[walman]

More questions.  Please help answer any that you can...

1) In static electricity, when electrons are removed from atoms of a body of matter, and are touched to an object with the opposite charge, does this equalize (neutralize) the charge of the previously positively/negatively charged object?  And if so, if the electrons are rubbed off to give it its +/- charge, where do they come from when they re-enter the atoms after contacting the other object?  Do they come from the other object that has a neutral or opposite charge?  If so, I assume that the transfer of electrons would still leave some atoms on either side with a +/- charge?  Assuming that this is correct, does that basically mean that almost all objects down that line will have a very light charge until all of the atoms are neutralized?

2) Do lightly charged objects exhibit minor (if not nearly undetectable) equalization effects (ie: spark and crackle sound) when they come in contact with neutral or opposite-charged objects?

3) Why does static electricity form best between two nonconducting materials?  Isn't it the case that nonconductors have fewer (if any) free electrons and therefore cannot develop a significant charge, if any?  I think I am likely wrong (in part or in whole) on this, but I wouldn't mind some clarification.

Thanks.

[xiankai]

(1) if by opposite charge you mean (-), it only neutralizes the charge of the previously positive object if it is a large enough earth, and if both bodies are good conductors. if it is not a large enough earth, then the charges will be equalized between the two bodies, rather than for the positive body itself. if one body is not a good conductor, the charges cannot flow freely and nothing much happens.

and yes, electrons are carriers of charge, so the electrons have to come from the other body. i suppose that ions are not considered in the context of the question as they are too big.

from a macroscopical viewpoint, only net charge matters - in a metal, ions flow in a sea of electrons so it is hard to tell if a single atom is charged because it lost electrons to the other object, or because its electron is just mobile. microscopically speaking, yes.

no idea what you mean by 'line' - perhaps that of their center of mass?

(2) depends on how 'small' is 'lightly charged' - sometimes you can see a spark between a doorknob and your hand, feel the 'shock' on a rubbed balloon, sometimes you cannot. they display effects, but whether it is detectable by human eye is in doubt

(3) charges are unable to move freely - only surface charges are traded between the two objects - the rest of the charge deep inside cannot move to equalize the net charge on the two objects