Sound Waves Review

SOUND WAVES AND
THEIR PROPERTIES

I CAN…

▹Identify the
characteristics of sound
waves.

▹Explain how sound
travels.

▹Describe the Doppler
effect.

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3

Multiple Choice

A sound wave is what type of wave?

• Compressional

• Transverse

• Electromagnetic

7

When an object vibrates, it exerts a force on the
surrounding air. For example, as the end of the
tuning fork moves outward into the air, it pushes
the molecules in the air together.

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As a result, a region where the molecules
are closer together, or more dense, is
created. This region of higher density is
called a compression. When the end of the
tuning fork moves back, it creates a region
of lower density called a rarefaction.

Making Sound Waves

Like other waves, a sound wave can be described by its wavelength and frequency. The wavelength of a sound wave is shown below. The frequency of a sound wave is the number of compressions or rarefactions that pass by a given point in one second. An object that vibrates faster forms a sound wave with a higher frequency.

9

Poll

Letter C is what part of the wave?

• Rarefaction

• Compression

• Wavelength

Multiple Choice

Letter B is what part of the wave?

• Rarefaction

• Compression

• Wavelength

17

Multiple Choice

Sound waves travel fastest in ______.

• Air

• Water

• Steel

• Glass

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20

What determines the loudness of different sounds?

The amount of energy a wave carries depends on its amplitude. For a compressional wave such as a sound wave, the amplitude is related to how spread out the molecules or particles are in the compressions and rarefactions (seen as expansions below).

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24

Multiple Choice

The ______ of a sound is how high or low it sounds.

• Pitch

• Frequency

• Amplitude

• Loudness

Multiple Choice

A tone that is lower in pitch is lower in what characteristic?

• Amplitude

• Frequency

• Wavelength

32

Multiple Choice

The change in frequency that occurs when a source of sound is moving relative to a listener is known as what?

• Doppler Effect

• Loudness Effect

• Pitch Effect

• Amplitude Effect

Multiple Choice

What is a reflected sound wave?

• Echo

• Refracted

• Pitch

• Loudness

Multiple Choice

The energy carried by sound waves increases as amplitude increases.

• True

• False