Scholarly articles are written by experts in the field and, additionally, peer reviewed by a panel experts in the field. They tend to include a lot of research and data, and the information in the article is backed up by a list of references.
Example of a journal with scholarly articles
Popular articles are often written by journalists for a general audience and are not reviewed by experts in the field. Popular articles quote sources but rarely include references.
Example of a magazine with popular articles
For more information on scholarly articles, see the tutorial Anatomy of a Scholarly Article.