8th Grade Integrated Science
Standard IV, Objective 4
Title: Technology and Hearing
Description: Students will investigate and describe how engineers have developed
devices to help us sense various types of energy. They will take an online “hearing test”
to check their hearing.
Time Needed: 50 minutes
Materials: Student page (below), computers and earphones for each student or group of
students or a classroom computer with speakers.
Procedures:
1. If students are going to use computers, ask them a day ahead of time to bring their own
earphones. If they do not have earphone, they can listen to the computer without them but
the classroom noise will interfere.
2. If the teacher is going to use the computer and broadcast the sounds, make sure your
speakers work well enough to transmit the web pages.
3. Read the introduction with the students and set up computers. Students will work
independently on the web guide.
Teacher background:
Normal Hearing
When something makes a noise, it sends vibrations, or sound waves, through the air.
The human eardrum is a stretched membrane, like the skin of a drum. When the sound
waves hit your eardrum, it vibrates. After the vibrations hit your eardrum, a chain
reaction is set off. Your eardrum, which is smaller and thinner than the nail on your
pinky finger, sends the vibrations to the three smallest bones in your body. First the
hammer, then the anvil, and finally, the stirrup. The stirrup passes those vibrations
along a coiled tube in the inner ear called the cochlea.
Inside the cochlea there are thousands of hair-like nerve endings, cilia. When the
Cochlea vibrates, the cilia move. Your brain is sent these messages (translated from
vibrations by the cilia) through the auditory nerve. Your brain then translates all that and
tells you what you are hearing. Neurologists don't yet fully understand how we process
raw sound data once it enters the cerebral cortex in the brain.
Student Sheet
Name______________________________________
Period_________
Title: Technology and Hearing
Introduction: Most of us take our hearing for granted. We communicate with others
easily and often through speech and listening. Unfortunately, we do not always take
good care of our hearing and damage the delicate mechanisms that allow us to hear.
When that happens, scientific engineering may allow hearing to be restored through the
use of hearing aids. In this activity you will learn how hearing works and what can be
done when it is damaged. Hearing aids:
Procedure:
1. Go to: http://www.dangerousdecibels.org/virtualexhibit/1whatsthatsound.html
2. Following the web guide through each activity on this website. Follow the interactive
suggestions on each page. Answer the questions below as you go:
Start with “What’s That Sound?”
a. How do the sounds change for a person with hearing loss?
b. Read “How Do You Hear?” Draw the hammer, anvil, stirrup and cochlea. Draw the
hair cells in the correct place.
c. How is sound transmitted through the ear?
d. How is hearing damaged?
e. Go to “How Loud is Too Loud”. List three sounds that are too loud:
f. How is sound carried?
g. Skip the next page.
h. What are two ways to measure a sound wave?
i. What is another way to describe amplitude besides “forceful”? What unit is
amplitude measured in?
j. What is frequency?
k. How does the sound of the 262 Hz frequency compare to the sound of 4186
Hz?
l. Besides frequency and amplitude, what else affects hearing damage?
m. In general, the correct responses in “Rock Your World” are related to:
n. Go to: http://www.egopont.com/hearing_tests.php?soundID=500&lang=en Read
the left had side the the page and make sure you do the loudness test. Be sure the
volume on your computer is set at a normal range. Turn it down if it is uncomfortable or
stop. What is your hearing range?
o. Once hearing is damaged, the only technological aids currently available are hearing
aids. Hearing aids aren't effective for everyone. Hair cells in the inner ear must pick up
the vibrations that the hearing aid sends and convert those vibrations into nerve signals.
So, you need to have at least some hair cells in the inner ear for it to work. And, even if
some hair cells remain, a hearing aid won't completely restore normal hearing. Hearing
aids work by placing an electronic device on or near the ear. The hearing aid has four
parts:
 A microphone picks up sound from the environment and converts it into an
electrical signal, which it sends to the amplifier.
 An amplifier increases the volume of the sound and sends it to the receiver.
 A receiver/speaker changes the electrical signal back into sound and sends it
into the ear. Then those impulses are sent to the brain.
 A battery provides power to the hearing aid.
Draw an expanded version of what you think the inside of a hearing aid would
look like, based on this information:
p. Would either one of these waves hurt your ears? Describe why or why not below the
wave:
Scoring Guide:
2. Following the web guide through each activity on this website. Follow the interactive
suggestions on each page. Answer the questions below as you go:
Start with “What’s That Sound?”
a. How do the sounds change for a person with hearing loss?
b. Read “How Do You Hear?” Draw the eardrum, hammer, anvil, stirrup and
cochlea. Draw the hair cells in the correct place. Hairs should be drawn in
Cochlea.
c. How is sound transmitted through the ear? Hits the eardrum, wiggles the
hammer, which move the anvil and the stirrup. The stirrup passes the vibration to the
cochlea which is lined with hair cells. When they vibrate, a message is sent to the
auditory nerve to the brain.
d. How is hearing damaged? Loud sounds
e. Go to “How Loud is Too Loud”. List three sounds that are too loud: most of
them
f. How is sound carried? In waves that move outward.
g. Skip the next page.
h. What are two ways to measure a sound wave? Amplitude and frequency
i. What is another way to describe amplitude besides “forceful”?
What unit is amplitude measured in? decibels dDB
loudness
j. What is frequency? How often waves are received, short wavelengths have
higher frequency.
k. How does a frequency of 262 Hz compare to the sound of 4186 Hz? It is lower
in pitch.
l. Besides frequency and amplitude, what else affects hearing damage? duration
m. In general, the correct responses in “Rock Your World” are related to: protect
your hearing.
n. Go to: http://www.egopont.com/hearing_tests.php?soundID=500&lang=en
Read the left had side the page and make sure you do the loudness test. Be
sure the volume on your computer is set at a normal range. Turn it down if it
is uncomfortable or stop. What is the frequency range of your hearing? Answers
will vary but should be between 20 and 20,000 Hz.
o. Once hearing is damaged, the only technological aids currently available are
hearing aids. Hearing aids aren't effective for everyone. Hair cells in the inner
ear must pick up the vibrations that the hearing aid sends and convert those
vibrations into nerve signals. So, you need to have at least some hair cells in the
inner ear for it to work. And, even if some hair cells remain, a hearing aid won't
completely restore normal hearing. Hearing aids work by placing an electronic
device on or near the ear. The hearing aid has four parts:




A microphone picks up sound from the environment and converts it into an
electrical signal, which it sends to the amplifier.
An amplifier increases the volume of the sound and sends it to the receiver.
A receiver/speaker changes the electrical signal back into sound and sends it
into the ear. Then those impulses are sent to the brain.
A battery provides power to the hearing aid.
Draw an expanded version of what you think the inside of a hearing aid would
look like, based on this information: answers will vary but should include all four
parts.
Conclusion: Which wave below has higher frequency? 1760
Amplitude? 1320
Would either one hurt your ears? Why? Cannot tell the amplitude.