| Subject
Matter: |
Science |
| Grade Levels:
|
9-12 |
| Time Allotment:
|
Two 60-minute class sessions
|
Overview
How come you sound so great in your bathroom shower but not so
great singing "Happy Birthday" at a party? Do sound
waves move air? How do whales transmit their songs for miles through
the ocean? How in the world did Beethoven compose music when he
was already deaf? In this lesson, students will discover the answers
to these questions by learning the basic principles of sound wave
production and how waves behave.
Learning Objectives
Students will be able to:
- Determine how materials transmit sound and what variables are involved in transmitting sound.
- Define key concepts of amplitude, frequency, pitch, intensity, displacement, Hertz, wave length, wave period and wave height.
Oregon Standards Available at:
http://www.ode.state.or.us/cifs
Science – Physical Science
Understand energy, its transformations and interactions with matter.
- Describe differences and similarities between different kinds of waves, including sound, seismic and electromagnetic, as a means of transmitting energy.
Media Components
Video
Check the link at http://www.opb.org/edmedia/trs/
to find access to the video(s) from unitedstreaming™ referenced in this lesson plan.
- "Elements of Physics: Waves: Sound and Electromagnetism" (20:00)
o Clip: "Sound Waves" (02:55)
- "Inquiring Minds: Secrets of Sound" (15:00)
o Clip: "Voice Change" (04:44)
Web
Materials
Per Student:
Per Group:
Session 1
- Metal clothes hanger
- Wooden spoon
- Metal spoons (one for each thickness of string and wire)
- Plastic spoon
- Oven rack (optional - sounds like a cathedral bell!)
- String (at least two thicknesses)
- Thin wire
- Yarn
Culminating Activity
- Balloon Babble: at least 30 balloons
- Sound Rules: a plastic ruler and a heavy book
- Wound Up: metal rod, wooden dowel, wind-up alarm clock
- The Rubber Band: milk carton, skinny rubber band, thick rubber band, 2 pencils
- Making Waves: flat pan, paper towels, toothpicks, water and trashcan for refuse
Per Class:
- Demonstration computer with Internet connectivity with projection screen for whole group instruction
- Sound effects CD and CD player with speakers
- Access to blackboard or whiteboard, markers/chalk
Prep for Teachers
When using media, provide students with a Focus for Media Interaction, a specific task to complete and/or information to identify during or after viewing of video, Web sites or other multimedia elements.
Session 1
Bookmark all Web sites in Portaportal and download video clips.
Choose audio track on sound effects CD for use in the Introductory Activity.
Schedule the computer lab or mobile lab and allow one computer per student. Check to see if QuickTime or Windows Media Player is installed on the demonstration computer you will use for instruction. You will also need to download the Shockwave plug-in for your Internet browser. This is found at http://www.macromedia.com. The computers must be Java-enabled as well and capable of playing sound. Make sure that this computer can be connected to a projector or a large-screen monitor for large-group instruction.
Preview the video clip, "Voice Change" (04:44), from the video, "Inquiring Minds: Secrets of Sound" (15:00), to become familiar with the pause spots for the Focus for Media Interaction on the Focus on Sound Waves handout.
Make copies of the Sound Waves Lab handout found at http://www.cedarville.edu/dept/sm/lee/project/labs/lab-sound.pdf. Make copies of the Focus on Sound Waves handout found at the end of this lesson plan. Make sure you print one with the answers and then make the student copies.
Gather and organize the materials for the group activity. Place each item (wooden, plastic, metal spoon, oven rack (optional) and metal hanger) at a different station around the room. Tie a half-meter of string to each item. For the metal items, tie another metal item with a varying thickness of string and wire as comparison.
Session 2
Preview the video clip, "Sound Waves" (02:55), from the video, "Elements of Physics: Waves: Sound and Electromagnetism" (20:00), and become comfortable with when to pause this clip.
Again, be sure that students can access your Portaportal account for the Internet bookmarks for this session. Depending on your tolerance level, you may need headphones for the computers for this session.
Copy the Sounds of Mystery handout for each student (located at the end of this lesson plan).
Introductory Activity
Step 1: Play five sound effects tracks from the sound effects CD. (If you have access to a laserdisc player, you can use generic barcodes for the tracks of the CD, speeding up the process of going from one sound to another.)
