Naked Science Forum
General Science => General Science => Topic started by: darrell on 13/06/2008 15:10:52
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darrell asked the Naked Scientists:
hi naked scientists :)
great show (http://www.thenakedscientists.com/HTML/podcasts/)
My question is on suntan and the heat from the sun. I like cyprus and visit the in-laws for 2 weeks each year, my older brother doesn't like foreign travel and so he holidays in the UK only.
But when I get home he says the same thing all the time, "you only got that tan because the heat is different there, if we had the same weather here, my tan would last longer than yours, because the heat is different."
Personally I think its just sour grapes, but could you tell me if what he says, has any substance??
many thanks, darrell
What do you think?
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Hi DARRELL,
I have to say that I think, like you, that this is silly............having said that....perhaps the geography of the location on the planet might well apply different filtration to the UV rays....but I reckon that 30 degrees C in direct sunlight here in the UK is gonna give you the exact same tan as the equivalent in Cyprus !.....
..though, as always, lets wait for an expert to come in from the sun and answer ...I just think that as long as it is ' Like for Like ' then I can't see how there can be a difference !!....and that's what I have to say about that !! [:)]
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The latitude of Cyprus is 35 degrees, the Latitude of the UK is approximately 53 degrees.
So a person in Cyprus will experience more hours of sunshine per day than in Britain.
So even if the sun were of equal intensity in both countries, in Cyprus there will be more sun exposure, and a greater sunburn/tan.
The greater number of hours of sunlight per day makes Cyprus hotter than Britain, but heat does not cause a tan.
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The latitude of Cyprus is 35 degrees, the Latitude of the UK is approximately 53 degrees.
So a person in Cyprus will experience more hours of sunshine per day than in Britain.
So even if the sun were of equal intensity in both countries, in Cyprus there will be more sun exposure, and a greater sunburn/tan.
The greater number of hours of sunlight per day makes Cyprus hotter than Britain, but heat does not cause a tan.
Wow...good stuff !!
So..please do confirm then that 10 minutes direct sunlight at 30 Celsius in Cyprus is NOT the same as 10 minutes direct sunlight at 30 Celsius in UK ?.....cos that was the point I was trying to make ..
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So..please do confirm then that 10 minutes direct sunlight at 30 Celsius in Cyprus is NOT the same as 10 minutes direct sunlight at 30 Celsius in UK ?.....cos that was the point I was trying to make ..
The higher the sun is above the horizon the less atmosphere its light has to pass through and the greater its intensity at that point on the Earth. In Cyprus (@35) the sun will spend more time higher in the sky than in the UK (@53) so generally the sunlight will be of greater intensity in Cyprus. So the Cyprians generally have more intense sunlight, and more hours-per-day of sunlight than the UK, (lucky b*gg*rs).
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So..please do confirm then that 10 minutes direct sunlight at 30 Celsius in Cyprus is NOT the same as 10 minutes direct sunlight at 30 Celsius in UK ?.....cos that was the point I was trying to make ..
The higher the sun is above the horizon the less atmosphere its light has to pass through and the greater its intensity at that point on the Earth. In Cyprus (@35) the sun will spend more time higher in the sky than in the UK (@53) so generally the sunlight will be of greater intensity in Cyprus. So the Cyprians generally have more intense sunlight, and more hours-per-day of sunlight than the UK, (lucky b*gg*rs).
Quality !!....THANK YOU !!
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Actually in the summer the days are longer in the UK than in Cyprus! The sun's UV will not have passed through so much atmoshere in Cyprus and this is the biggest effect; I don't think that temperature has anything much to do with it. Tanning is due to UV light not temperature.
There are different tans due to different wavelengths of the UV and I think it is also true that getting a tan slowly allows the skin to protect itself to some extent. Matbe this has something to do with the observation.
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"Cyprians generally have more intense sunlight, and more hours-per-day of sunlight than the UK"
Generally, e.g. over one year ...
[In Cyprus] There are approximately 3350 hours of sunshine per year.
http://www.aguide2cyprus.com/index.php/fuseaction/destination.home
Sunshine hours are greatest along the south coast of England (average of 1,750 hours of sunshine per year)
http://www.bbc.co.uk/schools/gcsebitesize/geography/weather/weatherukrev3.shtml