systems

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The Earth system is an example
of a closed system

Photo credit: USGS Digital Data Series DDS-21
Used with permission

The ocean is an example
of an open system

Photo credit: NOAA 
Used with permission

A system is a collection of interacting objects. Open systems are characterized by both energy and mass exchanges across the system boundary. Closed systems are characterized by energy, but not mass exchange across the system boundary. The earth system, i.e. the solid earth and its atmosphere, is a closed system as depicted on the right above. Solar energy can penetrate through the outer edge of the atmosphere and stream toward the surface warming the planet. The earth in turn cools by emitting terrestrial longwave radiation out to space.

The ocean can be considered an open system. The earth's oceans form a substantial portion of of the hydrosphere which is tightly coupled to the atmosphere (both considered open systems).

Suggested Web Sites:

• National Atmospheric and Oceanic Administration

• National Space and Aeronautical Administration

• United States Geological Survey

• United States Environmental Protection Agency