I just have a few conceptual questions: Is it as difficult to remove electrons from an insulator as it is to add to it? I understand insulators have a lower permittivity than conductors, and that they still allow charges to build upon the surface. However, I read that when you rub an insulator with a cloth, you are actually removing electrons. Can you add charges to an insulator by rubbing it with a cloth? So I'm curious which situation is more common. How can insulators of a uniform charge density exist? Additionally, are insulators with a uniform negative charge be as likely to occur as those of a positive charge? This one stumbles me because charges are supposed to build up on the surface. I do not understand how they can be dispersed evenly throughout a surface unless insulators in general allow electrons to move at a slower rate through its material. Can anyone please clarify? Thank you so much for anyone who helps. I really appreciate it.