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ladyvols1 eNotes educator| Certified Educator

The Earth has its color because 70% of the earth’s surface is covered by water. Our oceans and other bodies of water appear blue because of the way our sunlight is scattered as it goes through our atmosphere.  The size of oxygen and nitrogen molecules is almost the same, and they are similar to the wavelength of blue light.  This makes it possible for waves of blue light to pass through oxygen and nitrogen molecules in the atmosphere and are then reflect in all directions causing the scattering effect.  Wavelengths of red light are somewhat bigger, and they get around the oxygen and nitrogen molecules without being entirely blocked. This allows the red light part of sunlight to more easily pass through the atmosphere, while blue light doesn't get very far before being scattered.  It is much like the effect of an ice-berg which also looks blue.  All of the different colors in the light wave are absorbed except the blue, so the icebergs look like they have a blue light bulb inside them.  The water on earth reflects all the blue light and mostly absorbs the other colors.