[Jack Simth]

Originally posted by geoschmo:
Here's another puzzle, not really a riddle.

A man is sitting in a row boat in the middle of a lake holding a bowling ball. He drops the ball into the lake. What effect and to what degree does this have on the water level in the lake, if any. Assume for the purposes of this discussion that the bowling ball has a density such that it's weight is equal to four times it's volume of lake water.

Geoschmo

While in the boat, the bowling ball gets full displacement for its weight due to the nature of boats. Once in the lake, the bowling ball gets full displacement on its volume only. So, you have -4+1 = -3 bowling ball volume displacements (lake goes down).

So, the water level drops a number of inches such that the number of inches dropped * the surface area of the lake (after taking into account irregulariteis in the shape) is equal to three times the volume of the bowling ball. In other words, it will drop, but scarcely noticeably.

Also, the lake level may temporarily rise somewhat due to the splash and ensuing ripples.