All science and educational science websites should be entered into this category - In the broadest sense, science (from the Latin scientia, 'knowledge') refers to any systematic methodology which attempts to collect accurate information about the shared reality and to model this in a way which can be used to make reliable, concrete and quantitative predictions about events, in line with hypotheses proven by experiment. In a more restricted sense, science refers to a system of acquiring knowledge based on the scientific method, as well as to the organized body of knowledge gained through such research. Science as defined above is sometimes termed pure science to differentiate it from applied science, which is the application of scientific research to specific human needs. Fields of science are commonly classified along two major lines: the natural sciences, which study natural phenomena (including biological life), and the social sciences, which study human behavior and societies. A principal characteristic of these groupings is that they are empirical sciences, which means the knowledge must be based on observable phenomena and capable of being tested for its validity by other researchers working under the same conditions.