CHAPTER 17 Study Guide
17.1 Mechanical Waves
Key Concepts
A wave is created when a source of energy causes a vibration to move through a medium.
The three main types of mechanical waves are transverse, longitudinal, and surface waves.
Vocabulary
mechanical wave, p. 500; medium, p. 500; crest, p. 501; trough, p. 501; transverse wave, p. 501; compression, p. 502; rarefaction, p. 502; longitudinal wave, p. 502; surface wave, p. 503
17.2 Properties of Mechanical Waves
Key Concepts
A wave's frequency equals the frequency of the vibrating source producing the wave.
For waves traveling at a constant speed, wavelength is inversely proportional to frequency.
As energy of a wave increases, amplitude increases.
Vocabulary
periodic motion, p. 504; period, p. 504; frequency, p. 504; hertz, p. 504; wavelength, p. 505; amplitude, p. 507
17.3 Behavior of Waves
Key Concepts
Reflection does not change the speed or frequency of a wave, but the wave can be flipped upside down.
Refraction occurs because one side of a wave moves more slowly than the other side.
A wave diffracts more if its wavelength is large compared to the size of an opening or obstacle.
Interference can be constructive or destructive.
A standing wave forms only if the length of a vibrating cord is a multiple of one half wavelength.
Vocabulary
reflection, p. 508; refraction, p. 509; diffraction, p. 510; interference, p. 510; constructive interference, p. 511; destructive interference, p. 511; standing wave, p. 512; node, p. 512; antinode, p. 512
17.4 Sound and Hearing
Key Concepts
Many behaviors of sound can be explained using a few properties—speed, intensity and loudness, and frequency and pitch.
Ultrasound is used in a variety of applications, including sonar and ultrasound imaging.
As a source of sound approaches, an observer hears a higher frequency. When the sound source moves away, the observer hears a lower frequency.
The outer ear gathers and focuses sound into the middle ear, which receives and amplifies the vibrations. The inner ear uses nerve endings to sense vibrations and send signals to the brain.
Sound is recorded by converting sound waves into electronic signals that can be processed and stored. Sound is reproduced by converting electronic signals back into sound waves.
Most instruments vary pitch by changing the frequency of standing waves.
Vocabulary
sound waves, p. 514; intensity, p. 515; decibel, p. 515; loudness, p. 515; pitch, p. 515; sonar, p. 516; Doppler effect, p. 516; resonance, p. 521
Thinking Visually
Web Diagram Copy the web diagram below onto a sheet of paper. Use information from the chapter to complete the diagram.
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