Whether you opt for a sunless tan,a suntan,or prefer none at all,you should protect yourself from the sun's rays.To do so,you can cover up with long sleeves,pants,and hats,or slather on the sunblock.There are two types of sunblock: chemical and mineral.They differ in how they block UV rays(Fig.l).Chemical sunscreens have a chemical compound capable of absorbing UV rays.When the molecule absorbs the UV rays,it rearranges its electrons to form a higher-energy(excited)state,which then relaxes back to its original form,dissipating the energy of the UV light harmlessly as heat.
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