[ Hydrologic Cycle

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ARTICLE

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Hydrologic Cycle

Hydrologic Cycle

The water cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

describes how water is exchanged (cycled) through Earth

Earth : The third planet from the Sun, which has water in solid, liquid, and gas forms and is the main focus of the water cycle

's land, ocean

Ocean : A large body of saltwater that covers most of Earth’s surface, significant in the water cycle

, and atmosphere.

Grades

2 - 8

Subjects

Earth

Earth : The third planet from the Sun, which has water in solid, liquid, and gas forms and is the main focus of the water cycle

Science, Meteorology, Geography, Physical Geography, Geology
















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The water cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

describes how water is exchanged (cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

d) through Earth

Earth : The third planet from the Sun, which has water in solid, liquid, and gas forms and is the main focus of the water cycle

's land, ocean

Ocean : A large body of saltwater that covers most of Earth’s surface, significant in the water cycle

, and atmosphere. Water always exists in all three phases, and in many forms—as lakes

Great Lakes : A group of five large freshwater lakes in North America, located on the border between the United States and Canada: Lake Superior, Lake Michigan, Lake Huron, Lake Erie, and Lake Ontario.

and

Switzerland : A country in Central Europe known for its neutrality, Alpine landscapes, and well-developed financial sector.

rivers , glaciers

Glacier : A large, slow-moving mass of ice on land, which influences the availability of fresh water

glaciers : Massive, slowly moving bodies of ice that can form streams or pools as they melt.

and

Switzerland : A country in Central Europe known for its neutrality, Alpine landscapes, and well-developed financial sector.

ice sheets

ice : Solid form of water. On Earth, it is primarily found in glaciers, ice sheets, and ice caps.

ice sheets : Large masses of glacial land ice extending more than 50,000 square kilometers (19,300 square miles).

ice caps : Smaller than ice sheets, covering an area of less than 50,000 square kilometers.

Antarctic ice sheet : A massive ice sheet covering Antarctica, containing the majority of the world's fresh water.

, ocean

Ocean : A large body of saltwater that covers most of Earth’s surface, significant in the water cycle

s and seas, underground aquifers , and vapor

the water cycle consists of three major processes evaporation condensation and precipitation : These are essential parts of the water cycle; evaporation turns liquid water into gas, condensation turns vapor back to liquid, and precipitation is when water falls back to Earth as rain, snow, or hail.

Evaporation : The process where liquid water turns into vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

Evaporation and condensation processes release and absorb energy : These processes impact local temperatures and climate by releasing or absorbing heat.

in the air and cloud

Cloud : A visible collection of water droplets or ice crystals suspended in the atmosphere

s
.

Evaporation, Condensation, and Precipitation

The water cycle consists of three major processes: evaporation, condensation, and precipitation

the water cycle consists of three major processes evaporation condensation and precipitation : These are essential parts of the water cycle; evaporation turns liquid water into gas, condensation turns vapor back to liquid, and precipitation is when water falls back to Earth as rain, snow, or hail.

Evaporation : The process where liquid water turns into vapor

Condensation : The process where water vapor cools and turns into liquid

Precipitation : Any form of water, like rain or snow, that falls from the atmosphere to the surface of Earth

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

Evaporation and condensation processes release and absorb energy : These processes impact local temperatures and climate by releasing or absorbing heat.

.

Evaporation

Evaporation

Evaporation : The process where liquid water turns into vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

is the process of a liquid's surface changing to a gas. In the water cycle, liquid water (in the ocean, lakes, or rivers) evaporates and becomes water vapor

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

Water circulates through solid, liquid, and vapor : This describes the water cycle, where water shifts between different states, supporting life and environmental processes.

.

Water vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

surrounds us, as an important part of the air we breathe. Water vapor is

water vapor is a greenhouse gas : Water vapor, like carbon dioxide, helps insulate Earth and keeps it warm enough to sustain life. However, too much can contribute to global warming.

also an important greenhouse gas

water vapor is a greenhouse gas : Water vapor, like carbon dioxide, helps insulate Earth and keeps it warm enough to sustain life. However, too much can contribute to global warming.

