Why are there only 7 colours in the rainbow?

Answer 1

The number of colors in the rainbow is set by convention. People agreed on it. That is why. People LIKE simple answers. Plus, when you look at a rainbow, the human eye and brain PERCEIVES clear "bands of color" and we choose to name those. Red IS different from Blue.

There are seven "canonical" colors. R O Y G B I V . Many people, however, do not perceive indigo as a separate color from blue or violet, so that makes it six... Six or Seven are both "normally acceptable answers." When looking at a real rainbow, many people have trouble "finding the orange" and some people have trouble "finding the yellow" You can frequently symbolize a rainbow with only Red, Green, Blue and Purple, so, Five is "common" and Four would be workable answers to "how many colors"

The gay-pride flag uses only six colors ROYGBV

I have often wondered if the indigo was included only so that the neumonic would be simpler Roy G. Biv. is simpler to remember.

But as many of the OTHER posters have said, the edges of those canonical colors fade together. You get reddish-orange and orangish red and so forth. there's no sharp line where you can say "THIS IS RED and THAT IS ORANGE" although there are clear "bands of color" So, in another sense the answer is "an infinite number, since ever different wavelength of light is a color, and all the colors in the sun are there."

BUT BUT BUT BUT

The answer is _not_ "all the colors there are" because color perception is a function not only of wavelength but of saturation.

So, something that is of color blue, but very very dim, looks different than something the same color of blue, but very very bright. Also, some of our color perception comes from MIXING colors, and the rainbow UNMIXES them.

To put that another way, there is no "Purple with a greenish cast" in the rainbow. Neither is there "blue with a hint of yellow." The colors are all separated out.

So, the answer is 'Usually seven, but six or five for some people, but you can argue for an infinite number as they fade together."

Answer 2

There is more than seven "colors" in a rainbow, it's just that is what we percieve

Refraction is responsible for rainbows and for the splitting of white light into a rainbow-spectrum as it passes through a glass prism. Glass has a higher refractive index than air and the different frequencies of light travel at different speeds (dispersion), causing them to be refracted at different angles, so that you can see them. The different frequencies correspond to different colours observed.

You only see the visible spectrum because that what the eye can descern.

Answer 3

There are not only 7 colors. There are more. However, we decided to created seven colors. The visible light spectrum contains mixes of the various colors.

Answer 4

7 that are distinguishable to the human eye.
That doesn't mean there are only 7 colors in the rainbow.

Answer 5

They are the spectral colors formed by reflection, refraction and dispersions of the sun's rays in rain and mist.The sun doesn't reflect on the darker colors.

Answer 6

seven are the the DIFFERENT colors that when combined together FORM white light. So they are the BASIC colours or BUILDING BLOCKS of LIGHT !
Pleasure to HELP !
Salik

Answer 7

They all blend seamlessly from one to the other - there are seven because we have named seven of them. In fact all colours of light are in there.

Answer 8

All the colors are there, but you have a difficult time seeing them all

Answer 9

Because of the refraction index.

Answer 10

Because:
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