Lesson 268 of 1455
Primary Sources vs Secondary Sources
A primary source is the original — the first-hand account or original data. A secondary source describes or analyzes a primary source. Smart researchers use both, but they know the difference.
Builders · Research & Analysis · ~24 min read
A simple example
Imagine you're researching the moon landing. A primary source would be: NASA mission transcripts, a photograph from Buzz Aldrin's camera, the original landing telemetry data.
A secondary source would be: a textbook chapter explaining the moon landing, a documentary, a Wikipedia article. Both are useful — but they're different kinds of evidence.
Examples of primary vs secondary
Compare the options
| Primary source | Secondary source |
|---|---|
| Diary, letters, speeches by the actual person | Biography written about that person |
| Original scientific paper reporting an experiment | Review article summarizing the experiment |
| Court ruling text | News article describing the ruling |
| Interview transcript | Newspaper article quoting the interview |
Where to find primary sources
- Library of Congress (for US history primary documents)
- Online archives like archive.org
- Direct journal websites for original research
- Court records via PACER or Justia
- Government data sites (data.gov, BLS, Census)
Key terms in this lesson
The big idea: primary sources are what actually happened. Secondary sources are what someone said about what happened. Use both, but never confuse them.
End-of-lesson quiz
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