Visit our Website: ScienceScene (The MAPs Co.)

Visit our Website: http://www.ScienceScene.com (The MAPs Co.)

Dr. M. H. Suckley & Mr. P. A. KlozikEmail: [email protected]

SSoundound

Dr. Michael H. Suckley

Mr. Paul A. Klozik

Email: [email protected]

Meaningful Applications Of Physical Sciences

I. Naive Ideas Concerning Sound

II. Sound Production – Constructing Sound Devices

III. Building a Model Using the Characteristics Of Sound

IV. Applying The Model of Sound

I. Objectives - Naive Ideas Concerning Sound . . . . .

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II. Sound Production – Constructing Sound Devices

A. Viewing Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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B. Clucking Chicken . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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C. Talking Strips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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D. The Film-A-Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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E. How Do We Hear? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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F. How Is Sound Produced?. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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G. Extras – Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

III. Building a Model Using the Characteristics Of Sound A. How Does Sound Travel? 1. Does Sound Travel Through A Vacuum? (Demo). . . . . . . . . . . . . . . . . . . . . 12 2. Do Solids Conduct Sound Better Than Air? (Activity) . . . . . . . . . . . . . . . . . 13 3. Do Liquids Conduct Sound Better Than Air?. . . . . . . . . . . . . . . . . . . . . . . . . 15 4. The Speed of Sound In Various Substances . . . . . . . . . . . . . . . . . . . . . . . . . 16 5. Extras - Transmitting Mediums? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

B. Illustrating the Model Of Sound 1. What is a Sound Wave? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

2. FUNdamentals of Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 3. Using A Slinky to Investigate Sound a. What Causes High And Low Pitched Sounds . . . . . . . . . . . . . . . . . . . . . 25 b. Changing Pitch And A Moving Sound Source? (Doppler Effect) . . . . . . 29 c. Constructive and Destructive Interference d. Loudness, Energy and Amplitude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 4. Check Your Understanding of the Model . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 5. Extras - The Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

C. Resonance 1. One Vibrating Object Can Cause Another To Vibrate . . . . . . . . . . . . 39 2. Resonating Bar. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

IV. Applying The Model of Sound A. Speed of Sound in a Parking Lot. . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

B. Using Goldwave to Analyze Sound . . . . . . . . . . . . . . . . . . . . . . . . . 46

C. Determining the Frequency of An Known Sound (Tuning Fork) . . . . . . 50

D. Determining the Frequency of An Unknown Sound (Pan Flute) . . . . . . 51

E. Determining the Frequency of The Film-A-Horn . . . . . . . . . . . . . . 46

F. Outstanding Demonstrations By Workshop Participants

G. Extras - Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Acceptance of a New Concept

A widely accepted way to explain how learners adopt new understandings of phenomena is presented in the Conceptual Change Model (CCM)*.

There are two major components to the Conceptual Change Model.

The first component are the conditions that need to be met in order for a person to adopt a new understanding. There are three conditions leading to the adoption of a new concept. A learner has to:

(1) become dissatisfied with their existing conception, (2) find the new conception intelligible, (3) find the new conception plausible and fruitful.

The second component of the CCM is described as the status of the new conception. A conception has status when it meets any of the aforementioned conditions; however, the more conditions that the new conception meets, the higher the status the new conception obtains, and hence, a higher probability of being adopted.

References *Posner, G.J., K.A. Strike, P.W. Hewson, and W.A. Gertzog. 1982.

Accommodation of a scientific conception: Toward a theory of conceptual change. Science Educa tion 66: 211-27.

We Had A Great Time

I. Objectives/Benchmarks

1. Describe the motion of vibrating objects. 2. Explain how mechanical waves transfer energy. 3. Explain how sound travels through differ media. 4. Explain how echoes occur and how they are used. 5. Relate characteristics of sound that we hear to properties of sound waves.

6. Explain how sound recording and reproducing devices work. 7. Describe sounds in terms of their properties. 8. Explain how sounds are made.

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I. Naive Ideas Concerning Sound

1. Sounds can be produced without using any material objects.

2. Hitting objects harder changes the pitch of the sound produced.

3. Sound waves are transverse waves that travel the same as water and light waves.

4. Matter moves along with water waves as the waves move through a body of water.

5. When waves interact with a solid surface, the waves are destroyed.

6. Loudness and pitch of sounds is the same thing.

7. You can see and hear a distinct event at the same moment.

8. Sounds can travel through empty space (a vacuum).

9. The sound of a train whistle changes as the train moves by because the engineer

purposely changes the pitch of sound.

10. In wind instruments, the instrument itself vibrates, not the internal air column.

11. In actual telephones (as opposed to tin can telephones) sounds, rather than electrical

impulses, travel through the wires.

