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By Tom Brown
and Kim Boehringer
tudent interest in science has been
amplified at our elementary school.
During a recent unit on sound, students
in a fourth-grade class participated in a
series of dynamic sound learning centers followed
by a dramatic capstone event—
event an exploration of the
amazing Trashcan Whoosh Waves. It’s
It s a notoriously
difficult subject to teach, but this hands-on, exploratory approach ignited student interest in sound,
promoted language acquisition, and built
comprehension of key science concepts.
We share our successful experiences
with our fourth-grade students here.
January 2007 35
January 2007 35
PHOTOGRAPHS COURTESY OF THE AUTHORS
A Sound Background
The lessons began with an introductory discussion about
sound. First, the teacher asked students to brainstorm
what they know about sound and what they wondered
about it. Most students had heard of sound waves,
but they couldn’t explain exactly how they “worked.”
Other students connected the idea of vibrating objects to
sounds but couldn’t expand on that information.
The teacher explained that when our vocal chords
vibrate, they produce waves that travel through the air.
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.
Some students placed a hand on their vocal chords and
quietly hummed high and low notes to see if they could
tell any difference.
Next, the class discussed that sound waves carry energy that affects humans in various ways. For instance,
prolonged exposure to high-intensity (energy) sound
waves causes inner ear damage that, in turn, will cause
hearing loss. They talked about ways to prevent hearing loss, such as by keeping their headphones down to
a reasonable level and by using earplugs when they are
working in loud environments.
To conclude the introduction and to help guide
students in their hands-on explorations to come, the
teacher asked students to brainstorm some questions
about sound in their science journals. Students’ most
common questions were, “What is sound made of?”
and “How do we hear sound?” While enthusiastically
acknowledging their inquiries, the teacher suggested
36
Science and Children
Students exploring sound in “The First Phone” activity.
that today’s explorations would help them to find answers to these questions.
She encouraged them to make careful observations,
record their data, and write about their thinking in their
sound journals.
Center Time
Each center included a mini-exploration that addressed a sound-related concept along with one or two
guiding questions. The center activities originate from
teacher-centered sound demonstrations that have
been modified into student-centered explorations as
part of a professional development project we have
participated in called SMATHematics (see Internet
Resources). Students spent 10 minutes at each of the
centers with time being split equally between performing the activity and writing their observations and
ideas in their sound journals.
Tuning Fork Vibrations
Science Concept Introduced:
Students will understand that sound is produced by
vibrating objects and that some objects vibrate faster
(with a higher pitch) than others.
Materials:
Tuning fork(s) of various sizes (see Internet Resources),
plastic glass of water, paper towels, sound journals.
Procedure:
Students struck a tuning fork against the heel of their
shoes and then closely observed the vibrations being
careful not to place it too close to their ears. Then,
students exchanged tuning forks with each other and
observed the differences in sound with shorter and
longer forks. Finally, students struck the tuning fork and
placed the tines of the fork into a plastic cup of water
and observed. Students used paper towels to clean up
before rotating to the next station.
Guiding Questions:
Explain how you think the tuning fork caused the water
to splash. This demonstration helps students to see
that sound waves carry energy that can affect the things
around them. In this case, the vibrations from the
tuning fork transfer much of their energy to the water
causing it to splash, much to the delight of the students.
Why does one tuning fork sound differently than another? By carefully listening to each of the different
tuning forks, students recognize that shorter tuning
forks vibrate faster (with a higher pitch) than the
longer tuning forks. They can begin to understand
that certain characteristics of vibrating objects can
affect the quality of the sounds that are produced.
Recording Data:
At this center, students were asked to record their observations and draw a sketch of what they observed when
placing a tuning fork in water. They were then asked to
predict and explain the differences in sound between
a longer and shorter tuning fork.
Figure 1.
Rubber Band Guitars
Science Concept Introduced:
The pitch (speed) at which an object vibrates depends
on characteristics of the object, such as length, thickness, and tension.
Materials:
One shoe box for each group that so that each group
can construct their own guitar, scissors, variety of rubber bands, sound journals
Procedure:
Students cut a 3-inch wide hole toward one end of the
shoe box. They then stretch three or four rubber bands
of varying thickness around the shoe box and across the
hole. Students then pluck each of the strings and listen
carefully for differences in the sounds.
