Can someone explain what exactly happens when a capacitor is charged? At the positive plate, are loosely bound electrons pulled onto the plate from the dielectric or are whole molecules in the dielectric rotated and orientated so that the negative part of the molecule is close to the plate? Why don't electrons return to their rest position after the charging voltage is removed just like a spring returns to a zero displacement state when a force is removed? Also how can a capacitor work when the dielectric is a vacuum? If the dielectric is removed, does the charge disappear?