Citizen science is a term used for projects or ongoing program of scientific work in which individual volunteers or networks of volunteers, many of whom may have no specific scientific training, perform or manage research-related tasks such as observation, measurement or computation.
The use of citizen-science networks often allows scientists to accomplish research objectives more feasibly than would otherwise be possible. In addition, these projects aim to promote public engagement with the research, as well as with science in general. Some programs provide materials specifically for use by primary or secondary school students. As such, citizen science is one approach to informal science education.
The longest-running citizen science project currently active is probably the Audubon Society's Christmas Bird Count, which started in 1900. Other well-known examples of citizen science programs include World Water Monitoring Day, NASA's Stardust@home and Clickworkers, a variety of projects run by the Cornell Laboratory of Ornithology, such as Ebird, NestWatch, Project FeederWatch, and Celebrate Urban Birds and the Galaxy Zoo project. Citizen science networks are extensively involved in phenology, the observation of cyclic events of nature, in order to investigate how global warming affects plant and animal life in different geographic areas. Distributed computing ventures such as SETI@home may also be considered citizen science, even though the primary task of computation is performed by volunteers' computers.