James Dreben 
#ELI5 Why is water see through?
I'd never thought about it like this. Wow.
UrbanEdm@Jdreben @Daveography Follow up question: why is water transparent at the same frequencies as air?
Biggles 20X6!@Taco_lad @Jdreben @Daveography IR, for one. Sure, it's only partial blockage, but enough that outside of the visible spectrum, you can see air.
@UrbanEdm @Jdreben @Daveography that's not what IR spotlights, lasers and cameras show.
Water vapour in air blocks IR, heated air generates IR which can obscure vision, but the primary gaseous components of our atmosphere don't block IR.
@UrbanEdm @Jdreben @Daveography carbon dioxide *does* reflect or absorb IR, but as we know, it's currently at 422 parts per million, so not exactly prevalent on a small scale, but enough to make a big deal on a global warming scale