Water bending with comb: but where do the electrons go?

[sophiecentaur]

I've always assumed they would. I doubt that many of the demo's we've seen involve deionised water. I guess a similar experiment could be done with falling ballbearings or metal powder, which would be an extreme case.

I have to wonder about that (re-reading it after years).
The charging by induction involves two steps. You have to polarise the object and then earth part of it, to make one charge flow away then you have to disconnect the earth connection. The drops carry a permanent net non-zero charge once they have separated. This could be hard to do with iron filings or at least it would all be different. If you induce a polarisation of a mass of filings, in contact with each other, (say in a funnel) the ones exiting the bottom of the funnel would fly apart and not form drops like water.
I'm reminded of a technique of spray painting which keeps charged individual tiny droplets apart and they are then attracted 'round corners' as they approach the target, giving a good uniform covering.