1. Reviewing Main Ideas The Nature of Waves
Waves are rhythmic disturbances that transfer energy through matter or space.
Waves transfer only energy, not matter.
Mechanical waves need matter to travel through. Mechanical waves can be longitudinal or transverse.

2. Reviewing Main Ideas The Nature of Waves
When a transverse wave travels through a medium, that matter that makes up the medium moves at right angles to the direction that the wave travels.
When a longitudinal wave travels through a medium, matter moves back and forth along the same direction as the wave travels.

3. Reviewing Main Ideas Wave Properties
The movement of high points in a medium called crests and low points called troughs forms a transverse wave.
The movement of more-dense regions called compressions and less-dense regions called rarefactions forms a longitudinal wave.

4. Reviewing Main Ideas Wave Properties
Transverse and longitudinal waves can be described by their wavelengths, frequencies, periods, and amplitudes. As frequency increases, wavelength always decreases.
The greater a wave’s amplitude is, the greater the disturbance the wave causes.
A wave’s velocity can be calculated by multiplying its frequency times its wavelength.

5. Reviewing Main Ideas The Behavior of Waves
For all waves, the angle of incidence equals the angle of reflection.
A wave is bent, or refracted, when it changes speed as it enters a new medium.
When two or more waves overlap, they combine to form a new wave. This process is called interference.

6. Chapter Review
Question 1
What is a transverse wave?

7. Chapter Review
Answer
A transverse wave is one in which matter in the medium moves back and forth at right angles to the direction that the wave travels. A water wave is a transverse wave.

8. Chapter Review Question 2
In a __________, the matter that makes up the medium moves back and forth along the same direction that the wave travels.
Answer
The answer is longitudinal wave, also known as a compressional wave.

9. Chapter Review Question 3
As the frequency of a wave increases, its wavelength __________.

10. Chapter Review
Answer
As frequency increases, wavelength decreases.

11. Chapter Review Question 4
Which of the following statements is correct?
A. The smaller a wave’s amplitude is, the greater the disturbance from the wave.
B. The greater the wave’s amplitude is, the
greater the disturbance from the wave.

12. Chapter Review C. The amplitude of any transverse wave is the
distance from the crest to the trough of the
wave.
D. The amplitude of a transverse wave is
the distance from one wave crest to the next wave crest.

13. Chapter Review
Answer
The answer is B. Amplitude is half the vertical distance between a crest and a trough.

14. Chapter Review
Question 5
What is occurring in this diagram?

15. Chapter Review
Answer
This diagram represents wave interference. When two or more waves overlap and combine to form a new wave, the process is called interference.

16. Standardized Test Practice
Question 1
Which type of wave is represented here?
A. longitudinal
B. electromagnetic
C. seismic
D. transverse

17. Standardized Test Practice
Answer
The answer is A. The wave travels horizontally along the spring, in the same direction that the coils move.

18. Standardized Test Practice
Question 2
What is the distance from the rest position to the crest in the diagram called?
A. compression
B. wavelength
C. amplitude
D. frequency

19. Standardized Test Practice
Answer
The answer is C. The distance from the rest position to the crest or from the trough to the rest position is the amplitude.

20. Standardized Test Practice
Question 3
Which is represented by area A?
A. compression
B. crest
C. rarefaction
D. trough

21. Standardized Test Practice
Answer
The answer is C. A rarefaction is the less-dense region of a longitudinal wave.

22. Standardized Test Practice
Question 4
What is the speed of a wave that has a wavelength of 5.0 m and a frequency of 2 Hz?
A m/s
B m/s
C. 10 m/s
D m/s

23. Standardized Test Practice
Answer
The answer is C. Wave speed is equal to the frequency multiplied by wavelength.

24. Standardized Test Practice
Question 5
Which would you predict will happen if the flashlight is submerged and the beam directed upward?

25. Standardized Test Practice
A. The light waves would slow down and bend away from the normal.
B. The light waves would speed up and bend away from the normal.

26. Standardized Test Practice
C. The light waves would slow down and bend toward the normal.
D. The light waves would speed up and bend toward the normal.

27. Standardized Test Practice
Answer
The answer is B. Light waves travel slower in water than in air, so if the flashlight were submerged and directed upward, the light waves speed up and bend away from the normal.