A loud sound moves the hair cells much more than a soft sound. The inner ear fluid needs some room for its movement. The round window bumps in and out as the fluid moves. The electrical signals travel from the hair cells to the nerve of hearing up to the brain. The ear is not just for hearing.
Some parts have other functions as well.
Wax in your ear canal protects the other parts of the ear from dirt and bugs. But, too much wax in your ear canal can block sound from traveling further, cause you to hear less, and might require some attention from your doctor. The Eustachian tube makes it possible for a cold to cause this discomfort. It's through this passageway that cold germs travel from your nose and throat to your ears. In the grid of letters below are names of parts of the ear and other related words.