Greenhouse gas : Gases like water vapor and carbon dioxide that insulate Earth and help maintain its temperature

. Greenhouse gases such as water vapor

water vapor is a greenhouse gas : Water vapor, like carbon dioxide, helps insulate Earth and keeps it warm enough to sustain life. However, too much can contribute to global warming.

Greenhouse gas : Gases like water vapor and carbon dioxide that insulate Earth and help maintain its temperature

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

and carbon dioxide insulate Earth

Earth : The third planet from the Sun, which has water in solid, liquid, and gas forms and is the main focus of the water cycle

and keep the planet warm enough to maintain life as we know it. Increasing amounts of greenhouse gases in the atmosphere also contribute to global warming.

The water cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

's e vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

ation process is driven by the sun. As the sun interacts with liquid water on the surface of the ocean

Ocean : A large body of saltwater that covers most of Earth’s surface, significant in the water cycle

, the water becomes an invisible gas (water vapor

the water cycle consists of three major processes evaporation condensation and precipitation : These are essential parts of the water cycle; evaporation turns liquid water into gas, condensation turns vapor back to liquid, and precipitation is when water falls back to Earth as rain, snow, or hail.

Evaporation : The process where liquid water turns into vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

Evaporation and condensation processes release and absorb energy : These processes impact local temperatures and climate by releasing or absorbing heat.

). E vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

ation is also influenced by wind , temperature

temperature : A measure of the average kinetic energy of the particles in an object; an indicator of heat or cold.

, and the density of the body of water.

Condensation

Condensation

Condensation : The process where water vapor cools and turns into liquid

is the process of a gas changing to a liquid. In the water cycle, water vapor in the atmosphere condenses and becomes liquid

the water cycle consists of three major processes evaporation condensation and precipitation : These are essential parts of the water cycle; evaporation turns liquid water into gas, condensation turns vapor back to liquid, and precipitation is when water falls back to Earth as rain, snow, or hail.

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

Water circulates through solid, liquid, and vapor : This describes the water cycle, where water shifts between different states, supporting life and environmental processes.

.

Condensation

Condensation : The process where water vapor cools and turns into liquid

can happen high in the atmosphere or at ground level. Cloud

Cloud : A visible collection of water droplets or ice crystals suspended in the atmosphere

s form as water vapor

the water cycle consists of three major processes evaporation condensation and precipitation : These are essential parts of the water cycle; evaporation turns liquid water into gas, condensation turns vapor back to liquid, and precipitation is when water falls back to Earth as rain, snow, or hail.

Evaporation : The process where liquid water turns into vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

Evaporation and condensation processes release and absorb energy : These processes impact local temperatures and climate by releasing or absorbing heat.

condenses, or becomes more concentrated (dense). Water vapor

the water cycle consists of three major processes evaporation condensation and precipitation : These are essential parts of the water cycle; evaporation turns liquid water into gas, condensation turns vapor back to liquid, and precipitation is when water falls back to Earth as rain, snow, or hail.

Evaporation : The process where liquid water turns into vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

Evaporation and condensation processes release and absorb energy : These processes impact local temperatures and climate by releasing or absorbing heat.

condenses around tiny particles called cloud condensation nuclei (CC

Cloud : A visible collection of water droplets or ice crystals suspended in the atmosphere

cloud condensation nuclei (CCN) : Cloud condensation nuclei are tiny particles or specks such as dust, salt, or pollutants around which cloud droplets can form through condensation.

N)
. CCN can be specks of dust, salt, or pollutants . Cloud

Cloud : A visible collection of water droplets or ice crystals suspended in the atmosphere

s at ground level are called fog

Fog : A type of low-lying cloud or mist that does not fall as precipitation

or mist.

