Frank Bagdassarian, age 13, of Utica, N.Y., for his question:

CAN YOU EXPLAIN OSCILLATION?

Oscillation in physics, chemistry and engineering is the rapid and repeated motion back and forth past a central neutral position, or position of equilibrium.

A single motion from one extreme position to the other and back, passing through the neutral position twice, is called a cycle, and the number of cycles per second, or hertz, is known as the frequency of the oscillation.

The oscillations that are important in engineering generally have frequencies of from 200 to several hundred hertz. The vibrations important in physics and chemistry have frequencies of up to billions of hertz.

A swinging pendulum or a plucked violin string eventually comes to rest if no further forces are impressed on it. The force that causes it to stop oscillating is callled damping. In this example the damping forces are frictional, but other damping forces, such as electrical or magnetic, may enter into an oscillating system.