 | Term | Definition |
| |
Wave |
A "wiggle in space and time" a disturbance that repeats regularly in space and time and that is transmitted progressively from one particle or region in a medium to the next with no actual transport of matter |
| |
Vibration |
A "wiggle in time"; a repeating, to-and-fro motion of something |
| |
Period |
The time required for a pendulum to make one complete to-and-fro swing. in general, time required to complete one full cycle |
| |
Trough |
One of the places in a wave where the wave is lowest or the disturbance is greates in the opposite direction from a crest |
| |
Wavelength |
The distance from the top of the crest. |
| |
Frequency |
The number of vibrations per unit of time; measured in hertz |
| |
Sine Curve |
the curve whos shape is used to represent wave motion |
| |
Crest |
one of the places in a wave where the wave is highest or the disturbance is greatest |
| |
Hertz |
The SI unit of frequency. one hertz equals one vibration per second |
| |
Amplitude |
The distance from the midpoint to the crest of the wave, or from the midpoint to the trough |
| |
Transverse Wave |
A wave in which the vibration is at right angles to the direction in which the wave is traveling. |
| |
Longitudinal Wave |
A wave in which the vibration is in the same direction as that in which the wave is traveling |
| |
Constructive Interference |
Addition of two waves when the crest of one overlaps the crest of another, so that their individual effects add together. The result is a wave of increased amplitude. |
| |
Destructive Interference |
Addition of two waves when the crest of one overlaps the trough of another, so that their individual effects cancel each other. The result is a wave of decreased amplitude. |
| |
In Phase |
Term applied to two or more water waves whose crests (and troughs) arrive at a place at the same time, so that their effects reinforce each other |
| |
Out of Phase |
Term applied where two waves for which the crest of one wave arrives at a point at the same time as a trough of teh second wave arrives. Their effects cancel each other. |
| |
Interference Pattern |
A pattern formed by the overlapping of two or more waves that arrive in a region at the same time. |
| |
Standing Wave |
Wave in which parts of the wave remain stationary and the wave appears to not be traveling. The reuslt of intereference between an incident (original) and a reflected wave. |
| |
Node |
Any part of a standing wave that remains stationary |
| |
Doppler Effect |
The apparent change in frequency of a wave due to the motion of the source or receiver. |
| |
Blue Shift |
An increase in the measured frequency of light from an approaching source; called the blue shift because of the increase is towards the high, or blue, end of the color spectrum |
| |
Red Shift |
A decrease in the measured frequency of light (or other radiation) from a receding source; called red shift because decrease is towards low, or red, end of the color spectrum |
| |
Bow Wave |
The V-shaped wave produced by and object moving across a liquid surface at a speed greater than wave speed. |
| |
Shock Wave |
A cone shaped wave produced by an object moving at supersonic speed through a fluid. |
| |
Sonic Boom |
The sharp crack heard when the shock wave that sweeps behind a supersonic aircraft reaches the listener. |
| |
Pitch |
Term that applies to how high or low a sound appears to be. |
| |
Infrasonic |
Term applied to sound of pitch that is too low to be heard by the human ear; less than 20 Hertz. |
| |
Ultrasonic |
Term applied to sound frequencies above 20,000 hertz, the normal upper limit for human hearing. |
| |
Rarefaction |
A disturbance in air (or other matter) in which the pressure is lowered. |
| |
Condensation |
A pulse of compressed air (or other matter). |
| |
Forced Vibration |
The vibration of an object that is made to vibrate by another vibrating object that is nearby. The sounding board in a musical instrument amplifies the sound through forced vibration. |
| |
Natural Frequency |
A frequency at which an elastic object naturally tends to vibrate, so that minimum energy is required to produce a forced vibration or continue vibration at that frequency. |
| |
Resonance |
A phenomenon that occurs when the frequency of forced vibration on an object matches the object's natural frequency, and a dramatic increase in amplitude results. |
| |
Beats |
A throbbing variation in the loudness of sound caused by interference when two tones of slightly different frequencies are sounded together. |
