Physics 11 : Waves Basic Concepts

Part 1: Vocabulary

Vibration - a repeated pattern of motion of an object, also called periodic motion

Wave - a transfer of energy through a material without net movement of the material itself. Waves are caused by vibrations.

Medium - the material through which a wave moves

Amplitude (A) - the maximum displacement of an object from its rest position during a vibration, measured in metres

Period (T) - the time taken to complete each full cycle of a vibration or a wave, measured in seconds

Frequency (f) - the number of complete vibration or wave cycles completed in one second, measured in Hertz (Hz)

Wavelength - the distance travelled by a wave during one cycle or period, measured in metres

Transverse Wave - a wave which travels perpendicular to the axis of the original vibration (such as water waves)

Longitudinal Wave - a wave which travels parallel to the axis of the original vibration (such as sound waves)

Interference - When two or more waves travel through the same material at the same time, their displacements add up to give the net displacement of each part of the medium at any given time. Constructive Interference results in larger than normal displacements, while Destructive Interference results in smaller than normal displacements.

Standing Wave - the pattern produced when two identical waves travel through the same space in different directions. Stationary Nodes occur where the two waves continuously cause complete destructive interference, and Antinodes occur midway between the nodes, resulting in maximum amplitude constructive interference.

Resonance - maximum amplitude vibrations resulting from relatively small amplitude vibrations at a particular resonant frequency determined by the physical characteristics of the vibrating object or medium