MUSICAL ACOUSTICS
WAVES
Science of Sound, Chapter 3
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/
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)
REFLECTION OF AN IMPULSIVE WAVE
At a fixed end At a free end
SUPERPOSITION OF WAVE PULSES
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
REFLECTION OF PRESSURE (SOUND) PULSE
SPEED OF SOUND IN IDEAL GAS
OCEAN WAVES
WHEN THE WAVE ENTERS SHALLOW WATER IT SLOWS DOWN AND ITS HEIGHT INCREASES
REFLECTION – WATER WAVES
REFLECTION – SOUND WAVES
REFRACTIONTWO MEDIUMS
REFRACTION THROUGHA PRISM
ANGLE OF INCIDENCE
IMAGES FORMATIONBY LENSES
REFRACTION OF LIGHTBY WATER
INTERFERENCE OF WAVES FROM TWO IDENTICAL SOURCES
INTERFERENCE OF WATER
WAVES
DIFFRACTION OF WATER
WAVES BY A SLIT
DIFFRACTION OF LIGHT BY A PIN
DIFFRACTION OF LIGHT BY
A SCREW
DIFFRACTION OF LIGHT BY
A RAZOR BLADE
DIFFRACTION BY A SINGLE
SLIT
DIFFRACTION OF WATER WAVES
DIFFRACTION OF LIGHT AND SOUND WAVES
SPECTRAL ENERGY DISTRIBUTION OF A WHITE LED
LED SPECTRAL RESPONSE CURVE