How do I tell if I am looking at a primary or a secondary source?
Answer
In history, a primary source is from the time of the event that you are studying and is an eye-witness or first-hand account, for example, letters, diaries, memoirs, speeches, interviews, maps, photographs, government documents, and newspapers contemporary to the event. A secondary source in history is an account based on primary sources, for example, a 21st-century book or article on the U.S. Civil War.
In the sciences, a primary source reports the results of original research, typically in a peer-reviewed scholarly journal. A secondary source in the sciences is a book or article commenting on original research.