WW2010
University of Illinois

WW2010
 
  welcome
 
> online guides
 
  archives
 
  educational cd-rom
 
  current weather
 
  about ww2010
 
  index

Online Guides
 
  introduction
 
> meteorology
 
  remote sensing
 
  reading maps
 
  projects, activities

Meteorology
 
  introduction
 
  air masses, fronts
 
  clouds, precipitation
 
  el nino
 
  forces, winds
 
  hurricanes
 
  hydrologic cycle
 
> light, optics
 
  midlatitude cyclones
 
  severe storms
 
  weather forecasting

Light, Optics
 
  introduction
 
  mechanisms
 
  air, dust, haze
 
  ice crystals
 
> water droplets

water droplets
 
  coronas
 
  linings, iridescence
 
> rainbows

Rainbows
 
  how they develop
 
> primary rainbow
 
  secondary rainbow

User Interface
 
  graphics
> text

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Primary Rainbows
brighter than a secondary rainbow

A primary rainbow is brighter than a secondary rainbow and has colors changing from red on the outside to violet on the inside.

[Image: a primary rainbow (43K)]
Photograph by: Olthoff

We will focus on two raindrops to explain why this color pattern develops. Red light from the higher drop is directed toward the observer's eyes, while violet light is directed at a level above the observer.

From the lower drop, red light is directed to a level below the line of sight, while violet light is seen by the observer. This is why the colors of a primary rainbow change from red on the top of the arc to violet on the bottom.



how they develop
Terms for using data resources. CD-ROM available.
Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.

secondary rainbow