Primary scientific literature, what is it and how do I find it?
Two things are true for all primary scientific literature:
What is peer review?
Peer review is a step in the process of publishing scientific findings. An article which has been submitted to a journal for publication is critically scrutinized and evaluated by a group of experts in the field. These experts will look at the entire article for flaws in the design, method, results, and analysis of the experiment.
How can I tell if an article is reporting an actual experiment?
You have to read. Sometimes the title is a good clue. Sometimes the abstract will tell you. Sometimes you have to read a little further. What you are looking for is the fact that the author(s) performed an experiment, got results, and analyzed and/or summarized their findings. Look for sections called "Methods" or "Methodology" and "Results" and "Discussion" or Analysis".