Thinking of a clear sky, the first color that comes in mind is BLUE ! From our childhood we have painted blue skies, blue water, but hardly thought why the colorless water and the sky has chosen the color Blue from all the colors available in the universe !! :)
On the visible light spectrum, Blue lies between Violet and Green. Blue has a very short wavelength while Red on the other hand has the longest wavelength. Air scatters short wavelength more than longer wavelengths. Hence, blue is more strongly scattered in the atmosphere than long wavelength red light. That is why we see blue sky. Violet, though strongly scattered, is a minor component of the solar spectrum and is less efficiently detected by the human eye. Thus we are left out with just pure blue sky.
During sunrise and sunset, most of the light we see comes in nearly tangent to the Earth's surface, so that the light's path through the atmosphere is so long that much of the blue and even green light is scattered out, leaving the sun rays and the clouds it illuminates red. Therefore, when looking at the sunset and sunrise, you will see the color red more than any of the other colors.
This effect is called Rayleigh scattering, after Lord Rayleigh, the British physicist who discovered it. It was confirmed by Albert Einstein in later years.
Similarly, sea is seen as blue for the same reason. Water absorbs the longer wavelengths of red and reflects & scatters blue, and thus we see blue. The color of the sea is not only affected by the colour of the sky, but also by the algae and plant life in the water, which can make it look green; or by sediment, which can make it look brown.
On the visible light spectrum, Blue lies between Violet and Green. Blue has a very short wavelength while Red on the other hand has the longest wavelength. Air scatters short wavelength more than longer wavelengths. Hence, blue is more strongly scattered in the atmosphere than long wavelength red light. That is why we see blue sky. Violet, though strongly scattered, is a minor component of the solar spectrum and is less efficiently detected by the human eye. Thus we are left out with just pure blue sky.
During sunrise and sunset, most of the light we see comes in nearly tangent to the Earth's surface, so that the light's path through the atmosphere is so long that much of the blue and even green light is scattered out, leaving the sun rays and the clouds it illuminates red. Therefore, when looking at the sunset and sunrise, you will see the color red more than any of the other colors.
This effect is called Rayleigh scattering, after Lord Rayleigh, the British physicist who discovered it. It was confirmed by Albert Einstein in later years.
Similarly, sea is seen as blue for the same reason. Water absorbs the longer wavelengths of red and reflects & scatters blue, and thus we see blue. The color of the sea is not only affected by the colour of the sky, but also by the algae and plant life in the water, which can make it look green; or by sediment, which can make it look brown.
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