How Does The Ear Work?
The outer ear collects sounds. The middle ear is a pea sized, air-filled cavity separated from the outer ear by the paper-thin eardrum. Attached to the eardrum are three tiny ear bones. When sound waves strike the eardrum, it vibrates and sets the bones in motion that transmit to the inner ear. The inner ear converts vibrations to electrical signals and sends these signals to the brain. It also helps maintain balance.
A healthy middle ear contains air at the same atmospheric pressure as outside of the ear, allowing free vibration. Air enters the middle ear through the narrow eustachian tube that connects the back of the nose to the ear. When you yawn and hear a pop, your eustachian tube has just sent a tiny air bubble to your middle ear to equalize the air pressure.