A water drop in electrostatic orbit around a needle in 0𝑔pic.twitter.com/G2x3Ud195K
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What's going on?
• The needle has been given an electrostatic charge by rubbing it on silk
• Water droplets are placed by the needle w/ velocity v≠ 0
• H₂O has a slight separation of charge (i.e a dipole moment) so it feels the needle's charge
+ Coulomb's law --> orbit
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slight correction: As
@gravity_levity pointed out, the force induced from polarization doesn't go as 1/r² , and so Coulomb's law isn't quite enough to explain the orbit. What we can conclude from this however, is that the orbit is unstable.Show this threadThanks. Twitter will use this to make your timeline better. UndoUndo
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Are you sure this is correct? The force due to induced polarization is ~ 1/r^5 for a point charge, and ~ 1/r^3 for a line charge, neither of which admits a stable orbit.
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the experimenter said that only the needle was charged in the video .. I had thought that the distance from the needle made it seem as a point charge to the needle
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the water drop could have collected some charge too, no? Also, r or 1/r^2 for closed orbit (eg. ellipse), but not being closed is not the same as unstable.
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Right but per the discussion with
@gravity_levity we know that the potential of dipole induced forces go as 1/r^k k>2 where stability is impossible - 1 more reply
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Cool would be to create space lightning like this
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