Citizen science, also known as "informal science," "public participation in scientific research," or "PPSR," refers to science projects in which members of the public participate, usually on a volunteer basis. The extent of public participation in a citizen science project may range from help in collecting data to donating personal computer power to perform calculations.
Although one of the earliest citizen science projects was the Audubon Society's Christmas Bird Count, which was initiated in 1900, the citizen science movement has flourished over the last twenty-five years, with the development of Internet and mobile technologies. Today, many mobile apps exist that are intended for use by citizen scientists. See the Citizen Science Resources page for more information about mobile apps and other tools.