Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: paul.fr on 07/08/2007 22:20:36

Title: why do we not get sunburn driving a car?
Post by: paul.fr on 07/08/2007 22:20:36

After an hour outside you can have a sunburn, but spend numerous hours driving and no sunburn! why?

Title: why do we not get sunburn driving a car?
Post by: JP on 07/08/2007 23:15:44

Glass, like most matter, responds differently to different frequencies of light waves.  The glass in your car is transparent to visible light, but quite opaque to the ultraviolet radiation that causes sunburn, so it blocks out most of the harmful UV radiation.

*Edit: Glass does let through a bit of UVA radiation (which is the ultraviolet radiation closest to visible light), so you can get a tan through glass, and getting lots of sunlight in your car might still raise your cancer risk, but it's certainly not nearly as unhealthy as getting direct sunlight.