Such positions are referred to as nodes . Nodes are the result of the meeting of a crest with a trough. This leads to a point of no displacement. Standing waves are also characterized by antinodes . These are positions along the medium where the particles oscillate about their equilibrium position with maximum amplitude.
Antinodes are the result of a crest meeting a crest and a trough meeting a trough.
Standing wave patterns are always characterized by an alternating pattern of nodes and antinodes. Standing waves of many different wavelengths can be produced on a string with two fixed ends, as long as an integral number of half wavelength fits into the length of the string. Each wavelength corresponds to a particular frequency and is known as a harmonic . The shorter the wavelength, the higher is the frequency. The lowest possible frequency of a standing wave is known as the fundamental frequency or the first harmonic .