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Chapter Review
Sound waves transfer energy
through vibrations.
CONTENT REVIEW
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KEY CONCEPTS SUMMARY
1
Sound is a wave.
VOCABULARY
disturbance
Sound is a longitudinal wave that
travels through a
material medium,
such as air.
wave
2
Frequency determines pitch.
sound p. 517
vibration p. 517
vacuum p. 521
VOCABULARY
A sound wave with a lower frequency and longer
wavelength is perceived to have a lower pitch.
pitch p. 525
hertz p. 526
ultrasound p. 526
resonance p. 528
Doppler effect p. 530
A sound wave with a higher frequency and shorter
wavelength is perceived to have a higher pitch.
3
Intensity determines loudness.
A sound wave with a lower amplitude and
energy is perceived as a softer sound.
VOCABULARY
intensity p. 532
decibel p. 532
amplification p. 535
acoustics p. 535
A sound wave with a higher amplitude and
energy is perceived as a louder sound.
4
Sound has many uses.
VOCABULARY
Human uses of sound:
sonar
ultrasound
music
telephone
recording
Bats use sound to locate objects.
546 Unit 4: Waves, Sound, and Light
echolocation p. 539
sonar p. 539
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Reviewing Vocabulary
Copy and complete the chart below by using
vocabulary terms from this chapter.
Property of
Wave
Unit
of Measurement
Characteristic
of Sound
Frequency
1.
2.
3.
4.
loudness
Make a frame for each of the vocabulary
words listed below. Write the word in the
center. Decide what information to frame it
with. Use definitions, examples, descriptions,
parts, or pictures. An example is shown.
sound with a frequency too
high for humans to hear
used by
bats and
dolphins
ULTRASOUND
used in
sonar
used in medicine
5. resonance
8. acoustics
6. Doppler effect
9. echolocation
7. amplification
10. sonar
Reviewing Key Concepts
Multiple Choice Choose the letter of the best
answer.
11. Sound is a mechanical wave, so it always
a. travels through a vacuum
b. has the same amplitude
c. is made by a machine
d. travels through matter
13. In which of the following materials would
sound waves move fastest?
a. water
b. cool air
c. hot air
d. steel
14. Which of the following effects is caused by
amplification?
a. wavelength increases
b. amplitude increases
c. frequency decreases
d. decibel measure decreases
15. The frequency of a sound wave determines its
a. pitch
b. loudness
c. amplitude
d. intensity
16. As sound waves travel away from their source,
their
a. intensity increases
b. energy increases
c. intensity decreases
d. frequency decreases
17. A telephone mouthpiece changes sound
waves into
a. electric signals
b. vibrations
c. CD pits
d. grooves on a cylinder
Short Answer Look at the diagrams of waves
below. For the next two items, choose the
wave diagram that best fits the description,
and explain your choice.
a.
12. Which unit is a measure of sound frequency?
a. hertz
b. decibel
c. amp
d. meter
b.
c.
18. the sound of a basketball coach blowing a
whistle during practice
19. the sound of a cow mooing in a pasture
Chapter 16: Sound 547
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Thinking Critically
Using Math in Science
Read the line graph below showing freeway
noise levels at a toll collector’s booth. Use
the data in the graph to answer the next
four questions.
Freeway Noise Levels During Morning Rush Hour
Intensity (dB)
120
Look at the photograph of an instrument
above. Write a short answer to the next two
questions.
20. HYPOTHESIZE How might sound waves be
produced using the instrument in the
photograph?
21. APPLY How might a person playing the instrument in the photograph vary the intensity?
22. COMMUNICATE Two people are singing at the
same pitch, yet they sound different. Explain
why.
23. SEQUENCE Copy the following sequence chart
on your paper. Write the events in the correct
sequence on the chart.
Events
a. Sound waves race out from the wind chime.
b. Forces in air gradually weaken the chime
sound.
c. A breeze makes a wind chime vibrate.
d. A person nearby hears the wind chime.
24. COMPARE AND CONTRAST Write a description of
the similarities and differences between each
of the following pairs of terms: frequency—
amplitude; intensity—amplitude; pitch—
quality; fundamental tone—overtones.
548 Unit 4: Waves, Sound, and Light
100
80
60
6:30 6:45 7:00 7:15 7:30 7:45 8:00 8:15 8:30
Time, A.M.
25. Which is the noisiest quarter-hour?
26. Estimate the loudest level of sound that the
toll collector is exposed to.
27. If ear protection should be worn for a
sound level above 90 dB, should the toll
collector wear hearing protection? If so,
during which times?
28. Describe how you could turn the line graph
into a bar graph. Would the bar graph be as
informative? Explain your answer.
29. ANALYZE Look back at the picture at the start
of the chapter on pages 514–515. How are
sound waves being produced?
30. SUMMARIZE Write a paragraph summarizing
this chapter. Use the Big Idea on page 514 as
your topic sentence. Write examples of each
key concept listed on page 514.
Check your schedule for your unit project. How
are you doing? Be sure that you’ve placed data
or notes from your research in your project folder.
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Standardized Test Practice
For practice on your
state test, go to . . .
TEST PRACTICE
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Analyzing Experiments
Read the following description of the way scientists study animals’ hearing.
Then answer the questions below.
Scientists test the hearing ranges of a human by making a sound and asking the
person to say whether it was heard. This cannot be done with animals. Scientists use
different methods to find animals’ hearing ranges. In some experiments, they train
animals—by rewarding them with food or water—to make specific behaviors when
they hear a sound. Another method is to study an animal’s nervous system for
electrical reactions to sounds.
Researchers have found that dogs and cats can hear a wide range of sounds.
Both dogs and cats can hear much higher frequencies than humans can. Lizards
and frogs can only hear sounds in a much narrower range than humans can.
Elephants can hear a wider range than lizards and frogs but not as wide a range as
dogs and cats. Elephants can hear the lowest frequency sounds of all these animals.
1. What type of behavior would be best for scientists
to train animals to make as a signal that they hear
a sound?
a. a typical motion that the animal makes
frequently
b. a motion that is difficult for the animal to make
c. a motion the animal makes rarely but does
make naturally
d. a complicated motion of several steps
2. According to the passage, which animals can hear
sounds with the highest frequencies?
a. cats
c. frogs
b. elephants
d. lizards
Extended Response
Answer the two questions below in detail. Include
some of the terms from the word box in your answer.
Underline each term you use in your answer.
5. Suppose you are riding in a car down the street
and pass a building where a fire alarm is sounding.
Will the sound you hear change as you move up
to, alongside, and past the building? Why or
why not?
3. The high-pitched sounds of car brakes are sometimes
more bothersome to pet dogs than they are to their
owners. Based on the experimental findings, what is
the best explanation for that observation?
a. The dogs hear high-intensity sounds that their
owners cannot hear.
b. The dogs hear low-intensity sounds that their
owners cannot hear.
c. The dogs hear low-frequency sounds that their
owners cannot hear.
d. The dogs hear high-frequency sounds that their
owners cannot hear.
4. Which animal hears sounds with the longest
wavelengths?
a. cat
c. elephant
b. dog
d. frog
amplitude
frequency
distance Doppler effect
pitch
wavelength
6. Marvin had six glass bottles that held different
amounts of water. He blew air into each bottle,
producing a sound. How would the sounds
produced by each of the six bottles compare
to the others? Why?
Chapter 16: Sound 549