[Coda]

As for the other two questions!

And by sound "in" an object you mean it's because the atoms are in the object?

Yeah. This goes back to what I was saying about regions of different density.

From what I remember, friction happens because of temporary dipoles..and those cause a sticky effect between objects. Buut why does electrical resistance occur? From too many electrons bumping into each other o_o?

So I actually didn't know that about friction, but it makes sense. (Ever heard of cold welding? If you can get two surfaces of the same metal SO SMOOTH that you can put them together without even air getting in between them, physics has trouble telling where one object ends and the other begins, and they stick together with no adhesives or magnetism! And it's not even that hard to DO it -- junior machinists have been known to accidentally cold-weld steel nuts onto steel bolts by tightening them too far without any lubrication, and there's no way to get them apart without cutting or breaking something.)

But yes, your intuition is pretty close to right. Electrons can only go where there's room for them. Metals make room very easily. Nonmetals hold on to their electrons firmly. Since it takes energy to displace an electron, that reduces the amount of energy available to continue propagating the current.