Guiding Questions:
Explain how the rubber band produced sound when you
plucked it. The pitch of the vibration depends on both the
mass (thickness) of the rubber band and the tension on the
rubber band. The heavier the band, the lower the pitch,
and the tighter the tension on the band, the higher the pitch
of the vibration. Why do you think the rubber band vibrates
louder on the guitar then it does all by itself?
The air by the hole of the guitar moves back and forth
as the string vibrates. This causes the air to resonate with
the string and together they produce a louder sound.
This question was probably too
difficult as kids had a hard time
answering it.
Instructions to build the trashcan wave generator.
1. Use a utility knife to cut a 4–5 in
round hole in the middle of the
bottom of a round plastic trashcan
(20–30 gallons).
2. Cut a piece of shower liner (available
at home supply stores) or some thick
plastic about 12 inches wider than the
can opening on each side.
3. Attach a handle to the middle of the liner:
a small piece of wood attached with a
screw and a washer (see photograph).
4. Place the liner across the trashcan and
center the wood handle. Push in the
liner so that it bows slightly into the
can and allow the liner to overlap the
edges of the can. Secure the liner to the
can with tape or a bungee cord.
Your amazing wave generator is now
ready for use.
Recording Data:
At this center, students were
asked to record their observations and explain why
they thought that each of the
rubber bands sounded differently.
Drum It Up
Science Concept Introduced:
Vibrations can move through
different objects and materials.
Materials:
Play drum, drum sticks, uncooked rice, sound journals.
Procedure:
Students placed a small handful
of rice on top of the drum and
tapped gently with the sticks.
January 2007 37
Procedure:
Students tied a paper clip onto each end of the string and
then threaded the paper clips through the slit on the bottom of the cup and secured the paper clip with tape. Then
they repeated the process for the other cup. Students held
the cup to their ear and gently pulled the string tight. They
then took turns plucking the string and listening closely
to what they heard. Some even tried to talk to each other
through the cups. The students were surprised how well
the vibrations could travel through the string and to their
ears. Although the words themselves were not understandable, they could also transmit the vibrations from
their voices back and forth to each other.
Guiding Questions:
Students observed and listened closely as the rice
bounced up and down.
How do you think the sound is getting from one cup to the
other? Sound can travel through many materials including solids, liquids, and gases. In this case, the sound
travels through the string, cup, and air before reaching
your ear. While most students seemed to recognize that
the vibrations moved through the string and cup, they
were most interested in writing about how they could
feel the vibrations that were produced. Do you think
that real phones work in the same way? Explain. No, real
phones don’t act in the same way. Traditional phones
convert sound waves into electrical waves, which are
sent to the receiver and then converted back into sound
waves. Cell phones are actually mini-radios that use radio waves to communicate. Most of the students thought
that real phones did not act in the same way. One wrote,
“No, because it is a cup and the phone is electricity.”
Guiding Questions:
Recording Data:
What do you think caused the rice to move? The vibrations from the drum were transferred to the rice causing
it to vibrate (move) up and down. How could you tell
the drum is vibrating even if we didn’t have any rice?
You can tell the drum is vibrating because you can hear
the sound produced by the drum. Sounds are produced
by vibrating objects—in this case, the drum.
At this center, students were asked to record their
observations and describe what they heard when they
listened with the cup.
A student tests a rubber band guitar.
Recording Data:
In their sound journals, students draw a picture of what
they think is occurring at this center.
The First Phone
Science Concept Introduced:
Vibrations can move through different objects and
materials, including strings and cups and air.
Materials:
Four plastic cups with small slit cut in bottom, two 40inch pieces of cotton string, four paper clips, transparent tape, sound journals.
38
Science and Children
Assessment and Reflection
During these investigations, the teacher observed that
her students were “totally immersed in the content and
were not apprehensive about any language barriers that
they would normally have encountered.” According to
Maatta, Dobb, and Ostlund (2006), inquiry science
Connecting to the Standards
This article relates to the following National Science
Education Standards (NRC 1996):
Content Standards
Grades K–4
Standard C: Physical Science
• Position and motion of objects
provides an arena where English Language Learners can
try out their ideas about science using their expanding
second-language skills. Hands-on activities involving
opportunities to read, listen, talk, and write are key
to improving students understanding of both science
content and the English language.
