Amplitude (meters) The distance between the top of a crest (or lowest point of trough) and the point of equilibrium (below it says 'origin' - it means the same thing.) Wavelength (meters) The distance between the top of one crest to the next (consecutive wave). Frequency Number of waves in one second (not necessarily complete waves) Period Time needed to complete one full oscillation Click here to try a virtual oscilloscope: http://www.educationscotland.gov.uk/resources/s/sound/oscilloscope.asp