Data Bases • Custom Term Papers • Free Term Papers • Free Research Papers • Free Essays • Free Book Reports • Plagiarism? Links • Top 100 Term Paper Sites • Top 25 Essay Sites • Top 50 Essay Sites • Search 97,000 Papers @ DirectEssays.com • Search 101,000 Papers @ ExampleEssays.com • Search 90,000 Papers @ MegaEssays.com Free Essays • Term Paper Sites • Chuck III's Free Essays • Free College Essays • TermPaperSites.com • Free Essays • My Term Papers • Essay World • Planet Papers	Search Lots of Essays Back to Subjects - Science Blue skies and red sunsets Blue skies and red sunsets Throughout history, many people have wondered exactly what makes the sky blue and what makes some sunsets red. This can be done by examinations on how the scattering of sunlight by the Earth's atmosphere produces blue skies and red sunsets. Red sunsets have also been called orange sunsets because they are actually more orange in color. To understand why the sky is blue, one needs to understand a little about light. Light is a form of radiation, electromagnetic energy that travels in the form of waves possessing electric and magnetic properties. This form of energy does not need matter to propagate. We can characterize this energy by its wavelength -- the distance along a wave from one crest to another. Our eyes are remote sensors that are sensitive to light with wavelengths between approximately 0.4-0.7 microns (one micron is a millionth of a meter or one one-hundredth the diameter of a human hair). When light interacts with objects that are much smaller than the wavelength of the light, the light being scattered, rather than reflected. The electrons of such a small object are all shaken up and down at the same time by the electric field of the light wave, and they radiate that frequency of light in all directions. It turns out that the higher the frequency of the light, the more the light is scattered. The diameter of most molecules is much smaller than the wavelengths of visible light. A thin protective layer of ozone gas in the upper atmosphere absorbs most of the ultraviolet light from the sun, and the remaining ultraviolet sunlight that passes through the atmosphere is scattered by atmospheric particles and molecules. Of the visible frequencies of light, the high-frequency violet is scattered the most, followed by blue, green, yellow, orange, and red, in the order of decreasing frequency. Red is scattered less than a tenth as much as violet. Although violet light is scattered more than blue, our eyes are not very sensitive to violet and there tends to be more blue light in sunlight than violet. The blue predominates in our vision, so we see a blue sky. Since the lower frequencies of light are scattered the least by nitrogen and oxygen molecules (the primary components of our atmosphere), red, orange, green, and yellow light are transmitted through the atmosphere much more than violet and blue. Red, which is scattered the least, passes through more atmosphere than any other color. Therefore, when white light passes through a thick atmosphere, the higher frequency blue and violet is scattered the most while the lower frequencies such as red are transmitted with minimal scattering. Such a thicker atmosphere is presented to sunlight at sunset, since the path through the atmosphere is longer as the sun is lower on the horizon. This means that the sun becomes progressively redder as the sun goes down, going from yellow to orange. As incoming sunlight passes through a denser atmosphere, shorter wavelengths of light (violet and blue) are efficiently scattered away by particles suspended in the atmosphere. This allows predominantly yellow and red wavelengths of light to reach the observer's eyes, producing a yellowish-red sunset. When incoming sunlight encounters a heavy concentration of particles in the atmosphere, the shorter wavelengths of light (violet and blue) are scattered away, resulting in a red sunset. Red sunsets are often observed from a beach because of the high concentration of salt particles suspended in the air over the oceans. These particles effectively scatter shorter wavelengths of light, producing red sunsets. Dust and ash particles injected into the atmosphere by volcanic eruptions can also cause red sunsets. So the color of the sky really depends on how close to a straight path the light has to travel from the sun to your eyes. The more direct, the redder the light, the longer the path, the bluer the light. Many experiments have been done in the past to try and reproduce the blue affect as well as trying to reproduce the redness seen at some sunsets. The results that were found by scientist, who use large expensive machines can also be found by using items found around the house. Here's a way to make your own blue skies and reddish sunsets. When a flashlight beam penetrates a pitcher of clear water, there's little change in the color of the beam. Add a few drops of milk to the water, however, and you'll see the beam of light turn a reddish orange (Figure 1). The milk's molecules scatter the blue light (and some green and yellow, too) in all directions before it can reach your eyes, just as the air's molecules do for the rays of sunlight at sunset. Now look through the side of the pitcher, perpendicular to the beam. There's the blue light scattered to the sides (and in all directions), just as the air scatters blue light from sunlight to give us blue skies. Although researchers and scientist have proven scientifically, why the sky is blue and why sunsets are red, according to many Christians the reason the sky is blue and sunsets are red, is because of God. They believe that because he wills it therefore it is. Whether it is because of God or because of the wavelength of light, a blue sky or a red sunset, has the ability to brighten anyone’s day. Bibliography: 1) http://physics.about.com/science/physics/library/weekly/aao52300a.html “Why are Sunsets Red” 2) www.glenbrook.ki2.il.us/gbssci/phys/class/light/ul212f.html 3) http://members.aol.com/jimb3d/rainbow.html “Red Sky at Night” Word Count: 929
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