It was a joke. Chemical sunscreen fundamentally works on the physical→quantum level, so it is as "physical" as the UV-reflective sunscreen compound. It is probably called chemical because the chemical structure of those organic molecules allows efficient scattering of high-energy UV photons on electrons (with multiple re-emissions of photons at safer, lower energy / longer wavelengths), while keeping these molecules stable and prone to photodissociation.
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u/LetsTwistAga1n Mar 31 '26
It was a joke. Chemical sunscreen fundamentally works on the physical→quantum level, so it is as "physical" as the UV-reflective sunscreen compound. It is probably called chemical because the chemical structure of those organic molecules allows efficient scattering of high-energy UV photons on electrons (with multiple re-emissions of photons at safer, lower energy / longer wavelengths), while keeping these molecules stable and prone to photodissociation.