Question

How do different parts of the ear work together to help us hear sound? Explain.
[5 marks]
[Human ear]

Answer 1

The shape of the outer part of the ear is like a funnel. When sound enters it, it travels down a canal at the end of which there is a thin stretched membrane. It is called the tympanic membrane or the eardrum. Sound vibrations make the eardrum vibrate.
[1.5 marks]

The vibrations from the tympanic membrane reach the middle ear (ear ossicles) which contains three small bones - malleus (hammer shaped), incus (anvil shaped) and stapes (stirrup shaped). They amplify the sound vibrations.
[1.5 marks]

The stapes transmits the vibrations to the membrane of the oval window. The vibrations from the oval window transmit to the cochlea which is the inner part of the ear. The cochlea is filled with fluid which transmits the vibrations. The motion of the vibrations in the cochlea is detected by tiny hairs connected to nerves at this point.
[1.5 marks]

The vibrations are transformed into electrical signals and carried by the nerves to the brain where the sensation of the sound is realized. This is how we hear sound.
[0.5 marks]