The Balance Scale Puzzle

A balance scale is underwater with some lead on one side and some iron on the other so that the scale is balanced.  The water is then removed. What becomes true?   A) The side with the iron has more weight B) The scale continues to be balanced C) The side with the lead has more weight A hint is available, as well as the solution. Hint: The trick to solving this puzzle using your common sense is to exaggerate the density difference between the two materials. Instead of lead and iron, use lead and salt water. This makes no difference in the weighing experiment because in both cases, lead is the denser material. Solution: The answer is A). Underwater, lead weighs almost as much as it does out of water whereas salt water is almost weightless. This means if we have a cubic inch of lead on one side of the scale underwater, we'll need something like 20 gallons of salt water on the other side to balance it out. Out of water, the 20 gallons of salt water will obviously weigh more than the cubic inch of lead. Conclusion: If two substances weigh the same underwater, the less dense of the two will weigh more out of water.