properties of waves and sound barton spring 2014 honors physics
Post on 04-Jan-2016
214 Views
Preview:
TRANSCRIPT
Properties of Waves and Sound
Barton Spring 2014 Honors Physics
Difference between wave motion and particle motion:
• Both carry energy• Particles move and carry energy
through a transfer of matter• A wave is a disturbance that
carries energy through matter or space
Mechanical waves: (like sound)
• Require a medium through which to travel–ie: water, air, ropes, spring–CANNOT travel in a vacuum
• Pulse – single wave
Longitudinal wave - vibrates parallel to direction of wave’s motion Sound waves
Mechanical waves:
• Transverse wave - vibrates perpendicular to direction of wave’s motion
http://nanobioart.com/members/ageorge/
Mechanical waves:• Surface waves – characteristics of both
transverse and longitudinal waves; particles move parallel and perpendicular to direction of wave motion
Equilibrium position (rest position)
Wave calculations:
dv
t
Tf
1
v f
Wave behavior:• Speed of wave depends only on the medium it
passes through (not amplitude or frequency)
• Incident wave – wave that strikes a boundary• Reflected wave – returning wave that has
bounced back from a boundary• faster wave speed slower wave speed --- reflected
wave is inverted• slower wave speed faster wave speed --- reflected
wave is not inverted• http://paws.kettering.edu/~drussell/Demos/reflect/reflect.html <---- demos of waves on rope
Wave behavior: • Principle of Superposition – displacement of a medium caused by 2 or more waves is the sum of the displacements caused by individual waves
• Interference – result of superposition of 2 or more waves
• http://paws.kettering.edu/~drussell/Demos/superposition/superposition.html <---superposition videoshttp://www.circleofoneness.org/ether.html
CONSTRUCTIVE
DESTRUCTIVE
Wave behavior:• Refraction – change in direction of waves at
the boundary between two different mediums, bending of the wave
http://www.crd.bc.ca/watersheds/protection/geology-processes/Waves.htm
Perceiving sound:• Pitch – depends on
frequency• Loudness – depends on
amplitude– Sound level – measuring
scale of amplitudes– Decibel (dB) – unit for
measurement of sound level
• Medium determines wave speed http://raider.mountunion.edu/~miskeljp/ds/schedule.htm0
Doppler effect:
• Doppler effect – frequency shift due to sound source movement– Closer/towards higher frequency– Further/away lower frequency
• Equation:• Song: http://imagine.gsfc.nasa.gov/YBA/M31-velocity/Doppler-shift-3.html
Think about it:If the source and observer are moving towards each other, the waves get bunched together and the frequency goes up.If the source and observer are moving further apart, the frequency will decrease as the waves get stretched apart.Keep this in mind as you apply the equation!
top related