# How does rubbing cause the transfer of electrons from one object to the other? [duplicate]

I have just learnt about electrostatics. Why would there be a transfer of electrons? Is it because of the difference of the materials (i.e. triboelectric series)? So in the case of two different materials contacting each other, will there still be transfer of electrons?

• Welcome to Physics.SE. Please have a habit of referring Wiki before asking these questions... And, You may have an answer here already... – Waffle's Crazy Peanut Nov 18 '12 at 8:42
• Sorry, I will do so next time. – z_z Nov 18 '12 at 8:48
• I still have a question.. Air is very likely to lose electrons. Does this mean the matters around us are constantly gaining electrons? Why can't we feel it when we are touching the matter? – z_z Nov 18 '12 at 8:50
• – Waffle's Crazy Peanut Nov 18 '12 at 14:54

The ability to make material charged by rubbing is called the "triboelectric effect" – "tribo-" is related to rubbing in Greek. When two materials are in touch, a chemical bond develops between the surface molecules of both material, because of differences in their electrochemical potential. When separated, the electrons may stay with one of the materials.

Just for the sake of the argument, imagine that you "rub" Na and Cl. They naturally produce molecules of NaCl on the interface. But the molecule is really $Na^+Cl^-$, so when you separate them, the Na molecule remains positively charged while the chlorine is negatively charged. This is not a realistic example because Cl is a gas :-) but it works in a similar way for more realistic materials.

See half a dozen of other related articles on this server:

https://physics.stackexchange.com/search?q=triboelectric