The students will write a 10 to 15 minute journal entry about what they have learned about sound vibrations.
Concept Development
The sense of hearing begins with the ear and ends with the brain. The outer ear (Pinna) are only a small part of what makes hearing possible.
The hole in your outer ear is the ear canal which contains the ear drum. It stretches tightly across the whole canal and vibrates when air waves push it.
The inside of the eardrum is attached to the three smallest bones in your body, the hammer, anvil, and stirrup. These bones vibrate with the eardrum and send these vibrations to a covered window, which is the entrance to the next part called the cochlea or inner ear. The cochlea is a snail-shaped tunnel in your skull that contains the cells that communicate to the brain. (See transparency) [Diagram is a stretched out picture of the cochlea] The cochlea is filled with liquid and a long thin tissue runs along the full length, dividing the liquid in half. That tissue called the basilar membrane, is the secret to how hearing works.
The basilar membrane holds a little more than 15,000 hair cells. When the hair cells are bent, they signal the brain. Cells in the stirrup end of the membrane signal high-pitched sounds, and the ones at the opposite end signal low pitches (See transparency){a diagram of the parts of the inner ear}. The whole range is ordered nicely along the length. The basilar membrane moves in waves when the liquid is vibrating. High pitches cause waves at the stirrup end, and low pitches at the opposite end. The brain ╥listens╙ to which hair cells are signaling the most and decides which pitch the sound is.
Some fun facts about hearing
*There are no blood vessels near the cochlea. Can you imagine the deafening sound that would be produced by tidal waves in the liquid caused by your pulse?
*Listening to very loud sounds, especially for a long time, can cause serious hearing loss. One should avoid loud sounds such as loud music, aircraft, heavy machinery, or even loud vacuum cleaners.
*Why does your voice on a recording sound so different from your normal voice? Sound waves can get to your inner ear in two ways the standard way previously described, and the other way is through the bone around the cochlea. When you speak, your vocal cords shake the air and your skull and you hear both. The recording of your voice is only taken through the standard air path.
Anticipatory Set: Stop! Be Quiet! And Listen. Can you explain what is making the sounds that you hear?
Concept Development
All the sounds we hear are caused by something. In other words, all sounds have a source.
All sources of sound vibrate or shake back and forth. These vibrations move through the air to your ear and your brain tells you what the vibrations mean. For example, if your cat meows, she is the source of the vibrations making sound. You know the sound is a meow and not two dogs barking because the vibrations are different and your brain has learned the difference.
Sound sources can vibrate fast or slowly. The speed of vibration can change. We hear fast vibrations as having a high pitch (piccolo sound), slow vibrations have a low sound (bassoon sound), and there is a huge range in between.
The speed of vibration is called frequency. (For example, how fast the prongs on a tuning fork move back and forth).
The prongs can also change in the amount they vibrate or how far they move back and forth. If they move a little the sound is quiet (No movement means no sound). If they move back and forth a large amount, the sound is loud. This amount of movement is called amplitude. Frequency and amplitude can be changed separately. So piccolo can sound loud or quiet as can a bassoon.
Exploratory Activity 1
Materials:
Can with both ends removed
Balloon with the neck cut off
2cm by 2cm piece of mirror
Glue or double sided tape
Elastic bands
Strong flashlight
*Note: This experiment will be a demonstration.
Procedure:
1. Stretch the balloon tightly over one end of the can like a drum and wrap the elastic band around to hold it there.
2. Glue the mirror on the outside of the balloon about halfway between the edge and the center.
3. Place the can on its side on a table top with the mirror facing a light colored wall 1 to 2 meters away.
4. Darken the room.
5. Point the flashlight at the mirror from an angle to the right.
6. Look at the reflection on the wall .
7. Have a volunteer hold the can firmly so it does not move (may be taped firmly down).
8. Scream into the open end of the can. Try different pitches.
9. Watch the spot of light vibrate.
Concept Development
The sound waves from your vibrating vocal chords vibrated the balloon. The tightly packed molecules in the air pushed the balloon outward and the loosely packed ones pulled it back. If the pitch of the screams changed enough the spot should have vibrated more quickly with the high pitch than with the low pitch.
*If there wasn╒t much change you may want to try playing some music with a heavy beat (the 1812 Overture by Tchaikovsky works well). The spot will jiggle rapidly with the high notes and slowly with the low notes and will make huge jumps with thumps or cannon blasts. The balloon vibrates just as your ear drum does.
Closure: Give the students 10 to 15 minutes to write in their journal about what they have observed in the demonstration.
Evaluation: The students will be evaluated on their completion of the journal entry.
Day 2(hearing)
Objectives:
The students will perform the experiment about why we have two ears.
The students will complete the data sheet and calculations.
