Why is the grass green?
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Why is the grass green?
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Accepted Answer
Matt J
on 30 Sep 2012
Edited: Randy Souza
on 1 Oct 2012
13 Comments
Star Strider
on 26 Apr 2018
There is more power in the lower frequency region of the spectrum, according to the Wikipedia article on the Spectral composition of sunlight at Earth's surface (link).
Walter Roberson
on 26 Apr 2018
That chart shows increasing power from violet to blue. At close to the upper frequency of blue, it shows a cross-over: up to that point cloud cover does not have much effect, but on higher wavelengths (that is, more towards red) the power increases in direct sunlight and decreases as cloud gets heavier. The hypothesis of blocking excess energy would then suggest that leaves should be red-er to block the higher wavelength energy peaks while being absorbing mid wavelengths that are somewhat constant -- wavelengths in the green range.
The question I quoted as introducing the article was flawed in that it supposed that green means absorbing only in the red and not in the blue or violet, when really it is that green is rejected but red and blue are both absorbed.
An interesting question would be whether the color of plants tends to be different in areas that receive intense sunlight, where it may be more necessary to reject the high power red-er wavelengths that are not blocked by clouds in those areas. I see some hints that in deserts that plants tend to be less intensely green and more blue-gray or yellow -- though that could have to do with pore sizes, perhaps.
More Answers (2)
James Tursa
on 1 Oct 2012
Edited: James Tursa
on 3 Oct 2012
Green is waste light. Grass eats the red light and poops the green light.
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