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So this is a question for those who know phisics well (optics more specifically).
Does one gets sunburn faster under water than on surface?
Assuming the water is some kind of sea, not dirty. Little waves are present. The depth is 1 meter below the surface.
Historty: one of my friends has told me it is true (he states one of his friends is gosu diver and he derived this fact from him), but I have trouble believing it. He states the water works like a lence, which I don't really get: the lence takes rays from wider range and redirects them to the thiner one, what does it have to do with water in the sea?.. I know some kind of rays will get mirrored by the water surface so it should mean you get sunburnt slower.
Can someone clarify? Simple language plz.
Thanks
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United States13896 Posts
UV rays are scattered by water, and on top of that the surface of the water will reflect some of the rays outright, so your are more protected underwater.
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I think this is nonsense, why would you expect a flat water surface to behave like a lense? And even if a freak wave happened to refract the light like a lense, you probably would not be at it's focal length.
I suspect a more likely explanation is that the cooling effect of the water makes you feel like you have not been in the sun for long. So you expose yourself to the light longer.
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is awesome32274 Posts
Both the answers above are right
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I'm pretty sure that's just a misinterpretation of the fact that your face is more likely to get sunburnt if you don't put any lotion, probably because of the additionnal exposure from reflecting light. At least that's what happened to me from time to time (lived half my life in tunisia). I can't remember getting any bad sunburns on my body from staying in the pool/sea.
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I think you're all pretty cute
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On March 21 2009 00:56 Hammy wrote:
I'm pretty sure that's just a misinterpretation of the fact that your face is more likely to get sunburnt if you don't put any lotion, probably because of the additionnal exposure from reflecting light. At least that's what happened to me from time to time (lived half my life in tunisia). I can't remember getting any bad sunburns on my body from staying in the pool/sea.
This only happened because generally your face is ABOVE the water. You can consider the surface of the water more like a focusing mirror than a lens. The sun can be and often is amplified when it bounces off of the surface of the water, which is why it's the only place I will ever get sunburned.
To the OP Water itself however completely disperses out UV rays so no, it's pretty much impossible to get a sunburn underwater unless you're an albino or something.
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is awesome32274 Posts
On March 21 2009 01:03 frankbg wrote:
I think you're all pretty cute
I think YOU are pretty cute.
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HonestTea
5007 Posts
As punishment for saying something so utterly stupid, you should pretend like you can't know for sure unless you friend tests it out himself
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Your friend is a gosu diver, so he spends a lot of time outside (ie on the sunlight), so that's why he has sunburns. At least I'd reason so.
And what Heggie and IntoTheWow said is right in my opinion. Though it's always best to check it by asking someone that actually knows the anwser and explanation. (ie an expert)
Water reflects the sun at you. Right. But it reflects it almost for a same amount in every direction, so it does not burn you any more than anything else. (that's for the parallel component of the light, caused by reflections & direct light at the part of the body outside the water)
A part of the vertical component gets reflected back from the surface, so if you're under water, you'll get less "burns".
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If you stand in the water, you get burned faster as someone else mentioned, you will get ''double'' dose of rays because the water will mirror the rays upwards to your body again. Underwater your more protected.
It's true btw, people don't feel the ''hotness'' because of the coolness of the water, and thus they get burnt, and think you get burnt easier underwater.
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The worst sunburns I've ever had was during my sailor course. After spending ~10 hours on a boat/day for 2 weeks, my face was almost black, skin was peeling from my nose and ears and the bubbles started showing up.
The whole course was an awesome experience nevertheless.
Perhaps this diver your friend is referring to also spends a lot of time on a boat/near the water (you have to get to the diving spot somehow) and this way you get sunburnt much faster (normal sunlight + light reflected from the water), the snow works the same way.
Edit: God damned ninja posters 
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Ultraviolet rays penetrate water but lose half their intensity (radiation is absorbed and scattered plus some is reflected at the surface) and will not penetrate water very far.
So over all there are 3 reasons the submerged you is more protected than the dry you.
If overexposed, the parts of you that are above water, if you were near the surface, will burn faster than if you were on dry land because the surface of the water reflects some of the radiation!. This last thing is what your friend probably heard and got confused.
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simple enough language i hope
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Was he using waterproof sunscreen?
I know you can get sunburns underwater, but they should take longer.
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if you come into contact with a jellyfish?
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On March 21 2009 00:42 Cheerio wrote:
So this is a question for those who know phisics well (optics more specifically).
Does one gets sunburn faster under water than on surface?
Assuming the water is some kind of sea, not dirty. Little waves are present. The depth is 1 meter below the surface.
Historty: one of my friends has told me it is true (he states one of his friends is gosu diver and he derived this fact from him), but I have trouble believing it. He states the water works like a lence, which I don't really get: the lence takes rays from wider range and redirects them to the thiner one, what does it have to do with water in the sea?.. I know some kind of rays will get mirrored by the water surface so it should mean you get sunburnt slower.
Can someone clarify? Simple language plz.
Thanks
On March 21 2009 00:48 Heggie wrote:
I think this is nonsense, why would you expect a flat water surface to behave like a lense? And even if a freak wave happened to refract the light like a lense, you probably would not be at it's focal length.
I suspect a more likely explanation is that the cooling effect of the water makes you feel like you have not been in the sun for long. So you expose yourself to the light longer.
Ok what the fuck is a lence or a lense?
BoT, does the saltwater drying out your skin play any role?
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On March 21 2009 05:56 CharlieMurphy wrote:Show nested quote +On March 21 2009 00:42 Cheerio wrote:
So this is a question for those who know phisics well (optics more specifically).
Does one gets sunburn faster under water than on surface?
Assuming the water is some kind of sea, not dirty. Little waves are present. The depth is 1 meter below the surface.
Historty: one of my friends has told me it is true (he states one of his friends is gosu diver and he derived this fact from him), but I have trouble believing it. He states the water works like a lence, which I don't really get: the lence takes rays from wider range and redirects them to the thiner one, what does it have to do with water in the sea?.. I know some kind of rays will get mirrored by the water surface so it should mean you get sunburnt slower.
Can someone clarify? Simple language plz.
Thanks Show nested quote +On March 21 2009 00:48 Heggie wrote:
I think this is nonsense, why would you expect a flat water surface to behave like a lense? And even if a freak wave happened to refract the light like a lense, you probably would not be at it's focal length.
I suspect a more likely explanation is that the cooling effect of the water makes you feel like you have not been in the sun for long. So you expose yourself to the light longer. Ok what the fuck is a lence or a lense? BoT, does the saltwater drying out your skin play any role?
Like a magnifying glass lens.
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I was mocking them for spelling wrong. The ukrainian guy can be forgiven , but the UK guy, cmon.
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the water will reflect a bunch of UV rays, so im guessing you'd be more protected from sunburns
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You could try an experiment of your own buy putting a thin layer of water in glass case and then sitting under it and then doing the same thing without, you will notice the difference of radiation/heat.
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EPT
