Scholarly or peer-reviewed journals have collections of articles written by experts in a particular field. Their intended audience is other scholars and professionals. Journals are excellent for finding out what has been studied or researched on a topic and to find bibliographies that point to other related sources of information. Examples are: Journal of Child Psychology, Social Science Quarterly, American Journal of Political Science and Nursing Ethics, The word "journal" is not necessarily in the title of a scholarly publication.
Magazines are good sources of information or opinions about popular culture or current events. Popular magazines typically have colorful covers and lots of advertisements. Examples are Discover, Sports Illustrated and National Geographic.
Professional/Trade publications are targeted toward a specific industry or trade audience. This differs with scholarly journals, as trade publications are not academic in nature or peer reviewed. Trade publications are generally written by experts and professionals within a specific industry, targeting other members of that industry. They contain news of interest to those working in that field.