Step 2: On a blank sheet of paper, have the students write a paragraph or two of a story that the sounds could be used to amplify (so to speak!). Using the whiteboard or chalkboard, ask the students to categorize the sounds they heard. What moods do they evoke? Are some dangerous sounding? Are some soothing? Do any of the sounds bring back a memory? (Answers vary.)
Step 3: Ask if anyone would like to volunteer to read their story aloud. If you can, play back the sound as they read. It will sound like an old-fashioned radio show! Lead into the lesson with: "Sounds are used to warn us, to soothe us, to convey information or to entertain us. How can a force so invisible mean so much?"
Learning Activities
Session 1
Step 1: Distribute
the Focus on Sound Waves handout located at the end of this lesson
plan. As a Focus for Media Interaction, direct
the students to pay attention as we watch a video clip to complete
question #1 on their Focus on Sound Waves handout.
Step 2: Play the video clip, "Voice Change" (04:44), from the video, "Inquiring Minds: Secrets of Sound" (15:00), and pause after the segment on bone conduction (cue - the actor's appearance goes from skull back to his face) to check for understanding.
Step 3: Continue to play the clip and direct students to answer question #2 on their handouts. This handout is used again in Session 2 so it may be stowed in science notebooks, cubbies or whatever your mode of storage.
Step 4: Divide the students into five groups. Distribute the Sound Waves Lab handout found at http://www.cedarville.edu/dept/sm/lee/project/labs/lab-sound.pdf and instruct students to strike the object at each station against a table using the string wrapped around their index fingers. The first time, hear the object in the air. The second time, put the index fingers in the ears while striking the table with the object. It is important that the variable of intensity be minimized by striking with the same force each trial. Every student in the group must try with the fingers in the ears for each object. Record results on the Sound Waves Lab handout.
Step 5: Gather the students back and share answers for group discussion. Find out if the thickness of the string makes a difference. Does the material that is conducting the sound make a difference? (Yes. The metal has more overtones and conducts sound better than wood and better than plastic.) Would increasing the force of hitting the material make a difference? (Yes, it increases the intensity or loudness of the sound waves.)
Session 2
Step 1: Retrieve the Focus on Sound Waves handout. Say, "Yesterday, we heard the sounds, but how can we see the waves?" Make sure all the students have pencil and paper. For the Focus for Media Interaction, tell students to look for the answer to question #3 on the Focus on Sound Waves handout. The clip will be paused so students can respond.
Step 2: Play the video clip, "Sound Waves" (02:55), from the video, "Elements of Physics: Waves: Sound and Electromagnetism" (20:00). Pause after the slinky portion of the clip. Have the students record responses to question #3 on the Focus on Sound Waves handout.
Step 3: Have students go to their computers and access the Internet site found at http://www.nationalgeographic.com/volvooceanrace/interactives/waves/index.html. Ask students to follow the instructions on the Focus on Sound Waves handout and experiment with the three variables: wavelength, wave period and wave height. As a Focus for Media Interaction, answer question #4.
Step 4: Return the students' focus to the continuation of the video clip and play until the tuning fork segment is completed. Continue using the Focus on Sound Waves questions as a Focus for Media Interaction, continuing with questions #5 and #6. Finish playing the video clip and then have the students respond to question #6.
Step 5: Return to the computers. Students will visit the Web sites below to apply concepts in frequency, pitch and intensity. As a Focus for Media Interaction, the answers are recorded on the Focus on Sound Waves handout.
Harmonics on a Vibrating String http://www.philtulga.com/harmonics.html for question #7
NCTM Sound Wave http://illuminations.nctm.org/mathlets/soundwave/ for question #8
Step 5: As a check for understanding, call for answers for class discussion and then collect the Focus on Sound Waves handout.
Culminating Activity
This activity is a series of mysteries. The students must be sworn to secrecy when they visit a booth so that the fun of examining a problem and solving it are not diminished. Put the students into five groups and ask them to rotate through each of the five stations. The simple instructions and questions are posted at each station and the groups are given a handout titled "The Sounds of Mystery." At each station, students will encounter a short experiment and materials to solve it. Some sample station ideas are found at:
http://www.smm.org/sound/nocss/activity/handson.htm
http://www.galaxy.net/~k12/sound/groovygu.shtml
http://www.galaxy.net/~k12/sound/wondwave.shtml
- Balloon Babble: Get a partner and whisper a sentence near their ear. Now, inflate a balloon and whisper the same sentence in the partner's ear through the balloon. Trade places so that each partner gets to hear. Which way is better and why? (The air is compressed in the balloon so that the particles are closer together and interfere less with the transmission of the sound.)
