The watter cycle, forby kent as the hydrologic cycle or the H₂O cycle, describes the conteenous movement o watter on, abuin an ablo the surface o the Yird. The mass watter on Yird remains fairly constant ower time but the pairtitionin o the watter intae the major reservoirs o ice, fresh watter, saline watter an atmospheric watter is variable dependin on a wide range o climatic variables. The watter moves frae ane reservoir tae anither, sic as frae river tae ocean, or frae the ocean tae the atmosphere, bi the pheesical processes o evaporation, condensation, precipitation, infiltration, runaff, an subsurface flow. In sae daein, the watter gangs throu different phases: liquid, solit (ice), an gas (vapour).