Becky McCoy

Lesson Title: Sound – Standing Waves and Pitch Timing: 60 minutes

Target Audience:11th and 12th grade Physics course

Objectives:Students Will Be Able To:

Think about and examine how different musical instruments work. Explore tuning forks and which of their characteristics determine pitch. Serious play with filling cylindrical beakers to discover how pitch changes. Observe how the vocal mechanism can affect the quality of sound and pitch.

The Teacher Will Be Able To: Provide students with opportunities to explore more about sound through interaction and

observation. Assess student understanding of sound, frequency, pitch, resonance, etc.

Standards Assessed: New York State Standards, PhysicsPerformance Indicator 4.3: Students can explain variations in wavelength and frequency in terms of the

source of the vibrations that produce them, e.g., molecules, electrons, and nuclear particles. 4.3a An oscillating system produces waves. The nature of the system determines

the type of wave produced. 4.3b Waves carry energy and information without transferring mass. This energy

may be carried by pulses or periodic waves. 4.3c The model of a wave incorporates the characteristics of amplitude,

wavelength,* frequency*, period*, wave speed*, and phase. 4.3dMechanical waves require a material medium through which to travel. 4.3e Waves are categorized by the direction in which particles in a medium vibrate about an equilibrium

position relative to the direction of propagation of the wave, such as transverse and longitudinal waves.

4.3f Resonance occurs when energy is transferred to a system at its natural frequency.

Misconception(s) Addressed: Pitch is related to intensity. Frequency is connected to loudness for all amplitudes. Waves transport matter.

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Prior Knowledge: Wave Unit and previous lessons on sound.

Aim: Explore different aspects of sound including pitch, volume, and natural frequencies.

Concept Map Vocabulary: n/a

Necessary Preparation:COPIES

Sound Worksheets Station Posters

MATERIALS Computer and projector Two different sized plastic cylinders. Water. Guitar. Tuning forks of different pitches.

SET UP Have videos loaded. Have “Beats Working” Simulation ready. Have water and cylinders prepared. Designate where around the room each station is.

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Lesson Plan

Aim: Explore different aspects of sound including pitch, volume, and natural frequencies.

Physics Push-Up: KWL (5 minutes)Distribute packets and have students fill out their KWL chart individually using their notes from the last few classes.

Collect homework while this is happening.

Activity: Singing and Stations (35 minutes)Materials:

Computer and projection. Station worksheets. Station posters. Two different sized plastic cylinders. Water. Guitar. Tuning forks of different pitches.

Procedure: Notes from lecture should be taken in the notebook.

“What do you have to do in order to talk/hear?” Have students hum or sing and feel their larynx.

5 MINUTES: Show Pictures of Larynx and Palette:

http://en.wikipedia.org/wiki/File:Gray994.png

http://en.wikipedia.org/wiki/File:Gray954.png

http://en.wikipedia.org/wiki/File:Gray956.png

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The larynx is the home of the vocal folds which stretch thin and thick when they vibrate to produce different pitches. The entire larynx sits high or low in the neck to produce a different quality of sound. The palette is domed or flat to produce different reflection/resonance/quality.

“Different types of singing utilize the larynx mechanism in different ways.” CLASSICAL (Marilyn Horne): http://www.youtube.com/watch?v=jTuNUZEFBJk

o Larynx remains low and palette high. Sound reflects through the mouth and resonates through the head. Sounds echo-y.

BELT (Defying Gravity, Idina Menzel): http://www.youtube.com/watch?v=3g4ekwTd6Ig (start @ 3:10)o Belt is like talking on pitch with volume added. The pallet remains flat and the larynx high.

MIX (Tonight, GLEE): http://www.youtube.com/watch?v=mJ-XKY_WU8go Mix between both where larynx is low and palette is high, but sound is focused forward so it has

a speech-y quality.

