The purpose of the water cycle is to constantly replenish the most important natural resource needed for all living things to exist: water. NASA describes water as not only necessary to sustain life on Earth but to tie together the Earth’s lands, oceans and atmosphere in an integrated system. The water cycle functions such that water transfers form in continuous movement, according to HowStuffWorks.
The continuous recycling of water through nine processes makes up the hydrologic, or water, cycle, according to the Northwest River Forecast Center. The physical processes are evaporation, condensation, precipitation, interception, infiltration, percolation, transpiration, runoff and storage. The sun is the most important participant in the water cycle and responsible for its two critical processes: condensation and evaporation. Water is evaporated into the atmosphere as water vapor, cools and rises into clouds, condenses into droplets as precipitation, and falls back to Earth in the form of rain, sleet, hail or snow. The water cycle process improves the quality of water as it moves through different forms, however, influences such as water pollution decrease water quality. Kids Environmental Health explains that Earth has a limited amount of water in a closed system, and water that is currently used has been recycled many times since the Earth was formed. Water cannot be manufactured or created, and therefore, it must be preserved in a cycle of replenishment.