Interesting Exciting rainbow on the ground at the bus stop
source and attribution (it is a nature website called groovy green)
Today it was raining when I walked to the bus stop, and when I got there, I saw an interesting exciting rainbow in a bit of spilled gasoline. I asked Jane what she supposed caused the gasoline to reflect a rainbow pattern. Since the pattern remained the same from all angles, and the light was diffused by clouds, I figured that it was not simply light reflecting off the gasoline, and Jane agreed.
After the bus ride, I was able to find out the reason why. Since petrol is lighter than water, the petrol sits in a layer on top of the water. When light lands on the puddle, some of it reflects off the gasoline, while some of it goes through the gasoline to reflect off the water. That means that for any given point in the puddle your eye sees two different beams of light: one that bounced off the petrol, and one that went through the petrol and bounced off the water.
Since the light going through the petrol had to go a farther distance, it is knocked ever so slightly out of phase with the light that bounced off the surface. My eye saw this confusion as color, and when my brain got news that an entire spectrum of color was seen in a puddle, it started to become curious.
Update: Today at work Robin told me not to use the word interesting because it is boring. I thought this was weird since interesting means not boring, but he is the boss. He suggested I use “exciting” instead. That is why I changed my title.