WRITE ON BOARD: pitch = frequency & volume = amplitude

30 MINUTES: “Today we’re going to explore different aspects of sound via different stations. Each station has a poster (might be double sided) that gives directions and questions to answer. We’ll spend about three minutes in each station”

Have someone repeat the instructions.

Students count off by 9 and start at their respective stations.

STATIONS: with guiding questions posters and worksheets – 2-3 minutes each1. Filling plastic cylinders (what happens when you pour water in the big/little? what’s diff? why?

what happens when you tap on the bottom of the cylinder?)2. Guitar (why is it shaped this way? why is there a hole? what happens when strings are

tightened/loosened? why are strings different?)3. KWL 4. Tuning forks (show picture of piano keyboard w/ notes labeled and treble staff showing same

notes. use resonance box. have students identify middle c through c up the octave and note the frequencies. find the wavelengths for these frequencies in air 343 m/s. what’s the relation of the two “octaves”? why can you hear the pitch at a louder volume than the tuning fork alone?))

5. Beats (show Wolfram “Beats Working”. Identify parts of standing wave – what parts of the two pitches are interacting? draw the two waves at the anti node and the node. what would you hear at the node/antinode? try with the tuning forks.)

6. KWL7. Organ (show picture of organ pipes. have students draw them on their worksheet and draw the

standing waves in them. will longer or shorter pipes produce higher/shorter pitches?)8. Piano (picture of inside of piano. what changes about the strings? what does this change?9. KWL

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Students return to table and take 1 minute to finish their KWL Chart.

Activity Summary: Light Travels Faster Than Sound! (10 minutes)Take students outside with a drum. Have some students stand with the drum and others a generous distance away. When the drum is struck, it should be obvious that the sight of the drum being struck reaches the observers before the sound.

Homework: n/a

Exit Strategy:Hand in work sheet.

Extension Activity: spend more time with the drum or revisit any video or station.

Assessment:Formative:

Student discussions in small groups and whole class Sound Worksheet responses

Resources:Larynx Pictures:

http://en.wikipedia.org/wiki/File:Gray994.png http://en.wikipedia.org/wiki/File:Gray954.png http://en.wikipedia.org/wiki/File:Gray956.png

Marilyn Horne Habanera: http://www.youtube.com/watch?v=jTuNUZEFBJkIdina Menzel Wicked: http://www.youtube.com/watch?v=3g4ekwTd6IgGLEE Tonight: http://www.youtube.com/watch?v=mJ-XKY_WU8g

Notes & Adaptations:

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FILLING PLASTIC CYLINDERS

TAP THE BOTTOM OF EACH CYLINDER. WHAT SOUNDS

DIFFERENT?

FILL THE TALL CYLINDER AND NOTICE HOW IT SOUNDS.

FILL THE SHORT CYLINDER AND NOTICE HOW IT SOUNDS.

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HOW CAN YOU DESCRIBE WHAT HAPPENED USING THE SCIENTIFIC

TERMINOLOGY WE’VE DISCUSSED?

GUITAR STATION

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QUESTIONS TO CONSIDER:

HOW DOES A GUITAR PRODUCE SOUND?

WHAT IS SIGNIFICANT ABOUT THE GUITAR’S SHAPE?

WHY ARE THE STRINGS DIFFERENT?

WHAT’S WITH THE HOLE?

WHAT DIFFERENT PITCHES AND SOUNDS CAN A GUITAR MAKE?

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KWL

COMPLETE AS MUCH OF THE “W” AND “L” SECTIONS AS YOU CAN!

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

C D E F G A B C

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TUNING FORKS

A PIANO KEYBOARD ABOVE HAS THE PITCHES C, D, E, F, G, A, B, AND C LABELED. THE TWO “C” PITCHES HAVE THE SAME TONAL SOUND, BUT THE ONE

ALL THE WAY TO THE RIGHT IS ONE “OCTAVE” HIGHER, MEANING IT IS EIGHT NOTES ABOVE THE FIRST ONE.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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THE PICTURE ABOVE SHOWS WHAT THE MUSICAL SCALE WOULD LOOK LIKE (MINUS THE HIGHER “C”) ON A MUSICAL STAFF. EACH NOTE (PITCH) HAS ITS

OWN PLACE ON A LINE OR IN A SPACE.

