a repeating disturbance causing a wave at regular intervals.
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beats
Front
alternating constructive and destructive interference pattern formed when 2 waves have close, but slightly different frequencies. |f1-f2|
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mechanical wave
Front
a wave that transfers energy by physically moving the particles in the substance it travels through. Sound and water waves are examples. Light is a non-example.
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closed tube instrument
Front
A tube that is open at one end, but closed at the other.
High pressure reflects back low pressure => anti-node on one end and hard surface => node on other end, length= 1/4 wavelength
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pitch
Front
the frequency of a sound wave, which tells how "high" the sound is
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electromagnetic wave
Front
a wave that transfers energy by oscillating electric and magnetic fields. It does not require a medium. Light is an example. Sound is a non-example.
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Pulse
Front
A single disturbance in a medium, which causes a single wave.
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interference
Front
when multiple waves are passing through the same medium they combine their effects
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Blue shift
Front
the change in the wavelength of light due to an object moving away toward the observer. An apparently higher frequency.
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frequency
Front
how often a wave repeats, measured in Hz. Visualized as tighter pattern.
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natural frequency
Front
A frequency at which an elastic object, once energized, will vibrate. Minimum energy is required to continue vibration at that frequency. Also called resonant frequency.
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superposition principle
Front
when two or more waves travel through a medium at the same time, the resultant wave is the SUM OF the displacements
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incident
Front
when a wave strikes something. ex. the angle of the incident ray is equal to the angle of the reflected ray.
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anti-node
Front
position of increased motion on a standing wave
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traveling wave
Front
a wave that obviously moves along the length of the medium.
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Amplitude
Front
For a wave or vibration, the maximum displacement on either side of the equilibrium (midpoint) position.
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Doppler Effect
Front
An observed change in the frequency of a wave when the source or observer is moving
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absorption
Front
a material takes in energy and dissipates it instead of reflecting or transmitting it through
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Resonance
Front
The increase in the amplitude of vibration that occurs when external vibrations match the object's natural frequency
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reflection
Front
a wave bounces off a boundary
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Energy
Front
Measured by the amplitude in mechanical waves. This actually travels along the length of the medium (as opposed to mass, which is not propagating through the medium)
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propagate
Front
transmit through a medium
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harmonic
Front
whole number multiples of the fundamental frequency
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standing wave
Front
a wave that appears to stay in place, possessing nodes of non-movement and anti-nodes of increased oscillation.
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destructive interference
Front
when waves combine out of phase, producing a reduced amplitude
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constructive interference
Front
when waves combine in phase, producing a greater amplitude
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transverse wave
Front
A wave that moves the medium in a direction perpendicular to the direction in which the wave travels.
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open tube instrument
Front
A tube that is open at both ends.
High pressure reflects back low pressure, anti-node on both ends, length= 1/2 wavelength
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transmission
Front
a wave passes from one medium to another
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timbre
Front
the quality of a sound wave as determined by the overtones (additional harmonics) being produced by an instrument.
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stringed instrument
Front
fixed at both ends and vibrates between.
fixed ends => node on both ends,
length= 1/2 wavelength
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Red Shift
Front
the change in the wavelength of light due to an object moving away from the observer. An apparently lower frequency.
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longitudinal wave
Front
A wave in which the vibration of the medium is parallel to the direction the wave travels. Ex. Sound. A.k.a. compressional wave