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MUSICAL ACOUSTICS
WAVES
Science of Sound, Chapter 3
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WAVE PROPERTIES:•Reflection•Refraction•Interference•Diffraction•Doppler Shift
WHAT IS A WAVE?
Waves are disturbances that transport energy and information through a medium (but the medium itself is not transported).
Waves can be longitudinal (e.g. sound waves) or transverse (e.g. waves on a string or water waves).
ttp://www.animations.physics.unsw.edu.au/ //www.avnimations.physics.unsw.edu.au/
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Traveling wave on a rope
Reflection of a pulse:
at a fixed end
at a free end
Mirror image of an impulsive wave approaching:
A plane mirror (left)
A corner mirror (right)
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REFLECTION OF AN IMPULSIVE WAVE
At a fixed end At a free end
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SUPERPOSITION OF WAVE PULSES
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INTEFERENCE OF TWO IDENTICAL WAVES ON A STRING
At times t1 and t5 there is constructive interference;
at time t3 there is destructive interference.
Note that at points marked N, the displacement is always zero; this represents a STANDING WAVE
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REFLECTION OF PRESSURE (SOUND) PULSE
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SPEED OF SOUND IN IDEAL GAS
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OCEAN WAVES
WHEN THE WAVE ENTERS SHALLOW WATER IT SLOWS DOWN AND ITS HEIGHT INCREASES
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REFLECTION – WATER WAVES
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REFLECTION – SOUND WAVES
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REFRACTIONTWO MEDIUMS
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REFRACTION THROUGHA PRISM
ANGLE OF INCIDENCE
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IMAGES FORMATIONBY LENSES
REFRACTION OF LIGHTBY WATER
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INTERFERENCE OF WAVES FROM TWO IDENTICAL SOURCES
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INTERFERENCE OF WATER
WAVES
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DIFFRACTION OF WATER
WAVES BY A SLIT
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DIFFRACTION OF LIGHT BY A PIN
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DIFFRACTION OF LIGHT BY
A SCREW
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DIFFRACTION OF LIGHT BY
A RAZOR BLADE
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DIFFRACTION BY A SINGLE
SLIT
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DIFFRACTION OF WATER WAVES
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DIFFRACTION OF LIGHT AND SOUND WAVES
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SPECTRAL ENERGY DISTRIBUTION OF A WHITE LED
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LED SPECTRAL RESPONSE CURVE