eli5: Why is water clear in small amount but blue in large amount like an ocean?

Question

I thought it might be the reflection from the sky but if that was the case, why does the ocean appears more blue the deeper you go?

In: 2918

Answer 1

Also, for an ELI25, check out Beer’s Law.

https://en.m.wikipedia.org/wiki/Beer%E2%80%93Lambert_law

A = εLc

For water, the absorptivity (ε) is low, but in the ocean, the path length (L) is huge, so the overall absorbance (A) is large enough for the blue color to become visible.