.Information Literacy in the Sciences

According to the Library of Congress, 

• A primary source is a first-hand record of an event or topic created by a participant in or a witness to that event or topic. 
• A secondary source is second-hand information written or created after an event. The information about the event or topic was obtained from primary sources plus, perhaps, additional analysis.

Some information professionals also refer to tertiary sources. But students are rarely quizzed on this definition.

• A tertiary source is third-hand information written or created after an event. The information about the event or topic was obtained from secondary and primary sources plus, perhaps, additional analysis.

• A gray source (more commonly referred to as gray literature) is a source of information of an event or topic that is communicated before it is recorded in a stable primary source. Methods of communication for gray literature are via channels that tend to be informal or impermanent.

When referring to a primary source in the sciences, professors and scientific researchers are usually referring to a research publication authored the researchers who participated in the research project.

Most original science research project findings are published in journal articles.