| A | B |
|---|
| sound | form of energy that travels as waves |
| vibration | rapid back-and-forth movement |
| longitudinal wave | wave in chich the particles of the medium move back-and-forth in the direction of the wave motion |
| medium | substance through which waves can travel |
| echo | reflected sound waves |
| supersonic | faster than the speed of sound |
| sonic boom | loud noise caused by breaking the sound barrier |
| intensity | amount of energy in a sound wave |
| decibel | unit used to measure the intensity or loudness of a sound |
| pitch | how high or low a sound is |
| ultrasonic | above 20,000 Hz frequency |
| infrasonic | below 20 Hz frequency |
| timbre | sound quality |
| fundamental tone | lowest-pitched sound produced when a whole string vibrates |
| overtones | high-pitched sounds prooduced when parts of a string vibrate |
| music | sounds combining a pleasing quality, melody, harmony, and rhythm |
| noise | unpleasant sounds, with irregular patterns of vibrations |
| Doppler effect | apparent chang in the frequency of waves |
| hearing | one of the five human senses |
| ear | sense organ that detects sound |
| eardrum | thin sheet of tissue that vibrates when sound waves strike it |
| cochlea | organ that changes sound vibrations into nerve signals |
