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.
Mar 26, 2015
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.
Essential Questions
What is a wave?
What are the measurable properties of waves?
How are wavelength, frequency, speed calculated?
A. What is a wave?
Wavesrhythmic disturbances that carry energy through
matter or space (Video Clip)
Mediummaterial through which a wave transfers energysolid, liquid, gas, or combinationelectromagnetic waves don’t need a medium
(e.g. visible light) Video Clip
A. What is a wave?
Two Types:
Longitudinal Transverse
A. What is a wave?
Transverse Wavesmedium moves
perpendicular to the direction of wave motion
A. What is a wave?
Longitudinal Waves (a.k.a. compressional)medium moves in the same direction as wave
motion
A. What is a wave?
Wave Anatomy
rarefaction
compression
wavelength
wavelength
Amount of compression corresponds to amount of energy AMPLITUDE.
B. What are the measurable parts of a
wave?
Your ideas?
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 wrenchaffect 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.
B. What are the measurable parts of a wave?
Wave Anatomycrests
troughswavelength
wavelength
amplitude
amplitude
corresponds to the amount of
energy carried by the wave
nodes
Frequency ( f )
# of waves passing a point in 1 second
Hertz (Hz)shorter wavelength
higher frequency higher energy
1 second
B. What are the measurable parts of a wave?
C. How are wave properties calculated?
Velocity ( v )speed of a wave as it moves forwarddepends on wave type and medium
v = × f v: velocity (m/s)
: wavelength (m)
f: frequency (Hz)
WORK:v = × f
v = (3.2 m)(0.60 Hz)
v = 1.92 m/s
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
v
f
WORK: f = v ÷
f = (5000 m/s) ÷ (417 m)
f = 12 Hz
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 = ?
v
f
D. How do waves behave?
Reflection occurs when a wave bounces
back after striking a barrier.
D. How do waves behave?
Refraction occurs when a wave bends as it passes from one medium to another.
D. How do waves behave?
Video Clip: Wave Interference
LET’S REVIEW! (copy into notes)
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.
energymedium
transverselongitudinal
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
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 frequencyamplitude