This activity page will offer:
Insight into binaural hearing
hands-on exploration of how sound is located
chance to explore the characteristics of binaural hearing
In this activity, you'll explore binaural hearing in humans. You'll
see how two ears are utilized in determining the direction of a
sound's origin. Then, you'll produce auditory illusions by reversing
and extending the detection site for each ear.
Four plastic funnels
3-foot sections of plastic flexible tubing (that fits over the
soap and water (to wash and clean the funnels and tubing)
Steps (For the set-up)
- Work with two partners. Obtain two lengths of plastic tubing
and four plastic funnels.
- Wash, rinse, and dry the funnels before using them in this activity.
- Insert a funnel into each end of the plastic tubing so that
two "ear extenders" are formed. Each extender consists of a length
of tubing with an attached funnel at each end.
- The subject sits in the center of the room and closes his/her
eyes. The subject holds one funnel from each of the two "ear extenders"
over each outer ear.
CAUTION: Do not speak loudly into the other end of the extender.
Also, never place any object into the ear canal. This can cause
permanent hearing damage.
- A second student, called the helper, positions the free end
of each extender at each ear. For this first trial, the right
ear extender is positioned near the right ear. The left ear extender
is positioned near the left ear.
- The third student is the sound source. The sound source stands
about ten feet away and recites a sequence of numbers. The subject
must identify the location of the sound source as it moves around
- For the second trial, the helper reverses the positions of the
extenders so that the left extender is near the right ear. The
right extender is placed near the left ear.
- Step 6 is repeated and the subject is asked to identify the
position of the moving sound source.
- For the third trial, the helper returns the extenders so that
match correctly to the side of the body on which that ear is positioned.
The helper holds these extenders away from the subject's body,
creating a greater distance between the funnels. Again, the subject
must identify the location of the moving sound source.
- Which was the least confusing trial for the subject?
- Which was the most confusing trial for the subject?
- Did the quality of the sound differ as detected by the right
and left ear?
In this activity, you explored the binaural nature of hearing using
sound that traveled through a plastic tube. Could you duplicate
this inquiry strategy using electronic devices? Think about it.
How could you assemble a circuit using headphones and microphones
to produce this type of exploration? Share your design with your
instructor and with his/her permission construct the circuit.
In theater, movement can convey all sorts of concepts. Could it
also be used to explain binaural hearing? Work with a group of students
and compose a dance that demonstrates how binaural hearing is used
to locate objects. Movements should convey concepts such as sound
waves, nerve messages, and differences in volume and arrival time
of sounds. Perform this piece of kinesthetic communication for you
The Stroop effect is most often performed using words that are spelled
out in conflicting colors. The subject must then identify the color
of the letters, not the meaning of the word. Find out more about
What happens when you apply this type of confused message processing
to binaural hearing? Use a group of students to create an arena
for this type of inquiry. Have a subject identify the direction
from which a word describing a conflicting direction originates.
For example, the blindfolded subject hears the word "right", but
it is spoken from the left side of the subject. In response, the
subject must quickly point to the left.
Background on binaural (two ear) hearing and how it is used to locate
A source of sound files that confuse the arrival times and sound
levels to create interesting auditory illusions
Discusses another advantage of binaural hearing - the ability to
Advisors for this Guide:
Suzanne Panico, Science Teacher Mentor, Cambridge Public Schools,
Anne E. Jones, Science Department, Wayland Middle School, Wayland,
Gary Pinkall, Middle School Science Teacher, Great Bend Public Schools,
Great Bend, KS