Free Rainbows & Blue Sky Report Example

Visible light is a part of the electromagnetic spectrum containing electromagnetic (EM) waves of wavelengths from approximately 390 to 700nm (Elert). What we perceive as colors are in fact EM waves of different wavelengths.
The reason why we perceive the sky as blue is a phenomenon known as Rayleigh scattering. Light from the Sun, which contains all wavelengths in the visible spectrum and is, therefore, white, gets absorbed by molecules in the atmosphere and later re-emitted in a random direction. As light with shorter wavelengths (violet and blue) gets absorbed more, it is more prone to scattering (Bates 787) and more of it reaches our eyes. Our eyes are much more sensitive to blue then violet, so the sky appears blue to us.
Clouds, on one hand, appear white because the water droplets or ice crystals that form clouds reflect the light, and they reflect all wavelengths equally.
Rainbows, on the other hand, are created as a result of a different phenomenon called light dispersion. They are formed as light hits small water droplets in the atmosphere, getting refracted in the process. Light of shorter wavelength (blue and violet) refracts slightly more than the longer wavelengths (e.g., red). As a result, light of different wavelengths (and, therefore, color) gets physically separated, allowing us to see the different component colors of the spectrum (Waldman 177).

Works Cited

Bates, David Robert. “Rayleigh Scattering by Air”. Planetary and Space Science. 32 (1984): 785-790. Print.
Elert, Glenn. "The Electromagnetic Spectrum, The Physics Hypertextbook". Hypertextbook.com, 2010. Web. 16.Oct. 2010.
 Waldman, Gary (2002). Introduction to light: the physics of light, vision, and color. Mineola: Dover Publications. 2002. Print.