Is it the sky or the sea that copies the color blue as its color? Why?
In the first place, the sky is blue because the molecules in the atmosphere scatrter the blue part of the spectrum, and the red and yellow parts of the spectrum tend to pass straight through. To us looking from the ground, the blue light seems to be coming from everywhere (this is called ‘Rayleigh cattereing’); hence the sky seems blue. The reason why the sea seems blue is similar; but a little more complicated. The sea does reflect the blue colour of the sky (or can appear grey in overcast weather), but this only applies to the surface of the sea. As well as reflecting the blue from the sky, the water molecules scatter the blue light in much the same way as the air molecules in the sky. This accounts for the ‘natural faint blue colour’. In addition, the water also absorbs more of the red and yellow wavelengths (which warm the sea), leaving the blue part of the spectrum, as well as part of the green. This is why deep water can appear bluish-green. (The absorption of the red wavelengths
