Why does a rainbow have those colors, in that exact order? đ
Turns out you only need 3 ingredients to make one:
- Sunlight
- A drop of water
- Your eyeball
That's the whole recipe.
Start with the sun. It shines "white" light at us all day â except white isn't really a color.
It's red, orange, yellow, green, blue, indigo, and violet, all stacked on top of each other like notes in a chord.
Play them together and your brain hears "white."
Now drop in some water.
When light hits that droplet, it slooows down.
And when light changes speed, it bends.
Red bends one way.
Violet bends another.
Every color in between gets sorted into its own lane and pops out the back of the droplet at its own specific angle.
That's refraction.
Now add ingredient #3...you!
Sun behind you, rain in front of you, and every single droplet up there is firing one color of light straight at your face from one specific angle.
You're not looking at "a" rainbow.
You're looking at millions of water droplets, each handing you one wavelength, assembled into an arc by your own line of sight.
So a rainbow isn't just a thing in the sky.
It's really a transaction between a star, some water, and you.