The Doppler Shift

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The Doppler Shift
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The Doppler Shift
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The Visible Spectrum
White light splits into the colors of the rainbow
when passed through a prism.
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The Visible Spectrum
Red Orange Yellow Green Blue Indigo Violet
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The Visible Spectrum
R O Y G B I
V
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I would like to introduce...
RO Y G BIV
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Sometimes it gets reversed...
RO Y G BIV
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Sometimes it gets reversed...
RO Y G BIV
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Sometimes it gets reversed...
VI B G YOR
(Roys evil twin brother.)
But the order makes no difference.
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Theres more to the spectrum than what you can
see.
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Theres more to the spectrum than what you can
see.
Ultraviolet (UV)
Radio Waves
Microwaves
Gamma Rays
Infrared (IR)
X-Rays
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Pure White Light
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Glowing Gas
The fingerprint of an element.
Neon Light
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Glowing Gas
Hydrogen Light
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When sound is made by a stationary object, you
hear a certain frequency...
Insert constant sound here
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If you could see it, it would look like this...
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But when the sound moves towards you, it sounds
higher in pitch.
Waves get compressed.
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The faster the object moves, the higher the pitch.
Waves get compressed more.
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When the object moves at the speed of sound, the
waves overlap...
...and you get a sonic boom.
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Fly faster than sound, and youre gone before the
boom is heard.
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Fly faster than sound, and youre gone before the
boom is heard.
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Fly faster than sound, and youre gone before the
boom is heard.
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An on-line visualization

• http//www.phy.ntnu.edu.tw/java/Doppler/Doppler.ht
  ml

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(No Transcript)
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(No Transcript)
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When the sound moves away, it sounds lower.
Waves are stretched.
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What it Sounds Like.
Car 1
Deep Jet
Mortor
Bike 1
Prop2
Prop2
Prop 1
Race1
Race1
Whine Jet 1
Race2
Race2
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The same shifting happens with the light from a
moving star.
Lower Frequency
Higher Frequency
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The spectrum of hydrogen that is from a
stationary source.
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When the star is moving closer...
Stationary Hydrogen
Blue Shifted Hydrogen from star moving towards
Earth.
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And when a star moves away from us...
Stationary Hydrogen
Lines are shifted to the red end.
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And when a star moves away from us...
Faster
Stationary Hydrogen
Lines are shifted farther to the red end.
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Since the universe is expanding...

• All distant objects have a red shift.
• The farther the object, the more extreme the red
  shift.

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Astronomers use this relationship between
distance and speed to measure the distance to
distant stars and galaxies.