| A | B |
|---|
| sound | vibrations that are can detected (picked up) by human ears |
| vibration | a repetitive backwards and forwards motion that is the source of all sounds |
| pitch | a quality of a sound that depends on the frequency of the sound waves |
| high-pitched | high in pitch; a high note |
| low-pitched | low in pitch; a low note |
| frequency | the number of sound waves produced each second by a vibrating object |
| hertz (Hz) | the unit of measurement for frequency of vibration |
| ultrasound | a sound that is so high-pitched that it humans cannot hear it |
| infrasound | sounds that have too low a frequency for us to hear |
| hearing range / audible range | the range of frequencies of sounds that someone can hear |
