Primary Sources
A primary source is an original work that provides firsthand information about a topic. It provides original data about a topic or expresses the viewpoint of a person who witnessed or participated in an event.
Speeches, songs, photographs, newspapers, letters, interviews, journals, lab notebooks, patents, technical reports, original documents (e.g., birth certificates or property deeds), audio and visual recordings, research data, artifacts (e.g., money, clothing, tools, or furniture) and original works of art or literature often fit into this category.

Secondary Sources
A secondary source offers an interpretation of the information that has been gathered from one or more primary sources. In general, a secondary source had been produced after the event or time period that it discusses. A secondary source does not express the viewpoint of a person who witnessed or participated in an event—rather it collects, distills, and organizes information from a number of primary sources to provide a summary or generalized interpretation of an event, time period, or other topic.
Textbooks, biographies, reviews, data compilations, article abstracts, encyclopedias, dictionaries, atlases, audio or video recordings of secondhand accounts, and works of interpretation or criticism often fit into this category.

Source Format
The format of a source does not necessarily determine what kind of source it is. Even the most artistic work may prove to be a secondary source if it is offering an interpretation rather than a firsthand account of the topic in question. Note, too, that a secondary source (such as an encyclopedia or a textbook) will often use important and influential primary sources to illustrate the summary or interpretation it provides about a topic.

To determine whether a source is a primary source or a secondary source, ask the following questions:

• Who created the source?
• Why was the source created?
• Does the source offer a firsthand account of the topic?
• What is the creator’s relationship to what is being described in the source?
• Is the source providing an opinion about another person’s work or experience, or is it offering an opinion about the creator’s own experience?

Definitions taken from Britannica Digital Learning (PDF).

Get Started with Document Analysis
Document analysis is the first step in working with primary sources. Learn to think through primary source documents for contextual understanding and to extract information to make informed judgments.

Follow this progression:

1. Meet the document.
2. Observe its parts.
3. Try to make sense of it.
4. Use it as historical evidence.

Use the NARA Document Analysis Worksheets to practice the process of document analysis. Worksheets are available for photos, written documents, artifacts, posters, maps, cartoons, videos, and sound recordings.

Building Critical Thinking Skills
Working with primary sources helps to develop key concepts, including:

• Critical Analysis
• Making Connections
• Finding Sequences
• Mapping History
• Seeing the Big Picture
• Weighing Evidence

To many people, history is seen as a series of facts, dates, and events usually packaged as a textbook. The use of primary sources can change this view. As we use primary sources we begin to view our textbook as only one historical interpretation and its author as an interpreter of evidence, not as a purveyor of truth.

Through primary sources we confront two essential facts in studying history. First, the record of historical events reflects the personal, social, political, or economic points of view of the participants. Second, we bring to the sources our own biases, created by our own personal situations and the social environments in which we live. As we use these sources, we realize that history exists through interpretation.

Interpreting historical sources helps us to analyze and evaluate contemporary sources—newspaper reports, television and radio programs, and advertising. By using primary sources, we learn to recognize how a point of view and a bias affect evidence, what contradictions and other limitations exist within a given source, and to what extent sources are reliable. Essential among these skills is the ability to understand and make appropriate use of many sources of information.

Development of these skills is important not only to historical research but also to a citizenship where people are able to evaluate the information needed to maintain a free society.

Taken from the National Archives Educator Resources.

A Guide to Engaging Students with Primary Sources (PDF)
This thorough guide is suitable for anyone interested in learning how to assess the strengths and limitations of primary sources, in addition to offering specific lesson plans for grades 3–12 covering documents, photographs, oral histories, and objects, with direct access to primary source materials. Published by the Smithsonian National Museum of American History.

Primary Source-Based Lesson Plans
Created by the National Archives, these lessons correlate to the National History Standards and National Standards for Civics and Government and include cross-curricular connections.

DocsTeach
An online tool for for teaching with documnets, from the National Archives. For teachers, students, and history explorers. Access thousands of primary sources—letters, photographs, speeches, posters, maps, videos, and other document types—spanning the course of American history. Borrow from an ever-expanding collection of document-based activities created by the National Archives, and teachers around the world. Copy and modify activities for your students. Create your own activities using the online tools.