One of the most common types of term papers is the research paper. A research paper typically involves the student picking a specific topic that was studied in class and then delving in depth. Research papers involve extensive use of primary sources (material from the subject in question) and secondary sources (professionally published literature in the related field). These sources are then used to support the student's ideas and are compiled in a bibliography at the end of the paper. Research papers as term papers are common in all academic fields, especially in traditional liberal arts classes, such as history and philosophy.
Similar to a research paper is a synthesis term paper, which requires the student to pull together ("synthesize") some or all of the works they have dealt with in class that semester. Unlike a research paper, a synthesis paper is more holistic because it deals with broader generalities more so than the specific topic of the research paper. Additionally, a synthesis paper often does not have any sources except those that were read in class; instead of the secondary sources found in the research paper, the student is expected to provide his own discourse on the subject. A synthesis paper as a term paper is especially common in interdisciplinary classes.
An even more specific type of synthesis paper that can be used as term paper is a book review. This requires the student to analyze one specific work that was read in class. Thus, it is similar to a research paper because it focuses on only one aspect of the class; however, it differs because, like a synthesis paper, the student is expected to rely more on her own analysis than that of secondary sources (though secondary sources are not uncommon in book reviews, they are often used more sparingly than in a full-fledged research paper). A book report as a term paper is especially common in English and other literature classes.
Similar to the book review term paper is the peer-review paper as a term paper. Much like a book report, a peer-review paper focuses exclusively on one topic which, in this case, is a published scientific study. The student's job when writing a peer-review paper is to analyze and critique the study both on its validity within its field (e.g., if it is about the discovery of a new moon, how it stands in the field of astronomy as a whole), and also its validity in using the scientific method (e.g., did they use appropriate instruments, did they discount outliers). Peer-review papers as a term paper are especially common in the "hard" science classes, such as physics or biology.