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WavesWaves
Chapter 14 NotesChapter 14 Notes
What is a Wave?What is a Wave?
A wave is a periodic disturbance of matter (solid, liquid, or gas)
Examples include: Sound Light Ocean waves
A wave is a periodic disturbance of matter (solid, liquid, or gas)
Examples include: Sound Light Ocean waves
Wave EnergyWave Energy
Waves are also considered transfers of energy
Energy moves from one point to another while the substance vibrates while staying in place
Waves are also considered transfers of energy
Energy moves from one point to another while the substance vibrates while staying in place
Mechanical vs E-M WavesMechanical vs E-M Waves
Mechanical waves need a substance to travel through Substance is called a medium
Electro-magnetic waves can travel through emptiness (a vacuum)
Mechanical waves need a substance to travel through Substance is called a medium
Electro-magnetic waves can travel through emptiness (a vacuum)
ExamplesExamples
Name one type of mechanical wave
Name one type of Electromagnetic wave
Name one type of mechanical wave
Name one type of Electromagnetic wave
Mechanical WavesMechanical Waves
A medium could be a Solid Liquid Gas
In general waves travel fastest through solids and slowest through gases
A medium could be a Solid Liquid Gas
In general waves travel fastest through solids and slowest through gases
WavesWaves
As a wave moves from a source the energy spreads out
The waves spread out in concentric spheres
Each sphere forms a wave front
As a wave moves from a source the energy spreads out
The waves spread out in concentric spheres
Each sphere forms a wave front
Types of WavesTypes of Waves
Transverse Waves Particles of the medium move perpendicular to the direction of the wave
Longitudinal Waves Particles of the medium vibrate parallel to the direction of the wave
Transverse Waves Particles of the medium move perpendicular to the direction of the wave
Longitudinal Waves Particles of the medium vibrate parallel to the direction of the wave
Types of WavesTypes of Waves
Transverse Rope/String _________
Longitudinal Coiled spring _________
Transverse Rope/String _________
Longitudinal Coiled spring _________
Surface WavesSurface Waves
Occur at the boundary of two mediums A ball floating on water is a great example
Move both perpendicular and parallel and form a circle
Occur at the boundary of two mediums A ball floating on water is a great example
Move both perpendicular and parallel and form a circle
Characteristics of WavesCharacteristics of Waves
The relationship that best describes a wave is a sine curve
The relationship that best describes a wave is a sine curve
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Crest & TroughCrest & Trough
Crest - high point Trough - low point
Crest - high point Trough - low point
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Amplitude (A)Amplitude (A)
Measures the amount of particle vibration
Determines the energy of the wave
Measures the amount of particle vibration
Determines the energy of the wave
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AmplitudeAmplitude
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Wavelength ()Wavelength ()
Length of just ONE wave Length of just ONE wave
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NodesNodes
Point on wave where wave passes through origin
Point on wave where wave passes through origin
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Period (T)Period (T)
Period is the length of time for one wave to occur
Abbreviated with a capital T Measured in seconds Calculated as:
Total time / Number of waves
Period is the length of time for one wave to occur
Abbreviated with a capital T Measured in seconds Calculated as:
Total time / Number of waves
Frequency (f)Frequency (f)
Frequency of a wave is how often the wave occurs
Measures the rate of vibrations Abbreviated as a lower case f Measured in cycles per seconds (Hertz)
Calculated as: Number of waves / Total time of waves
Frequency of a wave is how often the wave occurs
Measures the rate of vibrations Abbreviated as a lower case f Measured in cycles per seconds (Hertz)
Calculated as: Number of waves / Total time of waves
Period & FrequencyPeriod & Frequency
You may notice something about the calculations for period and frequency
They are the inverse of each other
So, f = 1/T T = 1/f
You may notice something about the calculations for period and frequency
They are the inverse of each other
So, f = 1/T T = 1/f
Wave SpeedWave Speed
Not all waves travel at the same speed
Speed is determined by two things The frequency of the vibrations The medium of the wave
Calculation for wave speed is Speed = frequency x wavelength
Not all waves travel at the same speed
Speed is determined by two things The frequency of the vibrations The medium of the wave
Calculation for wave speed is Speed = frequency x wavelength
Wave InteractionsWave Interactions
Interactions include Reflection Refraction Diffraction Interference
Interactions include Reflection Refraction Diffraction Interference
ReflectionReflection
Reflection is the bouncing of a wave off of a surface or boundary
Boundaries can be Fixed Free
Reflection is the bouncing of a wave off of a surface or boundary
Boundaries can be Fixed Free
RefractionRefraction
Refraction is the bending of a wave as the wave passes from one medium to another medium
Refraction is the bending of a wave as the wave passes from one medium to another medium
DiffractionDiffraction
Diffraction is the bending of a wave as the wave passes around an obstacle or an edge Corner of a room Slit or hole
Diffraction is the bending of a wave as the wave passes around an obstacle or an edge Corner of a room Slit or hole
InterferenceInterference
Interference is the combination of two or more waves to form a new wave Constructive - waves becomes larger
Destructive - waves become smaller
Interference is the combination of two or more waves to form a new wave Constructive - waves becomes larger
Destructive - waves become smaller
Standing WavesStanding Waves
Standing waves form when a wave is reflected off of a boundary
Interference of the original wave interferes with the reflected wave causing the medium to vibrate in a stationary pattern
Creates nodes and anti-nodes
Standing waves form when a wave is reflected off of a boundary
Interference of the original wave interferes with the reflected wave causing the medium to vibrate in a stationary pattern
Creates nodes and anti-nodes
