| A | B |
|---|
| Crest | The top or highest point of a wave. |
| Decibel | The unit used to measure loudness of a sound. The symbol used is(Db). |
| Doppler Effect | change in the apparent frequency of a wave, because either the source of the wave is moving toward or away from the observer, or the observer is moving toward or away from the source of the wave (car blowing its horn as it passes by a person on the street) |
| Morse Code | a communications code invented by Samuel Morse in which letters of the alphabet and numbers are represented by combinations of short and long sounds. |
| Pitch | how high or low a sound is as determined by the frequency of a vibrating object (Objects vibrating faster have a higher pitch than objects vibrating slower. Larger objects vibrate more slowly and have lower pitch than smaller objects.) |
| Amplitude | the maximum displacement of a periodic wave. |
| communication tools | the various ways sound waves are used (musical instruments |
| compression | The area where particles or air are pushed closer together as a result of being near something that is vibrating. |
| Echo | A sound that is repeated because the sound wave reflected or bounced back from a distant object. |
| Echolocation | A method used by animals such as bats and dolphins to find their way or to locate prey by sending out sounds and then listening for the echoes that bounce back off objects in front of them. |
| Frequency | the number of vibrations in a given unit of time; how fast an object vibrates (measured in Hertz |
| Larynx | A structure in humans that contains the vocal cords and vibrates to produce sounds. |
| Oscillation | a single swing from one extreme limit to the other |
| Oscilloscope | Electronic equipment that provides visual images of varying wave quantities. |
| Overtone | A harmonic with a frequency that is a multiple of the fundamental frequency. |
| Radar | Measuring instrument in which the echo of a pulse of microwave radiation is used to detect and locate distant objects. |
| Rarefaction | where a sound wave spreads matter apart |
| Reflection | The bouncing back or change in direction of a wave after it strikes a barrier or an object. This may also be called an echo. |
| Resonance | the tendency of a system to oscillate at maximum amplitude at certain frequencies |
| Sonar | A machine that sends out sounds waves and uses the waves that are reflected back. This is used to help detect underwater objects. |
| Sound | Mechanical vibrations transmitted by an elastic medium. "falling trees make a sound in the forest even when no one is there to hear them" |
| Trough | The low point of a sound wave |
| Ultrasound | Using the reflections of high-frequency sound waves to construct an image of a body organ (a sonogram); commonly used to observe fetal growth. |
| Vibration | the rapid back and forth motion of an object |
| Volume | The magnitude of sound wave |
| Wave | a energy moving through a medium (solid |
| Wavelength | The distance between one crest or peak of a sound wave and the next crest or peak. The distance between two compressions |
| Harmonic | Relating to vibrations that occur as a result of vibrations in a nearby body. |
