system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5- how does sunscreen work?
gpt
Sunscreen prevents the harmful ultraviolet rays from the sun from damaging your skin. There are 2 types of sunscreen, chemical sunscreen and physical sunscreen. Chemical sunscreen contains chemicals that undergo chemical reactions when they absorb the ultraviolet radiation and release it as heat from you skin. Basically, the layer of chemicals absorbs the UV rays instead of your skin. Physical sunscreen, also called sunblock, contains minerals like titanium dioxide or zinc oxide that block the UV rays from your skin by reflecting them.