- Sound Rules: Extend a plastic ruler over the edge of a table and anchor it with a heavy book. Vary the lengths of ruler extending over the edge as you pluck it. What do you see when you change the length and what do you hear? (The longer the ruler, the more vibration and deeper sound.)
- Wound Up: Wind up a clock. Listen to it through a metal rod and a wooden dowel. Which does a better job of transmitting the sound? Why? (Metal does a better job because the particles are closer together.)
- The Rubber Band: Put the rubber bands around the milk carton the long way. Put one pencil under the rubber bands near each end of the carton. Pluck the skinny rubber band and listen. Now pluck the fat rubber band and listen. Does the skinny rubber band have a higher or lower pitch than the fat one? (Higher.) Pluck the rubber bands again and watch them vibrate. Does the whole rubber band vibrate or just the part between the pencils? (Part between the pencils. The pencils act as the damper on the "strings," as when someone places a finger on a string of a violin to change the pitch.) Make the length between the pencils shorter. First, pluck the skinny rubber band again and remember its sound. Move one of the pencils to the middle of the carton. Pluck the skinny rubber band again. Is the new sound higher or lower in pitch? (Higher.)
- Making Waves: Fill a pan halfway with water. Break the toothpick into three or four pieces. Put these pieces on top of the water. Be sure they are not touching the pan or each other. They will represent water molecules. (Make sure each group cleans the toothpicks out of the water for the next group.) Wet the paper towel but do not have it dripping. When the water in the pan is still, gently squeeze the paper towel so one drop falls in the middle of the pan. Ripples will occur. Which way do the ripples go? (They radiate out in a concentric circle away from the source of the droplet disturbance.) Do the toothpicks move as fast as the ripple? (No.) What is moving? (The wave is moving through the water particles.) What variable could be changed to make the ripples bigger? (Bigger drop, more force to the drop itself.)
Reconvene as a large group and share answers. Collect student work.
Cross-Curricular Extensions
Language Arts
Writing prompts can be developed to integrate sound wave concepts. For example: You are repairing a piece of equipment outside a space station on its surface. Besides the obvious language problem between you, a U.S. astronaut, and your Russian cosmonaut companion, there is no sound in space. How do you communicate? Social Studies
Conduct research to discover inventions that produce and transmit sound. What did these inventions contribute to the dissemination of information to improve the lives of their users? Music
Mathematically write a short line of music by noting frequency numbers. Using the Internet site found at http://lectureonline.cl.msu.edu/~mmp/applist/sound/sound.html, play your tune. Was it satisfying? What elements of music must be added to make it "musical" or more pleasant for listening? Technology Arts/Industrial Arts
Using a CAD software program, design an acoustically enhanced auditorium or classroom that is ideal for performance or instruction. Research wall materials and seating fixtures for optimum sound reproduction for listeners in the room. Health
Using the interactive sound table found on the Internet at http://www.nidcd.nih.gov/health/education/decibel/decibel.asp, have the students contrast safe sound environments with unsafe sound environments. Community Connections
- Invite an audiologist to discuss hearing loss due to environmental noise and the technology that exists to compensate for hearing loss.
- The symphony conductor or band director can demonstrate the louder instruments and talk about the ways orchestras and bands are protecting players from hearing loss.
- Biologists may be invited to talk about echolocation in bats and how an understanding of sound waves plays into that concept.
Additional Web Resource
Water Bottle Xylophone
Using the water bottles
online that are filled with varying levels of water, students play
tunes. What makes the pitch change?
http://www.philtulga.com/water.html
Focus on Sound Waves
Your Name_____________________________________________________
Time Block _______________
For the video clip, "Voice Changes" - Session 1
1. Low frequencies of sound travel better through solid material. Can you think of any solid materials that conduct sound?