Like e vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

ation , condensation

Condensation : The process where water vapor cools and turns into liquid

is also influenced by the sun. As water vapor

the water cycle consists of three major processes evaporation condensation and precipitation : These are essential parts of the water cycle; evaporation turns liquid water into gas, condensation turns vapor back to liquid, and precipitation is when water falls back to Earth as rain, snow, or hail.

Evaporation : The process where liquid water turns into vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

Evaporation and condensation processes release and absorb energy : These processes impact local temperatures and climate by releasing or absorbing heat.

cools, it reaches its saturation limit, or dew point

dew point : Dew point is the temperature at which air becomes saturated with water vapor, and water begins to condense to form dew or clouds.

. Air pressure is also an important influence on the dew point

dew point : Dew point is the temperature at which air becomes saturated with water vapor, and water begins to condense to form dew or clouds.

of an area.

Precipitation

As is

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

the case with evaporation and condensation, precipitation

the water cycle consists of three major processes evaporation condensation and precipitation : These are essential parts of the water cycle; evaporation turns liquid water into gas, condensation turns vapor back to liquid, and precipitation is when water falls back to Earth as rain, snow, or hail.

Evaporation : The process where liquid water turns into vapor

Condensation : The process where water vapor cools and turns into liquid

Precipitation : Any form of water, like rain or snow, that falls from the atmosphere to the surface of Earth

is a process. Precipitation describes any liquid or solid water that falls to Earth

Earth : The third planet from the Sun, which has water in solid, liquid, and gas forms and is the main focus of the water cycle

as a result of condensation in the atmosphere. Precipitation includes rain, snow, and hail.

Fog

Fog : A type of low-lying cloud or mist that does not fall as precipitation

is not precipitation

Precipitation : Any form of water, like rain or snow, that falls from the atmosphere to the surface of Earth

. The water in fog does not condense sufficiently to precipitate, or liquefy and fall to Earth

Earth : The third planet from the Sun, which has water in solid, liquid, and gas forms and is the main focus of the water cycle

. Fog and mist are a part of the water cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

called suspensions: They are liquid water suspended in the atmosphere.

Precipitation

Precipitation : Any form of water, like rain or snow, that falls from the atmosphere to the surface of Earth

is one of many ways water is cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

d from the atmosphere to the earth

Earth : The third planet from the Sun, which has water in solid, liquid, and gas forms and is the main focus of the water cycle

or ocean

Ocean : A large body of saltwater that covers most of Earth’s surface, significant in the water cycle

.

Other Processes

Evaporation, condensation, and precipitation are important parts of the water cycle

the water cycle consists of three major processes evaporation condensation and precipitation : These are essential parts of the water cycle; evaporation turns liquid water into gas, condensation turns vapor back to liquid, and precipitation is when water falls back to Earth as rain, snow, or hail.

Evaporation : The process where liquid water turns into vapor

Condensation : The process where water vapor cools and turns into liquid

Precipitation : Any form of water, like rain or snow, that falls from the atmosphere to the surface of Earth

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

. However, they are not the only ones.

Runoff

runoff : Runoff is the movement of water, usually from precipitation, that flows over the land's surface towards bodies of water like rivers or oceans.

, for instance, describes a variety of ways liquid water moves across land. Snowmelt , for example, is an important type of runoff

runoff : Runoff is the movement of water, usually from precipitation, that flows over the land's surface towards bodies of water like rivers or oceans.

produced as snow or glaciers

Glacier : A large, slow-moving mass of ice on land, which influences the availability of fresh water

glaciers : Massive, slowly moving bodies of ice that can form streams or pools as they melt.

melt and form streams or pools.

Transpiration

transpiration : Transpiration is the process by which water absorbed by plants is evaporated into the atmosphere from plant surfaces, particularly from the leaves.

evapotranspiration : The sum of evaporation and plant transpiration from the Earth's land and ocean surface to the atmosphere.

is another important part of the water cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

. Transpiration

transpiration : Transpiration is the process by which water absorbed by plants is evaporated into the atmosphere from plant surfaces, particularly from the leaves.

evapotranspiration : The sum of evaporation and plant transpiration from the Earth's land and ocean surface to the atmosphere.

is the process of water vapor

the water cycle consists of three major processes evaporation condensation and precipitation : These are essential parts of the water cycle; evaporation turns liquid water into gas, condensation turns vapor back to liquid, and precipitation is when water falls back to Earth as rain, snow, or hail.

