Howard Wershil, age 12, of Charlotte, N.C., for his question:
What is frequency?
The word frequent means ‘often’ in ordinary language. In the word frequency, our minds grasp two things. One is an event and the other is time. In winter the snow falls with frequency and skaters frequently fall down. The word frequency used in science has the same basic meaning, but it is more exact and precise.
One of the most useful tools is a hammer. The carpenter and the mechanic, the electrician and the handyman use it for a multitude of different jobs. Some of these jobs are specialized and call for special hammers. But the basic job of each hammer is hammering. Words are the tools of science, for without words and terms it is impossible to develop or to share an idea. The word frequency is somewhat like a hammer. It is useful in several branches of science.
In mathematics, frequency is the regular occurrence of a ratio of numbers. In statistics, frequency distribution is the regular occurrence of groups of people. In physics, frequency is the regular occurrence of sound vibrations; in electricity, frequency is the number of cycles per second produced by a generator. This word frequency is one of the busiest word tools in the world of science.
It may seem to have a different meaning in every different branch of science, but its basic meaning is always the same. It is the number of events occurring regularly in a certain period of time. The electrical frequency used in most homes is 60 cycles per second it is related to the magical performance of an electric generator.
Electric current is produced when copper is made to cut through the invisible lines of force surrounding a magnet. In a generator, copper coils may be turned through a magnetic field, or a giant magnet may be spun around the coils of copper. Electric wiring is linked to and from the generator, and current is pushed through the circuit each time the copper cut through the magnetic field.
A generator can give direct current that sends the flow of electricity in the same direction. But it was decided long ago that alternating current was best, and our generators produce current that alternates back and forth. With each turn of the generator, the electrons in the circuit move forward and backward in a cycle. The frequency of the generator is the number of cycles it generates in a second.
Voltage is the amount of push or strength that generates the electric current. It can be increased with a more powerful magnet or with more loops of the copper coil that cuts through the magnetic field. It can also be increased by speeding up the rate at which the coils of copper cut through, the lines of magnetic force. With each spin, electrons in the circuit move forward and backward. In a current of 60 cycles, the electrons complete 60 of these cycles every second.