Crest - The uppermost part of the wave, its highest point.
Trough - The lowest part or point on a wave.
Undisturbed level - The place half-way between the trough and crest.
Amplitude - The peak (greatest) value (either positive or negative) of a wave.
The distance from the undisturbed level to the trough or crest.
Wavelength - The distance betweeen a vibrating particle and the nearest one to it in the same place .
(The identical point on an adjacent wave) This is also the distance between two troughs or two crests.
Other Terms:
Density - A measure of how compact a material is. Normally measured in kg per m³.
Frequency - The rate of reoccurrance of a vibration, oscillation or cycle. This can be considered to be the number of complete oscillations in a vibrating system that occur in unit time.
Logarithmic scale - A constant ratio scale in which equal distances on the scale represent equal ratios of increase.
Medium - The means by which something is passed (e.g. water, air, rock, metal).
Oscillation - The movement to and fro between two points. Also the swinging between two points such as pendulum.
Period - The time taken for one complete oscillation.
Vibrate - To move back and forth.
Wave Velocity (c) or (v) - The speed of the wave in the direction it is travelling in. The velocity of a wave will depend on the medium in which it is travelling. (e.g. You can feel the vibration of a train coming on the tracks far sooner than you an actually hear it.) Waves travel faster through a solid than air.
