In 1960 a device called a laser was invented. It could store energy and release it all at once in an intense beam of light. This beam remained straight, narrow, and very concentrated, even after it had traveled millions of miles. Its uses were extraordinarily varied—a perfect example of the combination of scientific discovery and engineering applications. Lasers were used in surgery to weld damaged tissue in the eye, to burn away skin growths, and to repair decayed parts of teeth. They were used to measure distances. A mirror placed on the moon by the Americans who landed there allowed scientists to calculate the distance to the moon more accurately than ever before.
Lasers helped engineers make tunnels and pipelines straight. They enabled manufacturers to cut precisely into hard substances, such as diamonds. Lasers also transmitted radio, television, and telephone signals. They made it possible to show three-dimensional pictures on a television or film screen. Thus one invention had effects in dozens of activities.
