The outer ear includes the pinna, which collects sound waves and the ear canal, which transports sound waves to the eardrum, a paper-thin layer of tissue separating the outer and middle ear.
Sound waves cause the eardrum to vibrate, which in turn vibrates three tiny bones inside the middle ear called the malleus, incus, and stapes,
which pass the sound vibrations along to the inner ear.
The inner ear translates vibrations into electrical signals, which are picked up by the auditory nerve, sent to the brain, and interpreted as sound.
This complex process occurs instantly allowing us to hear the sounds around us as they happen.