Is it possible to repel raindrops with a electrical field?

Question

Response to first poster:
If water is electrically neutral then how is it that you can bend the water coming out of a tap with a charged comb?

Answer 1

No--they're electrically neutral. You could induce a very slight dipole moment in the water with an E-field, but that's about it.

Answer 2

I believe that it is possible to repel some raindrops to a very slight degree. The key to this question is "repel". In your example with the tap water and comb, the water stream "bends" because of static electricity. Static electricity will always and only attract electrically neutral objects. As the raindrops fall, they will physically interact with contaminants in the air and other rain droplets. These physical interactions will probably cause the transfer of electrons to and/or from the individual droplets. Therefore, some raindrops will have an overall charge associated with them. Because of this it would be possible to repel certain raindrops with an electric field. However, the repulsion would be so slight as to be negligible.

Answer 3

It should be possible to repel raindrops with an electric field. While pure water is electrically neutral and a poor conductor of electricity, raindrops and tap water both contain dissolved minerals like iron, copper, nickel, potassium, and others which make normal water (the stuff we drink) a better conductor. These dissolved ions definitely would interact with an electric field.

Water also is interesting because it is a polar molecule. This means that while the molecule itself is electrically neutral, one side tends to have a positive charge while the other side tends to have a negative charge (called an electric dipole). This is a very important property that makes water an excellent solvent and explains the strange crystal structure of ice that makes ice less dense than water. An electric dipole can be effected by the presence of an electric field.

Both explanations would suggest that drops of water can be affected by the presence of an electric field.

Answer 4

You can make water drops into induced dipoles. These dipoles will be experiencing forces from the gradient of the electric field (not the electric field itself). I am pretty sure Jackson "Classical Electrodynamics" has a page or two about forces on dipoles.

Your comb example is probably incorrect, because water is a conductor. If you have a continuous flow of water, the resulting geometry is more like that of an aluminum ball on a conducting string... which would be an electroscope which detects the field itself and not its gradient. That is not the same as the water droplets because the charge can flow of the ball/end of the stream, which makes it charged and not a dipole at all.

Sorry, everyone. You have to think this one through again. And probably so do I because it is far from trivial.