Vibration- An oscillation, or repeating back-and-forth motion, about an equilibrium position.
Wave- A "wiggle in space and time"; a disturbance that repeats regularly in space and time and that is transmitted progressively from one place to the next with no actual transport of matter.
Wave Period- The time it takes for the wave to go forward and back once.
Crests- One of the places in a wave where the wave is highest or the disturbance is greatest.
Troughs- One of the place in a wave where the wave is lowest, or the disturbance is greatest, in the opposite direction from a crest.
Amplitude- The distance from the midpoint to the maximum (crest) of a wave or, equivalently, from the midpoint to the minimum (trough).
Wave Length- The distance from the top of the crest, or equivalently, the distance between successive identical parts of the wave.
Frequency's- The number of events per time; measured in hertz. Inverse of period.
Hertz- The SI uint of frequency. One hertz is one vibration per second.
Transverse Waves- A wave that moves up and down.
Longitudinal Wave- a wave in which the vibration is in the same direction as that in which the wave is traveling, rather than at right angles to it.
Doppler Effect-The change in frequency of a wave due to the motion of the source or of the receiver.
Blue Shift- An increase in the measured frequency of light from an approaching
Red Shift- A decrease in in the measured frequency of light (or other radiation) from a receding source; called the red shift because the decrease is toward the low frequency, or red, end of the color spectrum.
Sonic Boom- The sharp crackheard when the shock wave that sweeps behind a supersonic aircraft reaches the listener.
Shock Wave- A cone-shaped wave produced by an object moving at supersonic speed through a fluid.