Electrostatics

To charge a plastic rod or ruler, you rub it with a cloth or some material. The electrons in the rod are positively charged, and in the cloth, negatively charged. When the two rub together, they attract each other.
Suppose that a rubber balloon is rubbed with a sample of animal fur. During the rubbing process, the positive atoms of the plastic are forced into close proximity with the negative atoms of the cloth. The two types of atoms are pressed together and are brought closer to the nuclei of the other atoms. The positive atoms of one material begin to interact with the negative atoms present on the other material. As such, the positive atoms of plastic begin to take negative atoms from the cloth. When the...