What is water cycle and how it is formed?

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The water cycle is the path that all water follows as it moves around Earth in different states. Liquid water is found in oceans, rivers, lakes—and even underground.
1. This PowerPoint file contains information about the
water cycle. The first slide shows a picture that
includes all processes in the water cycle. Subsequent
slides discuss each process individually. The last
slide provides information on the distribution of
water on the earth.
2. The water cycle is the continuous movement of
water on, above, and below the surface of the Earth
United States Geological Survey (http://ga.water.usgs.gov/edu/watercycle.html)
3. Evaporation is the process by which water changes
from a liquid to a gas. The rate of evaporation
depends on how dry the air is and the temperature
difference between air and water.
from hot
United States Geological Survey (http://ga.water.usgs.gov/edu/watercycle.html)
4. Transpiration is the process by which water
evaporates from plants
Evaporation and
transpiration are often
combined into a single
term called
United States Geological Survey (http://ga.water.usgs.gov/edu/watercycle.html)
5. Condensation is the process by which water vapor in
the air is changed into liquid water. As air rises it
cools. Cold air holds less water than warm air.
Thus, as the air cools, clouds form.
Some clouds form during
the day as the air
temperature and
evaporation increase. Other
clouds are associated with
weather systems, such as a
warm or cold front, in
which warm air is forced
over colder air.
United States Geological Survey (http://ga.water.usgs.gov/edu/watercycle.html)
6. Precipitation is water released from clouds in the
form of rain, freezing rain, sleet, snow, or hail. It
happens when clouds can no longer hold water. The
water then falls to the earth because of gravity.
A thunderstorm in
the western United
Thunderstorms form
when air is forced
upward at a very fast
rate and therefore
cools very quickly.
United States Geological Survey (http://ga.water.usgs.gov/edu/watercycle.html)
7. Infiltration is
SAND the process by
Water infiltrates
much faster and
which water
deeper into a soaks into the
sand compared
to a clay. This is ground.
because the pore
Water Infiltration is
spaces in the
sand are much faster on dry
larger than in
the clay and can
soils and in
therefore sandy soils
transport more CLAY
water. compared to
wet and clay
8. Surface runoff is precipitation or melted snow that
runs off over the landscape. Runoff occurs when the
rate of precipitation or snowmelt is greater than the
rate of infiltration.
Runoff water flows to
sewers in some urban
areas (then usually to
surface water), to
retention basins in
other urban areas (then
usually soaks into the
ground), and to rivers,
lakes, and wetlands in
nonurban areas.
Oregon State University Extension Service
9. Water that infiltrates the soil can either be taken up
by plants, evaporate, be stored in the soil, or become
ground water.
Soil holds
water but is
usually not
saturated with
Ground water
is water stored
in the saturated
part of soil or
United States Geological Survey (http://ga.water.usgs.gov/edu/watercycle.html)
10. Ground water moves from high to low elevations due
to gravity. It eventually flows to a spring, lake,
river, wetland, or well.
In this
ground water
flows to a
stream and a
United States Geological Survey (http://ga.water.usgs.gov/edu/watercycle.html)
11. Water in lakes, streams, and wetlands may come
from precipitation, surface runoff, and ground water
Water in lakes, streams, and wetlands can evaporate, flow to a lake,
stream, or the ocean, or infiltrate into the ground.
12. Water in oceans comes from precipitation, runoff,
ground water discharge, and streams
Water in the ocean may stay there fore a long time,
but some of it evaporates
United States Geological Survey (http://ga.water.usgs.gov/edu/watercycle.html)
13. Water in ice and snow, including glaciers and
icecaps, comes from precipitation
Water in glaciers and icecaps is stored for a long time. Some evaporates
and glaciers slowly flow toward oceans and lakes.
United States Geological Survey (http://ga.water.usgs.gov/edu/watercycle.html)
14. 97% of the earth’s water is in the oceans. Of the
remainder, 69% is in glaciers and icecaps, 30% in
ground water, and 1% in lakes, rivers, and wetlands.
Very little water is stored in the atmosphere.
United States Geological Survey
15. Although there are many excellent
websites that deal with the Water Cycle,
the United States Geological Survey has
by far the most comprehensive
information on the Water Cycle