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Asked by to Aimee, Chris, Dave, Greig, Laurence on 16 Jun 2014. This question was also asked by .
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Greig Cowan answered on 16 Jun 2014:
The sun produces light in a wide range of wavelengths (colours). Some of these wavelengths are called ultra-violet (UV) since they have a wavelength smaller than that of blue-violet coloured light. You can’t see this light with your eyes since the wavelength is too small, but this doesn’t mean that it can’t have an effect on your body. The UV light carries a lot of energy and because of it’s small wavelength it can penetrate below your skin. This can cause damage to the tissue below your skin which is why we get red and burnt.
Our bodies have a defence mechanism against this which is to produce a dark pigment called melatonin. This is the pigment that gives people freckles but after exposure to the sun more of your skin will be covered with melatonin and you will start to get a sun-tan. The skin that contains melatonin can more easily absorb the UV light, preventing further damage.
Sun cream also prevents burning since it contains an active ingredient that absorbs the energy from the UV light before it penetrates into your skin.
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Dave Jones answered on 16 Jun 2014:
The Sun produces light in all colours, just like the colours of the rainbow, except it also produces light either side of those colours in ranges that we can’t see. One side is really harmless, this is the low energy side that contains radio waves and infrared radiaton. The otherside has the high energy rays including the type which are just too blue for our eyes to see called Ultraviolet or UV rays. Most of these are blocked by the atmosphere but some still get through (especially in areas where the ozone layer has been damaged). When this UV radiation comes into contact with your skin in damages the cells, stopping them from working or breaking them. It is this damage to the skin cells which is called sunburn.
Suncream blocks these UV rays and stops them from reaching your skin, keeping you safe from sunburn. You have to keep reapplying though as this layer of chemical gets absorbed or washed off by sweat (or water if you go for a swim), so keep safe and keep applying suncream regularly!
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Laurence Perreault Levasseur answered on 18 Jun 2014:
Greig’s and Dave’s answers already pretty much say it beautifully!
But one last question, maybe, is how does sunscreen block those UV rays? It does it in 2 ways.
First sunscreen has inorganic ingredients in it, and those reflect the UV light so that it never reaches the skin. So if you could see in UV wavelengths, your skin would look like a mirror!
Second, sunscreen has organic ingredients that absorb the rest of the UV light that hasn’t already been reflected. Once absorbed they convert it to heat, so the UV rays cannot go inside the skin to do damage.
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Aimee Hopper answered on 19 Jun 2014:
Sun cream has been developed to reflect or absorb the UltraViolet part of the suns light, the part that creates the sunburn. This means that the UV cannot get through the skin to kill the living cells underneath, and so doesn’t cause the body to repair itself.
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