12. Noise pollution is annoying, but it is essentially harmless.12

Viewing Sound

Balloon

Mirror

Laser

Laser Support1

Clucking Chicken

Talking Strips

Notice ridges on plastic strip. As the finger nail moves over the ridges the plastic strip vibrates in a pattern we recognize as words.

You’re the GreatestTalking Strips

http://www.ioa.com/~ladottofy/

The Film-A-Horn

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The Film-A-Horn -- The Equipment

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The Film-A-Horn -- Inserting the Tube

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The Film-A-Horn -- Tube Inserted

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The Film-A-Horn – Pacing the Membrane

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The Film-A-Horn – Attaching the Membrane

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The Film-A-Horn – Membrane Attached

The Finished Horn

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How Do We Hear?

How is Sound Produced?

Extras – Production of Sound

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Extras – Production of Sound cont.

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How Does Sound Travel? - Through the Air

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Does Sound Travel Through A Vacuum?

Do Solids Conduct Sound Better Than Air?

ConductorSound Travels Through

Air Conductor

String

Thin Wire

Nylon Fish Line

Do Liquids Conduct Sound Better Than Air?

VELOCITY OF SOUND IN VARIOUS SUBSTANCES

Substance Temp Co M/Sec Ft/Sec Solids Aluminum - 5,094 16,704 Copper 100 3,290 10,800 Copper 200 2,950 9,690 Iron and soft steel - 5,000 16,410 Nickel - 4,973 16,320Liquids Alcohol 20.5 1,213 3,890 Benzene 0 1,166 3,826 NaC1 10% solution 15 1,470 4,823 NaC1 20% solution 15 1,650 5,414 Water 13 1,435 4,708Gases Air 0 330 1,089 Carbon Dioxide 0 258 846 Hydrogen 0 1,268 4,160 Oxygen 0 317.2 1,041

Extras - Transmitting Mediums

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Transmitting Mediums cont.

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1


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FUNdamentals of Sound

III. Three Types Of WavesA. Torsional waves when the disturbance occurs as a twisting effect in a plane that is perpendicular to the direction on the wave motion (examples: twisters, hurricanes, tornados).

B. Longitudinal waves when the disturbance occurs in the same direction of the wave motion. (examples: sound, people standing in line, cars taking off from one red light and coming to a stop at another red light.)

C. Transversal waves when the disturbance occurs at right angles to the direction of the wave motion. (examples: water, light, radio, electromagnetic.)

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Illustrating the Model Of Sound – Waves in Nature

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Nature of Waves

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What is a Sound Wave?

Imagine putting on a pair of very high-powered magnifying glasses, so that you could see the molecules of air in the small rectangular space shown in the diagram.

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If the room was quiet, with little or no noticeable sound present, the air molecules in this little rectangular space it might look like:

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If a very brief sound, that is a single pulse consisting of one compression and one rarefaction, was made by the Speaker on the left.

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And you looked at the air molecules in the little rectangular space between the Speaker and the Listener they might now look like this:

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If you looked at the air molecules in the little rectangular space a short time later they might have looked like this:

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If the pulse is repeated regularly, a pattern may be created. We call this pattern of compressions and rarefactions pressure waves, or sound waves. This is what Sound waves might actually look like!

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I. Characteristics Of A Wave

A. Pulse: a single disturbance in a medium.

B. Frequency: the number of occurrences of some event per unit of

time.

(example; the number of times the meter stick goes up and down in one minute.)

C. Amplitude: the measurement of the distance the medium moves from

the

zero point to the maximum displacement. (example; the distance of the

very end of the meter stick - from standing still to the farthest distance away from

that zero position.)

D. Wavelength: the distance along a wave front — from any starting

point

to the next successive starting point. (example; looking at a slinky in motion.

Begin with the very beginning of a pulse to the very beginning of the next pulse.)

E. Loudness: occurs with the addition of energy to the vibrating

medium.

Illustrating the Model Of Sound – FUNdamentals of Sound

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Wavelength

Period = .5-sec.

Time = 1 sec

Frequency = 2 Hz

Amplitude

Five Basic Characteristics of Waves.

1. Wavelength (l), is the distance from a point on a wave to the next point

2. Amplitude (A), is the maximum displacement. Amplitude indicates the loudness of a sound.

3. Period (t), is the time (in seconds) that it takes for a wave to travel one full wavelength.

4. Frequency (f), is the number of vibrations (waves) per second. This indicates the pitch of a sound.

5. Wave speed (V), is the rate the wave is traveling; the units of measurement are meters/sec.

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FUNdamentals of Sound

II. Components Of Light and Sound waves

A Energy is needed to form any Light or Sound wave.

