The amplitude, A, is the wave's maximum disturbance from it undisturbed equilibrium position and represents the energy being transferred by the wave. Generally, the energy of a mechanical wave is proportional to the square of the wave's amplitude; i.e., if a wave's amplitude triples, its energy content will become 9-times greater. On a vibration graph, the period, T, is the time between two adjacent in-phase points on a vibration graph. The reciprocal of period is frequency, f. It represents the numbers of waves that pass a given location each second along the wave's path. period frequency time required for only ONE vibration total number of vibrations EACH second sec/vib (or just) seconds (sec) vib/sec (or just) hertz (hz) All wave motion is generated by a source that moves or vibrates. Consequently, the frequency of a wave is a property of its source, not of the medium through which its energy subsequently travels. On a waveform graph, the wavelength, λ, is the distance between two adjacent in-phase points on a waveform graph. A crest is a point of maximum positive amplitude along the wave while a trough is a point of maximum negative amplitude. property vibration(history) waveform(snapshot) wave shape yes yes amplitude yes yes period yes no wavelength no yes