Introduction

We have now learned about force and motion, mass and energy, the law of gravity, and the concept of matter as being made up of tiny moving molecules. With the help of these ideas we have been able to make sense of a wide variety of observations, from the paths of the planets across the sky to the melting of ice and the boiling of water. Is this enough for us to understand how the entire physical universe works?

For an answer all we need do is run a hard rubber comb through our hair on a dry day. Little sparks occur, and the comb then can pick up small bits of dust and paper. What is revealed in this way is an electrical phenomenon, something that neither gravity nor the kinetic theory of matter can account for.

In everyday life electricity is familiar as that which causes our lightbulbs to glow, any of our motors to turn, our telephones and radios to bring us sounds, our television to bring us sights. But there is more to electricity than its ability to transport energy and information. All matter turns out to be electrical in nature, and electric forces are what bind electrons to nuclei to form atoms and what hold atoms together to form molecules, liquids, and solids. Most of the properties of the ordinary matter around us-an exception is mass-can be traced to electrical forces.