Asi es como el sol te ve... And its not even technically an ad. Artist Thomas Leveritt used a specially equipped video camera to demonstrate the UV-blocking power of sunscreen to passersby in Brooklyn, New York. The effect was dramatic. A UV filter, it seems, can make you see sunscreen in an entirely different light [Update: Leveritt has stopped by to talk about his video – look for him in the comments]: The science at play here is relatively straightforward. The filter on Leveritts camera allows him to capture ultraviolet radiation, which is of a higher energy and shorter wavelength than that typically visible to human eyes. There are three varieties of UV light: UVA, UVB, and UVC. The sun emits all three, though the latter two are mostly absorbed by our planets atmosphere, which is a good thing. UVC is the highest in energy, and the most dangerous, from a carcinogenic standpoint. UVB is less energetic, but still powerful enough to damage DNA. UVA is the least energetic, and the least dangerous, of the three, but can still cause skin damage; in large enough quantities, all forms of UV radiation can lead to increased risk of skin cancer. The association between sun exposure and cancer risk is mirrored by that between sun exposure and the formation of freckles, including – as the video so clearly demonstrates – freckles that are imperceptible to the naked eye. Freckles, after all, are just patches of skin where concentrations of the pigment melanin are high. Like sunscreen, melanin has UV-absorbing properties. Areas where UV light is absorbed appear dark when viewed through a UV-filter, which is why patches of melanin-rich skin are set in such stark contrast here. Its also why sunscreen – which absorbs UV light so your skin doesnt have to – appears black as oil. I do have one issue with the video: I think the association that it draws between freckles and unhealthy skin is a touch too simple. Yes, fair skin that freckles and burns easily IS a risk factor for skin cancer, but freckles, themselves, are almost always harmless. Whats more (and this, I think, is a point that always needs emphasizing): Just because you have a dark complexion or are freckle-free doesnt mean your skin is healthy, per se, or that you neednt worry about skin cancer. The fact is that people with dark complexions are more likely than their fair-skinned counterparts to die from skin cancer once they have it. The statistics supporting this claim can be bit confusing at first, but Ill do my best to summarize them here. First and foremost: Data from the CDC clearly indicate that white people are far more likely to develop melanoma that any other ethnicity, and more white people die of skin cancer every year than any other group. youtu.be/o9BqrSAHbTc
Posted on: Mon, 18 Aug 2014 08:01:23 +0000