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SCOPE goes to the sun
One of the best things about a holiday is lying on the beach soaking up the sun's warm rays. But did you know that the sun is actually a huge ball of fire? It's a million kilometres wide and burns at 15.6 million degrees. Its energy output is estimated to be 386 billion, billion megawatts. This can seriously affect our skin. Burning rays Too much sun can cause sunburn, premature ageing or skin cancer. This is because some of the sun's rays are harmful. The sun is a giant star and it sends out three sets of rays:
Suntan So how does our skin tan? First of all, we need to understand a little about our skin. Skin has several layers and the outer layer is called the epidermis. This is like the barrier between us and the world. Within this, there are cells called melanocytes. When these cells feel the sun's rays, they start to produce melanin, a brown pigment. They send this to the surface of the skin and this is what causes your skin to go brown or tan. Melanin takes around five to seven days to build up and it provides a more protective barrier to the sun. Freckles happen when melanin is distributed unevenly. Sunburn Sunburn is like any burn to the skin. The skin goes red as blood flows to the area, trying to repair the tissue. It eventually fades back to white and it can be very painful. Sunburn happens when you spend too long in the sun. Sunburn does not turn into a tan and it can actually cause long-term damage to the skin. The best way to avoid it is to use sunscreen. Sunscreen can protect the skin against sunburn by putting up a barrier to block harmful ultraviolet rays. For example, ultraviolet light can't burn you through glass, so you are safe in a greenhouse or car because the sun's rays can't get through and burn you. The chemicals in sunscreen, like para-aminobenzoic acid, try to do the same job, by blocking or absorbing the ultraviolet light. All sunscreens have a Sun Protection Factor, or SPF. If you would normally burn in 10 minutes without sunscreen, applying an SPF 15 sunscreen may provide you with an estimated 150 minutes of protection before you burn. However to protect your skin against sunburn, experts recommend you use a sunscreen with as high a factor as possible, ideally 30 or 35. You may also need to keep re-applying it as it can wash or sweat off. Learn more: Find out more about The Sun as a planet [http://www.solarviews.com/eng/sun.htm] Find out more about how the sun affects us [http://www.bbc.co.uk/science/hottopics/sunshine/index.shtml] Read more about how suntans work [http://science.howstuffworks.com/sunscreen.htm] |
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