Water have a cycle named WATER CYCLE also known as the hydrologic cycle, the water cycle describes the process by which the
various forms of water move about the planet in a fairly constant balance. But
just because it's fairly balanced doesn't mean we have all the water we need, whenever
we want it. But first, what is the cycle, really? What is the water cycle?
Like all circular items, the water
cycle has no true
beginning and no end, though the water changes state from liquid to solid -- as
ice and snow, for example -- and as vapor. The cycle is the process by which
the water, in whatever form, goes from place to place, ocean to cloud to rainwater to river and back again through a cycle of rising air
currents, precipitation, runoff and a few other processes.
Four steps in the water cycle
·
Evaporation occurs when water transforms from
liquid to gas, usually as a result of the sun's warming rays. Evaporation often
technically includes transpiration from plants (the vapor the
"breathe" out as they grow), though together they are specifically
referred to as evapotranspiration.
·
Condensation occurs as the vapor rises into the
atmosphere, creating clouds and fog. Once clouds are formed, advection -- the
movement of water in its various states -- through the atmosphere. Without
advection, the cycle would screech to a halt, as the water would evaporate and
precipitate (the next step) in the same place.
·
Precipitation occurs when the vapor that condensed comes back out of the sky as rain,
snow, sleet, hail. Most of it comes back to the ground or body of water, but
some of it is intercepted by plant foliage and evaporates back to the
atmosphere instead of making it to the ground, in a process called "canopy
interception."
·
Runoff is the process by which water moves
across land and includes both surface runoff -- when water travels over land --
and channel runoff -- when it gets into streams and rivers. As is bubbles and
rambles along, it can drain into the ground, evaporate into the air, run into
and become stored in lakes or reservoirs, or be gathered up for human uses.
