Sun Protection Factor
The Food and Drug Administration defines SPF as a measure of how much solar energy is required to produce sunburn on protected skin. It has nothing to do with time of exposure.
Amount
In an Interscience article on the relation of SPF and the amount of sunblock applied, it was confirmed that applying sunblock more generously results in better protection.
Cancer
Sunblock can effectively block UVA and UVB rays. Regardless, studies such as "Sunscreen Use and Malignant Melanoma" performed by Interscience have found that sunblock users can experience higher a likelihood of skin cancer, most likely because they allow themselves more time sunbathing.
Chemical Sunblocks
The University of California's School of Medicine states that chemical sunblocks work by absorbing the energy of UV radiation before it affects your skin.
Physical Sunblocks
The University of California's School of Medicine explains that physical sunblocks can be made with zinc oxide or titanium dioxide. Both work by reflecting or scattering UV radiation before it reaches your skin.
Article Written By Devin Wieland
Devin Wieland has been a freelance writer since 2005. His pieces have appeared in publications such as "Insight," "Devozine," "The Aboite Independent," "On the Line," "AlienSkin," and "The Express." Wieland holds a Bachelor of Arts in professional writing from Taylor University.
