10/18/2007
Crave the Wave (B)
Description
• In this event students will demonstrate
knowledge and process skills needed to
solve p
problems and answer q
questions
regarding all types and areas of waves
and wave motion.
Event Parameters
• Scientific calculator
• Resource Binder
– All materials must be 3-hole punched and in
binder such that they can’t fall out
– Must fit in 3” by 12” by 12” box without
compression
Competition Format
• Stations
– Draw and label diagrams
– Record observations
– Make predictions
p
– Interpret data
– Generate inferences
– Solve problems
– Formulate and evaluate hypothesis
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10/18/2007
Competition Format
• Questions and activities from:
– General wave characteristics
– Wave types
– Wave Phenomenon
– Electromagnetic Waves
– Spectroscopy (State)
– Earthquake / Seismic Waves (State)
– Boundary Effects (National)
Wave Characteristics
• Wavelength
– Distance from peak to
peak or trough to
trough
– Measured in a unit of
distance (cm, m, etc.)
Wave Characteristics
• Amplitude: Height of peak or trough
Low Amplitude
High Amplitude
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Wave Characteristics
• Frequency
– Number of peaks or
troughs passing a
given point in one
second
– Measured in hertz or
cycles per second
Low Frequency
• Period
– Time between two
successive troughs or
peaks
High Frequency
Wave Types
• Longitudinal: Motion of particles parallel to
motion of the wave
• Transverse: Motion of particles perpendicular to
motion of the wave
Wave Types
• Surface: The particles transporting the wave
undergo a circular motion.
– Surface waves on the ocean
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Wave Types
• Torsional: the particles transporting the wave
under a twisting motion as the medium rotates
back and forth around the direction of the wave.
Sound and Light Wave Phenomenon
• Reflection
• Angle of incidence =
angle of reflection
Sound and Light Wave Phenomenon
• Refraction -- the
bending of light as it
passes from one
medium to another
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Sound and Light Wave Phenomenon
• Diffraction -- the ability of a light or sound wave
to go around a small object.
If opening is larger than
wavelength, the wave goes
straight thru
If opening is comparable
to or smaller than
wavelength, the wave
bends
Sound and Light Wave Phenomenon
• Constructive Interference
– two or more waves have a displacement in the
same direction
– reinforce each other.
Sound and Light Wave Phenomenon
• Destructive Interference
– Two waves have a displacement in the opposite
direction
– Cancel each other.
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Sound and Light Wave Phenomenon
• Standing Wave
– Medium fixed at both ends
– Wave reflected back and forth
– Ag
guitar string
g
Sound and Light Wave Phenomenon
• Doppler Effect
Sound and Light Wave Phenomenon
• Doppler Effect
– Lower frequency -- object moving away
– Higher frequency -- object approaching
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10/18/2007
Electromagnetic Waves
Electromagnetic Spectrum
Electromagnetic Waves
Electromagnetic Waves
AM Radio
Information carried by changes in amplitude
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Electromagnetic Waves
FM Radio
Information carried by changes in frequency
Spectroscopy
• Primary Colors of Light
– Red
– Green
– Blue
Spectroscopy
• Primary Colors of Light
– Red
– Green
– Blue
• Primary Colors of Pigments (Primary Pigments)
– Magenta
– Yellow
– Cyan
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Spectroscopy
Spectroscopy
Absorption Spectra
Emission Spectra
Spectroscopy
How spectra are formed
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Earthquake / Seismic Waves
• P-waves (Primary Waves)
– basically sound waves that travel thru the earth from
the epicenter of an earthquake.
– Longitudinal wave; it "shakes" things in the same
di ti it travels.
direction
t
l (if a P
P-Wave
W
is
i ttraveling
li W
Westt to
t
East, all the things in the way, like people and
buildings, will oscillate or move back and forth in the
West-East direction)
Earthquake / Seismic Waves
• S-waves (Secondary Waves)
– transverse waves; This means they make the earth
vibrate perpendicularly to the direction of the wave
– travel much slower and much more destructive than
P-Waves.
– It causes buildings to be thrust upward from the
ground then the ground drops out from under it as
the wave travels by.
Earthquake / Seismic Waves
• Rayleigh-waves
– This is a combination P and S-Wave
– It's both longitudinal AND transverse; It's analogous
to an ocean wave.
– The surface vibrates forward and backward in the
direction of the wave and also up and down
perpendicular to the direction of the wave.
– The result is the surface moving in a vertical circular
path - back and forth AND up and down. The
Rayleigh wave is particularly damaging because it
tells structures to move in two directions at once.
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10/18/2007
Earthquake / Seismic Waves
• Love-waves
– Sort of a Rayleigh Wave on its side.
– the surface to moves forward and backward AND
left and right at the same time (like a surface circle)
– Very damaging
Earthquake / Seismic Waves
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