Janet Raloff of Science News magazine, and Ira Flatow of NPR's Science Friday join host Steve Curwood to discuss recent findings that shed new light -- and new uncertainty -- on old issues, from the health effects of chocolate to disappearing frogs. When a science discovery makes the headlines, we often assume that researchers have found the truth about a subject. But Raloff and Flatow say that good science builds on, or even contradicts previous work.