Upon completion of the exploration, the class discussed each center and the teacher highlighted key
concepts. Using simple sentence structures and speaking
slowly, she wanted to make sure that her students understood that sound was produced by vibrating objects,
that objects vibrate with different pitches, and that sound
waves carry energy in ways that affect humans. She then
had her students repeat and rephrase the main ideas to
each other in their own words, making sure to enunciate
the words clearly. In doing so, she provided the scaffolding and language support that was needed for her English
language learners (Rice, Pappamihiel, and Lake 2004).
By having students write about what they explored in
class, she also helped develop their understanding of how
language is related to meaning within a particular subject
area. In simulating the actions of scientists, students were
asked to make and record careful observations as they
completed each of the sound centers. After diligently constructing and testing his rubber band guitar, one student
wrote that “by stretching the string (rubber band) and by
sliding your finger on the string you can change the pitch
of sound.” By participating in purposeful, guided experiences related to key ideas about sound, students were able
to build their academic understanding of sound.
As a wrap-up for this lesson, most of the students
were asked to write a paragraph in their journal explaining what they learned about sound. Recognizing that
academic writing poses a challenge to most English
language learners, the teacher allowed students to complete their journal in various ways (Bravo and Garcia
2004). The students with limited English proficiency
were allowed to draw and label their ideas relating to the
tuning forks, drums, or phones. Others were encouraged to use diagrams and concept maps to help organize
their ideas. These modifications, and the supportive
“sticky note” comments that the teacher included when
returning their journals, enabled students to demonstrate their growing understanding and feel successful
in their pursuit of scientific understanding.
A Blast of a Finale
As a culminating event, the teacher used a trashcan wave
generator (See Figure 1, page 37, for building instructions) to “blast” each student with a “silent” sound wave
(because of their low frequency). To produce the wave,
the teacher pulled the handle back on the trashcan and
then pushed it quickly into the can. The teacher moved
around and aimed a wave at each student. Students
had a rare and delightful opportunity to feel the waves
because of the strong pressure (amplitude) that was
readily detectable as the passing waves pushed against
their faces.
After each group had their chance to shoot their own
sound waves by moving the handle quickly or slowly, the
teacher explained that, as with the tuning forks, the pitch
of a sound depends on how fast the waves are produced
by the vibrating object (or trashcan). She then spoke with
a “girly” voice as she shot several waves quickly and then
switched to a “manly” voice as she shot a few slowly.
The trashcan wave generator demonstration was a
fitting end to a memorable hands-on experience about
sound. Having worked through the sound learning
centers previously, students were comfortable discussing their ideas and observations about the trashcan
wave generator and they were eager to apply their new
understandings to the demonstration at hand. The ease
of discussion and the quality of students’ comments let
the teacher know that the concrete hands-on experiences had truly helped her students begin to develop a
foundation of understanding about sound—a difficult
topic for many students to understand. ■
Tom Brown ([email protected]) is assistant
professor of elementary science education at Kennesaw
State University in Kennesaw, Georgia. Kim Boehringer ([email protected]) is a
fifth-grade teacher at Fair Oaks Elementary School
in Marietta, Georgia.
Resources
Bravo, M., and E. Garcia. 2004. Learning to write like scientists: English language learners’ science inquiry and writing
understandings in responsive learning contexts. Paper presented at AERA Annual Meeting, San Diego CA.
Maatta, D., F. Dobb, and K. Ostlund. 2006. Strategies for
teaching science to English learners. In Science for English
Language Learners, eds. K. Fathman and D. Crowther.
Arlington, VA.: NSTA Press.
National Research Council (NRC). 1996. National science education standards. Washington, DC: National Academy Press.
Rice, D.C., N.E. Pappamihiel, and V.E. Lake. 2004. Lesson
adaptations and accommodations: Working with native
speakers and English language learners in the same science
classroom. Childhood Education (80):121–127.
Internet
Educational Innovations
www.teachersource.com
Flinn Scientific
www.flinnsci.com
SMATHematics
http://webtech.kennesaw.edu/tbrown/curiosity/sound.htm
January 2007 39