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A theory states that humans are bound to the earth by electric force, which I believed is not so, but don't know how to prove it wrong.

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    $\begingroup$ I think this question only makes sense if we pretend to be ignorant of a large part of physics and experimental evidence. So my question is, what are we allowed to use to prove it wrong? $\endgroup$
    – user1583209
    Nov 28, 2016 at 10:01
  • $\begingroup$ What theory states this? Did you mean a conjecture? $\endgroup$
    – RedGrittyBrick
    Nov 28, 2016 at 12:16

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See if you can find a Van de Graff generator to play with (follow safety instructions). Charge the sphere positive. Does gravity pull it towards the ground or push it up towards the sky? Now charge it negative. Same question.

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Weird question … If humans were bound to earth by an electric attraction, that would in turn mean that humans and earth are each carrying an electric charge … But humans neither attract nor repell each other (at least not in the sense of physics), which contradicts the assumption.

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  • $\begingroup$ Could it be that the electrostatic force between humans is too small to be detected as is the gravitational force of attraction between humans? $\endgroup$
    – Farcher
    Nov 28, 2016 at 9:43
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    $\begingroup$ A back of the envelope calculation of how much charge must reside on a human for them to feel the same force due to gravity (between humans) gives me 6E-06C, a charge that I am fairly sure we could measure $\endgroup$
    – jm22b
    Nov 28, 2016 at 12:25
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    $\begingroup$ No sparks flying as humans walk. $\endgroup$
    – anna v
    Nov 28, 2016 at 13:24
  • $\begingroup$ @Jacobadtr how are you doing that computation? In principle you could put a very large charge to the Earth, so that the force between humans would be so feeble to require at least a Cavendish experiment to be detected; in the same way as how this works with gravitation. $\endgroup$
    – DarioP
    Nov 28, 2016 at 14:31
  • $\begingroup$ @DarioP just by equating Newton's universal law of gravitation and Coulomb's law. I see your point. $\endgroup$
    – jm22b
    Nov 28, 2016 at 15:00

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