Earth's water is in constant motion. Water moves at different speeds in different places, and in different forms. Water is continuously being exchanged among Earth's surface, atmosphere, and interior. Water is essential for life and for sculpting the world around us.
Click on image for full size
Courtesy of the Earth Science Literacy Initiative

Earth Science Literacy - Big Idea 5

Earth is the water planet.

Big Idea 5.1
Water is found everywhere on Earth, from the heights of the atmosphere to the depths of the mantle. Early in Earth’s history, surface water accumulated through both outgassing from its interior and the capture of some extraterrestrial ice. Water vapor in the atmosphere condensed and rained out as the planet cooled.

Big Idea 5.2
Water is essential for life on Earth. Earth is unique in our Solar System in that water has coexisted at Earth’s surface in three phases (solid, liquid, and gas) for billions of years, allowing the development and continuous evolution of life.

Big Idea 5.3
Water’s unique combination of physical and chemical properties are essential to the dynamics of all of Earth’s systems. These properties include the manner in which water absorbs and releases heat, reflects sunlight, expands upon freezing, and dissolves other materials.

Big Idea 5.4
Water plays an important role in many of Earth’s deep internal processes. Water allows rock to melt more easily, generating much of the magma that erupts as lava at volcanoes. Water facilitates the metamorphic alteration of rock and is integral to plate tectonic processes.

Big Idea 5.5
Earth’s water cycles among the reservoirs of the atmosphere, streams, lakes, ocean, glaciers, groundwater, and deep interior of the planet. The total amount of water at Earth’s surface has remained fairly constant over geologic time, although its distribution among reservoirs has varied.

Big Idea 5.6
Water shapes landscapes. Flowing water in streams strongly shapes the land surface through weathering, erosion, transport, and deposition. Water participates in both the dissolution and formation of Earth’s materials.

Big Idea 5.7
Ice is an especially powerful agent of weathering and erosion. Water expands as it freezes, widening cracks and breaking apart rocks. Movement of massive glaciers can scour away land surfaces. The flowing ice of glaciers covers and alters vast areas of continents during Ice Ages.

Big Idea 5.8
Fresh water is less than 3% of the water at Earth’s surface. Most of this fresh water is stored as glaciers in Antarctica and Greenland. Less than 1% of Earth’s near-surface water is drinkable liquid fresh water, and about 99% of this water is in the form of groundwater in the pores and fractures within soil, sediment, and rock.

Last modified July 29, 2009 by Becca Hatheway.

You might also be interested in:

Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Condensation

Condensation is the process by which water changes its state from a vapor or gas to a liquid. Condensation is responsible for the formation of clouds. Common examples of condensation are: dew forming on...more

Rain

Rain is precipitation that falls to the Earth in drops of 5mm or greater in diameter according to the US National Weather Service. Virga is rain that evaporates before reaching the ground. Raindrops form...more

Solid

Solid is one of the four common states of matter. The three others are gas, liquid, and plasma. There are also some other exotic states of matter that have been discovered in recent years. Unlike liquids...more

Evidence of Evolution

This Windows to the Universe Exploratour examines the scientific evidence of biological evolution. Take the tour to travel through 10 web pages about the scientific theory that explains how and why living...more

Earth as a System

The first time people got a glimpse of the whole Earth was December 1968. Apollo 8 astronauts, en route to and from the Moon, took pictures of the Earth from space.  In their photographs, the Earth looks...more

Albedo

This picture shows a part of the Earth surface as seen from the International Space Station high above the Earth. A perspective like this reminds us that there are lots of different things that cover the...more

Magma

If you could travel to the center of the Earth, you would find that it gets hotter and hotter as you travel deeper. The heat is naturally produced by decay of radioactive elements. Within the Earth’s...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA