Sounds all Around

Introduction:

As teachers, we recognize that sounds are part of our student’s everyday sensory experience. As youngsters, they devote a tremendous amount of time and energy in learning how to correctly produce and interpret the sounds of their native tongue. Although their interpretation of these sounds as meaningful words may now seem automatic, it takes a great deal of our brains’ time and energy to figure out these wave patterns when we are young. This process is made even more difficult in schools like where a majority of students are learning the unique patterns of their non-native language.  While each of our national science reform documents are based on the idea that at active, hands-on approach to science is needed to build student understanding, the importance of such concrete explorations are magnified for students who are engaged in a second language acquisition. 

Most students realize that sounds are created when objects vibrate.  Some recognize that the as objects vibrate, they produce waves that travel from one place to another.  For example, when our vocal chords vibrate, they produce compressional waves that travel through the air - usually to the ear of the listener. When these waves enter the ear of a listener, they can be interpreted as sounds.  Our vocal chords can vibrate at different rates and the faster they vibrate, the more waves per second they produce and the higher the pitch (frequency) of the sound. A soprano singer produces more waves per second than someone who sings base. 

But although students hear what we are saying, the concept of waves traveling though the air is a difficult one for children to grasp. In this exploration, we begin with a series sound centers that builds understanding because they allow students to actually hear, feel, and even see the sound-like compressional waves.  While as teachers we may be tempted to skip such explorations to simply explain the concepts, we must remember that the acquisition of concepts must begin with concrete experiences involving real things. 

National Science Standard: Unifying Concept

Nature is constantly changing but there are many repeating patterns.

Georgia Performance Standards:

Students will exhibit curiosity, honesty, openness and skepticism S(K-5)CS1

Students will investigate sound and it's properties S1P1, S4P2

Exploration

At each center, students are provided with a simple laminated sheet that provides directions for the exploration.  Following the completion of each center, students are asked to reflect on their learning by writing or drawing in their sound journals. Such reflective writing helps the students to make relevant connections in order to build their understanding and promote their language development.  Each of the centers used in this exploration is summarized below:  

1.  Tuning Fork Vibrations

Materials:   Tuning fork(s)      plastic glass of water   paper towels    Sound Journals

Procedure: 

Students use the heel of their shoes to strike a tuning fork and then closely observe the vibrations. Students then exchange tuning forks with each other and observe the differences in sound with shorter and longer forks. Next, students strike the tuning fork and place the prongs of the tuning fork into a plastic cup of water and observe. Students use paper towels to clean up before rotating to the next station.

Guiding Questions:

       1.  Explain how you think the tuning fork caused the water to splash?                                                             2.Why does one tuning fork sound differently than another?

2.  Rubber Band Guitars

Materials: Shoebox for each group, scissors, variety of rubber bands, Sound Journals

Students use scissors to cut a 3-inch wide hole toward one end of the shoebox. They then stretch three or four rubber bands of varying thickness around the shoebox and across the hole.  Students then pluck each of the strings and listen carefully for differences in the sounds. 

Guiding Questions:

1.      Explain how the rubber band produced sound when you plucked it.

2.      Why do you think the rubber band vibrates louder on the guitar then it does all by itself?

3.  Drum it Up

Materials: Play drum, drum sticks, uncooked rice, Sound Journals. 

Students place a small handful of rice on top of the drum and tap gently with the sticks. Students are asked to observe and listen closely to what is happening. They then draw a picture of  what they think is occurring at this center.

1. What do you think caused the rice grains to move?

2. How could you tell the drum is vibrating if we didn't have any rice?   

4.  The First Phones

Materials: Plastic cups with small slit cut in bottom, 40 inch pieces of cotton string, paper   clips, scotch tape, Sound Journals.   

Students tie a paperclip onto each end of the string and then thread the paperclips through the slit on the bottom of the cup and secure paper clip with tape. Process is then repeated for other cup. Students hold the cup to their ear and gently pull the string tight. They then take turns plucking the string and listening closely to what they hear.

