hat brand and SPF of sunscreen absorbs the most UVA and UVB rays? If we were to test what brand and SPF of sunscreen absorbs the most UVA and UVB rays, we figured that the Coppertone Sport with both SPF 15 and 30 would be the brand that would prove to be the best.
Our hypothesis was wrong. When reading our results it was difficult to decide which sunscreen was the most absorbent, but we were very sure that it was not the Coppertone Sport. Brands like the Safeway SPF 15 sunscreen absorbed the most at 310nm but when the wavelength increased, absorbency dropped, therefore showing that it is only very effective against UVB rays. The Lorťal Ombrelle sunscreen dropped a lot, just like Safeway brand, but it dropped in different places. We were most impressed with Fruit of the Earth sunscreen which had about equal absorption of UVA and UVB rays and was consistent all the way across the board.
Our results showed us that there is something very wrong with the SPF labels on sunscreen. Youíll notice on our graphs, that the two best absorbents against 310nm (UVB rays) were really SPF 15. After being the top here, they didnít drop down far below the best for the following nm either. Below these results we noticed that the very worst results were from a SPF 30 sunscreen, this was the Hawaiian Tropic. So what does that tell us? Quite possibly that SPF doesnít mean as much as we think it does. Maybe it means the companies are lying to us. Maybe it means we tested bad product. Maybe it shows our testing was false. Maybe it shows that every hundredth of a gram had to be dissolved in order for the sunscreen to work 100%. Either way though, SPF appeared to be much less of predictor than people are lead to believe.
Though after hearing the information given, Iím sure it is very easy to side with the companies and say that our testing was just not executed properly and we have bad results. I assure you, this is not true. In doing our experiment we were extremely careful to control every aspect. Many tests were done several times just to be sure they were true, and lastly each and every sample was treated exactly the same during all parts of the experiment. Our testing was done thoroughly and with little error and room for doubt.