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Types of Waves Harmonic Waves Sound and Light Waves Superposition and Interference The Doppler Effect Resonance. Waves can be transverse For example: Light waves, water waves and waves on a string... Waves can be longitudinal For example: Some seismic waves and sound waves….
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Types of Waves Harmonic Waves Sound and Light Waves Superposition and Interference The Doppler Effect Resonance
Waves can be transverse For example: Light waves, water waves and waves on a string... Waves can be longitudinal For example: Some seismic waves and sound waves… Please, be patient. It takes awhile for the animations to start.
Waves in Time • Waves are like many springs oscillating in time. • They have a period (T), • a frequency (f) and • an amplitude (A). T t f = 1/T
Waves in Space • Waves also oscillate in space. • They have a wavelength and • a speed.
Sound is a longitudinal wave It travels through any gas, solid or liquid as a variation in pressure. It has a speed that depends on the material (medium) that it travels through. It has a wavelength and a frequency that determine the pitch. It has an amplitude that determines the volume.
Light is a transverse wave • It travels through vacuum as a variation in electric and magnetic fields. • It has a speed that never changes. • c = 3 x 108 meters/second • It has a wavelength and a frequency that determine the color. • It has an amplitude that determines the intensity.
Transverse waves oscillate perpendicular to the direction of propagation. Properties: wavelength amplitude speed propagation direction polarization This is necessary to get the proper timing!
T t f = 1/T Each point on a transverse wave oscillates perpendicular to the direction of propagation. Properties: period frequency amplitude polarization
y λ x v Longitudinal waves oscillate parallel to the direction of propagation. Properties: wavelength speed propagation direction
t A T f = 1/T x Each point on a longitudinal wave oscillates parallel to the direction of propagation. Properties: period frequency amplitude
y λ x v Sound is a longitudinal wave It travels through any gas, solid or liquid as a variation in pressure. It has a speed that depends on the material (medium) that it travels through. Properties: wavelength speed propagation direction period frequency amplitude Pitch Density (of medium) Location Pitch Pitch Volume
x Definition of interference Constructive interference occurs when both waves have the same phase. Destructive interference occurs when both waves have opposite phase. y phase
The frequency of sound changes depending on whether you move toward or away from the object emitting the sound v is the velocity of the observer with respect to the source. vs is the velocity of the sound. v is positive if the observer is moving toward the source and negative if the observer is moving away from the source. http://webphysics.ph.msstate.edu/jc/library/15-6/index.html
For pipes the wavelength of a wave must fit within the length of the pipe. Other waves can only be made by force. Speed of sound in air is 343 meters/second = f xλ