The students will write an essay on reasons for having two ears using facts and terms from class.
Anticipatory Set:
When the students aren╒t looking throw or drop something heavy away from yourself. When the class looks towards where the sound came from ask them how they knew where to look.
Concept Development
We have two ears so we can hear accurately in depth. One ear gives us a crude idea of the direction something is. Two ears tells us where and give an idea of how far away the sound is. The brain ╥listens╙ for loudness and time differences between the ears and quickly calculates where the sound source must be.
Materials:
Large earmuffs or a large winter headband for each pair.
A good blindfold for each pair.
*Note: You will need lots of space for this experiment. No two groups should be within earshot of each other.
Data Sheet {two sheets that have places to record accuracy of the subject with or without earuffs and a place to find the percent of accuracy for each}
Procedure:
1. Divide class into pairs.
2. One person is the subject- he/she should kneel in an open space.
3. Blindfold the subject.
4. The experimenter will then snap their fingers at many different locations around the subject. Stay more than an arms length away. (Be sure to move silently so as not to give away your position.)
5. See how well she/he can point to where you are.
6. Do several trials of 10 snaps each. Record how many times the subject points accurately during each trial, on the data sheet.
7. Once the subject is well trained, keep the blindfold on and cover the ears with the earmuffs or headband. Make sure both pinnas are fully covered.
8. Repeat steps 4 through 6.
9. Change partners and repeat the experiment.
10 . Use the information on the data sheet to calculate the percent accuracy of the subject.
11. Write all of the pair╒s percent accuracy scores on the board and compare. Put the ╥without earmuffs╙ and ╥with earmuffs╙ on different sides of the board.
Closure:
Were you better at pointing with the earmuffs on or with them off? Why does this happen. Have the students write a short essay about this using terms and facts from the concept development.
Evaluation:
Students will be evaluated on completion of data sheet and calculations; participation and the use of terms and facts from class in their essay.
Day 3(hearing)
Objectives:
The students will create a device to amplify sound.
The students will explain how their device works using their knowledge about sound and sound waves.
Anticipatory Set: Stop and listen again. Listen for the faintest sound you can hear. What was it? (Have the students say what they heard and if there are some unusual things that a lot of students did not hear have the class listen for that sound.) Are there any ways that we can hear even fainter sounds?
Application Activity
Materials: Have a lot of different materials available around the room for the student to experiment with. Be sure to have the following materials.
String
Straws
Rubber Tubing of various lengths
Paper or Styrofoam Cups
Tape
Funnels
Rubber bands
Scissors
Glue
Sea Shells
Paper
Paper Towel Tubes
Procedure: Let the students explore and experiment with the different materials individually or in groups and make one or more devices to use for amplifying sound.
Closure: Come together as a large group and ask the students to demonstrate their inventions and tell how it works.
*Note: The students should be able to explain how their invention works based on what they have learned previously about sound and sound waves.
CD: The sound waves spread out in all directions so normally only a few of them reach your ear. The inventions gather all the sound waves and concentrated and directed them to your ear.
Fun Facts:
*These inventions will also work in reverse. Try talking into the listening end of the device and notice the amplification of your voice.
*Most of the inventions will be similar in some way to the stethoscope. The stethoscope was invented, originally, in 1819 by the French doctor Rene-Theophile-Hyacynthe Laennec to listen in on all of the beats, gasps and gurgles inside you.
Evaluation: The students will be evaluated on creating a working invention to amplify sound. They will also be evaluated on their ability to explain how the invention works using information already learned about sound and sound waves.
Other Materials To Use With This Unit
Books
My Five Senses by: Aliki
Do You Know What I Know by: Helen Borten
The Magic School Bus Inside the Human Body by Joann Cole
I Touch by Rachel Isadora
Our Senses and How They Work by Herbert Spencer
First Delights, a Book About the Five Senses by Tasha Tudor
Filmstrips
Taste, Smell, and Touch by Encyclopedia Britannica Educational Corp
Your Senses of Smell and Taste by Encyclopedia Britannica Ed. Corp
Sources
Tytla, Milan. Come to Your Senses: All Eleven of them. Annic Press Ltd.
Toronto, Ontario, Canada.1993.
Parker, Steve. Touch, Taste and Smell. Franklin Watts, NY NY, 1989.
Thank you for downloading part 3 of my five senses unit. Sorry that it had to be done in three parts but it was too big to do all together.
The worksheets and diagrams that go along with this unit are not in here because they are either hand drawn or graphics and won't go on here. Anyhow, If you would like them, send me your address and $2 (for stamps and copying) and I'll gladly send them out to you. Kathy Frey 4756 Bloomington Avenue South Minneapolis MN 55407.
Thanks again and If you have and questions or comments please Email me... KathKathy
