What is the physics of static electricity? Why do electrons jump from one object to another?

Question

I know static a charge is produced when fur is rubbed on amber etc. I want to know what caused the electrons to move.

When I look up reasons I get answers like this "Sometimes the outer layer (the negatively-charged electrons) of atoms are rubbed off, producing atoms that have a slight positive charge." How do you rub off and electron??? Why does it not happen if the objects are just pressed together.

Answer 1

Electrons are loosely held by many materials. When you just place a balloon on your head, a small number of electrons actually is transferred from your hair. However, rubbing the balloon on your hair increases the number of electrons that are transferred and creates extra electrons on the balloon. This happen because the force your apply with friction is greater than the electric force holding that electron onto your hair.

Answer 2

Ooof.......that's a tough one. I think I'll answer by first saying that in order to answer your question, I'd have to be able to define what an electron is. Unfortunately nobody really knows for certain what exactly an electron "is." At least not at the moment.

But I digress...... All objects can acquire an electric charge by gaining or losing a small amount of electrons(whatever those are).The most common method of doing this involves the property of "electronegativity." this means how "greedy" a substance is for electrons. When two different materials are rubbed together, for example, a few of the electrons are dislodged, and if one is more electronegative, the electrons will be more likely to stay in that object. Thus one object acquires a negative charge, the other one acquires an equal but opposite positive charge.

The reason the electrons are dislodged is very complicated, and I'm not sure I understand it myself. Suffice it to say that electrons are able to move relatively freely, and jump from one object to another, unlike positively charged atomic nuclei. Objects will in fact aquire a tiny charge when simply touched together. The reason this is amplified by rubbing, may be because you are moving regions depleted of electrons away and replacing them with electricaly neutral areas. So the electronegative object is able to acquire and store more electrons due to a smaller local charge difference.

This is not the whole story though, now that we have separated two charges, the real trouble is keeping them there. Electromagnetism is a tremendously strong force, millions and billions of times stronger than gravity. Electrons, once dislodged, will be attracted to any positively charged object, and will try to rush back in to equalize the difference in charges. If for example, you try to charge a metal rod, the electrons will just tend to rush back through the metal (which is a good conductor), towards any positive charges.

So in order to make a charge difference between two objects, and keep it there, both objects must either be poor conductors of electrons, or be "insulated" from any possible path of conduction.

Another side note is that all materials can conduct electrons, some are just a lot better at it. Thus no object can be kept charged forever, as electrons will eventually leak back towards any positive charges. Objects that normally are poor conductors can be induced to conduct electrons much more readily, by a powerful electric field. This is what happens with lightning, (or any other electric spark.) When the charge difference between the cloud and the ground becomes great enough, the air reaches it's "breakdown point" and creates a conductive path to the ground.

Answer 3

Because if you look at an atom, the electrons are around it, protons and neutrons are always together and not move, but the electron are on the out side so it can transfer to another object.

Answer 4

you ought to take delivery of e (the cost on a million electron) = -a million.6x10^-19 making use of this you may say that the cost of each and every of the electrons is (5x10^20) x (a million.6x10^-19), as you have already mentioned this could be your cost in Coulombs so all you ought to good is the answer to the equation above with a "C" afterwards to indicate cost. wish this explains, in case you ought to anymore i'm happy to help.

Answer 5

Sounds like a question from electrodynamics from Jackson.
My dried skin also cause the cotton T shirt to has static sparks.

Answer 6

conductors have electrons that move easily. insulators hold onto their electrons. When you get two insulators, it's about who holds on to their electrons more to steal from the other.

Answer 7

They move from electronegative to electro positive body.