Articles can be fresh, contemporaneous with events. Electronic journals, now proliferating on the Web, appear faster than their print counterparts. Originality of ideas or research is a standard requirement of most editorial boards. It has quality control. If you are looking at a periodical with no references, footnotes, endnotes, or bibliography, it's probably not a scholarly journal.
Popular magazines vary widely in quality.
Some are so well-written, reputable, and even authoritative that they may be reliable sources of information, though they lack the thorough documentation of scholarly journals. Smithsonian , Natural History , and The Economist come to mind. Other periodicals report current news and are careful to authenticate stories before publication. The New York Times , Time , and Newsweek fall into this category. The kind of popular magazine found on supermarket racks is more likely to summarize trends, provide practical advice, or promote a certain viewpoint than report original research.