Question:
Having spent several hours out in the sun with 450,000 of my closest friends at
big Rolling Stones show in Toronto this past Wednesday, I've gotta know . . .
how does sunscreen work?
I brought some SPF 30 with me, and kept applying the stuff to my exposed skin
every two hours or so, and walked out with the same skin tone I walked in with.
Over the course of several hours, however, I watch several other people around
me go from pasty white to lobster red.
What's in this magical stuff, and how does it work?
Answer:
Zinc Oxide and the like simply block UV radiation.
The other sunscreens (there are three varieties of sunscreen chemicals
in addition to the body's melannin) work by absorbing UVB radiation and
re-radiating the energy as heat.