1. Physics A First Course
Vibrations, Waves, and Sound
Chapter 21

2. Vibrations, Waves, and Sound Sound
21.1 Properties of Sound
21.2 Sound Waves
21.3 Sound, Perception and Music

3. 21A Investigation: The Properties of Sound
Key Question:
How do we know sound is a wave?
*Students read text section 21.1 AFTER Investigation 21A

4. 21A Investigation Topics
Identify the range of frequencies heard by the class.
Conduct a survey and make a histogram of the results.
Prove that sound is a wave.
Demonstrate why beats occur.
Find a mystery frequency.

5. Chapter 21.1 Objectives and Vocabulary
Explain how pitch, loudness, and speed are related to waves.
Explain the Doppler effect.
Describe how sound is created and recorded.
pitch
decibels
acoustics
subsonic
supersonic
shock wave
Doppler effect

6. Complex sound is made from many frequencies.

7. Common Sounds and their loudness (decibels)

8. Speed of Sound 330 m/sec 660 mile/hr
faster in solids and liquids than in air

10. Chapter 21.2 Objectives and Vocabulary
reverberation
Fourier's theorem
Learn how sound is made and know the factors that affect the speed of sound.
Know that the speed of sound changes in different materials.
Recognize the importance of the wavelength of sound.
Describe sound interactions.
Compare the superposition principle and Fourier's theorem

13. 21B Investigation: Wave Properties of Sound
Key Question:
How are the properties of waves used in the design of musical instruments?
*Students read text section 21.3
AFTER Investigation 21B

14. 21B Investigation Topics
Make a simple musical instrument.
Explain how a musical instrument controls frequency and wavelength.
Produce complex sounds.
Identify the frequencies of musical notes.

15. Chapter 21.3 Objectives and Vocabulary
Describe how the meaning of sound is related to frequency and time.
Learn how we hear sound.
Describe the musical scale, consonance, dissonance and, beats in terms of sound waves.
Learn about the role of harmonics in how instruments sound.
frequency spectrum
sonogram
cochlea
rhythm
musical scale,
note
octave
beat
consonance
dissonance