1. Chapter 16.4 How You Hear SoundPg

2. The Human Ear
The function of the ear is to gather sound waves and send or transmit, information about sound to your brain
Your ear has three main sections:
The Outer Ear
The Middle Ear
The Inner Ear
Each section has its own unique function

3. The Outer Ear The outer ear looks and functions like a funnel
The main function of the outer ear is to funnel sound waves
The components of the outer ear are the ear canal and eardrum

4. The Outer Ear
The outer ear collects sound waves and directs them into a narrow region called the ear canal
The ear canal is a few centimeters long and ends at the eardrum
The eardrum is a small tightly stretched, drumlike membrane
Sound waves make your eardrum vibrate

5. The Middle Ear The middle ear is located behind the eardrum
The middle ear contains the three smallest bones in your body
The hammer
The hammer is attached to the eardrum and vibrates when the eardrum vibrates
The hammer transmits vibrations to the anvil first and the stirrups second
The anvil
The stirrup

6. Inner Ear The inner ear is separated from the middle ear by a membrane
When the stirrup vibrates it vibrates against the membrane and the vibrations pass into the cochlea
The Cochlea is a fluid-filled cavity shaped like a snail shell
The cochlea contains more than 10,000 tiny structures called hair cells

7. The Inner Ear
The tiny hair cells have hairlike projections that float in the fluid of the cochlea
When vibrations move through the fluid the hair cells move, causing messages to be sent to the brain via the auditory nerve
The brain processes the messages and tells you what you’ve heard

8. Hearing Loss
When hearing loss occurs a person may have difficulty hearing soft sounds or high-pitched sounds
There are many different causes of hearing loss such as, injury, infection, exposure to loud sounds, and aging

9. Causes of Hearing Loss
Injury: Hearing loss can occur when the eardrum is damaged or punctured.
This is why it is dangerous to stick objects in your ears
Infection: Can cause damage to the delicate inner ear and cause permanent hearing loss

10. Causes of Hearing Loss
Extended exposure to loud sounds can damage hair cells in the ear
The damaged hair cells will no longer be able to send signals to the brain
This type of damage can be prevented!
Aging: This is the most common form of hearing loss and it occurs gradually
As people get older their hair cells in the cochlea begin to die ( AND THEY CANNOT BE REPLACED)
People with this kind of hearing loss often have difficulty hearing high-frequency sounds

11. Hearing Aids
For certain types of hearing loss, hearing aids can restore some ability to hear
Hearing aids amplify sounds entering the ear, and others can amplify specific frequencies that they person has lost the ability to hear
Hearing aids come in all different sizes

12. Partner Project
Ask Your Partner what sound they hear throughout the day
List at least 15 sounds your partner hears
Ask them to rank the sounds they hear ask either painful, quiet, normal, loud
Then ask them to rate each sound as pleasant, neutral, or annoying
Also for each sound record the source, location, time of day, and time exposed to the sound
How are the sound ratings similar? How are they different?

13. Sound
Source
Location
Time of day
Time of exposure
Painful, quiet, normal, loud?
Annoying, pleasant, neutral?