When we cut brown wood from a tree, the wood intrinsically remains brown in our hands. When we pull a red petal from a rose, the petal intrinsically remains red in our hands. When we pour white milk from a pitcher, the milk intrinsically remains white in our glass. If the paradigms were continued, we would continually, time after time, find that these elements around us are simply…the color we see them to be. Here we find that empiricism holds true time and time again in every basic characteristic of our surroundings from day to day life- except for two of the most basic, the two we see every day- water and air. The healthy individual sees these basic elements on a regular basis. And every day that we see them, in the ocean or in the sky, the two elements are blue. But every day we touch them, or isolate a sample from the rest…they are not. Why is the sky, and why is water mostly blue in appearance? And why does a sky change colors during sunset?

The answer is not as simple as one might expect. In fact, it actually took scientists an extremely long time to actually determine why the sky is blue. After all…the sun is yellow, and casts white light, and space is black, and the clouds are white, and the ground is any color but blue. So where does this blue even come from?

Light from the sun appears white when directly beneath it. But, as taught to most in high school, white light actually consists of a mass variety of colors all combined: red, orange, green, yellow, blue, indigo, and violet (ROYGBIV). Another lesson we learned in high school is that these colors travel in different types of waves with varying wavelengths. Some more frequent, some less. Some more choppy, some less. These colors, all together, travel in a straight line, headed in just one direction…unless something is present to disrupt this path, disperse, and separate the colors.

In the sky surrounding earth, one would assume there is nothing to disrupt that path of white light but clouds and airplanes. Assuming this would be assuming wrong. In the sky are a variety of objects to disrupt the path of white light, ranging from pollen to dust to salt to a massive variety of gases, all of which disperse the light, absorbing it and reemitting it, or reflecting it. And because the color blue travels in more choppy waves, it is more widely dispersed and spread across the sky. Hence, when we look up around that sun and beside those white clouds, we see the color blue. However the light coming from the sun that is directly above us has less distance to travel, and collaterally, has less distance to run into obstacles such as gas or pollen. For this reason, the sun appears white when directly above us.

As for why the sky turns all sorts of different colors during sunset? The lower the sun descends in the sky, the more distance that white light has to travel over the Earth to meet our eyes. Different obstacles closer to the ground are then present to obstruct the path of light. Different colors are then more widely dispersed than blue. And in turn, these different colors and different strengths of the sun’s rays meet us. Most often, it happens to be the color orange or the color red.

Now, we’re left with the pending question, why is water blue? After all, in a glass or jar, it is clear. Sadly, again, we’re left with the unsettling answer that nobody really knows. One theory is that the ocean dominantly reflects the sky’s blue; its water particles acting as a massive network of miniature mirrors to continuously pass the color around. The other theory suggests that it’s the same reason the sky is blue- particles of the ocean easily reflect and disperse blue light and its short, choppy wavelength. To those wondering why the ocean is sometimes green…well there’s no accepted answer either. Many assume it’s the yellow pigment from plants mixing with the color blue. As for the validity of the claim, time will have to tell with increasing scientific observations, as learned in class. There will always be mixed theories, accepted and then disproved later, as learned in class.

One final theory suggests that the ocean is blue from all the waving it does…and receiving nothing in response.