If something blocks visible light, does it also block ultraviolet light (specifically UVA)? I am thinking of things such as:

* cardboard (from a cereal box)
* a thick cotton towel
* aluminum foil

Those things will block most UV, yes, aside from possibly the towel.  Towels don't block all visible light, they have holes...but they'll block most visible and most UV light for sure.  But there are things which are transparent in either UV or IR which block visible light.  The stuff you mention is not in that category.


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Dr. Stephen O. Nelson


I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.


I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.

Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.

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