Can't Understand:cause of Superconductivity(and other)

[rakeen]

"One explanation for superconductivity is that the electrons that make up the
current move in coordinated pairs. One of the electrons in a pair may electrically
distort the molecular structure of the superconducting material as it moves
through, creating nearby a short-lived concentration of positive charge. The other
electron in the pair may then be attracted toward this positive charge. According
to the theory, such coordination between electrons would prevent them from
colliding with the molecules of the material and thus would eliminate electrical
resistance. The theory worked well to explain the pre-1986, lower temperature
superconductors, but new theories appear to be needed for the newer, higher
temperature superconductors."

what does 'coordinated pairs" mean? well, the later electron actually 'colliding' with the shotr-lived positive charge which is a part of that superconductor's molecule. and if the first electron distorts the molecular structure and creates positive charge then it should be attracted by that;(right?). oesn't that means the electrons are colliding with 'something' and is creating heat(capacitive resistance)?

and what is the Tolerence rate(I'm talking about color code of resistance) of Black,Brown,Red and Orange? because I've found different info on different source. In the book by Ishaq says, Black,Brown,Red and Orange are 1,2,3,4 whereas Tofajjal's indicates 0,0,2,0 ! Does those value changes with different material?(I wonder why dont teachers mention these data in question)

Is soil(not gound) conductive?
sometimes we see a DC and AC source are connected, why doesn't it blast?
where does electrons go if we connect a wood(or any non-conductor) to a electric source?
can we measure the current flow of an AC source with ammeter? will the indicator will move towards and backwards(as we know AC current changes direction)?

[nisha]

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