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LISTEN TO EACH OF THE TUNING FORKS. WHAT DO YOU NOTICE?

CHECK THE FREQUENCY OF EACH TUNING FORK. HOW DOES THE

PITCH CHANGE WITH FREQUENCY?

WHAT MIGHT BE THE RELATIONSHIP BETWEEN LOW “C” AND HIGH “C”?

FIND THE WAVELENGTH FOR EACH PITCH FOR AIR – 343 M/S.

STRIKE THE TUNING FORK AND PLACE THE END AGAINST THE

RESONANCE BOX. WHY CAN YOU

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HEAR THE PITCH LOUDER THAN THE TUNING FORK ALONE?

BEATSUSE THE SIMULATION “BEATS WORKING.”

LOOKING AT THE DEMONSTRATION, DRAW A STANDING WAVE AND

IDENTIFY THE NODE AND ANTINODE.

WHICH PART OF THE PITCHES (FIRST

TWO GRAPHS) INTERACT AT EACH PART OF THE WAVE?

WHAT WOULD YOU HEAR AT THE NODE AND ANTINODE?

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SEE IF YOU CAN HEAR BEATS (THE

AUDIO VERSION OF THE BEATS) WITH TWO TUNING FORKS.

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ORGAN

IN AN ORGAN, OPEN PIPES ALLOW STANDING WAVES TO OCCUR AT

CERTAIN FREQUENCIES, WHICH ARE

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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DETERMINED BY THE LENGTH OF THE PIPE.

WOULD A LARGER OR SMALLER PIPE PRODUCE A HIGHER OR LOWER

PITCH?

THE STANDING WAVE WITHIN THE PIPE STARTS WITH A NODE AND

ENDS WITH AN ANTINODE – WHAT WOULD THE DRAWING OF THE STANDING WAVE LOOK LIKE?

TRY DRAWING WHAT THE STANDING WAVE MIGHT LOOK LIKE FOR A PIPE

4.6M LONG (1.25 X )?

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WHAT OTHER INSTRUMENTS CAN YOU THINK OF THAT ARE BUILT THIS

WAY?

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PIANO

A PIANO WORKS BECAUSE A SMALL HAMMER HITS A STRING. THE STRING FOR EACH NOTE IS A

DIFFERENT LENGTH.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

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WHAT COULD YOU ASSUME ABOUT EACH DIFFERENT STRING IN ORDER

TO MAKE DIFFERENT PITCHES?

WHAT MIGHT BE THE RELATIONSHIP BETWEEN PITCHES OF THE SAME

NAME (AKA “C” OR “D”) AT DIFFERENT OCTAVES? AN OCTAVE

IS LIKE THE MULTIPLE OF A CERTAIN PITCH.

WHAT IS UNIQUE ABOUT A PIANO’S SHAPE AND WHY MIGHT IT BE

DESIGNED THIS WAY?

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WHAT DOES THE PEDAL DO IF IT ALLOWS THE STRINGS TO CONTINUE

TO VIBRATE?

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SOUND WORKSHEETName _____________________________________ Date ______________

K W L

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STATIONS: At each station follow the directions and answer the questions on the station’s poster. Record your thoughts and answers below.

1. FILLING PLASTIC CYLINDERS

2. GUITARS

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3. KWL – WORK ON THE “W” AND “L” SECTIONS OF YOUR CHART.

4. TUNING FORKS

5. BEATS

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6. KWL – WORK ON THE “W” AND “L” SECTIONS OF YOUR CHART.

7. ORGAN

8. PIANO

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9. KWL – WORK ON THE “W” AND “L” SECTIONS OF YOUR CHART.