River Colour

[bainbrig]

What makes a river blue (like the Nile south of Luxor)? Is there something in the rocks?

BB

[ToraToraTora]

things are blue when the blue end of the spectrum is scattered more than the red end because it is a shorter wave length.

[TonyV]

lot of different factors IMHO, not least what time of day and tide times

[bainbrig]

The Nile. Blue sky, blue water.

The Thames. Blue sky, murky brown water.

So not a reflection then. (or, the sea, blue sky, green sea).

Caribbean, blue sky, blue sea.

A layman’s explanation please!

[237SJ]

The reason the Caribbean sea is blue is because the sea bed is sand. You won't get a (pale) sea if the bed is rock

[bainbrig]

Why is most sea off the UK greenish?

Why is most sea when seen from a plane greenish?