Evaporation : The process where liquid water turns into vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

Evaporation and condensation processes release and absorb energy : These processes impact local temperatures and climate by releasing or absorbing heat.

being released from plants and soil. Plants release water vapor

the water cycle consists of three major processes evaporation condensation and precipitation : These are essential parts of the water cycle; evaporation turns liquid water into gas, condensation turns vapor back to liquid, and precipitation is when water falls back to Earth as rain, snow, or hail.

Evaporation : The process where liquid water turns into vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

Evaporation and condensation processes release and absorb energy : These processes impact local temperatures and climate by releasing or absorbing heat.

through microscopic  pores called stomata . The opening of stomata is strongly influenced by light, and so is often associated with the sun and the process of e vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

ation . Evapotranspiration

transpiration : Transpiration is the process by which water absorbed by plants is evaporated into the atmosphere from plant surfaces, particularly from the leaves.

evapotranspiration : The sum of evaporation and plant transpiration from the Earth's land and ocean surface to the atmosphere.

is the combined components of e vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

ation and

Switzerland : A country in Central Europe known for its neutrality, Alpine landscapes, and well-developed financial sector.

transpiration

transpiration : Transpiration is the process by which water absorbed by plants is evaporated into the atmosphere from plant surfaces, particularly from the leaves.

evapotranspiration : The sum of evaporation and plant transpiration from the Earth's land and ocean surface to the atmosphere.

, and is sometimes used to evaluate the movement of water in the atmosphere.

States of Water

Through the water cycle, water continually circulates through three states: solid, liquid, and vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

Water circulates through solid, liquid, and vapor : This describes the water cycle, where water shifts between different states, supporting life and environmental processes.

.

Ice

ice : Solid form of water. On Earth, it is primarily found in glaciers, ice sheets, and ice caps.

ice sheets : Large masses of glacial land ice extending more than 50,000 square kilometers (19,300 square miles).

ice caps : Smaller than ice sheets, covering an area of less than 50,000 square kilometers.

Antarctic ice sheet : A massive ice sheet covering Antarctica, containing the majority of the world's fresh water.

is solid water. Most of Earth

Earth : The third planet from the Sun, which has water in solid, liquid, and gas forms and is the main focus of the water cycle

's fresh water is ice, locked in massive glaciers, ice sheets

ice : Solid form of water. On Earth, it is primarily found in glaciers, ice sheets, and ice caps.

ice sheets : Large masses of glacial land ice extending more than 50,000 square kilometers (19,300 square miles).

, and ice caps

ice : Solid form of water. On Earth, it is primarily found in glaciers, ice sheets, and ice caps.

ice sheets : Large masses of glacial land ice extending more than 50,000 square kilometers (19,300 square miles).

ice caps : Smaller than ice sheets, covering an area of less than 50,000 square kilometers.

.

As ice

ice : Solid form of water. On Earth, it is primarily found in glaciers, ice sheets, and ice caps.

ice sheets : Large masses of glacial land ice extending more than 50,000 square kilometers (19,300 square miles).

melts, it turns to liquid. The ocean

Ocean : A large body of saltwater that covers most of Earth’s surface, significant in the water cycle

, lakes, rivers, and underground aquifers all hold liquid water.

Water vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

is an invisible gas. Water vapor is not evenly distributed across the atmosphere. Above the ocean, water vapor is much more abundant, making up as much as four percent of the air

Water vapor makes up about four percent of air above oceans : The higher concentration of water vapor over oceans affects humidity and climate conditions in coastal regions.

. Above isolated deserts, it can be less than one percent

Water vapor concentration is less than one percent above deserts : Scarce water vapor in deserts leads to low humidity, influencing dry climate conditions.

.

