We've been talking about journal articles but there are actually three kinds of periodical articles. Journal articles are scholarly and academic. Many are written by professional scholars in a particular field. The content of journal articles is usually substantiated with footnotes and a bibliography. Most journal articles list the author's name, and sometimes their academic credentials and institutional background, as well.
Journals tend to be very text oriented, without a lot of pictures or advertisements.
Many magazine articles will not list authors. Most magazine articles will not include bibliographies or footnotes. Magazines have pictures and advertisements, both of which offer information to the investigative reader. Newspaper articles cover news, politics, local, national and world events, and weather in addition to providing the latest on sports, entertainment and political figures, and popular culture values and phenomena. Newspapers serve wonderfully for retrospective research, as well.