National Geographic : 1958 Sep
A GLOSSARY FOR THE ATOMIC AGE ACCELERATOR. A machine that speeds up elec trically charged particles for use as atom-smashing bullets and as research tools. ALPHA RAYS. Particles constituting the least pene trating form of radiation. Can be stopped by paper. ATOM. Smallest unit into which an element can be divided without losing its distinguishing character istics. Electrically neutral, though its parts carry charges. BETA RAYS. Nuclear particles intermediate in penetrating power between alpha and gamma rays. CHAIN REACTION. Splitting atoms release neu trons that in turn split other atoms in a self-sustaining process. See fission. CRITICAL MASS. Amount of nuclear fuel, such as uranium, needed to set up a chain reaction. DEUTERIUM. Heavy isotope of hydrogen. Mixed with oxygen, it forms heavy water. DEUTERONS. Nuclei of deuterium atoms. ELECTRONS. Smallest major constituents of an atom. Negatively charged, they orbit around the nuclei, giving atoms their chemical properties. ELEMENT. The raw material of all matter. Each of the 92 natural and 10 man-made elements con sists of only one type of atom with its related isotopes. FISSION. Process in which the nucleus of a heavy atom splits when it encounters an extra neutron, releasing energy and other neutrons. If enough fis sionable atoms are present to constitute a critical mass, the reaction can become self-sustaining, as in the atom bomb (page 314). FUSION. Reaction in which energy is released when nuclei of two light atoms are briefly welded together (page 320), as in the hydrogen bomb. GAMMA RAYS. Most penetrating form of nuclear radiation. Consist not of particles, as alpha and beta rays, but of waves like X rays. HOT. Dangerously radioactive. ION. Atom which has gained or lost electrons, thereby acquiring an electrical charge. ISOTOPES. Forms of the same element having identical numbers of protons and electrons-thus being identical electrically and chemically-but with vary ing numbers of neutrons, hence differing in weight. U-235 and U-238 are both isotopes of natural ura nium, one having three more neutrons than the other. MOLECULE. Generally, two or more atoms form ing a stable compound such as HO-two atoms of hydrogen and one of oxygen-a molecule of water. NEUTRONS. One of two major types of particles making up the atomic nucleus. Electrically neutral. NUCLEUS. Heart of the atom. Made up of neu trons and protons, its positive charge is neutralized by orbiting electrons. PARTICLES. Subatomic units of matter: among others, protons, neutrons, electrons. PROTONS. With neutrons, make up atomic nuclei. Equal neutrons in weight, but are electrically positive. RADIATION (RADIOACTIVITY). Emission of atomic particles or rays by nuclei of unstable atoms. Rays thus released can penetrate and change matter. RADIOISOTOPE. Radioactive form of an element. REACTOR. Nuclear furnace heated by fission. 306 Another scientist, sporting a crew cut, con tributed a breezy general observation. "New discoveries bring new problems; so this business changes from month to month. We may not always know where we're headed -how could we? But, wherever it is, we seem to be getting there jet propelled." This exuberant figure of speech is not as extreme as it might appear. Admittedly, a number of observers, including some indus trialists and Congressmen, believe the atomic energy program is not moving either fast enough or far enough in some fields. Yet it has been not quite 16 years since the late Enrico Fermi and his colleagues achieved the first sustained nuclear chain reaction. Com pared with previous technological revolutions, this is a mere moment in time. Today only a few nations, principally the United States, Great Britain, and the U. S. S. R., can claim well-advanced programs for harnessing the atom. However, the bright potential for all men is abundantly evident. This September the United Nations sponsors its Second International Conference on the Peaceful Uses of Atomic Energy at Geneva, Switzerland, with more than 2,000 delegates exchanging knowledge and ideas. Atom Power Plants Now a Reality In 1954, when The National Geographic published an early survey of the peaceful atom, privately operated power plants using nuclear energy were merely bright dreams on paper.* In the United States three such plants now generate electricity for homes and industries, four additional ones are under con struction, and 11 more are planned. All have been licensed by the AEC, which assists in their planning and, usually, their financing. The figures do not include the AEC's own ex perimental power program, which encompasses a number of prototypes now producing power for Government installations. Their reactors, or atomic furnaces, represent half a dozen different approaches to the problem of eco nomical nuclear power. An atom-powered merchant vessel, the N. S. (Nuclear Ship) Savannah, will cruise the ocean highways by 1960. A tanker, now building, may be converted to nuclear energy, and other projects are in the study stage. Companies engaged in this peaceful pur suit owe a large debt of know-how to the United States Navy. The nuclear submarine * See "Man's New Servant, the Friendly Atom," by F. Barrows Colton, NATIONAL GEOGRAPHIC MAGA ZINE, January, 1954.