Module Glossary

amplitude: the measure of the maximum displacement of a wave from the equilibrium position

angle of incidence (θi): the angle that an incident ray makes with the normal line

angle of reflection (θr): the angle that a reflected ray makes with the normal line

antinodal line: areas of full constructive interference

antinode: a place on a standing wave with maximal amplitude

constructive wave interference: overlapping of waves so the crests match with crests and troughs match with troughs

crest: the highest point in a wave

destructive wave interference: overlapping of waves so crests match with troughs

Doppler effect: the observed change in frequency and wavelength of a wave produced by a source moving relative to an observer

equilibrium position: the position where the medium would normally rest

incident ray: the ray that depicts the direction of the wave front that is moving from the point of origin toward the barrier

longitudinal wave: a wave in which the medium moves in the same direction as the wave

medium: the substance that acts as a carrier for a wave

nodal line: areas of full destructive interference

node: a place on a standing wave with minimal amplitude

normal line: an imaginary line that is perpendicular to the boundary

path difference: the difference between two path lengths

path length: the distance between a source and an observer

phase shift: for two sine waves, the change in angle needed to change the first sine wave into the second

point source: a source that radiates waves as if it were a point

ray: a line perpendicular to the wave front depicting the direction the wave is moving

reflected ray: a ray that depicts the direction of the wave front moving away from the barrier

reflection: a change in direction when a wave strikes and bounces from a surface

resonant frequency: the frequency at which an object naturally vibrates

standing wave: a wave that appears not to be travelling (stays in a constant position)

transverse wave: a wave in which the medium moves at right angles to the direction of the wave

trough: the lowest point in a wave

universal wave equation: the speed of the wave is equal to the product of the wave frequency and the wavelength

wavelength: the distance between consecutive crests (or troughs)

wavelet: a secondary wave