"Periodical" is a term used to describe any publication that is published multiple times (periodically). Periodicals include materials such as popular magazines, scholarly journals, and newspapers.
When conducting research it is important to distinguish between journal articles and magazine articles. Journal articles are typically referred to as "scholarly," while magazine articles are usually considered "popular". A third category, "trade" magazines or journals, are written for professionals in a particular field but are not strictly research related. When you are doing research, most of your sources should be scholarly.
Below are additional criteria to consider when differentiating between journals and magazines.
|Criteria||Scholarly Journal||Popular Magazine||Trade Magazine/Journal|
|  Content||In-depth, primary account of original findings written by the researcher(s); very specific information, with the goal of scholarly communication.||Secondary discussion of someone else's research; may include personal narrative or opinion; general information, purpose is to entertain or inform.||Current news, trends and products in a specific industry; practical information for professionals working in the field or industry.|
|  Author||Author's credentials are provided; usually a scholar or specialist with subject expertise.||Author is frequently a journalist paid to write articles, may or may not have subject expertise.||Author is usually a professional in the field, sometimes a journalist with subject expertise.|
|  Audience||Scholars, researchers, and students.||General public; the interested non-specialist.||Professionals in the field; the interested non-specialist.|
|  Language||Specialized terminology or jargon of the field; requires expertise in subject area.||Vocabulary in general usage; easily understandable to most readers.||Specialized terminology or jargon of the field, but not as technical as a scholarly journal.|
|  Graphics||Graphs, charts, and tables; very few advertisements and photographs.||Graphs, charts and tables; lots of glossy advertisements and photographs.||Photographs; some graphics and charts; advertisements targeted to professionals in the field.|
|  Layout &   Organization||Structured; includes the article abstract, goals and objectives, methodology, results (evidence), discussion, conclusion, and bibliography.||Informal; may include non-standard formatting. May not present supporting evidence or a conclusion.||Informal; articles organized like a journal or a newsletter. Evidence drawn from personal experience or common knowledge.|
|  Accountability||Articles are evaluated by peer-reviewers* or referees who are experts in the field; edited for content, format, and style.||Articles are evaluated by editorial staff, not experts in the field; edited for format and style.||Articles are evaluated by editorial staff who may be experts in the field, not peer-reviewed*; edited for format and style.|
|  References||Required. Quotes and facts are verifiable.||Rare. Little, if any, information about source materials is given.||Occasional brief bibliographies, but not required.|
|  Paging||Page numbers are consecutive throughout the volume.||Each issue begins with page 1.||Each issue begins with page 1.|
|  Other Examples||
Annals of Mathematics, Journal of Abnormal Psychology, History of Education Quarterly, Almost anything with Journal in the title.
Sports Illustrated, National Geographic, Time, Newsweek, Ladies Home Journal, Cooking Light, Discover
Architectural Record, PC World, Restaurant Business, American Libraries, Psychology Today, School Band and Orchestra
Based on Scholarly vs. Popular Materials by Amy VanScoy, NCSU Library