Sunlight is made up of all the colors of the rainbow: red, orange, yellow, green, blue, indigo and violet. The gas molecules in the atmosphere interact with the sunlight before the light reaches our eyes. The gas molecules in the atmosphere scatter the higher-energy (high frequency) blue portion of the sunlight more than they scatter the lower-energy red portion of the sunlight (this is called Rayleigh scattering, named for the physicist Lord John Rayleigh). The Sun appears reddish-yellow and the sky surrounding the Sun is colored by the scattered blue waves.
When the Sun is lower in the horizon (near sunrise or sunset), the sunlight must travel through a greater thickness of atmosphere than it does when it is overhead, and even more light is scattered (not just blue, but also green, yellow, and orange) before the light reaches your eyes. This makes the sun look much redder.
Caution: Never stare directly at the Sun.
Extra Credit Question for everyone: What do the letters of this acronym stand for?
Roy G. Biv
Questions for middle school students:
1) How many miles away from the earth is the sun?
2) How long does it take the sun's light to reach the earth?
3) The continuous fusion of WHAT? into WHAT? keeps the core of the Sun cooking at HOW MANY DEGREES? degrees Fahrenheit.
4) How long would it take traveling nonstop at 70mph to reach the sun?
Look here for answers to #s 1 through 4.
5) What bends more - violet light or red light? You can find the answer here. The author of this answer is Lou Bloomfield, Professor of Physics, University of Virginia.
6) Does light refract? Why or why not?
Refract: The turning or bending of any wave when it passes from one medium into another of different density. (source: Answers.com)
sources:
Enchanted Learning
Answers.com
windows.ucar.edu.com
Howthingswork.virginia.edu
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