • put wires through the other half and folded them over so that when the two halves were placed together, the two ends were both in the salt/toothpaste mixture
  • put the halves together and put a piece of cotton (or something else) around one of the exposed wire ends coming out of the potato halves
  • waited a few minutes and then touched the other wire to the cotton and it started on fire

HERE is a forum where people are talking about the video and many seem to think it's real.

Is this video showing something possible or was it faked?

  • 1
    Can you please provide a link to the video and also some information as to what part of the video you think is fake so it is clear in your question what is being addressed (that is try not to make your question dependent on the video).
    – going
    Commented Jul 21, 2011 at 0:18
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    @Denys P.: I kind of rewrote this, as I found the video I think you watched along with some references, and think it's a perfectly legitimate question for this site. I see this is your first activity here, and so I hoped to keep your question alive (I believe it's old form would have been closed). Spend some time looking at some other questions so you get a feel for what kind of quality is expected. Welcome to skeptics.SE!
    – Hendy
    Commented Jul 21, 2011 at 1:20
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    Argh, I want to jump up and down saying "Fake! Fake!" but there are all these annoying expectations of evidence here. Bah. (Exit stage left muttering about both wires being treated identically, so there is no "potential difference", so there is no electrical current, so no spark.)
    – Oddthinking
    Commented Jul 21, 2011 at 2:33
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    I'm quite skeptical, but think the idea is spoofing the fact that you can generate current from a potato (LINK). But... there's no mention of needing different metals, which is key, and as @Oddthinking pointed out, two of the same wire terminating in the same solution won't do anything. Also, powering an LED != enough potential difference to arc and light a piece of cotton.
    – Hendy
    Commented Jul 21, 2011 at 13:45
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    @Ham, watching the video it appears to be sparks and/or heat from the current running between the ends of the wires, that touch the cotton wool.
    – Oddthinking
    Commented Jul 21, 2011 at 14:23

1 Answer 1


Making electricity from potatoes is nothing new. However for that to happen you need two different metals (typically copper and zinc). It may have been different metals in these wires, but they don't say so. And you need an acid. Which salt and toothpaste isn't. And it won't be enough electricity to make a spark.

There might be some sort of chemistry happening with starch+salt+something in toothpaste, but I doubt it. And even if it would generate electricity, it surely will not do so if you put both wires in the toothpaste. One needs to go in the potato, the other in the paste.

So this is bogus, without a doubt.

  • 3
    you don't need a acid just a electrolyte which salt dissolved in a polar liquid (like the water content of the gel toothpaste) IS. but you still need 2 different metals for it to work Commented Jul 22, 2011 at 14:34

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