Why is the sky blue?
White light from the sun is a mixture of all colors of the
rainbow. This was demonstrated by Isaac Newton who used a prism
to separate the different colors and so form a spectrum. ROYGBIV
A clear cloudless day-time sky is blue
because molecules in the air scatter blue light from the sun more than
they scatter red light.
When we look towards the sun at sunset we see red and orange
colors because the blue light has been scattered out and away from the
line of sight.
The colors of light are distinguished by their different
wavelengths. The visible part of the spectrum ranges from red light with
a wavelength of about 720 nm to violet with a wavelength of about 380 nm
with orange, yellow, green, blue and indigo between.
The three different types of color receptors in the retina
of the human eye respond most strongly to red, green and blue wavelengths
giving us our color vision.
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