Color and Light by xri35382


									              Color and Light
Intro question…. How is light different than normal
 What is light? Wave or Particle
Is light a wave? (ENERGY)
Is light a bunch of particles? (Matter)
Light is unique, it is what we call an
 Electromagnetic wave
How is light like a particle (matter)?
    Does not need a medium to travel through
      Can travel through a vacuum
     high energy (intensity of light) does not
     effect light the same way as normal waves
    Photoelectric effect
          How is light like a wave?
Light can diffract (bend around stuff)
Cannot travel through polar filters
Can exhibit Doppler Effect (change freq. Depending
  on motion of source)
Can interfere     (constructive or destructive)   and refract
  (bend when travelling between diff. Media)
Has no mass

We refer to all of this as the dual nature of light
  This means………. Light is special
     Many diff. Kinds of “light”
 A wide spectrum of types of light that we call
  Electromagnetic Radiation
 These include…… infrared, radio, ultraviolet, gamma
  rays, microwaves, x-rays, & visible light
 All exhibit same exact characteristics but vary b/c of
  wavelength & frequency
 All types travel at the same speed
   at The speed of light….300,000,000 m/s
 We can only „see‟ the small portion that is
 „visible light‟
 The rest is invisible to the human eye
Electromagnetic Spectrum
                     Visible Light
 Wavelength range From about 700 nm to 400 nm
 1 nm= 1 x 10^-9 m
 Different colors have different wavelengths & frequencies
 Infinite amount of different colors
        Absence of Light??
Black or White??
White is combination of all colors of
Black is complete lack of light, all colors
 have been taken away
Black would be the absence of Light!!
 Dispersion--the breaking up of light into its
 component colors when travelling through a prism
Why does it happen
  different wavelengths (colors) of light travel through a
   medium at different speeds, the amount of bending is
   different for different wavelengths.
  Violet (short ) is bent the most and red(long ) the least
  short wavelengths travel more slowly (lower frequency)
   through a medium than longer ones do
  its colors can be separated (dispersed)
   by this difference in behavior.
Any transparent substance that can
 separate colors
Red bent least, violet most
Opposite of dispersion
  Combining of colors of light using a lens or
   mirrors to form white light
Newton‟s Disk exhibits recomposition

Series of mirrors
               Newtons Disk
When spun fast enough all
 the colors will turn white
Utililizes the principle of
 persistence of vision
  Human eye retains an image
   for 1/30th of a second
  Connection… wheels on tv
  Fiber optic blinker
      How we see things….Subtractive
             Theory of Light
Keep taking away colors until you wind up w/ one
Objects absorb every color other than the color it
  However, most colors we see are various combinations of
  Ex. A blue shirt may reflect mostly blue, some purple,
   maybe some green, depending on the shade it appers
What happens when light goes through filters
Objects we see act like light filters
Colors combine the same way that
  pigments/paints do
Subtractive Theory of Light
  Why are objects different colors?
Is a certain object always going to be a certain
 color no matter what??
  Depends on what kind of light is hitting it
     Additive theory of light
Add colors of light to each other until one
  is made
Simple adding of different colors of light,
  no filters involved
• Ex. TVs,
• projectors

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