Why sky is blue and how does rainbows occur?


Rainbows and Blue Sky
The blue sky and rainbows are most fascinating displays of nature.  From the time, memorial people with no idea on how rainbows and sky blue take place believe in various ancient cultures which explain their occurrences.  This article elaborates the science behind rainbows and sky blue.  Rainbows do not occur in a single location and it is not a thing, but it is an optical phenomenon which takes place when the viewer's position, sunlight and atmospheric conditions are fulfilled.   For the rainbow to occur, water droplets must exist in the air; the sun should be behind the viewer and with the absence of clouds from the sun.  Rainbow is a complete cycle; however, due to the viewer's position, it appears as a half cycle.  When the sun shines on water droplets in the air, and as the light passes through the water droplets they refract since water is denser than air, therefore, light travels slower in water droplets than in air Sci jinks . The light bounces back off the droplets and return to the way it came from and again bend as it comes out of water droplets.  Sunlight consists of numerous colors (wavelengths) which refract at different angles when the sun shines get into water droplets.  For instance, violet which is the shortest wavelength refracts the most while the longest wavelength (red) bends the least of all the wavelengths.  At the time the sunlight is exiting the water droplet, it is separated in all of its unique wavelengths.  The light that is reflected on the observer with the sun behind the viewer are composed of all the rainbow's colors (wavelengths) with the longer wavelength(red) existing on the top during the shortest wavelength(violet) on the bottom.   The reflection inside the water droplets results in a double rainbow, where the secondary rainbow appears fainter than the primary rainbow. The secondary rainbow occurs due to the second reflection inside the water droplet, while primary takes place from a single reflection inside the droplets. The secondary light exits the water droplets at a different angle 50˚C contrary to 42˚C of the primary rainbow. The order of the wavelengths is changed with violet on the top and red on the bottom for the double rainbow (primary and secondary rainbow). 

Sunlight always appears white; however, it contains several colors (wavelengths) of the rainbow.  Light travels in a straight line but can bend, reflect or scatter when interrupted by an object. For example, when sunlight sparkles via a prism, it is separated into its distinct wavelengths of visible light. Studies indicate that the light people see is one of a tiny constituent of various types of light energy beaming about people and the universe. Earth's atmosphere scatters the blue color more than the other components of sunlight. Light from the sun is scattered in all directions by the air components when it reaches the earth’s atmosphere.  The blue color is scattered more than the other wavelengths by the small molecules of the air because it travels as small waves.  Therefore, it is what makes the Sky blue most of the time.  As the sunlight passes through the air the blue sky fades to a white or a lighter blue as it approaches the earth's horizon NASA Space Place .The light reaching the earth's surface appears white due to numerous scattering and reflection (the scattering mixes the wavelengths together; therefore, the observers can only see the white or less blue color).    

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