Scholarly information is most often produced by scholars for other scholars. The vocabulary used is specialized and expert. The intended audience for this material generally has or is acquiring advanced knowledge. The author of such work is an expert in his/her field; usually with advanced degrees, most commonly a PhD. The publication has been peer-reviewed. And the sources for the work are always cited.
Popular works are intended for a general audience of readers. Advanced knowledge is not usually required to read and use this material. The author may not be a recognized expert or practitioner in her/her field. The work has not gone through a rigorous peer-review process. The sources for such a work may not be cited at the the end of the work.
Check out these two examples below to see the differences in action. Read the abstracts. To the left of the abstracts, you will see pdfs; click on each to see the complete article. Which one is scholarly and which one is popular?
Here's a quiz that will let you know if you can recognize peer-reviewed materials. No sweat, you got this!