TOPIC 1.3: Sound - edu.gov.mb.ca · Topic 1: Waves• SENIOR 3 PHYSICS Topic 1.3 – 42 SPECIFIC...

TOPIC 1.3: SoundStudents will be able to:S3P-1-17 Investigate to analyze and explain how sounds are produced,

transmitted, and detected, using examples from nature and technology. Examples: production of sound by a vibrating object, drums, guitar strings, cricket,hummingbird, dolphin, piezocrystal, speakers…

S3P-1-18 Use the decision-making process to analyze an issue related to noise inthe environment.Examples: sonic boom, traffic noise, concert halls, loudspeakers, leaf blowers…

S3P-1-19 Design, construct (or assemble), test, and demonstrate a technologicaldevice to produce, transmit, and/or control sound waves for a usefulpurpose. Examples: sound barrier or protective headphones to reduce the effects of noise,electromagnetic speakers, echo chamber, microphone, musical instruments, guitarpickup, electronic tuner, sonar detector, anechoic chamber, communication devices…

S3P-1-20 Describe and explain in qualitative terms what happens when soundwaves interact (interfere) with one another.Include: production of beats

S3P-1-21 Experiment to analyze the principle of resonance and identify theconditions required for resonance to occur.Include: open- and closed-column resonant lengths

S3P-1-22 Experiment to calculate the speed of sound in air.S3P-1-23 Compare the speed of sound in different media, and explain how the

type of media and temperature affect the speed of sound. S3P-1-24 Explain the Doppler effect, and predict in qualitative terms the

frequency change that will occur for a stationary and a moving observer.S3P-1-25 Define the decibel scale qualitatively, and give examples of sounds at

various levels.S3P-1-26 Describe the diverse applications of sound waves in medical devices,

and evaluate the contribution to our health and safety of sound-wave-based technologies.Examples: hearing aid, ultrasound, stethoscope, cochlear implants…

S3P-1-27 Explain in qualitative terms how frequency, amplitude, and wave shapeaffect the pitch, intensity, and quality of tones produced by musicalinstruments.Include: wind, percussion, stringed instruments

S3P-1-28 Examine the octave in a diatonic scale in terms of frequencyrelationships and major triads.

Topic 1: Waves • SENIOR 3 PHYSICS

Topic 1.3 – 42

SPECIFIC LEARNING OUTCOME

S3P-1-17: Investigate to analyzeand explain how sounds areproduced, transmitted, anddetected, using examples fromnature and technology.

Examples: production of sound by avibrating object, drums, guitarstrings, cricket, hummingbird,dolphin, piezocrystal, speakers…

GENERAL LEARNING OUTCOMECONNECTION

Students will…Understand essential lifestructures and processespertaining to a wide variety oforganisms, including humans(GLO D1)

Entry-Level KnowledgeThe phenomenon of sound is a part of thestudent’s everyday sensory experience. Theprevious units on characteristics of wavesare the basis for understanding the natureof sound. Sound is also an excellent topic toaddress many varied STSE applications,ranging from noise pollution to music.

Notes to the TeacherMost sounds are waves produced byvibrations. The vibrating source moves thenearby air particles, sending a disturbancethrough the surrounding medium as alongitudinal wave. We use our eyes for thedetection of light and our ears enable us todetect sound. The compressions of soundwaves cause the eardrum to vibrate,which, in turn, sends a signal to thebrain. There are many interestingexperiences that students will havewith sound. Ask students if theyhave ever heard the ocean in aseashell. Actually, the sounds theyhear in a seashell are outside noisesthat resonate in the shell, creatingthe illusion of hearing the ocean.

Sound waves can be demonstrated in classwith a tuning fork. The tines of the tuningfork are struck with a mallet and, as theyvibrate back and forth, they disturbsurrounding air molecules in a series ofcompressions and rarefactions. Thepropagation of these waves is very similarto longitudinal waves in a coil spring toylike a Slinky™. A sound wave can berepresented mathematically as a transversewave with the crests corresponding toregions of high pressure and the troughscorresponding to regions of low pressure.

Note: Even though the wave is representedmathematically as a transverse wave, soundis physically a longitudinal wave.

SUGGESTIONS FOR INSTRUCTIONPr

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transverse aspect longitudinal aspect

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SENIOR 3 PHYSICS • Topic 1: Waves

SKILLS AND ATTITUDES OUTCOMES

S3P-0-4b: Work cooperativelywith a group to identify priorknowledge, initiate andexchange ideas, proposeproblems and their solutions,and carry out investigations.

S3P-0-4c: Demonstrate confidencein their ability to carry outinvestigations in science andto address STSE issues.

S3P-0-4e: Demonstrate acontinuing and moreinformed interest in scienceand science-related issues.


Students will…Demonstrate curiosity,skepticism, creativity, open-mindedness, accuracy, precision,honesty, and persistence, andappreciate their importance asscientific and technologicalhabits of mind (GLO C5)

DemonstrationsStrike a tuning fork, and then place it on asound box, piece of wood, or the top of amusical instrument such as a violin or anacoustic guitar. Often we cannot see thetines of the tuning fork vibrate because thefrequency is very high. When we place thetuning fork on another surface, thevibrations are transmitted to that surfaceand the sound is amplified.

Place the vibrating tuning fork in a beakerof water or near a suspended pith ball todemonstrate a transfer of energy.

Hold a steel strip or plastic ruler in place atthe edge of a table. Pull the free end to oneside, and then release it to demonstrate theoscillations necessary to produce waves.Although we cannot hear the air movement,there is a displacement of the air particlesas the sound is transmitted to our ears.

Sound waves are mechanical waves; that is,they can only be transmitted in a medium.We can use a ringing bell in a vacuum jar toillustrate that as the medium (air) isremoved, the sound disappears.

Senior Years Science Teachers’Handbook ActivitiesStudents use Rotational CooperativeGraffiti, page 3.15, to describe sound, itsproduction, transmission, and detection.

Class DiscussionStudents describe how compressions andrarefactions are formed.

Students describe how the vibration of anobject is linked to the compressions andrarefactions of longitudinal waves.

Research ReportStudents research how animals in naturemake different sounds. Many animals usesounds as a defense mechanism by shakinga rattle, by scratching, by beating wings, orby vocalizing.

Students research how sound is produced innature (e.g., a cricket, a hummingbird, or adolphin).

Students provide some examples toillustrate the detection of sound (e.g.,human ear, microphone, oscilloscope).

Class DiscussionStudents identify the source of a sound,explain how the sound is transmitted, andexplain how this sound is detected. Studentsalso link the explanation to the concept ofwaves.

SUGGESTIONS FOR INSTRUCTION SUGGESTIONS FOR ASSESSMENT


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S3P-1-17: Investigate to analyzeand explain how sounds areproduced, transmitted, anddetected, using examples fromnature and technology.

Examples: production of sound by avibrating object, drums, guitarstrings, cricket, hummingbird,dolphin, piezocrystal, speakers…


Students will…Understand essential lifestructures and processespertaining to a wide variety oforganisms, including humans(GLO D1)

Student Activity Using a variety of objects, students canproduce different sounds and explain howthe sound is produced and transmitted.Examples could include a guitar stringbeing plucked, a drum being hit, or airbeing blown through a straw.

Students can also observe the vibration ofan electromagnetic speaker. By placing anobject such as a piece of light plywood infront of the speaker, you can feel thevibration of the speaker. You can also placelight, non-magnetic particles on a speakercone to observe their motion.

SUGGESTIONS FOR INSTRUCTION

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S3P-0-4c: Demonstrate confidencein their ability to carry outinvestigations in science andto address STSE issues.



Students will…Demonstrate curiosity,skepticism, creativity, open-mindedness, accuracy, precision,honesty, and persistence, andappreciate their importance asscientific and technologicalhabits of mind (GLO C5)


SUGGESTED LEARNING RESOURCES

Applets (Websites)<http://www.mta.ca/faculty/science/physics/suren/applets.html>

<http://www.kettering.edu/~drussell/forkanim.html>This applet shows longitudinal wavesproduced by a vibrating tuning fork, usingparticles and areas of high and lowpressure.

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SPECIFIC LEARNING OUTCOMES

S3P-1-18: Use the decision-making process to analyze anissue related to noise in theenvironment.Examples: sonic boom, traffic noise,concert halls, loudspeakers, leafblowers…

S3P-1-19: Design, construct (orassemble), test, and demonstratea technological device to produce,transmit, and/or control soundwaves for a useful purpose.Examples: sound barrier or protectiveheadphones to reduce the effects of noise,electromagnetic speakers, echo chamber,microphone, musical instruments, guitarpickup, electronic tuner, sonar detector,anechoic chamber, communicationdevices…


Students will…Understand essential lifestructures and processespertaining to a wide variety oforganisms, including humans(GLO C3)

Notes to the TeacherOutcomes S3P.1.18 and S3P.1.19 can beintroduced at any time during this topic.They are intentionally placed at thebeginning in order to suggest a context forlearning about sound. It is suggested thatthese outcomes be introduced to students atthis point and that they guide theinvestigations into sound that follow. Thetopic could culminate with the designactivity described in outcome S3P.1.19. It isalso possible that outcome S3P.1.19 could becombined with the outcomes in the Fieldstopic on electromagnetism.

Student ActivityUsing their own experience, students canbrainstorm and generate a list of sources ofnoise in different environments. Thenstudents can investigate ways in whichunacceptable noise can be reduced.

Students work in groups to design,construct (or assemble), test, anddemonstrate a technological device toproduce, transmit, and/or control soundwaves for a useful purpose. Examples couldinclude the following.

• Use a 9-volt battery to power apiezoelectric buzzer. Students arechallenged to build a device that is nolarger than 15 cm x 15 cm x 15 cm tohouse the buzzer and reduce the noiselevel. Materials could include cottonbatting, foam bits, cardboard, tonguedepressors, plastic sandwich bags, etcetera. A variation has each team ofstudents provided with a certain amountof “money” they use to purchase theirmaterials. A rubric can be used to assessthe project for effectiveness, economy, andstyle.

• Students design and build their ownmusical instruments. They can comparethe frequency of the notes on theirinstruments with an oscilloscope or anelectronic tuner. Some students may evenbe motivated to build quality instruments,such as dulcimers or violins, from readilyavailable kits.

• Students can build a sonar detectingsystem using an ultrasonic motiondetector. The team is required to detectand diagram a hidden landscape using itssystem.


Topic 1.3 – 47



S3P-0-3c: Identify social issuesrelated to science andtechnology, taking intoaccount human andenvironmental needs andethical considerations.

S3P-0-3d: Use the decision-making process to addressan STSE issue.

S3P-0-4c: Demonstrate confidencein carrying out scientificinvestigations and inaddressing STSE issues.



Students will…Demonstrate appropriatecritical thinking and decision-making skills when choosing acourse of action based onscientific and technologicalinformation(GLO C4)

Senior Years Science Teachers’Handbook ActivityStudents read a current events article aboutsound pollution in the city (e.g., should leafblowers be banned?). They complete anAnticipation Guide before and after readingthe article.

Research Report/PresentationStudents research and report on how sounddevices work to produce, transmit, detect, orreduce sound (e.g., car muffler, concert hallbaffles).



Applets (Websites)Keyword Internet Search: build a musicalinstrument, noise pollution, musicalinstrument making<http://www.oriscus.com/mi/making.asp>


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S3P-1-20: Describe and explainin qualitative terms whathappens when sound wavesinteract (interfere) with oneanother.Include: production of beats


Students will…Demonstrate a knowledge of,and personal consideration for,a range of possible science- andtechnology-related interests,hobbies, and careers(GLO B4)

Notes to the TeacherSound beats are the periodic and repeatingfluctuations heard in the intensity of asound when two sound waves of slightlydifferent frequencies interfere with oneanother. The sound changes from loud tosoft, then loud again, and so on. Thediagram below illustrates the waveinterference pattern resulting from twowaves with slightly different frequencies.

A loud sound is heard when the wavesinterfere constructively and thiscorresponds to a peak on the beat pattern.No sound is heard when the waves interferedestructively. The beat frequency is the rateat which the sound alternates from loud tosoft and equals the difference in frequencyof the two sounds. If two sound waves withfrequencies of 440 Hz and 442 Hz interfereto produce beats, a beat frequency of 2 Hzwill be heard.

The human ear is only capable ofhearing beats with small beatfrequencies (e.g., 8 Hz or less).Musicians frequently use beats to tuneinstruments. If two different soundsources, such as a piano string and atuning fork, produce detectable beats,then their frequencies are not identicaland they are not in tune. The tension ofthe string is then adjusted until thebeats disappear.


Wave 1

Wave 2

Beats

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SKILLS AND ATTITUDES OUTCOME

S3P-0-2f: Record, organize, anddisplay data, using anappropriate format.Include: labelled diagrams,tables, graphs


Students will…Understand how stability,motion, forces, and energytransfers and transformationsplay a role in a wide range ofnatural and constructedcontexts(GLO D4)

DemonstrationBeats can be produced in a classroomdemonstration using two tuning forks.Strike the forks with a rubber mallet andobserve the waves on an oscilloscope. Varythe beat frequency by adjusting the positionof a mass on one of the forks.

Senior Years Science Teachers’Handbook ActivitiesStudents use Concept Frames to illustratethe characteristics of beats.

Pencil-and-Paper TasksStudents label constructive and destructiveinterference on a diagram.

Students calculate the beat frequency of twotuning forks (or other vibrating sources).



Applets (Websites)<www.wiley.com/college/howthingswork>

<http://www.physicsweb.com> A program can be downloaded to visuallydemonstrate the production of beats usingtwo transverse waves.

<http://explorescience.com/activities/activity_page.cfm?ActivityID=44>Hear beats produced for fixed frequencies.Change frequencies and hear the number ofbeats change.

<http://www.cs.earlham.edu/~rileyle/Applet.html>Adjust the frequency and see the programgraphically plot the beats produced.

Adjustable Masses

malletmallet

adjustable masses


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S3P-1-21: Experiment to analyzethe principle of resonance andidentify the conditions requiredfor resonance to occur.Include: open- and closed-columnresonant lengths


Students will…Demonstrate appropriatescientific inquiry skills whenseeking answers to questions(GLO C2)

Notes to the TeacherEvery object tends to vibrate with a naturalfrequency. Resonance is the vibrationalresponse of an object to another object thatis vibrating at the same natural frequency.Resonance can be illustrated with a numberof simple demonstrations.

DemonstrationsSuspend several pendula from a tightstring. Two of the pendula should be of thesame length, and the others of differentlengths. Set one of the identical pendula inmotion, and soon the other(s) will begin tovibrate in resonance.

Run a moistened fingertip around the edgeof a long-stemmed glass and hear the soundproduced. This is the resonant frequency.Students can fill up the glass with waterand note the resulting sound differences.

Singing rod: Hold an aluminum rodexactly in the middle (at a node). Runmoistened fingertips up and down the rod toproduce a resonance frequency (seediagram).

Two identical tuning forks are mounted onresonance boxes separated by somedistance. One of the forks is struck with amallet. Soon after, the other fork will beginto vibrate in resonance.

A resonance tube can be used to increasethe intensity of the sound from the tuningfork. Suspend a glass tube with its lowerend in water and a tuning fork at its upperend. Strike a tuning fork and hold it abovethe end of the tube (see diagram next page).


Clampclamp

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S3P-0-2b: Propose problems, statehypotheses, and plan,implement, adapt, or extendprocedures to carry out aninvestigation.

S3P-0-2d: Estimate and measureaccurately, using SystèmeInternational (SI) units.

S3P-0-2e: Evaluate the relevance,reliability, and adequacy ofdata and data-collectionmethods.Include: discrepancies in dataand sources of error



The air column is closed at one end andopen at the other. If a tuning fork is heldover the open end, the loudness increases atspecific lengths of the column. Typically, ina demonstration or experiment, the lengthof the column is changed by adding water(see diagram). The resonant lengths of aclosed-air column are 1/4 λ, 3/4 λ, 5/4 λ, andso on. Resonance may also be produced onopen-air columns such as organ pipes. Theresonant lengths of an open-air column are1/2 λ, lλ, 3/2 λ, and so on.

Student ActivityUsing a number of glass test tubes filledwith water, students can produce differenttunes. Students can also perform alaboratory activity on resonance in open andclosed pipes.

Knobknob

Class DiscussionA classic in physics: students can view theTacoma Narrows Bridge collapse andexplain the collapse of the bridge(video/DVD).

Students describe the conditions necessaryfor resonance to occur.

Students compare and contrast resonance inopen- and closed-air columns.

Pencil-and-Paper TasksStudents solve problems to calculateresonance length for different frequencies.

Laboratory ReportStudents describe their observations fromtheir experiment with open- and closed-piperesonance.



Videodisc (the Tacoma Narrows BridgeCollapse)

Conceptual Physics Alive: Sound II


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SPECIFIC LEARNING OUTCOMES

S3P-1-22: Experiment tocalculate the speed of sound inair.

S3P-1-23: Compare the speed ofsound in different media, andexplain how the type of mediaand temperature affect the speedof sound.



Notes to the TeacherThe speed of a sound wave describes howfast the disturbance is passed through amedium. The speed of sound, like otherwaves, depends on the properties of themedium. Generally, the speed of sound isfastest in solids, then liquids, and slowest ingases. (See Appendix 1.9: Data Table forSpeed of Sound for a data table on the speedof sound in various media.)

Present students with a table of values forthe speed of sound in different media andtemperatures. They should note that soundtravels faster in a solid medium and thatsound travels faster in the same medium ifthe temperature is higher.

Students commonly confuse the concepts ofspeed and frequency. Carefully differentiatebetween these two concepts. Help themremember that speed is “how fast” andfrequency is “how often.”

Student ActivityA good way to begin investigating the speedof sound is with a rough estimate usingechoes. Find a large wall in the school andtry to determine the time between a loudnoise, such as the clap of your hands orsome wooden blocks, and its echo. The timewill be very fast, so first try an estimation.You could also try repeatedly clapping sothat the sound and the echo are in phase. Inthis way, you can find the time for 10 claps.Using the appropriate distance, calculatethe speed of sound (see Suggested LearningResources).

The resonance experiment can be used toaccurately calculate the speed of sound.

Another experiment to calculate the speedof sound can be performed with amicrophone and an oscilloscope or CBLprobe and associated program. Place themicrophone at the end of a long (3 m) carpettube. Connect the microphone to theoscilloscope and snap your fingers. Theoscilloscope will record the snap and its echoas peaks on the screen. Use these peaks todetermine the time it took the sound totravel twice the length of the tube.


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S3P-0-2d: Estimate and measureaccurately, using SystèmeInternational (SI) units.

S3P-0-2e: Evaluate the relevance,reliability, and adequacy ofdata and data-collectionmethods.Include: discrepancies in dataand sources of error

S3P-0-2g: Interpret patterns andtrends in data, and infer orcalculate linear relationshipsamong variables.


Students will…Understand the properties andstructures of matter as well asvarious common manifestationsand applications of the actionsand interactions of matter(GLO D3)

Teacher ObservationsStudents experimentally determine thespeed of sound.

Class DiscussionStudents explain how the type of mediumand the temperature of a medium affect thespeed of sound.

Pencil-and-Paper TasksStudents solve problems for calculating thespeed of sound in air and for calculatingspacing between resonances in open andclosed pipes.



MultimediaVideo Encyclopedia of PhysicsDemonstrations (1992) videodisc,Chapter 24, Properties of Sound

SoftwarePhysics with CBL Experiment 24: Speed ofSound (Vernier, 1998)

Student ActivityCBL Experiment 24: Speed of Sound(Vernier, 1998)

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S3P-1-24: Explain the Dopplereffect, and predict in qualitativeterms the frequency change thatwill occur for a stationary and amoving observer.



Notes to the TeacherThe Doppler effect can be observed whenthe source of waves is moving with respectto the observer. There is an apparentupward shift in frequency when theobserver and the source areapproaching each other and anapparent downward shift in frequencywhen the observer and the source aremoving away from each other.Students will be most familiar withthe Doppler effect from emergencyvehicles such as police and ambulancesirens. As the vehicle approaches with itssiren blasting, the pitch (frequency) of thesiren will be higher. After the vehicle passesthe observer, the pitch (frequency) of thesiren sound will be lower.

Note that the Doppler effect is not an actualchange in the frequency of the source. Thesource of the sound always emits the samefrequency. The observer only perceives adifferent frequency because of the relativemotion between them.

DemonstrationEmbed a buzzer in a foam ball and swing itaround in a circle.

Use diagrams to illustrate the frequencydifferences that occur when an objectapproaches, meets, and passes by anobserver.

Senior Years Science Teachers’Handbook ActivitiesStudents use Three-Point Concept Framesfor the Doppler effect and shock waves.


buzzer with batterybuzzer with battery

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SKILLS AND ATTITUDES OUTCOME

S3P-0-2b: Propose problems,state hypotheses, and plan,implement, adapt, or extendprocedures to carry out aninvestigation.



Class DiscussionStudents predict the frequency changes thatoccur in the Doppler effect and will explainthese changes.

Pencil-and-Paper TasksStudents diagram the frequency changesthat occur in the Doppler effect.

Research Report/PresentationStudents research and report on theapplication of the Doppler effect in radarand ultrasound imaging.



Applets (Websites)<http://www.walter-fendt.de/ph11e> This is an animation of a car approachingand then passing an observer.

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S3P-1-25: Define the decibelscale qualitatively, and giveexamples of sounds at variouslevels.


Students will…Identify the factors that affecthealth and explain therelationships among personalhabits, lifestyle choices, andhuman health, both individualand social(GLO B3)

Notes to the TeacherThe vibration of an object produces a soundwave by forcing the surrounding airmolecules into an alternating pattern ofcompressions and rarefactions. Energy,which is carried by the wave, is imparted tothe medium by the vibrating object. Theamount of energy that is transferred to themedium depends on the amplitude of theoriginal vibration. For example, if moreenergy is put into plucking a guitar string,more work is done displacing the string agreater amount and the string vibrates witha larger amplitude.

The intensity of a sound wave is the energythat is transported past a given area perunit of time. If the amplitude of a vibrationincreases, the rate at which energy istransported also increases. Consequently,the sound wave is more intense. As a soundwave carries its energy through a medium,the intensity of the sound wave decreases asthe distance from the source increases. Thedecrease in intensity can be explained bythe fact that the wave is spreading out overa larger surface area.

The scale used to measure the intensity ofsound is the decibel scale. The decibel scaleis not a linear scale. It is based on multiplesof 10 since human hearing can detect alarge range of intensities. The threshold ofhearing is assigned a sound level of0 decibels (0 dB) and a sound that is10 times more intense is assigned a soundlevel of 10 dB. A sound that is 100 timesmore intense (102) is assigned a sound levelof 20 db. A sound that is 1000 times moreintense (103) is assigned a sound level of30 db, and so on. (A table showing theintensity levels and examples of each isincluded in Appendix 1.10: Sound IntensityLevels Table.)

Student ActivityPlay music (in mono) from a tape recorderthrough a pair of stereo speakers. Thinkhow the speakers should be arranged toproduce sounds of different intensities.


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S3P-0-3c: Identify social issuesrelated to science andtechnology, taking intoaccount human andenvironmental needs andethical considerations.

S3P-0-2c: Formulate operationaldefinitions of major variablesor concepts.


Students will…Identify and demonstrateactions that promote asustainable environment,society, and economy, bothlocally and globally(GLO B5)

Class DiscussionStudents interpret a table of sound intensitylevels and use it to associate commonsounds/noises.

Research Report/PresentationStudents research noise pollution and makesuggestions on how to reduce it.


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S3P-1-26: Describe the diverseapplications of sound waves inmedical devices, and evaluate thecontribution to our health andsafety of sound-wave-basedtechnologies.Examples: hearing aid, ultrasound,stethoscope, cochlear implants…


S3P-0-2i: Select and integrateinformation obtained from avariety of sources.Include: print, electronic, and/orspecialist sources, resourcepeople


Students will…Describe scientific andtechnological developments,past and present, andappreciate their impact onindividuals, societies, and theenvironment, both locally andglobally (GLO B1)

Many students use their physics to advanceto medical careers. The histories of thestethoscope, hearing aids, and ultrasoundare very rich and inspiring for thesestudents. Today, many medical devices usethe physics of sound as a diagnostic tool anda method of treatment. The use of sound inmedical technology has its roots in themilitary development of sonar. Sonar is thetechnique of sending out sound waves andobserving their echoes to characterizesubmerged objects. Early ultrasoundinvestigators explored ways to apply sonarto medical diagnosis.

Student ActivityStudents investigate an application of soundwaves in a medical device and evaluate thecontribution of this device to the medicalfield.

Collaborative TeamworkStudents can work in research teams toreport on the following people’scontributions to the development of medicaldevices employing the principles of sound.• René T.H. Laennec • Samuel H. Maslak• Ian Donald• Alexander Graham Bell


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S3P-0-3a: Analyze, from a varietyof perspectives, the risks andbenefits to society and theenvironment when applyingscientific knowledge orintroducing technology.


S3P-0-4d: Develop a sense ofpersonal and sharedresponsibility for the impactof humans on theenvironment, anddemonstrate concern forsocial and environmentalconsequences of proposedactions.


Students will…Recognize that scientific andtechnological endeavours havebeen and continue to beinfluenced by human needs andthe societal context of the time(GLO B2)

Visual DisplaysStudents prepare a poster presentation andgallery walk on the historical developmentof medical devices that use the physics ofsound as their basis of operation.

Research Report/PresentationStudents prepare a presentation on thecontributions of René T.H. Laennec, SamuelH. Maslak, Ian Donald, and AlexanderGraham Bell to the development of medicaldevices.

Group/Peer AssessmentPresentations can be evaluated usingrubrics negotiated in advance.



Internet Search Keywords: history ofhearing aids, ultrasound, stethoscope <http://www.pbs.org/wnet/soundandfury/index.html> Sound and Fury homepage, excellentresource on the ear and cochlear implants(includes animations).

<http://www.ob-ultrasound.net/history.html>A short history of the development ofultrasound in obstetrics and gynecology byDr. Joseph Woo.

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S3P-1-27: Explain in qualitativeterms how frequency, amplitude,and wave shape affect the pitch,intensity, and quality of tonesproduced by musical instruments.Include: wind, percussion, stringedinstruments



Notes to the Teacher Most musical instruments consist of avibrating source and a structure to enhancethe sound through mechanical andacoustical resonance. A stringed instrumentconsists of a vibrating string and aresonating sound board or hollow box. Windinstruments contain either open- or closed-air columns of vibrating air; the initialvibration is created by a reed or by theplayer’s lips. Percussion instrumentsinvolve striking one object against the other.Students can examine and explain how avariety of musical instruments (e.g., stringinstruments, percussion instruments, windinstruments) produce sound.

For wind instruments, the length and shapeof the resonating air column determines thequality of the sound. Blowing harder canproduce a second standing wave or a secondharmonic. For string instruments, studentscan change the length of the vibratingstring and note the change in pitch.Plucking the string harder produces alarger vibration and an increase in soundintensity. Pluck the string at differentpositions along the length of the string tohear the change in harmonics. Resonatingboxes amplify the sound. The shape of theresonating box (e.g., guitar versus violin)determines the quality of tones produced.

For percussion instruments, students canstrike a drum at various places to note thedifferent pitch produced. Similar objects ofdifferent size (e.g., tuning forks) also vibrateat different frequencies.

Student ActivityStudents can perform the Singing Strawexperiment. Suck a liquid up into a strawand hold it there with your tongue. Pull thestraw out of the liquid and pinch thebottom. Now remove your tongue from thestraw and blow across the top of the straw.At the same time, slowly release your gripon the bottom of the straw. You should heara change in pitch as the liquid drains outthe bottom of the straw.


