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> IR, it penetrates water better than visible or UV. What? IR is lower energy than visible red and that's the first color to go when you get a few feet under w
by eric_h 9y ago
> IR, it penetrates water better than visible or UV.
What? IR is lower energy than visible red and that's the first color to go when you get a few feet under water (with no local light source).
- dheera 9y agoWater does absorb infrared well but it's not because it has lower energy. Infrared is absorbed well due to the spectrum of vibrational transitions. Ultraviolet is also absorbed well, due to electronic transitions. There is a "window" in the visible light that is not absorbed well by many transitions.
- eric_h 9y ago> but it's not because it has lower energy...There is a "window" in the visible light fair enough, I got my physics a bit wrong there, but I was under the impression that that window was in the blue/green part of the spectrum since I do know that water is good at blocking UV and even cosmic radiation. I also know that it's good at blocking visible red, because if you go further than about 20-30 feet down on a sunny day and cut yourself, your blood looks green. Is there an additional window in the infrared part of the spectrum that supports GP's point?