What brand and SPF of sunscreen absorbs the most UVA and UVB rays? We thought that the ‘Coppertone Sport’ sunscreen of both SPF 15 and 30 would be of the greatest absorbency. Reasoning being that it was a ‘sport’ sunscreen and what it had over some of the competing sunscreens was that it was both waterproof and sweat proof.
First we dissolved the sunscreens in alcohol. Then we made a series of dilutions with different concentrations (10%, 1%, 0.1%, 0.01%). To be able to go forth and measure the effectiveness of our sunscreen products, we had to use a UV sensitive device called a spectrometer. Without having such a thing to use, we had to take a mini field trip to the University of Regina to access this device. It was set up and programmed for us to use. We filled cuvettes with samples of the different solutions that we made. Once the samples were read, we recorded multiple kinds of results. To finalize our results we decided to measure how much sunscreen actually dissolved in each sample by filtering the 10% diluted sunscreen solutions.
We found that we hypothesized incorrectly. Brands like the ‘Safeway’ SPF 15 sunscreen absorbed the most at 310nm but when at a higher wavelength the absorption decreased. Therefore our results show that sunscreens with SPF’s are only very effective against UVB rays but still have some protection against UVA rays.