When researching your History Day projects, it is important to keep in mind the differences between primary and secondary sources. According to the National History Day Contest rules, you must use both primary and secondary sources for your project and separate them in your required bibliography. Additionally, the use of available primary sources is an important part of the "historical quality" judging criteria (the category as a whole is worth 60% of the total score of your project).
A primary source, according to the History Department of the University of Colorado at Boulder's guidelines, is:
a record left by a person (or group) who participated in or witnessed the events you are studying or who provided a contemporary expression of the ideas or values of the period under examination. Letters, autobiographies, diaries, government documents, minutes of meetings, newspapers, or books written about your topic at that time are examples; non-written sources include interviews, films, photos, recordings of music, and clothing, buildings, or tools from the period.
Secondary sources, according to the CU-Boulder History Department guidelines, are:
accounts written by people who were not themselves involved in the events or in the original expression of the ideas under study. Written after the events/ideas they describe, they are based upon primary sources and/or other secondary works. Thus, an early 20th-century historian could prepare a secondary study of the American Civil War through her reading of documents from that period, interviews with veterans, examination of weapons, and so on.
Most history web sites should be considered secondary sources; that is, the author will have collected images, sounds, and writings that may themselves be primary sources, but, having been put together as a web page by an author they comprise a secondary source. Most history web sites will also have commentary or analysis written by the web page author that definitely constitute secondary source material and should not be used as primary source material. Photos, images, sound recordings, etc., that you take from web sites can be used as primary sources, but you must cite the secondary source they came from, making sure to credit the web page author with collecting the images or sounds into one location for you. Some online sources, such as the Library of Congress or the National Archives, have parts of their collections (such as letters, photos, diaries) digitized and on the internet and these may be considered primary sources as well, just make sure to attribute the item you use to its source.