The water cycle (hydrologic cycle) is the path that water takes
from earth to the air and back again.
The sun's radiation energy evaporates water of oceans and lakes.
The evaporated water condenses and makes droplets in the clouds.
Precipitations (rain, snow, drizzle,) start when these clouds
come over a cool land area and water backs to the earth. Some of
the precipitation changes into underground water which is called
groundwater. But most of the water returns to the sea
Salty water in oceans
Water of rivers takes salts mineral with itself and the salt
remains dissolved in the ocean because it does not evaporate. So
the remaining water gets saltier and saltier.
Earth's water supply is provided by oceans and oceans cover 70%
of earth's surface. No other planet in the solar system has
liquid water. The seas and the oceans are the home of the first
animals and they are their home at present also. Weather and
temperature of earth is affected by oceans. The oceans absorb
incoming radiation of sun and the ocean currents distributing
this energy around the earth. This energy heats the earth and
air during winter and cools it during summer.