Guiding Questions:

1.      Explain how do you think the sound is getting from one cup to the other? 

2.      Do you think that real phones work in the same way? Explain.

5. Too Loud

Materials: Computer with Internet Connection,  Sound Journals.

Students go to National Institute on Deafness Website http://www.nidcd.nih.gov/health/education/decibel/decibel.asp

At the site, they read about the decibels and complete in an interactive auditory activity called “How Loud is Too Loud.”

Guiding Questions:

1.      Do you think that the communities where we live are getting quieter or louder overall?  Explain why you think this.

2.      What are some things that you can do to prevent your hearing from being damaged?

Part 2: Trash Can Whoosh Waves

1. Take a round plastic trash can (20-30 gallons) and cut a five to six inch diameter round hole in the middle of the bottom.
2. Place some shower liner (home supply store) or some thick plastic across the open top of the can. Push the liner so that it bows slightly into the can and allow about 10 inches of liner to overlap the edges of the can. Use tape or a bunji-chord to secure the liner to the can.
3. Attach a handle to the liner by attaching a screw and a washer from inside the liner to a small piece of wood on the outside of the liner.
4. To produce a whoosh wave. Pull the handle back and then push it quickly into the can. A small but distinct compressional wave will be produced that will easily be felt by your students. Move around and hit each of your students with a wave. Try to see if the wave will travel across the entire room.
5. Hit one or two of your students with a series of waves as you explain that our vocal chords produce series of waves that are very similar.
6. To produce a whoosh wave that you can see, fill your can with fog from a fog machine (can be purchased or rented cheaply from most party supply stores).  The fog is manufactured so as to not set off fire alarms but try to limit the amount that is produced to 4-5 trashcans so as to avoid a build up of fumes.  
7. Have each of your students predict what the shape of fog wave will be as it leaves the can. The actual shape is very surprising and fascinating.
8. Aim the can above the students and pull the handle back and push quickly to release the wave. Once again, hit each of your students with a wave and then release a series of waves so students can visualize the patterns of waves that our vocal chords (and other vibrating objects) produce.
9. Have small groups of volunteers (or the teacher) come up and produce a series of waves that represent sounds of different pitches and volumes.
10. Refill the can with fog as needed.

Guiding questions:

1. How could we use the trashcan to show sound waves of different pitches and volumes?
2. What do you think caused the fog to form into rings as it came out of the trash can?

Concept Discussion: Vibrating objects produce waves. When our vocal chords vibrate, they produce waves that travel through the air.  Each sound wave contains energy that travels in the form of a compressional wave. The wave travels into our ear where specialized hair cells convert the sound wave into a nerve impulse that is sent to the brain. After a long period of hard work and practice, the brain learns to interpret these patterns as meaningful speech.  Prolonged exposure to high intensity (energy) sound waves can cause damage to the hair cells which, in turn, causes hearing loss.  For example, truck drivers often lose some of the hearing in their left ear. Why do you think this is so?  Also, about 1/3 of senior citizens suffer from significant hearing loss. You can help prevent hearing loss by keeping your stereo down to a reasonable level and by using earplugs during load jobs such as mowing the lawn.

The unusual rings are formed when the fog wave hits the front end of the trash can. The fog that hits the can is slowed down (by increased drag) and this causes a spiral (vortex) to form in the shape of a ring. The spiraling ring is a pretty stable structure and so it holds together very well.  Spirals (vortexes) are found in nature as tornados, dust devils and water spouts. 

Teacher Notes: The best material to use at the end of the trash can is shower liner but you can also use thick plastic bags or drop cloths. You can purchase or rent a fog machine from party stores like Party City. Although the fog is non-toxic, the fog machine should be used sparingly within an enclosed classroom. Fill the trashcan up a few times but don’t spray the fog repeatedly in the room. 

Evaluation and Closure:   Student writing or journal entries should be evaluated to check for student understanding.