Matter is composed of neutral atoms. The electrical neutrality of the atoms is due to the fact that the positive charge of the nucleus of the atom is compensated by the negative charge of the electrons that surround it. The outermost electron may either be only loosely connected to the rest of the atom (Fig.1a) or be more firmly embedded in it (Fig.1b).

Atoms of the first type tend to part with electrons to adjacent atoms, while those of the second type tend to tear electrons away from adjacent atoms. It is because of this phenomenon that, for e.g., glass becomes positively charged when it is rubbed with a silk cloth (Fig.2a), whereas ebonite acquires a negative charge on being rubbed with a woolen cloth (Fig 2b).

Electrostatic phenomena include such as simple as the attraction of plastic wrap to your hand after you remove it from a package to apparently spontaneous explosion of grain silos, to damage of electronic components during manufacturing, to the operation of photocopiers. Electrostatics involves the buildup of charge on the surface of objects due to contact with other surfaces. These charges then remain on the object until they either bleed off to ground or are quickly neutralized by a discharge: e.g., the familiar phenomenon of a static 'shock' is caused by the neutralization of charge built up in the body from contact with nonconductive surfaces.

If two small balls, suspended pendulum wise, are given electric charges of the same sign e.g by touching each ball with a glass or ebonite rod charged by friction in the manner described, they will be pushed some distance apart by mutually repellent force exerted by the two similarly charged balls, as in Figs 3a and 3b. On the other hand two oppositely charged balls will attract each other, as in Fig 3c, and when they come into contact, their charges will neutralize each other.

A positive charge means that there is a deficiency of electrons while a negative charge means that there is a surplus of electrons in relation to the neutral condition of the atoms. Electrons are the elementary particles of electricity. Each electron has a charge E = 1.602 x 10^-19 coulomb, a rest mass M_o = 0.9108 x 10^-27 grammes, and a radius of 2.82 x 10^-13cm.

Since similar charges repel each other, the electrons so arrange themselves at the surface of an electrical conductor e.g a metal ball that the space inside it contains no charge and is thus entirely free from electrical forces (Fig 4a and 4b). When a charged conductor is brought near an uncharged one, a separation of charges is induced on the latter (Fig.5a).