Jimmy Manell, age 1J_, of Phoenix, Ariz., for his question:

What is an electron?

We live in an age of electronics, of studying the electron, and putting it ';o work. On a quiet evening at home you may listen to radio or TV, plug in an electric heater, turn on a reading lamp or use the telephone. All these modern wonders and far, far more are performed for us by hard working electrons. Electrons work to send and receive our radio and TV programs. Electrons make electric current, which runs the heater and the telephone. About 3 billion, billion electrons move every second to keep your reading lamp burning.

A single electron is too small to imagine. If people were the size of electrons, it would take everyone in the world, plus half that number again to weigh one ounce. Electrons become useful only when countless numbers of them work together. The electron is an atomic particle. Most electrons are bound, firmly attached, to an atom. Some, however, come loose or can be pried loose. It is these free electrons that can be made to work for us.

In the nucleus of the atom are the protons which are particles of positive electricity. A proton is the smallest unit of positive electricity. The electrons circle the nucleus as planets orbit the sun. Each electron is the smallest possible charge of negative electricity.

We have still much to learn about positive and negative electricity. We know that the two opposite forces attract each other. We know that the two forces in the atom aim at some kind of balance, for a normal atom has an equal number of protons and electrons. We knew that negative repels negative and positive repels, or tends to move away from, positive.

Electrons tend to arrange themselves around the nucleus in shells, The inside shell is complete with two electrons, the second with eight, the third with 16. A normal copper atom has 29 electrons, three complete shells and a lone electron in a fourth shell. This lone ranger can be jogged free. Voltage from . generator jolts countless numbers free and sends them moving clear around the circuit. This is what makes electric current.