Densities & volumes
Not directly aviation but most aviation people seem clued up on densities. Here is a simple brain teaser with a not-so-simple answer. I am not sure of the answer myself but would appreciate a reasoned logical explanation from some smart thinker out there.
" A boat is floating in a pond. Someone throws an anchor over the side. Does the water level in the pond go up, down or stay the same?"
(yes, the effects are negligible, we all know that, but what is the theoretical answer?)