Scientific Concepts

The Cycle

Cloud Formation 

The Water Cycle
Cloud Formation

Precipitation is one key to the water cycle. Rain comes from clouds, but where do clouds come from? 

Through the process of evaporation and transpiration, water moves into the atmosphere. Water vapors then join with dust particles to create clouds. Eventually, water returns to Earth as precipitation in the form of rain, snow, sleet, and hail. 

All clouds contain water vapors. You rarely ever see clouds in the desert because there is very little water to evaporate and form clouds. Coastal regions can receive a lot of rain because they pull up moisture from surrounding waters. 

Cloud size are influenced by many complex factors, some of which we still do not understand very well. These include: heat, seasons, mountain ranges, bodies of water, volcanic eruptions, and even global warming. 


Have you ever wondered why clouds have such unusual names? 

In 1802 an Englishman by the name of Luke Howard invented the cloud naming system that is still in use today. Howard used Latin names to describe clouds. (The first part of a cloud's name describes height, the second part shape.) 

The prefixes denoting heights are: cirro, high clouds above 20,000 feet (6,250 meters), alto and mid level clouds between 6,000 - 20,000 feet (1,875 - 6,250 meters). There is no prefix for low level clouds. 

The names denoting shapes are:cirrus mean curly or fibrous, stratus means layered, while cumulus means lumpy or piled. 

Nimbo or nimbus is added to indicate that a cloud can produce precipitation. 

Given that information, describe what each of the following clouds would look and act like? 

  • Cumulonimbus 
  • Nimbostartus 
  • Cirrocumulus 
  • Altostratus 



Copyright © 1995-8 The Evergreen Project, Inc.