Most of us know the order of a rainbow’s colors: red, orange, yellow, green, blue, dark blue, purple – but my question is why is the order like this, and not different? Does this has something to do with some ultra high level of physics?
Also this is my first ever ELI5, if I’m doing something wrong feel free to point it out for me.
In: Physics
White light is made up of waves of different lengths.
When white light is shined through fine water droplets, those droplets break down the white light into its separate parts; the different waves that are visible to our eyes.
(They don’t really break it down, it’s more like magnifying a gazillion times, so you can see what the white light is ‘made of’. If you have an old inkjet printer, try printing a grey area. It will look grey, but if you look closely, the grey is actually made up of Blue, red and yellow dots. Same goes for light. Look VERY closely, and you’ll see the different colors. The water vapor between you and the light source, usually the sun, will do the magnifying for you.)
Violet has the shortest wavelength, and red the longest. Every other color is in between.
What we perceive as white light is generally light of all the colors across the visible spectrum. When rainbows happen, this white light is bent by the water in the air, and the degree to which they are bent is determined by the wavelength of the light. This wavelength is also what our eyes detect and perceive as color. So we see a rainbow that progresses nicely from one end of the spectrum to the other. If you look up the visible light part of the electromagnetic spectrum (which is organized by wavelength) you’ll see the same progression as you do in rainbows
It’s not some ultra high level of physics, it’s wave lengths. Red having the longest wavelength and violet having the shortest, which is why ROYGBIV is the order of every rainbow.
Each color is light traveling at different frequencies. The warm colors have higher frequencies and the cooler ones have low frequencies.
As to why we specifically perceive red as red or blue as blue. That’s just how we make sense of the different frequencies. There’s not any real reason. Maybe in our most ancient ancestral proto lifeforms being able to tell color was useful in avoiding harmful chemicals or knowing what’s safe to eat and we just never had lost the capability.
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