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Kai Zhang
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Why is the sky blue?  (part 1)

The most commonly taught answer is that blue has a shorter wavelength so it scatters more going through the atmosphere.  This is at best an incomplete answer.  Purple has a shorter frequency than blue, so why is the sky not purple and blue.

The answer is the sky actually is purple and blue.  It just so happens that exactly the same receptors in our eyes for that shade of purple and blue are the same receptors that detect pure blue and pure white.  Our brains just pick the wrong set.  Think about the dress that is gold/white or blue/black.  Our eyes can be tricked.  Bees and some birds can actually see the sky as it actually is.

Yet what is light, color, frequency, and why would it scatter and how?  Light is little packets of energy.  That is why you can power cars, houses, and death ray lazers with it.  Color and frequency are kind of the same thing.  They way we interact with light by perceiving colors does not help us understand how it functions in a meaningful way.  Not if you want to build spaceships armed with photon torpedoes.  

And as a species we really really want to do this.  So we create similes, analogies, and mathematical tools to understand fundamental forces and particles like light. 

#sciencecommunication   #science   #energy   #light   #color  

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Simple and clear!
This is how pie got its value, that is 3.14.
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Audi Sends Self-Driving Car on 550-Mile Journey to #CES2015 - By Caleb Chen Audi is putting the pedal to the metal on their new self-driving car initiative, sending it alongside other drivers from San Francisco to Las Vegas just in time for CES 2015. That’s right; the German car company is sending their driverless vehicle on a nearly 550-mile journey to show off their technology. […] http://ow.ly/2SW85Z

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