NOTES 22, Waves
Objective 1: Know the terminology used to describe waves.
Objective 2: Differentiate between pulse waves and periodic waves.
Objective 3: Describe and give examples of transverse and longitudinal waves.
1. Medium – The material through which a disturbance travels.
2. Mechanical wave – a wave that propagates through a deformable, elastic medium.
3. Pulse wave - a single, non-periodic disturbance moving through a medium.
4. Periodic wave - a wave whose source is some form of periodic motion.
5. Transverse wave - wave in which the particles of the medium move perpendicular to the
direction of the energy, i.e., water wave, light wave (or EM wave).
6. Longitudinal wave - wave in which the particles of the medium move parallel to the direction
of the energy, i.e., sound wave.
7. Crest - high point of transverse wave.
8. Trough - low point of transverse wave.
9. Amplitude (A) - distance from rest position of medium to crest or trough.
10. Displacement (x) - distance the medium is moved away from equilibrium; measured in meters.
11. Wavelength (λ) - distance
between corresponding points on 2
successive waves (measured in
meters).
12. Compression – An increase in
density and pressure in a medium,
such as air, caused by the passage of
a sound wave.
13. Rarefaction – A decrease in density and pressure in a medium caused by the passage of a
sound wave.
14. Period (T) - the time required for one wave to pass a fixed point; measured in seconds.
15. Frequency (f) - the number of times the wave medium oscillates completely in 1 s (measured
in cycles per second or Hertz).
16. Phase angle – a shift, left or right, from a reference wave.
17. Wave speed (v) - the rate at which a wave moves through a
medium.
Types of Waves | Parts of a Wave
Objective 4: Draw and explain displacement-time and
displacement-position graphs for transverse and longitudinal
waves.
18. Transverse Wave...
19. Longitudinal Wave...
Objective 5: Know and apply the relationship between wave speed, wavelength, and
frequency.
20. The wave equation is:
v f
21. It can be derived from our basic equation for velocity:
v
dist wavelength 

  f
1
time
Period
f
Objective 6: Understand that waves transfer energy.
22. Waves transfer energy by transferring the motion of matter rather than by transferring matter
itself.
23. The rate at which a wave transfers energy depends on the amplitude at which the particles of
the medium are vibrating. The energy transferred is proportional to the square of the wave’s
amplitude (e.g., if A is doubled, the energy it carries is increased by a factor of four).
24. The amplitude of a wave gradually diminishes over time. This effect is called damping.