Maybe you recycle cans, glass, paper and metal. Did you know that nature recycles, too? One of
the things nature recycles is water. Water goes from the ocean, lakes and rivers into the air. Water falls from
the air as rain or snow. Rain and snow eventually find their way back to the ocean. Nature’s recycling
process for water is called the water cycle. The water cycle has four stages: storage, evaporation,
Đề Anh 10 Chuyên 2009
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precipitation and run-off. Water on Earth gets stored in oceans, lakes, rivers, ice and even underground.
Water goes from storage into the atmosphere by a process called evaporation. When water evaporates, it
changes from a liquid into a gas, called water vapor. Water vapor goes up into the atmosphere. Water returns
to Earth as precipitation in rain or snow by changing into drops of water when the air gets cold enough.
Clouds are collections of water droplets. Most precipitation falls into the oceans and goes right back into
storage.
Water that falls on land always flows from higher places to lower ones - This flow is called run-
off. Water from land flows into streams. Streams join together to make rivers and eventually the water flows
into storage in the ocean, then the water cycle starts all over again.