We know the importance of protecting our skin from the sun but one of the toughest decisions is picking the right level of SPF, Sun Protection Factor.
Sari Custer with the Arizona Science Center did an experiment to demonstrate the effectiveness of different SPF numbers. Using UV, Ultra Violet light that we can't see, sensitive beads that instantly change color in the sunlight to demonstrate a sunburn she covered three groups of beads with sunscreen covered plastic using an 30 SPF spray, 45 SPF lotion and 70 SPF lotion.
After just seconds in the sun removing the layer of 30 SPF showed some of the beads maintained their original color but most changed their hue demonstrating weak coverage. The 40 SPF layer revealed a lot more unchanged beads, providing a lot more protection than the spray. In theory, the 70 SPF should have protected the most beads of any group and when revealed it did in fact work the best.
"The chemicals in the sunscreen should protect the beads from changing, just like with our skin." said Custer, "Final result, the higher the SPF the better the protection and for longer."
She adds that spray-on sunscreen works best when rubbed in to make sure no spots are missed. Also, the reflection of the sun off other objects like water or mirrored surfaces can expose poor coverage spots on your skin just as easily as direct sunlight. Sweat or water can create vulnerable spots. Lastly, no matter the brand of sunscreen you use, Custer says you should reapply every two hours.