I just saw the new video by It’s Okay To Be Smart (https://youtu.be/FnDP1sjKGfU) and got confused when he said that glass is opaque to the UV light. If it is in fact UV light repellent, why are you still able to get tanned when exposed to the sunlight for example through a car side window?
In: Physics
Glass is at least partially transparent to UV light. The video did not give enough nuance. It is certainly opaque to infra-red light though.
Here is the best source I found: https://www.koppglass.com/blog/optical-properties-glass-how-light-and-glass-interact#:~:text=The%20color%20of%20a%20glass,appear%20blue%20to%20the%20eye.
UV is between 100-400 nm on the first graph and roughly the region 300-400 is allowed through. I have no iea what kind of glass this is though as you can greatly change its properties with the adition of other trace elements.
Here is a different source with a better graph on the third page (look at the dotted line). “https://wp.optics.arizona.edu/optomech/wp-content/uploads/sites/53/2016/10/tie-35_transmittance_us.pdf
In cars, glass has been treated with extra layers of other stuff to absorb UV light to protect the occupants. This appears to mostly apply to the windshield.
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