The Ear and the Sense of Hearing
Objectives
Ÿ Students will understand that the ear contains organs that detect sounds.
Ÿ Students will understand that vibrations are transferred through the middle ear
then into a liquid in the inner ear.
Suggested Grade Level
6th grade
Subject Areas
Science
Timeline
Two 50-minute periods
Background Knowledge
There are three main sections of the ear, the outer, middle, and inner ear. The outer
ear "funnels" sounds into the ear canal. The outer ear can be compared to the
shape of satellite dishes, which are used to receive and send information into
space. Students will do an activity to "change" the shape of their outer ear. They
will observe how this new shape improves their hearing. The middle ear is the next
section, which contains three small bones, the hammer, anvil and stirrup. These
bones increase the size of the vibrations and transfer the sound to the inner ear.
When astronauts orbit earth they experience what is known as weightlessness. This
can be very disorienting and nauseating to the astronauts. This is because the
vesicular system (inner ear) has liquid in it and the weightlessness causes the fluid
to behave differently than on earth. In space this liquid in the ear is not where it
usually is and will cause a person to feel nauseated, will throw off a persons sense
of direction such as knowing which way is up or down. The students will need to
know that sound travels in waves, sound waves must travel through a medium, and
that sound waves exist even if no one is around to detect them. For the first day’s
lesson, the teacher will have to go outside and mark a straight line, using flour,
across the width of a football field. This will be the line the teacher will walk along
with the timer. There will have to be enough blindfolds for half of the class. Mark the
golf tees with different symbols. For the second day’s lesson, cut the shapes of the
three middle ear bones out from transparency paper. Label the transparencies
hammer, anvil, and stirrup. The shapes of the transparencies is not the important
part of the lesson. The students can see detailed pictures in their text. The
transparencies are used because you are able to see the vibrations transfer "from
bone to bone" better.
Materials
Meter sticks
Golf tees
Icy lids from a convenience store
Calculators
Timer
Blindfolds
Lesson
Day 1
1. Have students pair up.
2. Blindfold one student, and the other will guide the student that is blindfolded.
Students will be blindfolded for two reasons. One reason is so they can't see
the other students and it will not turn into a competition. The other so they can
focus on their sense of hearing.
3. Walk along the line, previously marked, with a timer continuously beeping.
4. The students will be led away from the beeping and stop when they can no
longer hear the sound.
5. At this point they will put their golf tee into the ground. Each tee will be marked
with a symbol so they will know which one is theirs.
6. Have students measure with a meter stick from the line to their tee.
7. Record data.
8. Now have students put the dome shaped icy lid, next to their ear with the top part
touching their ear and repeat the activity they just did.
9. Students should be able to conclude that by changing the shape of the outer ear
allowed them to detect sound better.
10. Read together, "Capturing a Whisper from Space", published by NASA. This
informative article tells about mechanical explores that have ventured out to
study Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune. These
robots have been our eyes and ears on their journeys to far-off planets. Signals
must travel billions of kilometers. This article explains that the signal from a
spacecraft can be focused by a curved reflector dish such as the artificial outer
ear the students used.
Day 2
1. Tell students to look at a picture in their text and read about the function of the
middle ear.
2. Show students how the vibrations can be transferred in the middle ear by
touching all three pieces of transparency together.
3. Use a tuning fork to apply a vibration to the "hammer". The "anvil" and the
"stirrup" will consequently vibrate. Have the stirrup in liquid. The students will
see that the liquid is vibrating. This demonstrates that the bones can transfer
vibrations into the liquid of the cochlea (vesicular system).
4. Read with students about the function of the inner ear.
5. Have the students answer the following open-ended question: Brainstorm with
students how the space environment may effect the normal function of the inner
ear.
6. Show students the video Shuttle Life in the World of Weightlessness from the
NASA educator resource center.
7. Explain to students that when the liquid and the hairs in the cochlea are exposed
to micro-gravity, astronauts may feel nauseous and disoriented.
Extensions
Ÿ Students will create an outer ear designed for a specific animal. This new outer
ear must serve a purpose in the animal’s life such as avoiding predators or
aiding in detecting or catching prey.
Ÿ Students will create a model of the ear, using any materials they find around the
house. It does not have to look like a human ear but it must have the three main
parts; middle, inner, and outer.
Evaluation/Assessment
Have students fill in a flow chart regarding the parts of the ear and their functions. On
the back of the flow chart, the students will have to diagram how sound travels
through the inner ear. This chart will be turned in and graded.
Resources
Information about NASA’s deep space network http://deepspace.jpl.nasa.gov/dsn,
To order a poster with an article on the backside “ Capturing A Whisper From
Space”
http://seaborg.nmu.edu/nasa/