taylaj: The sun puts out visible light that we can see, it also puts out light we can’t see called ultra Violet or UV light.
Our skin absorbs the UV light which causes damage we can see and feel as sunburn and eventually cancer.
Sun screen is a combination of ingredients including metals like zinc or titanium which reflect most of the light away from our skin instead of allowing it to be absorbed. And organic chemicals which absorb the UV light before it can get to our skin
It’s like a camouflage to hide our skin from the UV light.
DakotaReddit2: Finally one I can comment on! I just did about two weeks of research on this.
Two types of sunscreen active ingredients: Chemical and Physical
Chemical ingredients absorb the wavelengths of light that are harmful to your skin.
Physical ingredients are usually metallic and reflect the wavelengths of light that would be harmful to your skin!
There are typically a lot of different chemical active ingredients, and only a few physical variants. The sunscreens with chemical active ingredients are usually cheaper than the ones that contain physical active ingredients. You can find out why if you research more, as it gets more involved!
Edit: someone also pointed out that physical ingredients are classified as “inorganic”, and chemical ones “organic”.
xBirdisword: Sunscreen works by combining organic and inorganic active ingredients. Inorganic ingredients like zinc oxide or titanium oxide reflect or scatter ultraviolet (UV) radiation. Organic ingredients like octyl methoxycinnamate (OMC) or oxybenzone absorb UV radiation, dissipating it as heat. Some sunscreens protect us from the two types of damaging UV radiation: UV-A and UV-B. Both UV-A and UV-B cause sunburns and damaging effects such as skin cancer.
Literally the first result on google
https://www.loc.gov/rr/scitech/mysteries/sunscreen.html
SatanDarkofFabulous: So one thing I haven’t seen mentioned is that there are two types of UV. A and B. B causes more apparent damage and A causes less obvious damage like eye damage and skin cancer. UV B is a shorter wavelength and in turn is higher energy. Imagine a tiny little wrecking ball. UV C also exists but is involved with the ozone layer. Hope this helps explain what exactly is being blocked.
Vegeta_is_king_: So if I look a bath in the strongest possible spf, then went to the beach and laid out all day, would I never get sunburnt or tan?
randy05: Follow-up question.
If sunscreen/sunblock blocks UV light therefore inhibiting getting a tan, then why people use it when attending the solarium??