Answer: wood as when you knock on a door, earth as in an earthquake, rubber as in rubber band, wire as in stereo speakers
2. Whale sounds are heard miles away. What elements of sound reproduction do you know now that explains this?
Answer: Sound travels through solids faster than in the air. Humpback whales produce moans, grunts, blasts and shrieks. Each part of their song is made up of sound waves. Some of these sound waves are high frequency. If you could see these sounds, they would look like tall, pointed mountains. Whales also emit low frequency sound waves. These waves are like hills that are spread apart. These sound waves can travel very far in water without losing energy. Researchers believe that some of these low frequency sounds can travel more than 10,000 miles in some levels of the ocean!
Sound frequencies are measured in units called Hertz. The range of frequencies that whales use are from 30 Hertz (Hz) to about 8,000 Hz (8 kHZ). Humans can only hear part of the whales' songs. We aren't able to hear the lowest of the whale frequencies. Humans hear low frequency sounds starting at about 100 Hz. (http://www.learner.org/jnorth/tm/hwhale/SingingHumpback.html)
For the video clip, "Sound Waves" – Session 2
3. Does the air move when sound waves compress through it? Why/why not? How do you know?
Answer: The air does not move as the sound waves pass through. If it did, it would be called wind.
4. Sound waves
are like water waves that you can see. Go to http://www.nationalgeographic.com/volvooceanrace/interactives/waves/index.html.
Click on the button/bar titled "Water Particles."
Read the explanation. As you move the slider bars
to change the three variables (wave height, wavelength,
wave period), what do you notice?
Answer: Wave period changes the speed of the particles and it corresponds to frequency in a sound wave; wave height changes the size of the pattern of movement and corresponds to amplitude in sound waves; wavelength is the same term for both water and sound and measures the distance of one wave. The water wave particles move around their pattern slower when the wavelength is long.
5. Where have you seen this action occur in the natural world?
Answer: When a duck swims through a stream, when fish jump, when you skip a stone across a pond and in the movie "Jurassic Park" when you see the puddle ripple as the Tyrannosaurus Rex is approaching.
6. How does the frequency range serve a dog and a bat? What are the advantages of a higher frequency range for the dog and bat?
Answer: Dogs' excellent hearing was probably one of the first reasons we tolerated wolves and early dogs near our camps. For centuries we have used them as sentries and guards, alerting us to possible danger. This is especially important at night when it's hard for us to see (http://www.nhm.org/exhibitions/dogs/formfunction/hearing.html). Most bats use echolocation to find their prey. They also need to hear well to avoid capture by owls, hawks, foxes and even cats.
Online Activities
7. Harmonic Series on a Vibrating String Web site at http://www.philtulga.com/harmonics.html
As the fractions get smaller, what happens to the string's vibrating speed or frequency?
8. NCTM Sound Wave Web site at http://illuminations.nctm.org/mathlets/soundwave/
Record your answers here as you complete the activity as outlined in the Web page.
a. After adjusting the sliders to change the two variables, how does each slider affect the sound that is produced?
b. What effect do the changes in the sound have on the animation of the string and the particles that you see? How do these observations correspond to the observations from part a?
c. What is the motion of your particle that you clicked on to make a red color?
d. How does the movement of the second particle compare to the first particle?
e. What do you observe about the behavior of the column of points?
Sounds of Mystery
Your Name_____________________________________________________
Time Block _______________
After conducting the Sounds of Mystery experiments, write down your answers on this sheet.
Balloon Buddy: Did the balloon change the sound of your partner's whisper? How and why?
Sound Rules: What did you hear when you compared the sound produced by a long piece of the ruler with the sound of a short piece?
What did you see when you compared the vibrations of a long piece and a short piece of the ruler?
Wound Up: Which does a better job transmitting the sound - metal or wood? Why?
The Rubber Band: Is the skinny rubber band higher or lower than the fatter one?
Does the whole rubber band vibrate or just the part between the pencils?
Does the skinny rubber band have a higher or lower pitch than the fat one?
How does changing the length of the rubber band affect the pitch? How does this apply to musical instruments? Be specific.
An object that is long or fat will have a pitch that is ______________ (higher/lower) than an object that is skinny or short.
Making Waves
In what direction do the ripples move?
Are the toothpicks moving as fast as the ripples?
What is moving?
What variable could be changed to make the ripples bigger?
Note: Clean your toothpicks out of the water for the next group. Thanks!
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