Sometimes the nature of a source (whether it is primary, secondary, or tertiary) is determined by how you, the researcher, are using it in your paper. These labels are not mutually exclusive!
Ex. Imagine you are researching and find a newspaper article from 1985 that reviews a scientific research paper from that time period. While it was written as a secondary source that analyzes another primary source, it also may be a very telling bit of evidence about the time period in which it was written. Maybe it was sharing the findings of a scientific study that was controversial at the time. You as a researcher in the twenty-first century could analyze this newspaper article as a primary source that reveals the cultural attitudes around that topic. If you're writing a literature review of a particular topic, the evolution of those attitudes over time might be useful information for your paper.
As a student and scholar of STEM, a primary source in your research will look different than the primary sources in a history class. The key that defines a primary resource in the fields of STEM is original research that has been peer-reviewed. This means the source is sharing the findings of an original research study done by the authors and that their peers (other experts in their field) have reviewed and found credible. Possible formats include:
Watch out for reviews, editorial articles, or other written sources that are simply reporting or reflecting on a research study that are not the study itself. These are NOT primary sources. The original study will contain sections called "Materials and Methods" or other similar variations of this name in which the specific methodologies of the study are described. In a paper with original research there will also be details like the research setting, participants, experiment controls, data collection, data analysis, and possibly ethical considerations. To filter out reviews from your search results in the library catalog or in a database, limit format type to "articles" or "peer-reviewed articles" and make sure the "reviews" format checkbox is unchecked.
Source: Gould Library at Carleton College
Screenshot retrieved from: Oniszczenko, W. (2022). Age, COVID-19-related fear, insomnia symptoms and cyberchondria: a mediation model. Neuropsychiatry & Neuropsychology / Neuropsychiatria i Neuropsychologia, 17(3/4), 152–158. https://doi.org/10.5114/nan.2022.124695
Secondary sources for STEM subjects are sources that interpret or comment on the original research found in primary sources. They are one step away from the source material, also known as "secondhand." The purposes of these sources may include summarizing a study and then making suggestions for future applications or perhaps synthesizing the results with those of another study to say something new about a topic. Possible formats of STEM secondary sources include:
Tertiary sources, also known as reference sources, are the furthest removed academic sources from an event/topic. Their purpose is typically to identify and aggregate many primary and secondary sources in one place based on topic. They also tend to provide a broad overview of a topic based on fundamental research and common knowledge. Possible formats may include:
These sources are great places to start when you are beginning a research project on a topic you are not very familiar with as they can reveal the most important terminology used by scholars. Those special terms or jargon are often great search terms to use while researching in databases or library catalogs.