B Light waves are made by continuous succession of oscillating magnetic and

electric fields. These fields travel as a wave, an EM (Electromagnetic) wave.

C. Sound waves are made by the vibrations (moving back and forth) of

the particles of an object.

D. A medium is NOT needed to transport the Light energy.

E. A medium is needed to transport the Sound energy.

F. Waves are formed when energy is transported from one place to another.

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Illustrating the Model Of Sound

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What Causes High and Low Pitched Sounds

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What Causes High and Low Pitched Sounds – The Straw

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Illustrating the Model Of Sound

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Wave Patterns

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http://www.explorelearning.com/index.cfm?method=cResource.dspView&ResourceID=28

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If you strike a tuning fork and rotate it next to your ear, you will note that the sound alternates between loud and soft as you rotate through the angles where the interference is constructive and destructive. Each tine of the fork produces a pressure wave which travels outward at the speed of sound. One part of the wave has a pressure higher than atmospheric pressure, another lower. At some angles the high pressure areas of the two waves coincide and you hear a louder sound. At other angles, the high pressure part of one wave coincides with the low pressure part of the other.

Constructive and Destructive Interference Using a Tuning Fork

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Constructive and Destructive Interference - Investigating Beats

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• When two sound waves of different frequency approach your ear, the alternating constructive and destructive interference causes the sound to be alternatively soft and loud - a phenomenon which is called "beating" or producing beats. The beat frequency is equal to the absolute value of the difference in frequency of the two waves.

• Arising from simple interference, the applications of beats are extremely far ranging.

http://www.explorelearning.com/index.cfm?method=cResource.dspView&ResourceID=48

Constructive and Destructive Interference Investigating Beats

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Changing Pitch - The Doppler Effect

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The Doppler Effect

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Changing Pitch - The Doppler Effect

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Loudness and Amplitude - Inverse Square Law

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One Distance Unit Two Distance Units Three Distance Units

Object Strength = 1 Strength = 1/4 Strength = 1/9

1. Hold the laser 1 meter as indicated in the table and shine on a flat surface. You will notice squares reflecting on the surface. Select one of the squares and draw it on the surface.

2. Hold the laser 2 meters from the surface. Align the same square with one side and bottom. Determine the number of original squares it would take to fill the larger square.

3. Hold the laser 3 meters from the surface. Align the same square with one side and bottom. Determine the number of original squares it would take to fill the larger square.

1/91/411/D2 ∞ intensity

941Distance Squared (D)

941Number of Squares

3-Meters2-Meters1-MeterDistance

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Loudness

Decibels Watts/m2

10 —— 10-11

threshold of hearing-average 20 —— 10-10 rustle of leaves whisper at five feet 30 —— 10-9 broadcast studio average dwelling 40 —— 10-8 quiet office New York City at midnight; household refrigerator 50 —— 10-7 average office quiet automobile 60 —— 10-6 conversation; average restaurant quiet typewriter 70 —— 10-5 automobile passing average factory 80 —— 10-4 noisy restaurant; printing press truck passing 90 —— 10-3 inside train; noisy factory heavy city traffic

100 —— 10-2 train - - - - - - - Does Damage to Ear Drum riveter

110 —— 10-1 boiler factory punch press

120 —— 100 THRESHOLD OF PAIN airplane motor at 20 feet

130 —— 101 pneumatic rock drill 0

Reference Wave

Frequency = 3 Frequency = 3 Frequency = 5 Frequency = 1Loudness = 1 Loudness = 2 Loudness = 1 Loudness = 1

Check Your Understanding of the Model Modeling Frequency and Wavelength

1

Remember Frequency is equal to number of vibration divided by time (sec).

f = vibrations / seconds

Figure G Figure H Figure I

Figure E Figure F

.2-sec..2-sec.

Figure D

.2-sec.

.2-sec..2-sec.

Figure A Figure B Figure C

.2-sec..2-sec..2-sec.

.2-sec.

Check Your Understanding of the Model Sound

80.022.223.546.160.044.4 60.0 11.10Frequency

.20.18.17.13.20.18 .20.180Time

16446128 12 20 Numberof Waves

IHGFEDCBA

Sound Model

0

9

Extras Illustrating the Model Of Sound

3

Extras Illustrating the Model Of Sound cont.

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1


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Stop And Go Balls - Resonance

Tie about 1-meter of string between two supports. Suspend the balls from the string using pieces of string.

Start one of the ball swinging. Note that the other ball, with the same length of string, begins to respond to this motion.

