Primary sources (also called original sources or direct evidence) are unaltered, first-hand accounts of an event. They are usually created at the time that event took place although they can also be created retrospectively at a later date by a participant in those events. They are original documents from the time period and usually do not describe or interpret other documents. They can also be creative artistic works such as paintings, music or novels.
Examples of primary sources:
Secondary sources are interpretations and evaluations of primary sources. They are not evidence, but rather commentary on and discussion of evidence. A newspaper article is a primary source if it reports events, but it is a secondary source if it is an opinion piece which analyses and comments on those events. Secondary sources can simplify the process of finding and evaluating the primary literature e.g. a chemistry textbook.
Examples of secondary sources:
It is not always easy to distinguish between primary and secondary sources. Many sources can be considered either primary or secondary depending on the context in which they are examined. If you are studying how news is reported on the internet, then the Age website may be a primary source. However, if you are studying an election campaign and you are using an article from the news site examining the campaign, then the website would be a secondary source as the website is one step removed from your topic.