Download Light! - Hays High Indians

Light!
Don’t forget that light travels
faster than sound . . . that’s why
so many people appear bright
until they speak.
Particle or wave?
• Light is a particle (“corpuscular”) !
– Newton
• Light is a wave!
– Huygens
• Max Planck, 1900:
– How does emitted radiation relate to temp?
– Mathematical “fudge factor”
• Assumed energy (I.e., temperature) was chunked,
discrete, not a continuous function
. . . and
there
is
light.
Light production
• Bohr model
– Incident photon excites electron to higher
energy level
– Electron drops to lower energy level,
emitting photon
– Jump size proportional to photon energy
• Animation
• But it gets even better . . .
stuff of
TheThe
stuff
ofNobels
Nobels
• Einstein
– Light is quantized
– Photoelectric effect
Energy of emitted
photons depended
on frequency of
incident light, NOT
intensity
– Physics Nobel, 1921
• Wavicles!
Mathematics
Mathematics . . .
• Speed of a wave = frequency x
wavelength
c = 
• Energy of light = Planck’s constant
x frequency
E = h
Planck’s constant = 6.626 x 10-34 Js
Polarizationby
by Transmission
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Transmission
Polarization
Reflection
Polarization by
by Reflection
Polarization by
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Scattering
Dark Suckers - conceptual
• http://www.math.buffalo.ed
u/~sww/ZAP/index.html
• A new candle has a white
wick. You will notice that
after the first use, the wick
turns black, representing
all the dark which has been
sucked into it. If you hold a
pencil next to the wick of
an operating candle, the tip
will turn black because it
got in the path of the dark
flowing into the candle.
Dark Sucker “Theory”
• This intrinsic darkness is bound into the electrons
of the surface material.
• The reason host materials get warmer as they
release their intrinsic darkness is that there is a
binding energy between darkness and its host
material.
• Incidentally, the retinas of your eyes contain
special pigments that send signals to your optic
nerves when dark is sucked out of them —
sucking out yellow-frequency darkness is
experienced as seeing yellow light.
• http://home.netcom.com/~rogermw/darksuc
ker.html
Dark Sucker “Theory”
• Eventually, the surface can become so hot that it
glows with incandescence, and becomes a dark
sucker itself.
• It should be noted that objects which glow due to
their own heat, called "blackbody radiation",
always cool off as a result of this radiation. This
cooling off is merely the darkness being sucked
into the blackbody radiator (hot dark sucker) and
making the dark sucker itself into the darkness's
new host material.
• The darkness-to-new-host binding process
consumes heat to form its new bonds, each of
which has its own binding energy, and the
blackbody gets colder as a result.
•
•
•
•
Chapter 14, sections 1 & 4
p. 523, 1-6; p. 525, #1-3;
p. 550+, 1-13,37-45
Color mixing lab