Primary sources are usually defined as original sources created at the time of an event. However historian and archivist Michael Eamon says, "what makes an object a primary source or a secondary source often depends on how you use it."
Primary sources include documents, but also photographs, art, film, sound recordings etc. Another primary source might be interviews with people who've lived through events of the recent past.
"Primary documents have clear advantages over textbook accounts. Historical documents... provide personal points of entry into history...offer eyeopening perspectives for students who believe that history is impersonal and therefore irrelevant to their lives. ...However, the usefulness of primary documents is not limited to their ability to entertain students.... In the process of thinking critically about these documents, students develop a deeper understanding of the content... Students who learn to use primary documents effectively learn how to “do” history like historians, interpreting evidence to piece together a narrative of historical explanation and to make richer sense of the everyday world around them."
from Sandwell, Ruth (2008). Using primary documents in Social Studies and History. In The Anthology of Social Studies: Issues and Strategies for Elementary Teachers (available on LearnAlberta)