If, while standing on the bank of a stream, you wished to spear a fish
swimming in the water out in front of you, would you aim above, below,
or directly at the observed fish to make a direct hit?  If you deciced
instead to zap the fish with a laser, would you aim above, below, or
directly at the fish?

Hi daisy001,
  
To spear the fish you would need to aim below the observed fish to
make a direct hit. With a laser, you would aim directly at the fish.
  
"In both cases, of course, the light coming from the fish is refracted
away from the normal as it travels through the water surface to your
eyes. As a result, the fish appears closer to the surface than it
really is. (a) If you are using a bow and arrow to spear the fish you
should realize that the arrow will not deviate as it enters the water;
it will continue along the original straight line path from the bow.
Therefore, in order to strike the fish you should aim below where the
fish appears to be.
  
(b) When you use a laser gun to hit the fish then you should realize
that the beam will be refracted as it enters the water. In fact, the
laser beam will travel along exactly the same path as the light from
the fish (although in the opposite direction!). Therefore, in order to
hit the fish you should aim you laser gun directly where the fish
appears to be."
http://courses.science.fau.edu/~rjordan/busters_33/answers_8b.htm#Ex_9 
  
  
Search terms:  [ spear fish above water ]
  
  
Hope that helps!
  
  
Jackburton