Book 7, Question 110
Why Do Oil Slicks Shimmer Like Tiny Rainbows?
Oil slicks shimmer like tiny rainbows because a very thin layer of oil on water works like a bubble wall. Light bounces off the top and bottom of the oil film, and the waves interfere. Those are mini rainbows in parking-lot puddles!
From the book
Page from A Million Whys Book 7
More fun facts
- The rainbow on a street puddle comes from oil from the road floating on top of the water.
- Spilled oil spreads quickly across water, forming a thin slick.
- As it keeps spreading, the slick gets thinner and thinner until it becomes a sheen that often looks like a rainbow.
- Most oils float, but heavy oil can sometimes sink, especially when mixed with mud and sand.
- NOAA scientists help decide which shorelines to protect and where to put cleanup equipment during an oil spill.
Sources: NOAA, NOAA Ocean Service
Questions kids ask
Why is there a rainbow in a puddle?
A thin layer of oil from the road floats on the water and makes rainbow colors.
Does all oil float?
Most does, but heavy oil can sink, especially when mixed with mud and sand.