Why does oil on water turn rainbow colored?

Question

Whenever you see petroleum oil spilled on a wet surface, it turns rainbow colored. That doesn’t happen with olive oil, or other liquids. Why do petroleum products change color that way?

In: 78

Answer 1

Eli5: light hits your brain differently based on its wave speed (thinks surfing). You see different colors based on the speed of the wave.

When that wave hits the oil you see that first wave bounce back and hit your eye. But some of that gets through then bounces back off the water then back and forth, like ripples, making the wave slower and slower.

So you see the waves at various speed and your brain interprets it in different colors.