measuring waves

The wavelength is "the length of the wave" and is the distance from one crest to the next crest. This is the same distance as one trough to the next trough. The wavelength is represented by the Greek letter lambda. This is measured in metres.

All of the wave properties are connected together by the wave equation:

speed = frequency x wavelength.

The frequency, f, of the wave, is the total number of complete waves that pass a fixed point in one second. Wave frequency is measured in hertz (Hz).

The period, T, of a wave, is the length of time it takes one complete wave to pass a point - this is measured in seconds. The frequency, f, and period, T, are related by the equation:

f = 1/T.

The speed, s, of a wave, is a measure of how fast a complete wave travels from one point to another. It is given in metres per second (m/s).

Heinrich Rudolf Hertz, 1857-1894

Heinrich Hertz was born in Hamburg, Germany in 1857. He carried out an experiment in his laboratory which produced radio waves. When he was asked what use his experiment might have, he said "It's of no use whatsoever. This is just an experiment - we just have these mysterious electromagnetic waves that we cannot see with the naked eye. But they are there." His work was soon recognised by others as the beginning of a new "electric age." His experiments triggered the invention of the wireless telegraph, radio, television, and radar. He became so famous that he even had his picture on a German stamp!