Final answer:
When sound waves enter the ear, they first strike the tympanic membrane, which is a thin membrane located at the end of the ear canal.
Step-by-step explanation:
When sound waves enter the ear, they first strike the tympanic membrane. The tympanic membrane is a thin membrane located at the end of the ear canal. When sound waves hit the tympanic membrane, it vibrates and transmits the vibrations to the middle ear.