Skin cancer, the most common type of cancer within humans, has approximately 3.5 million cases each year. The evidence supports that the use of sunscreen can help to prevent different forms of skin cancers. There are a multitude of brands that make sunscreen, each claiming to be better than the next. The two main types of sunscreen are physical and chemical. Physical sunscreens deflect the ultraviolet (UV) rays of the sun and are normally made of zinc oxide or titanium dioxide, whereas chemical sunscreen absorb the suns UV rays and can be composed of many different ingredients. It was hypothesized that the physical sunscreens would do a better job at protecting against the sun’s rays than the chemical sunscreen brands. In this experiment E. coli growth was tested under UV light exposure with an application of five different brands of sunscreen. The control was exposed to UV with no sunscreen protection. After exposure to the UV light, the bacteria were set aside to grow and colonies were counted for survival. A statistical ANOVA was used to look at the significance between each brand of sunscreen, physical and chemical. Through the statistical analysis it was found that there was no significant difference between each brand of sunscreen. However, there was a significant difference in E. coli counts between each sunscreen application and the control. There was no statistical difference in E. coli counts between sunscreen types, indicating both types of sunscreen provide the same amount of protection from UV radiation
