Standing Waves  (Transverse)

A string is connected to a vibrator at one end and the other end goes over a pulley then has weights attached. A signal generator controls the frequency of the vibrator.

As the frequency is increased a number of standing wave patterns are see.

Waves from the vibrator travel on the string and are repeatedly reflected at the ends. At certain values of f, and hence of , standing wave patterns form. They occur when the length of the string is equal to a whole number of half wavelengths. (each closed loop above is a half wavelength)

Unlike in a normal progressive wave, all points on the string within a loop oscillate in phase.

When the string of a musical instrument is plucked or bowed, a disturbance is created. The energy given to the string settles into the standing wave patterns possible for that particular length of string. The speed of the wave in the string, and hence the frequencies at which these waves occur, also depends on the mass per unit length of the string and the tension in it.