SOUND Entry # 10 Sound: the vibration of particles that travel in a longitudinal wave. a mechanical wave which travels through a medium When that disturbance reaches the air near your ears, you hear sound When the vibrations reach the air near your ear, you hear sound High frequency = High pitch Low frequency = Low pitch. How we hear sound The Ear: Parts of the Ear: Outer Ear Middle Ear Inner Ear Outer Ear: Includes: Ear Ear Canal Eardrum Collects and funnels sound waves inwards Middle Ear: Includes three bones: Hammer Anvil Stirrup Makes sounds louder. Inner Ear: Contains the Cochlea which is filled with sensitive hairs and liquid. Sound waves move as vibrations through the cochlea. Hairs have nerve endings which send messages to the brain when the hairs vibrate. Brain converts to sound.