The ear is divided into three major parts. The three major parts are the external, middle and the inner ear. The inner ear is located behind the eye socket, down within the temporal bone. It deals with hearing and equilibrium. Sound travels faster in water than in air. The middle ear has an open space filled with air, but the inner ear is filled with fluid. The inner ear has a chamber called the bony labyrinth. The bony labyrinth contains a plasma like fluid called perilymph.