When sound waves enter the outer ear, the vibrations impact the ear drum and are transmitted to the middle and inner ear.
In the middle ear three small bones called the malleus (or hammer), the incus (or anvil), and the stapes (or stirrup) amplify and transmit the vibrations generated by the sound to the inner ear. The inner ear contains a snail-like structure called the cochlea which is filled with fluid and lined with cells with very fine hairs. These microscopic hairs move with the vibrations and convert the sound waves into nerve impulses–the result is the sound we hear.
Exposure to loud noise can destroy these hair cells and cause hearing loss!
What is noise?
Noise and vibration are both fluctuations in the pressure of air (or other media) which affect the human body. Vibrations that are detected by the human ear are classified as sound. We use the term 'noise' to indicate unwanted sound.
Noise and vibration can harm workers when they occur at high levels, or continue for a long time.