|Some of these experiments require a blindfold. Keep in mind that some people do not like to be blindfolded...you could ask them to keep their eyes closed, but don't count on them having their eyes closed for a very long time. You might also be interested in some background information about the ear and hearing.|
What Was That?
It is surprising all the noises that you can hear in the classroom even when everyone is quiet. Well, what are they? Write down everything you can hear when everyone is trying to be quiet. Can you hear the clock? Wind? Talking? Breathing? Cars? Airplanes? Footsteps? See what interesting noises everyone can hear.
It's time to go outside to take a walk-about. Find a nice place to have a seat. Perhaps in a park or on a bench near a busy street. Now listen. Write down everything you can hear. Can you hear the wind? Cars? Airplanes? Go back to class and compare the sounds that everyone heard. Did you hear the same things?
Where can you hear sirens, the wind, musical instruments, the roar of a crowd, a waterfall, and the ocean all in one place.? One place is on a recording. There are many CD, tape and record collections of different sound effects. Play a sound effect and see if everyone can guess what made each sound.
Requires Shockwave Plug-in
Jiggling coins, clinking glasses, clapping hands...think you know what these sound like? Test the ability of people to identify several sounds with this game. People should close their eyes or turn away from the "sound maker." Make each sound and see if everyone knows what it is. Example sounds:
In the Middle
Let's get a little more scientific here (hear?) Blindfold one person and have him sit in the middle of the class. Have the other people form a large circle around the blindfolded person. Point to one of the people in the circle and have him say the seated person's name. The seated person must then try point in the direction of the voice and identify the name of the person who said his name. Try this experiment with the seated person using both ears and then again with one ear closed. How accurate can the center person identify the caller and where the call came from? Are two ears better than one?
Sound Shakers/Noise Makers
Let's make some NOISE!. Explore the sense of sound with these easy-to-make sound shakers (noise makers). Find some plastic film containers, plastic yogurt or cottage cheese cups, or other plastic juice bottles. Make sure that the containers have covers for the tops. Fill the containers 1/2 or 1/4 full with dry seeds, uncooked beans or rice, pebbles or sand. Seal the top of the container with glue or tape (you don't want the seeds, beans, rice, etc. all over the floor). Decorate the container with glue and magazine cutouts, stickers or colored paper, then shake, shake, shake. Compare the sounds made by the different materials.
You could also play a guessing game with your sound shakers: have people guess what is inside of your sound shaker just by listening to the noise your shaker makes.
Mix and Match
In this activity you will use your sense of hearing to find a "sound match." First you need to make your sound pairs just like in the activity "Sound Shakers/Noise Makers," except use the same type of container for all the shakers. Use the same type of film canister or yogurt container for all the shakers. Fill pairs of containers with similar material. For example, you could fill 2 containers with sand, 2 other containers with a few pennies, 2 other containers with marbles. When you shake a container, there will always be one other container that sounds the same.
Mix up the containers and let each student pick one. Students then shake their containers and hunt around the room trying to find their matching noise maker by listening to the sound of the other noise makers.
You hear the ringing of the phone in the middle of the night, but you just can't find it. You can hear it, but you can't see it. Where is that thing? Just how good is the ability to find things using only the sense of hearing. Blindfold a person. Have him cover one ear. Take a watch or stopwatch that "ticks". An electric watch will not work. Ask the student to tell you when he hears some "ticking". Approach the blindfolded person from several different angles and record the distance when the subject says "I can hear the ticking". Keep track of the angles and the distances. Repeat the same experiment with the student's other ear closed. Then do it again with both of his ears opened.
Questions and Comparisons:
Two Ears are Better Than One: Sound Localization
To show the importance of two ears, try this one. Make an X on the floor with tape or chalk or erasable marker. Measure distances in a straight line in increments of 5 ft (1.5 m) from the X and label each of these points with the distance it is from the X (5 ft, 10 ft, 15 ft, etc.) Now for the test. Place a blindfolded subject on the X. Now, you stand on one of the points away from the X. Say the subject's name. The subject must now tell you which line you are standing on. Try it when the subject uses one and both ears. Make it harder with shorter distances from the X. Are 2 ears better than one in judging distance?
For most people, it will be easier to judge distance using two ears. Our brains use the loudness of sounds and the differences in time for sounds to reach each ear to make accurate determinations of sound locations.
Marco Polo is a game that requires people to localize sounds. The game is often played in the swimming pool, but you can play it outside too. One person is "IT". The other players must stay in the pool or within an outlined space (such as a basketball court). The object of the game is for "IT" to tag any other player; the catch is that "IT" must keep his or her eyes CLOSED. To help find other players, "IT" can say, "Marco". The other players must respond with the word "POLO". Using this sound, "IT" tries to tag someone. A person who is tagged becomes the new "IT".
A Penny Saved is a Penny Heard
Here is another way to test your
hearing acuity. Collect 10 or more U.S.
pennies - the more pennies you collect, the better the "sample". Recently,
I noticed that the U.S. government changed the metals that it uses to make
a penny. Pennies are not 100% copper. For one thing, newer pennies look
different - they are more shiny. To me, new pennies also
Try to figure out WHEN they changed the formula of the penny. Take your
collection of pennies and drop them, one at a time, on a hard surface...a
table or floor will work. Newer pennies have a "tinny," "dull" sound.
Older pennies have a more "full," "ringing" sound. Keep track of the
pennies that you think are old and which ones are new. When did they make
the switch to the new penny formula? My guess, based on my perceptions of
the penny sounds, is that 1982 was the last year that they made pennies
with the old metal formula. From 1983 on, I think they made pennies
out of copper-plated zinc.
It's easy to make a model of the eardrum (also called the "tympanic membrane") and see how sound travels through the air. Just stretch a piece of plastic wrap over a large bowl or pot (any container with a wide opening will work). Make sure the plastic wrap is stretched tightly over the container. The plastic represents the eardrum. Place about 20-30 grains of uncooked rice on the top of the plastic wrap. Now you need a noise maker. A tin cookie sheet or baking tray works well. Hold the cookie sheet close to the plastic wrap. Hit the cookie sheet to create a "big bang" noise and watch the rice grains jump.
The "big bang" produces sound waves (changes in air pressure) that cause the plastic sheet to vibrate which causes the rice grains to move. Sound waves vibrate the eardrum in much the same way.
A good animated demonstration from KidsHealth shows How the Ear Works.
The Magic School Bus - "Gets An Earful", interactive sound matching game.
A Virtual Tour of the Ear
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