For more than a century, physicists debated which way a submerged sprinkler sucking in water would spin. Careful experiments provide an answer. Scientists say they have solved in detail what may be the most famous lawn-care-related problem in all of physics. The so-called Feynman sprinkler problem is named after one of the best-known physicists of the 20th century, Richard Feynman, even thou... [1147 chars]