Wikipedia accurate as Britannica--AP circa Dec 15

...is about as accurate in covering scientific topics as Encyclopedia Britannica, the journal Nature wrote...[using] peer review....Based on 42 articles reviewed by experts

Of eight "serious errors" the reviewers found--including misinterpretations of important concepts, four came from each source....

...the free service...having the speed and breadth to keep up on topics....not covered in Britannica

dalehileman