Published: June 2007
Learn More
In Learn More the National Geographic magazine team shares some of its best sources and other information to expand your knowledge of our featured subjects. Special thanks to the Research Division.
By Emily Krieger, National Geographic Staff

Did You Know?

People who live in or study the Earth’s cold places have many different words to describe various types of ice and snow. In many cases, size determines the definition. For example, an ice sheet has a domed shape and covers more than 19,300 square miles (50,000 square kilometers), while an ice cap, also domed, is smaller than 50,000 square kilometers. Because they flow, glaciers are sloped and generally smaller than ice caps. In other cases, age and structure determine the definition. New snow must not only be recent but must preserve the original form of the snow crystals. Névé is young snow that has partially melted, refrozen, and been compacted. Névé that lasts a full season is referred to as firn. Over many years, firn can become compacted into ice.

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