You'll find a wealth of source material on the Internet, usually in digital collections from libraries, archives, museums, and government organizations. The trick is how to find them. Google is an option, but you might also consider trying directories and catalogs that specialize in scholarly resources. We recommend the folliwng:
Below are a few examples of the kind of material you can find online.
In addition to the above, there are published digital collections that aren't freely available on the Web; you can access these through the University Library. Some that you might find useful for your research in this class are:
The Education and Social Sciences Library has a collection of school textbooks, including history textbooks. Consult their Curriculum Collection Guide for information on using this collection, and links to other textbook collections in the United States. The following is additional secondary material on locating and using history textbooks as primary sources: