CAN YOU HEAR ME?
INTRODUCTION This delightful activity
works well with children in Second through Fourth grades. We use
it for topics on Sound, Hearing, Animals, and Echolocation.
PURPOSE This activity shows
children how the extra large ears of some animals, such as the Spotted
Bat or a rabbit, help them to have much more sensitive hearing than animals
with smaller ears.
MATERIALS 1/2 sheet of poster
board (14" x 22")
PROCEDURE Read the story to the children. Discuss why the animal has such large ears. Ask if they would like to be able to hear better, and tell them that you can help them do that. Starting from the short end, roll the poster board into a cylinder. Holding the bottom of the cylinder, work the top of the cylinder open, forming a cone with the top opening about 7-8 inches in diameter and the bottom about one inch in diameter. Hold the cone in place with tape. Hold the cone to your ear, and you now have an "ear" which is about the size of a Spotted bat's ear, if he were as large as you! Ask a child to come
and stand in front of you. Tell him(her) that you are going to say
something, and he should tell you if he hears you. Very softly, whisper
a few words, such as "Science is fun!" or "I like your smile!" Ask
him if he heard you. If he did, whisper something else even more
softly. Next hold the "bat´s ear" to the child´s ear,
making sure that the small end is centered over the ear canal. Just
as softly as before, repeat the phrase you whispered. Ask the child
if he heard you, and if he did, have him tell the class what you said.
If he did not understand, try the same phrase again, speaking more distinctly.
Repeat with several children.
EXPLANATION "The ear has three
parts - the outer, the inner, and the middle ears. The outer ear includes
the visible part outside our head and the ear canal, which ends at the
eardrum. The middle ear contains three tiny bones called ossicles. The
inner ear contains the cochlea, housing thousands of hair cells and nerve
endings. When sound waves travel down the ear canal and strike the
eardrum, it vibrates. This causes the ossicles to vibrate. The sound is
then transmitted to the inner ear. Vibrations set the fluid within the
cochlea in motion, stimulating the hair cells. The movement of the hair
cells stimulates the auditory nerve endings, which send the sound pattern
to the part of the brain that interprets it."3
The larger ear of the rabbit or Spotted Bat enable more sound waves to
enter the outer ear and be funneled into the ear canal. Thus, these
animals are able to hear many more sounds than animals with smaller ears.
ADDITIONAL SUGGESTIONS We always ask the child to stand in front of us, with his back to us. Because we try to speak very softly, but also very distinctly, children will often be able to read our lips when we whisper a phrase to them, and we do not want them to be able to do that. In fact, the class can participate a little more this way, also, because they often read our lips and know what we have said even when the child in front of us cannot hear us until we put the "bat's ear" up to their ear. Before leaving the
"bat´s ear" with the teacher, we discuss the dangers of using the
bat´s ear with the children. They are usually able to understand
that if they can hear a whisper with the "ear", it would most likely hurt
if someone yelled into it. In addition, they should whisper into
it because that is the fun of the "game" that they can play with their
friends.
1. P\hoto of a Spotted Bat from the Royal British Columbia Museum web site. "Bats: Creatures of the Night " http://rbcm1.rbcm.gov.bc.ca/notes/bats.html 2. Ruth Lercher Bornstein, Rabbit´s Good News, Clarion Books, NY, 1995. 3. http://ericir.syr.edu/Projects/Newton/13/lessons/hear.html
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