1. Part I - Characteristics of Waves
Waves & Sound
Part I - Characteristics of Waves
Learning Goal
SOL PS 8 – The student will investigate and understand characteristics of sound and technological applications of sound waves.

2. Essential Questions What are the measurable properties of waves?
What is a wave?
What are the measurable properties of waves?
How are wavelength, frequency, speed calculated?

3. A. What is a wave?
Waves
rhythmic disturbances that carry energy through matter or space (Video Clip)
Medium
material through which a wave transfers energy
solid, liquid, gas, or combination
electromagnetic waves don’t need a medium (e.g. visible light)
Video Clip

4. A. What is a wave?
Two Types:
Longitudinal Transverse

5. A. What is a wave? Transverse Waves
medium moves perpendicular to the direction of wave motion

6. A. What is a wave? Longitudinal Waves (a.k.a. compressional)
medium moves in the same direction as wave motion

7. A. What is a wave? Wave Anatomy compression wavelength rarefaction
Amount of compression corresponds to amount of energy  AMPLITUDE.

8. B. What are the measurable parts of a wave?
Your ideas?

9. B. What are the measurable properties of wave?
Simulation: Waves on a String
Answer the following:
1) How does the amount that I wiggle the wrench
affect the wave?
2) How does the speed that I wiggle affect the wave?
3) Switch to “Oscillate”:
What happens when I change amplitude?
What happens when I change frequency?
What happens when I change damping?
Explain these three underlined words.

10. B. What are the measurable parts of a wave?
Wave Anatomy
corresponds to the amount of energy carried by the wave
crests
wavelength
amplitude
nodes
troughs

11. B. What are the measurable parts of a wave?
Frequency ( f )
# of waves passing a point in 1 second
Hertz (Hz)
1 second
shorter wavelength  higher frequency  higher energy

12. C. How are wave properties calculated?
Velocity ( v )
speed of a wave as it moves forward
depends on wave type and medium
v =  × f
v: velocity (m/s)
: wavelength (m)
f: frequency (Hz)

13. C. How are wave properties calculated?
EX: Find the velocity of a wave in a wave pool if its wavelength is 3.2 m and its frequency is 0.60 Hz.
GIVEN:
v = ?
 = 3.2 m
f = 0.60 Hz
WORK:
v =  × f
v = (3.2 m)(0.60 Hz)
v = 1.92 m/s  v f

14. C. How are wave properties calculated?
EX: An earthquake produces a wave that has a wavelength of 417 m and travels at 5000 m/s. What is its frequency?
GIVEN:
 = 417 m
v = 5000 m/s
f = ?
WORK:
f = v ÷ 
f = (5000 m/s) ÷ (417 m)
f = 12 Hz  v f

15. D. How do waves behave? Reflection occurs when a wave bounces
back after striking a barrier.

16. D. How do waves behave?
Refraction occurs when a wave bends as it passes from one medium to another.

17. D. How do waves behave?
Video Clip: Wave Interference

18. LET’S REVIEW! (copy into notes)
energy
A wave is created when a source of ________ causes a vibration to move through a _________.
There are several types of mechanical waves including _____________ waves and ____________ waves.
Draw an example of each.
medium
longitudinal
transverse

19. LET’S REVIEW! (copy into notes)
A _____________(compression) wave is a wave in which the vibration of the medium is ____________ to the direction in which the wave travels.
This type of wave consists of a repeating pattern of _____________ and _____________.
longitudinal
parallel
compressions
rarefactions

20. LET’S REVIEW! (copy into notes)
All waves exhibit certain characteristics: __________, ___________, and ___________.
Draw a transverse wave and label the three things listed above.
Draw a longitudinal wave and label the three things listed above.
wavelength
amplitude
frequency