20.2. Hearing Sound http://www.ck12.org
such as the voices of co-workers, are not interfered with in this way and may be amplified instead so they can be
heard more clearly. This type of hearing protector is recommended for higher noise levels and situations where it’s
important to be able to hear lower-decibel sounds.
FIGURE 20.11
All types of hearing protectors help reduce the risk of hearing loss, but they don’t all work the same way.Lesson Summary
- The outer ear catches sound waves and funnels them to the middle ear. The middle ear amplifies the sound
waves and passes them to the inner ear. The inner ear changes the sound waves to electrical signals. The
signals travel to the brain, which interprets the sounds. - Loud sounds can cause hearing loss by damaging hair cells in the inner ear. The louder the sounds are, the
less exposure is needed to cause hearing loss. - Hearing loss due to loud sounds can be prevented by wearing hearing protectors. They reduce the amplitude
of sound waves entering the ears.
Lesson Review Questions
Recall
- What is the function of the outer ear?
- How does the middle ear amplify sound?
- Describe the structure of the cochlea.
- State how hair cells detect sound waves.