Sound is produced when something vibrates (oscillates).
Vibrations are transferred to the surrounding air molecules, which starts a chain reaction...
...eventually reaching the ear drum, then the bones of the middle ear, hair cells in the inner ear...
...eventually stimulating a specific site in the brain.
Vibrating body produces alternating pressure changes in the surrounding air as it alternately pushes against the air, then pulls back (compression and rarefaction)
Graph of pressure fluctuation versus time is called a "waveform"
Since this graph consists of similar, repeated patterns, it is called a "periodic" waveform. One complete pattern is called a "cycle"
Number of cycles per second is called "frequency," which corresponds to what musicians call "pitch." Cycles per second is abbreviated Hz (Hertz)
The magnitude of the pressure changes is called "amplitude," and corresponds to "loudness." Often measure in decibels (dB)