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Resonance - Resonance in a Closed Tube

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1/2 Wavelength

1 Wavelength

Data – Resonance in a Closed Tube

% % (5) % Error = 100 x Error / V T

meter/sec meter/sec (4) Error = VE – V T

Determining Outcomes (Percent of Error)

meter/sec meter/sec (4) Experimental Velocity of sound VE = f x l

meters meters (3e) Wavelength l = 4 x L

meters meters (3e) Measured Length of air column for Resonance (L)

Determining the Velocity of Sound Using Resonance

meters meters Predicted Length of Column for Resonance: Column Length = l ÷ 4

meters meters Since V = f x l then l = V ÷ f Determine wavelength (l)

meter/sec meter/sec(2a) Velocity of sound in the air (Theoretical) VT = 330 m/sec.+ (.6 m/sec. 0C x T)

Using the Velocity of Sound to Predict Resonance .

0C 0CAir Temperature ( 0C )

512 Hertz 480 Hertz Resonance Tube

1

3

Resonance – Resonance Rings

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Resonance - The Resonating Bar

Speed of Sound in a Parking LotBy: Jan Paul Dabrowski

Consider this 1922 description of a demonstration of the speed of sound in air: When a pistol is fired at a distance of several hundred feet, we see the flash a few seconds before we hear the report. The interval is the time required for the sound to travel the intervening distance, since for short distances light is practically instantaneous.

Materials: air horn, camera strobe flash, strobe sound trigger.

Plug the flash into the sound trigger and positioned next to the air horn. When the horn is blasted, the sound trigger flashes the strobe. One group of students operates the air horn/strobe device. Another group, with stopwatches, are located several hundred meters away. When the air horn is sounded the watches are started the instant the strobe flash is seen. The stopwatches are stopped when the sound from the air horn is heard.

Using the measured distance and the averaged stopwatch readings, the speed of sound can be calculated using a distance of 343 m and the mean time of 0.97s.

V = d/t

V = 343 m. / 0.97 s

V = 354 m/s

1

Observers start their stopwatches when they see the flash of light created at the same instant a loud sound occurs. They stop their stopwatches when they hear the sound. Using their data calculate the speed of sound.

BANG!

Speed Of Sound in a Parking Lot

1. The Temperature was 23.1 ºC 2. Theoretical Speed of Sound = 330 m/sec. + (.6 m/sec. x Temperature)

= 330 m/sec. + (.6 m/sec. x 23.2 ºC) = 343.9 m/sec4. Calculate Percent of Error ((EXP. – Theo) / Theo) x 100

2 0

1.08-sec.331.2-m3

1.06-sec.331.2-m2

1.01-sec.331.2-m1

Experimental Velocity d/tTimeDistanceTrial

Using Goldwave to Analyze Frequency of Sound

C:\01- Physical Science Materials\MAP Workshops\Sound\Gold Wave 4.01\GOLDWAVE.EXE

Using Goldwave to

Analyze Frequency of An Known Sound(480-hz)

1

% 1.18f. Percentage of Error:

Hertz 485.67e. Experimental Frequency:

seconds 0.00206d. Time for one wave:

seconds 0.02059c. Time for ten waves:

seconds 0.09732 b. Start time for 10 waves:

seconds 0.11791a. End time for 10 waves:

1. Determining the frequency of a Known source of sound (480-hz)

Using Goldwave to Analyze Frequency of An Known Sound (480-hz)

0

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Using Goldwave to Analyze Frequency of A Pan Flute

Pan Flute Short

Pan Flute Long

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% g. Percentage of Error:

f. Theoretical Frequency:

Hertz e. Experimental Frequency:

seconds d. Time for one wave:

seconds c. Time for ten waves:

seconds b. Start time for 10 waves:

seconds a. End time for 10 waves:

3. Determining the frequency of the Pan Flute

Air Column Resonance (Film-A-Horn)

http://hyperphysics.phy-astr.gsu.edu/hbase/waves/opecol.html#c1

Using Goldwave to Analyze Frequency of The Pan Flute - Data

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Using Goldwave to Analyze Frequency of The Film-A-Horn

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% 2.11 g. Percentage of Error:

795.6 f. Theoretical Frequency: (tube length 0.108-m)

Hertz 778.8 e. Experimental Frequency:

seconds 0. 00128 d. Time for one wave:

seconds 0. 01284 c. Time for ten waves:

seconds 0.10204 b. Start time for 10 waves:

seconds 0.11488 a. End time for 10 waves:

3. Determining the frequency of the Pan Flute

Air Column Resonance (Film-A-Horn)

http://hyperphysics.phy-astr.gsu.edu/hbase/waves/opecol.html#c1

Using Goldwave to Analyze Frequency of The Film-A-Horn - Data

1

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Resonance - Causing Objects to Vibrate

We Had A Great Time

CIRCUITS: http://www.explorelearning.com/index.cfm?method=cResource.dspView&ResourceID=398&ClassID=700215

Visit our Website: ScienceScene (The MAPs Co.)

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