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S3P-0-2i: Select and integrateinformation obtained from avariety of sources.Include: print, electronic, and/orspecialist sources, resourcepeople


Students will…Describe and appreciate thesimilarity and diversity offorms, functions, and patternswithin the natural andconstructed world(GLO E1)

Hoot Tubes: Insert a wire screen in anopen-ended glass tube. Heat the end withthe screen. The tube hoots when it isremoved from the flame. The sound stopswhen the tube is held horizontally.

Demonstration

Senior Years Science Teachers’Handbook ActivitiesStudents research and report on a family ofmusical instruments (see Senior YearsScience Teachers’ Handbook, Chapter 14).

Students use Compare and ContrastFrames: Students can compare and contrastinstruments that are similar in structurebut different in sound: violin versus bassfiddle, horn versus tuba, small bell versus alarger bell.

Students can compare the frequency of thesounds produced by each instrument.

wirescreen

Class DiscussionsStudents identify the type of musicalinstrument and how this instrumentproduces sound.

Students explain, in qualitative terms, howfrequency and pitch are related, howamplitude and intensity of sound arerelated, and how wave shape and quality oftone are related.

Performance AssessmentStudents design and build a musicalinstrument (see outcome S3P.1.19).



MultimediaPhysics: Cinema Classics (video/DVD)

SoftwareExploring Physics and Math with the CBLSystem (Texas Instruments, 1994)

Student Activity: CBL Lab Activity 26:Nature of Sound (Texas Instruments)

ReferencesInternet Search Keywords: physics of music

The Science of Sound (Thomas Rossing,1990)


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S3P-1-28: Examine the octave ina diatonic scale in terms offrequency relationships andmajor triads.



There are many different musical scales. Ofthem all, the diatonic is the most basic. Anythree notes whose vibration frequency ratiosare 4, 5, and 6 will produce a major chord(triad). A diatonic scale consists of threesets of major triads. Within an octave, threemajor triads can be constructed as follows:

Physicists commonly use a frequency of256 Hz for middle C. In terms of frequency,in order to reach the higher C (above middleC), we simply double the frequency; that is,middle C is 256 Hz and the next higher C isat 512 Hz. The other frequencies can befound from the 4, 5, 6 ratios. For example:

C = 256 HzE = 256 x 5/4

∴ E = 320 Hz

C D E F G A B C1 D1

4 5 6

4 5 6

4 5 6

Student ActivityUsing the frequency ratio of 4, 5, 6, studentscalculate the frequency for each note in thediatonic scale. From these calculations, wefind that the note A = 426.6 Hz. Musicianstypically use A = 440 Hz. Interestedstudents might want to research the varioustypes of musical scales that makeadjustments in the frequencies so that thenotes are equally spaced apart and differentinstruments can play together (i.e.,chromatic and equal tempered scales).

Chromatic scale: consists of C, C#, D, D#,E, F, F#, G, G#, A, A#, B, and C (allintervals in the chromatic scale arehalftones or semitones).

The tempered scale is a scale in whichthere is a constant change of frequencybetween notes.

Teacher or Student Demonstration Play examples of music from differentcultures (e.g., Eastern music) and comparethe frequency changes between the notes.


Topic 1.3 – 63



S3P-0-2c: Formulate operationaldefinitions of major variablesor concepts.

S3P-0-2g: Interpret patterns andtrends in data, and infer orcalculate linear relationshipsamong variables.



Students will…Describe and appreciate thesimilarity and diversity offorms, functions, and patternswithin the natural andconstructed world(GLO E1)

Pencil-and-Paper TasksStudents complete Compare and ContrastFrames for fretted and non-frettedinstruments.

Given a frequency for a specific note,students determine the frequency of thetone one or two octaves above the specificnote and/or one or two octaves below thespecific note.

Given a frequency, students determine thefrequencies of the major triad.

Research Report/PresentationStudents research and report on themusician’s equal tempered scale.



Physics for a Modern World (Alan Hirsch,1986)

The Science of Sound (Thomas Rossing,1990)

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Topic 1.3 – 64


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