Charles II once stood before a group of scholars at a meeting of the Royal Society of England. And he proposed this question to his august assembly: “Gentlemen, if I place upon these weigh scales a pail of water weighing in all 10 lbs.; and then place in this water 5 live fish, each weighing one pound, why is it the scales still remain at precisely 10 lbs.?”
Well, the wise men heatedly debated the matter, trying to solve the king’s question. One suggested: “Your Highness, fish have a great number of air sacs which buoy them up. Perhaps this is the answer!” Another muttered something about a “theoretical vacuum.” Others propounded theories of “ungravitating gravitation.”
Finally the king’s voice silenced their discussion: “Gentlemen! You’re all mistaken. When one places 5 one-pound fish in a pail of water weighing 10 lbs., the scales must necessarily read 15 lbs.! Your failure to answer my question discloses the fact that you place too much confidence in me, your king.”