Accessibility options


water cycle

Water Cycle  
Part of the National cirriculum

dam at Marmolada - Click to enlarge
water cycle - Click to enlarge
Click images to enlarge

Natural circulation of water through the upper part of the Earth. It is a complex system involving a number of physical and chemical processes (such as evaporation, precipitation, and infiltration) and stores (such as rivers, oceans, and soil).

Water is lost from the Earth's surface to the atmosphere by evaporation caused by the Sun's heat on the surface of lakes, rivers, and oceans, and through the transpiration of plants. This atmospheric water is carried by the air moving across the Earth, and condenses as the air cools to form clouds, which in turn deposit moisture on the land and sea as precipitation. The water that collects on land flows to the ocean overland – as streams, rivers, and glaciers – or through the soil (infiltration) and rock (groundwater). The boundary that marks the upper limit of groundwater is called the water table.

The oceans, which cover around 70% of the Earth's surface, are the source of most of the moisture in the atmosphere.

© RM 2009. Helicon Publishing is division of RM.


 
 

Encyclopaedia Search

Click a letter for the index
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Or search the encyclopaedia:
 
 
All results tagged with the symbol denotes content that is relevant to the national curriculum

Advertisement starts



Advertisement ends


Advertisement starts



Advertisement ends

Country Search

 
 

Dictionary search

 
 

Burundi Flag

Burundi Flag
Green expresses hope. White symbolizes peace. It is said that the saltire may have been based on the former flag of Belgian airline, Sabena. Red represents the blood shed in the struggle for independence. Effective date: 27 September 1982.

Health Search

 
 
Search all Diseases Medicines

Advertisement starts



Advertisement ends

Skip to page content | Text onlyGraphical version of this page

Tiscali Quicklinks. Please visit our Accessibility Page for a list of the Access Keys you can use to find your way around the site, skip directly to the main navigation, to the page content, or to more links within reference.

web |  shopping |  this site |  video |  local services

Page Footer


Access keys


You will need to use different key combinations in order to use access keys depending on your internet browser, find out which on our accessibility page.
  • (0) Navigate to Accessibility page.
  • (1) Navigate to Home page.
  • (2) Navigate to My email.
  • (3) Navigate to My Account.
  • (4) Navigate to Site Map page.
  • (5) Navigate to Contact us page.
  • (6) Navigate to Members channel.
  • (7) Navigate to Services channel.
  • (8) Navigate to News & Info channel.
  • (9) Navigate to Entertainment channel.
  • ([) Skip down to the Primary navigation block.
  • (]) Skip down to the more links within this section block.
  • (=) Bypass all navigation and jump to the content.
  • (x) Text only version of this page.
Background images used:
furniture images used in the site icons used in the site images used in the header