Colours of the rainbow

[RandBlade]

Odd question but I'm wondering what colours you say there are in the rainbow?

The reason I'm asking is my daughter is currently watching an episode of Mickey's Mouse Clubhouse and they're repeatedly singing and repeating the six colours of the rainbow: red, orange, yellow, green, blue, purple.

I wonder if that's Disney oversimplifying it or does anyone actually think there are six colours of the rainbow? I've always known the seven colours of the rainbow as: red, orange, yellow, green, blue, indigo, violet. Remembered through the mnemonic Richard of York gave battle in vain.

I know Americans like to do things differently, like dropping the u from colour, renaming the philosopher's stone the sorcerer's stone and keeping eggs in the fridge rather than the cupboard. But have you guys dropped an entire colour from the rainbow too?

Alternatively and tangentially-related to Disney is this like Pluto being dropped and I'm just old and remember it different to how it's now taught?

[Ominous Gamer]

Indigo is just a bastard mix of blue and purple, so it's easy to omit. Just like 99% of the other in between colors.

That being said, I don't remember being taught the rainbow was limited to certain colors, but more along the lines that it had all the colors.

[RandBlade]

To me that's like say orange is just a bastard mix of red and yellow. I find it interesting though that you weren't taught the colours, we were.

[Ominous Gamer]

Difference is that red and yellow are primary, purple is not.

[RandBlade]

Indeed nor is orange or green.

It is interesting (and I'm not sure how it works scientifically) that purple is a mix of blue and red but is after blue in the rainbow. We think of the rainbow ending at violet/purple but as far as mixing colours is concerned it's more like a continuum that wraps back around to red.

[Ominous Gamer]

that's why orange is a secondary. but indigo isn't balanced like orange. I called it an in between color, but i guess the technical term is intermediate.

I'm curious now if the color wheel was designed before we understood wavelengths. Its primary, secondary, intermediate and complementary labels are useful for kids learning patterns, but its not scientific in any matter.

[RandBlade]

Is orange a secondary colour? My understanding is that scientifically now the secondary colours are the printing colours - cyan, magenta and yellow.

[Ominous Gamer]

That would follow RGB as the primaries.

There is a camp for that. But I was going with traditional colors. Which, hey, loops back to how color education has changed over the years.

[RandBlade]

Indeed.

[EyeKhan]

Technically speaking, a rainbow should have every color in the visible spectrum of sunlight - or, roughly, light of and between wavelengths of 400 to 700 nanometers. I'm not sure it's possible to count the individual colors within, though you could probably go with the number of colors within that spectrum that the human eye can distinguish, or about a million. (See below). Oh, and I can see green in the rainbow, so I agree there are seven basic colors.

So going off of unique frequencies, there are more colors in a rainbow than there are stars in the Universe or atoms in your body, but that goes far beyond what we can perceive. Your imperfect eye can (probably) only discern about a million distinct colors when you view a rainbow, or anything else, for that matter.

http://scienceblogs.com/startswithab...-in-a-rainbow/

[Aimless]

We can distinguish many more colors in the rainbow but the number of "main" colors of the spectrum is somewhat arbitrary. Newton for example divided the spectrum into five colors. I think this is another instance of the general American anti-establishment pathology or a result of some dude going "wtf is 'indigo'?"

[RandBlade]

And "wtf is 'violet'" too. I wonder if they'll be talking about infrared and ultrapurple next?

Newton started with 5 but added 2, it was him who settled on the 7 I still think of and is still taught here.

[GGT]

The Weather Channel still used ROYGBIV when talking about rainbows (video of rare "twin" rainbows, turned out to be just one with a mirror image making it look like two). But I think schools dropped indigo and violet in favor of purple some time ago. Not sure why, since ROYGBP just doesn't sound as good.