|MadSci Network: Other|
Dear user, The simplest suggestion would be a photo cell with a filter cutting off all but the ultraviolet part of the sun spectrum. Applying a thin film of the sun block (take care to be precise in film thickness) and measuring the yield of electricity or other characteristics of the cell , one can get a rough estimate. Another variant would be a piece of photographic paper with the same filter and a layer of sunblock. Some sunblocks work on a different principle then just filtering off the UV radiation. For these one can only suggest a suitable biological model such as human skin. Apply a number of sunblocks, expose the skin for a measured length of time, when the tan develops, take a picture of the skin area and estimate or measure the darkening of the different areas. Take care not to burn yourself. HiH. A.G.E.
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