Fluid mechanics is the study of the effects of forces and energy on liquids and gases.
Hydrostatics is a comparatively elementary subject with a few classical results of importance but little scope for further development. Fluid dynamics, in contrast, is a highly developed branch of science that has been the subject of continuous and expanding research activity since about 1840. The development of fluid dynamics has been strongly influenced by its numerous applications. There are also many less immediately obvious applications. Fluid dynamics is studied both theoretically and experimentally, and the results are described both mathematically and physically.