Sound waves are produced when objects vibrate
causing regions of high and low pressure to travel through the air.
Each sound wave has a specific frequency (which is related to pitch)
amplitude (which controls loudness), and waveform (which determines the timbre, or quality, of the sound).
When sound waves reach the outer ear, they are captured by the pinna and funneled through the ear canal to the eardrum
causing the eardrum to vibrate.
These vibrations are passed through the tiny bones of the middle ear, which amplify the vibrations.
The vibrations are transmitted to the cochlea in the inner ear
where they form ripples on the basilar membrane, bending the hair cells
which convert the vibrations into a pattern of neural impulses which the brain can interpret.
The impulses are carried by the auditory nerve to the auditory cortex for processing and interpretation.