Young George (7) wants to know why there are only seven colours in the rainbow...where's brown, for example?

Question

Loxie, you are D***head.

Answer 1

erm... lol, have absolutley no idea, just trying to answer all your questions. ;-)

Answer 2

Two parts to this one.

First, brown is a combination of different colors. When the human eye recieves multiple colors from the right parts of the spectrum, it sees brown. White is all the colors together, and black is no light. Other colors can be made as combinations of colors as well. For example, your TV can make all different colors using only red, green and blue (look at it closely!). That's just how the human eye sees things.

Second, there are 7 (Red Orange Yellow Green Blue Indigo Violet) because that's what Newton saw. I'm not kidding. There are an infinite number of colors in a rainbow, but telling the difference between one shade of red and a slightly different shade of red is difficult and not very exciting.

Sir Issac Newton, famous for his law of gravitation, also did a lot of work in optics, especially with breaking up the spectrum of light with a prism. One sees a rainbow when white light is broken up by a prism. For whatever reason, Newton counted those seven colors in the rainbow. Some think he may have added indigo (a shade of violet) to make the total number of colors 7, which, in many ways, is a more interesting number than 6. In any case, Newton's rainbow description has stuck around, and so that's how we think about rainbows today.

Answer 3

"Brown" is not really a colour - it's a hue.

A rainbow, and it's seven colours is what you get if you separate white light into all it's constituent wavelengths. Think about paint, rather than light, because the rules are different, and paint is easier to explain to a child. You get the primary colours (red, yellow and blue for paint). Mixing any *two* of these together in various concentrations gives you colours in a rainbow. However, mixing *three* together will give you the "other" colours - slowly add the third primary colour to a mix of the other two and you will slowly, but surely come up with brown. If you could mix exactly equal quantities of all three, you would get black.

As a rainbow is light, the primary colours are different (green is a primary colour of light, not yellow) but the principle is the same. Colours in a rainbow are made up of combinations of *two* primary colours but never three. This is the easiest way to explain it to your child, and you can demonstrate it with paints so he understands better.

Answer 4

There is a distinction that is identified between the 'additive' colors of light (colors of a spectrum) and the 'subtractive' colors of pigment.

In simple terms if you begin to add the colors of light together in the 'pitch black' of darkness (the absence of light) you will distinguish between the different visible colors of the spectrum and if you mix all the 7 colors of light you will get white light. Hence the Black (no light) and White (total light).

In pigment terms you start with a 'white' page and if you add all the primary colors together (of which there are just 3 Red, Blue and Yellow - but which can be combined in pairs to create the three secondary colors - Purple, Green and Orange) you will end up with a sort of purply/browny/grey 'approximation' to black.

In nature although we see things as various 'broad colors' in fact those colors which may be seen as brown range from dark oranges through to very dark purply browns.

When a rich dark Orange created from deep Red and Yellow pigments, is tinted with a little Blue - it will look brown - so it is really a 'pigment' color made from a combination of all three Primary colors added in different amounts.

I suppose you could say in the spectrum of light - there will be some parts of the overlapping spectrum between red and yellow lights that are distinct orange - and when the light is 'lowered' this may be seen to approximate to a 'brownish' color - a 'virtual color' created as 'light is reduced'.

So brown is really a 'trick of the light' or a color found in 'subtractive' pigment colors...

(On a side note - If you are a watercolor painter in particular - it is true 'black' that really never appears on your palette - as the intense 'blackness' of black too much for a world of light - where 'some' light ALWAYS is found (very few places exist where there is truly NO light (above ground that is) - so watercolorists use Payne's Grey which is a 'lightened' version of grey-black and can be useful for heavy shadow.)

Answer 5

Brown is a 'mixed' colour. Show him how to make brown by putting red & purple together. Try it alone first so you get the right colour.

Stumped said that there are 7 primary colours - there are not. There are only three Red, Yellow and Blue. All the other colours can be mixed from them. White and black are not considered colours.

Answer 6

The ROYGBIV colors cited frequently are not red only, orange only, and so on. For example, if we start with R and move right on the seven cited rainbow colors, the color gets less red and more orange. But it doesn't just suddenly change from red to orange...it's a gradual change.

The colors of a rainbow are spectral colors that depend on the wavelengths...shorter wavelengths mean bluer color, longer wavelengths mean redder color. So the red you see on one side of a rainbow means the longer wavelengths of colorless light (which is a combination of all the wavelengths). These longer wavelengths are reflected off the raindrops that help form the rainbow.

At the other end of the rainbow, we see violet (the V in ROYGBIV). We see those shorter wavelengths because they. too, are reflected off the rain drops, but at a different angle from the red wavelengths. The difference in the angles of reflection is what determines which wavelengths are reflected so we can see them as ROYGBIV colors.

Brown and other colors like it are not spectral colors based on white light being seen as its parts (i.e., ROYGBIV). They are colors resulting from mixing pigments of various colors (like in crayons or paint).

Answer 7

The rainbow shows seven colors because the water vapor in the sky acts as a prism to separate white light into its components. Brown is a combination of purple and red.

Answer 8

because brown is a combination of colours on different sides of the visible part electromagnetic spectrum... thats the range we can see, you know how you get red orange yellow green blue indigo and violet. Well notice how the colours you'd mix together to make brown aren't anywhere near eachother. ...so you can't get brown in a rainbow!

Answer 9

there can be a million different colors of crayons
but the rainbow is a natural arc of colored light in the sky caused by refraction of the sun's rays by rain
its not just a list of colors
its just what naturally is there

Answer 10

only pretty colours are allowed in the rainbow and brown is not a pretty colour

Answer 11

red orange yellow green blue indigo violate
Richard of york goes battling in vain