Hello
As much as I know static electricity is not the result of rubbing. Rubbing only helps different parts of the materials to come into contact. I am regarding this to the tutorial on 'basic concepts of electricity-static electricity'

 

Actually there are materials that will 'release' excess electrons when physically rubbed. Frictional contact is a proven method of electron transference. Because of resistance only fractional currents can be produced, but you can get some high voltage this way.

And No it is not the electrons themselves which are being physically rubbed off a material, the rubbing is what brings the small charges on the two surfaces close enough together that they then can influence each other.

 

Ancient Greeks rubbed amber in fur to generate static electricity.

The word "electron" came from the word "electric" which came from the word "amber".

 

A neutral molecule with an incomplete electron shell will have a tendency to gain or lose electrons such that the result is a completely filled electron shell, even though that may result in the molecule having an overall positive or negative charge. So dissimilar materials will have different tendencies to gain or lose electrons.

It is the rubbing of disssimilar materials that both puts the materials close together and provides the energy necessary to transfer the electrons.

(The triboelectric series is a listing of common materials, ordered by their tendency to gain or lose electrons.)

So the actual physics may get complex, but what is wrong with saying that it is the rubbing that causes the static electricity?

Any why not say that the electrons are being physically rubbed from one material to another? If it is not the electrons being physically rubbed off, then how else would you explain the process?

 

van de graaff generator for example is not working by rubbing, it works by just contacting two insulators with different triboelectric coefficients. The main principle is making contact (rubbing may increase the intensity by making more contact area ) and saying rubbing makes static electricity is misleading. Electrons can travel from material to material by physical contact, they don't have to be rubbed of.

 

Electrons can travel from material to material by physical contact, they don't have to be rubbed of.

Here's another example of physics at work: http://en.wikipedia.org/wiki/Galvanic_corrosion