Chlorophyll. Wavelengths. Eye. And how these give us color vision.
1-Minute NomNom
Green vegetables look green because when light falls on them, the chlorophyll (see below) in the vegetables absorb all the colors of the spectrum except green. This is reflected into our eye.
If we blanch the vegetables, they look brighter. Blanching removes the air pockets that reflect white light which dulls the green of the chlorophyll we see (explained in this 1-Minute NomNom).
Why this happens has a lot to do with wavelengths of light and how our eye is activated by light.
Chlorophyll … when there are air pockets
The chlorophyll most commonly found in plants, chlorophyll a,
- absorbs blue light (which has wavelengths around 465 nanometers)
- absorbs red light (which has wavelengths around 665 nanometers)
- reflects green light (which has wavelengths around 510 nanometers)
Thus our eyes perceive the vegetables and plants as green.
In our eyes’ retina, we have two types of photoreceptor cells (cells that are sensitive to light): cones and rods. The cones give us color vision (don’t worry about the rods yet).
There are three types of cones. One cone is sensitive to light of long wavelengths (red), another to medium wavelengths (green), and the third to short wavelengths (blue).
When we don’t blanch the vegetables, the light reflected by chlorophyll activates the medium wavelengths cone (i.e. green), while the air pockets reflect light that activate all three cones, which we see as while light and which dulls the sensation of green from the chlorophyll.
Chlorophyll … when there are no air pockets
When we blanch them, the air pockets expand and escape. Thus most of the light that is reflected into our eyes is the green from the chlorophyll. Only the medium wavelengths cone is activated, giving us a brighter perception of green, and that of a yummier meal.
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photos: in order – depositphotos/iakovenko123; zhuzhu; BigAlBaloo; edesignua; gnohz
