In the Arts:
1. Was the source created during the time period you're studying? If the answer is yes, you are looking at a primary source.
2. Is it an object from a particular time in history? (Archie Bunker's chair? An Emily Dickinson poem?) This also counts as a primary source.
3. Was the source written after an event took place? If so, it is a secondary source.
In the Sciences:
1. Is the source reporting original research?
2. Did the author(s) carry out this original research?
If the answer to the two above questions is yes, it is a primary source.
Based on the How Do I...: Find Primary Sources guide created by the librarians at Cline Library, Northern Arizona University in Flagstaff, Arizona.