waves. what’s in a wave? a wave is a disturbance/movement that transfers energy through matter or...
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Waves
What’s In a Wave?What’s In a Wave?
A wave is a disturbance/movement that
transfers energy through matter or space.
Waves DO NOT transfer matter, but they DO transfer energy
Ex: ‘The Wave’ in a stadium
A wave is a disturbance/movement that
transfers energy through matter or space.
Waves DO NOT transfer matter, but they DO transfer energy
Ex: ‘The Wave’ in a stadium
Waves and EnergyWaves and Energy
A wave will travel as long as it has energy
to transfer
Ex: pebble in a pond - ripples soon die out
A wave will travel as long as it has energy
to transfer
Ex: pebble in a pond - ripples soon die out
A medium is the matter a wave travels through.
• solid, liquid or gas
Not all waves need a medium -• Electromagnetic waves - travel through space
Waves that can only travel through matter - MECHANICAL waves
• Transverse & Longitudinal
A medium is the matter a wave travels through.
• solid, liquid or gas
Not all waves need a medium -• Electromagnetic waves - travel through space
Waves that can only travel through matter - MECHANICAL waves
• Transverse & Longitudinal
You can think of a wave as a moving series of high points and low points.
A crest is the high point of the wave. A trough is the low point.
You can think of a wave as a moving series of high points and low points.
A crest is the high point of the wave. A trough is the low point.
Amplitude, Frequencyand Wavelength
Amplitude, Frequencyand Wavelength
AmplitudeAmplitude The amplitude is the maximum height
the wave rises above the level surface.
The more energy a wave has the greater its amplitude.
The amplitude is the maximum height the wave rises above the level surface.
The more energy a wave has the greater its amplitude.
FrequencyFrequency The frequency of a wave is the rate at
which every point on the wave moves up and down.
Frequency means “how often”. Measured in cycles per second, or hertz
(Hz)
The frequency of a wave is the rate at which every point on the wave moves up and down.
Frequency means “how often”. Measured in cycles per second, or hertz
(Hz)
WavelengthWavelength Wavelength is the distance from any point
on a wave to the same point on the next cycle of the wave.
The distance between one crest and the next crest is a wavelength.
Wavelength is the distance from any point on a wave to the same point on the next cycle of the wave.
The distance between one crest and the next crest is a wavelength.
WavelengthWavelength
PeriodPeriod
The time required for one cycle of awave.
A complete motion that returns to itsstarting point.
Measured in units of time (seconds, minutes, hours)
The time required for one cycle of awave.
A complete motion that returns to itsstarting point.
Measured in units of time (seconds, minutes, hours)
The speed of wavesThe speed of wavesThe speed of a water wave is how
fast the wave spreads, NOT how fast the water surface moves up and down or how fast the dropped ball moves in the water.
The speed of a water wave is how fast the wave spreads, NOT how fast the water surface moves up and down or how fast the dropped ball moves in the water.
How do we measure the wave speed?
SpeedSpeed
v = f
frequency (cycles/sec)
wavelength (m)
speed (m/sec)
Mechanical WavesMechanical Waves
TRansverse: Matter in the medium moves back and forth at right angles to the direction the wave is moving
ex: Ocean Waves
TRansverse: Matter in the medium moves back and forth at right angles to the direction the wave is moving
ex: Ocean Waves
Mechanical WavesMechanical Waves
Longitudinal: Matter in the medium moves back and forth in the same direction the wave is moving
ex: Earthquake wavesAlso known as
Compressional Waves
Longitudinal: Matter in the medium moves back and forth in the same direction the wave is moving
ex: Earthquake wavesAlso known as
Compressional Waves
Transverse WaveTransverse Wave
Transverse and Longitudinal Waves
Transverse and Longitudinal Waves
A transverse wave has its oscillations perpendicular to the direction the wave
moves.
A longitudinal wave has oscillations in the same direction as the wave moves.
A transverse wave has its oscillations perpendicular to the direction the wave
moves.
A longitudinal wave has oscillations in the same direction as the wave moves.
Transverse wavesTransverse wavesThe oscillations of a transverse
wave are not in the direction the wave moves.
The oscillations of a transverse wave are not in the direction
the wave moves.
Longitudinal wavesLongitudinal wavesThe oscillations of a longitudinal
wave are in the same direction that the wave moves.
The oscillations of a longitudinal wave are in the same direction
that the wave moves.
Four wave interactionsFour wave interactions
When a wave encounters a surface, four interactions can
occur:
reflection, refraction, diffraction,
or absorption.
When a wave encounters a surface, four interactions can
occur:
reflection, refraction, diffraction,
or absorption.
Wave animationsWave animations
http://www.kettering.edu/~drussell/Demos/waves/wavemotion.html
http://www.kettering.edu/~drussell/Demos/waves/wavemotion.html