I've got a few communication questions...
-Why do images appear sharper underwater when wearing a diving mask?
-where would you aim a spear in order to hit a fish if you are viewing it from the air?(i know it's straight down, but why?)
please answer.. if not all just one.. thank you so much.. i really need to know these
-where would you aim a spear in order to hit a fish if you are viewing it from the air?(i know it's straight down, but why?)
Because of the refractive index of water with respect to air, view from at an angle with the vertical will give a parallax error. This is why pools appear less deep than they really are.
Viewing from the top will give an error of the depth, but the angle of attack remains correct.
See
http://answers.yahoo.com/question/index?qid=20081015040354AA7Juvr