vibration wave- an oscillation or repeating back-and-forth motion, about an equilibrium position.
waves-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- a "wiggle in space and time"
crests- one of the places in a wave where the wave is highest or the disturbance is greatest.
troughs- one of the places 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).
wavelength- the distance from the top of the crest of a wave to the top of the following crest, or equivalently, the distance between successive identical parts of the wave.
frequency- the number of events (cycles, vibrations, oscillations, or any repeated event) per time; measured in hertz (or events per time). Inverse of period.
hertz- the SI unit of frequency. One hertz (Hz) is one vibration per second.
transverse waves- a wave with vibration at right angles to the direction the wave is traveling.
longitudinal waves- 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 source; called the blue shift because the apparent increase is toward the high-frequency, or blue, end of the color spectrum. also occurs when an observer approaches a source.
red shift- a decrease 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, end of the color spectrum.
shock wave-a cone shaped wave produced by an object moving a supersonic speed through a fluid.
sonic boom-the sharp crack heard when the shock wave that sweeps behind a supersonic aircraft reaches the listener