| A | B |
|---|
| wave | A disturbance that transmits energy through matter or space. |
| medium | A substance through which a wave can travel. |
| outer ear | The part of the ear that acts as a funnel to direct sound waves into the middle ear. |
| middle ear | The part of the ear where the amplitude of sound vibrations is increased. |
| inner ear | The part of the ear where vibrations created by sound are changed into electrical signals for the brain to interpret. |
| pitch | How high or low a sound is perceived to be. |
| infrasonic | The term describing sounds with frequencies lower than 20 Hz. |
| ultrasonic | The term describing sounds with frequencies higher than 20,000 Hz. |
| Doppler effect | The apparent change in the frequency of a sound caused by the motion of either the listener or the source of the sound (refers to sound only). |
| loudness | How loud or soft a sound is perceived to be. |
| decibel | The most common unit used to express loudness. |
| noise | Any undesired sound, especially nonmusical sound, that includes a random mix of pitches. |
| echo | A reflected sound wave. |
| echolocation | The process of using reflected sound waves to find objects. |
| interference | A wave interaction that occurs when two or more waves overlap. |
| sonic boom | The explosive sound heard when a shock wave from an object traveling faster than the speed of sound reaches a person's ear. |
| standing wave | A wave that forms a stationary pattern in which portions of the wave do not move and other portions move with a large amplitude. |
| resonance | What occurs when a object vibrating at or near a resonant frequency of a second object causes the second object to vibrate. |
| diffraction | The bending of waves around a barrier or through an opening. |
| sound quality | The result of several pitches blending together through interference. |
