The Water Cycle
All of life on Earth depends on the water cycle. It is also an
absolutely essential part of our weather and to the formation of
rivers and streams. The water vapour evaporated from streams, lakes,
or the ocean is added to by plant roots, which absorb some of the
groundwater, pull it up their stems and trunks to their leaves,
and release it into the atmosphere. Water droplets condense around
microscopic particles to form clouds. When the clouds become saturated,
the water falls back to earth as rain or snow and rejoins the stream's
journey to the sea. This process is called the water cycle or hydrological
cycle.
There are therefore, four main stages in the water cycle:
- evaporation
- condensation
- precipitation
- run-off.
Click on the image to view the Water Cycle process video clip (Windows
Media Audio/Video file .asf - 704 kb) published with kind permission
from the Physical Geography CD "Physical world" by Granada
Learning.
Click the link for the text-only
version of the video narration.
Task: Identify where the labels should be on the diagram.
Water may be stored for short periods or for millions of years
during this cycle.
- Water can be stored as liquid water in lakes or seas, or in
spaces in the rock or soil as groundwater.
- Water can be stored as ice in snow fields or ice caps.
- Water can be stored as water vapour in the air, or as droplets
in the clouds
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