Scholarly Periodicals publish articles that are useful for serious scholastic research; often, instructors will insist that students use only scholastic periodicals for their research work.
Scholarly periodicals are also referred to as Academic Journals or Academic Newspapers, Journals, or Refereed Journals. "Refereed" means that not only is the journal edited, but that every article included in the journal is reviewed by authorities in the subject field of the journal, to decide whether or not the article should be published.
Criteria of a scholarly journal or other scholarly periodical:
The journal is mostly read by people involved in or interested in the field of study covered by the journal
Articles are often lengthy, and include footnotes or endnotes and works cited information
Graphs, charts, statistical information, and tables are often used to support the text or research
The vocabulary is geared to the field of study covered by the journal
The articles are very often peer reviewed (refereed)
Non-Scholarly Periodicals publish articles that are not considered or meant to be of a highly serious, scholastic nature.
This is not to say that the articles in any given non-scholastic magazine or newspaper are false or badly written. It only means that, for scholarly research purposes, non-scholarly periodicals do not have the recognized level of authority that a scholastic journal usually has.
Some criteria of a magazine or other non-scholarly periodical:
The periodical appeals to a general audience; the vocabulary is geared to all readers
Graphs, tables, and research studies are seldom included
The articles usually do not have footnotes, endnotes, or bibliographies (works cited)
The articles tend to be short in length, usually under 10 pages