The Water Cycle and Climate

The water cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

has a dramatic influence on Earth

Earth : The third planet from the Sun, which has water in solid, liquid, and gas forms and is the main focus of the water cycle

's climate

climate : The weather conditions prevailing in an area in general or over a long period.

 and ecosystems .

Climate

climate : The weather conditions prevailing in an area in general or over a long period.

is all the weather

Precipitation : Any form of water, like rain or snow, that falls from the atmosphere to the surface of Earth

climate : The weather conditions prevailing in an area in general or over a long period.

temperature : A measure of the average kinetic energy of the particles in an object; an indicator of heat or cold.

conditions of an area, evaluated over a period of time. Two weather

Precipitation : Any form of water, like rain or snow, that falls from the atmosphere to the surface of Earth

climate : The weather conditions prevailing in an area in general or over a long period.

temperature : A measure of the average kinetic energy of the particles in an object; an indicator of heat or cold.

conditions that contribute to climate

climate : The weather conditions prevailing in an area in general or over a long period.

include humidity

humidity : The amount of water vapor present in the air.

and

Switzerland : A country in Central Europe known for its neutrality, Alpine landscapes, and well-developed financial sector.

temperature

temperature : A measure of the average kinetic energy of the particles in an object; an indicator of heat or cold.

. These weather

Precipitation : Any form of water, like rain or snow, that falls from the atmosphere to the surface of Earth

climate : The weather conditions prevailing in an area in general or over a long period.

temperature : A measure of the average kinetic energy of the particles in an object; an indicator of heat or cold.

conditions are influenced by the water cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

.

Humidity

humidity : The amount of water vapor present in the air.

 is simply the amount of water vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

in the air. As water vapor is not evenly distributed by the water cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

, some regions experience higher humidity than others. This contributes to radically different climate

climate : The weather conditions prevailing in an area in general or over a long period.

s. Islands or coastal regions, where water vapor makes up more of the atmosphere, are usually much more humid than inland regions, where water vapor is scarcer.

A region's temperature

temperature : A measure of the average kinetic energy of the particles in an object; an indicator of heat or cold.

also relies on the water cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

. Through the water cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

, heat is exchanged and temperature

temperature : A measure of the average kinetic energy of the particles in an object; an indicator of heat or cold.

s  fluctuate . As water e vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

ates , for example, it absorbs energy and cools the local environment. As water condenses, it releases energy and warms the local environment.

The Water Cycle and the Landscape

The water cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

also influences the physical geography of Earth

Earth : The third planet from the Sun, which has water in solid, liquid, and gas forms and is the main focus of the water cycle

. Glacial

glacial retreat : Glacial retreat is the process of glaciers melting faster than their ice can be replaced by new snow or ice, which can lead to reduced freshwater resources.

glaciers : Massive, slowly moving bodies of ice that can form streams or pools as they melt.

melt and erosion

erosion : The process by which natural forces like water, wind, or ice wear away rocks and soil.

caused by water are two of the ways the water cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

helps create Earth

Earth : The third planet from the Sun, which has water in solid, liquid, and gas forms and is the main focus of the water cycle

's physical features.

As glaciers

Glacier : A large, slow-moving mass of ice on land, which influences the availability of fresh water

glaciers : Massive, slowly moving bodies of ice that can form streams or pools as they melt.

slowly expand across a landscape , they can carve away entire valleys , create mountain peaks, and leave behind rubble as big as boulders. Yosemite

Yosemite Valley : A glacial valley in Yosemite National Park, located in the western Sierra Nevada of Central California, USA.

Yosemite National Park : A national park in California, USA, known for its stunning granite cliffs, waterfalls, and giant sequoia trees.

Valley , part of Yosemite National Park

Yosemite Valley : A glacial valley in Yosemite National Park, located in the western Sierra Nevada of Central California, USA.

Yosemite National Park : A national park in California, USA, known for its stunning granite cliffs, waterfalls, and giant sequoia trees.

in the U.S. state of California

California : A state in the western United States, known for its diverse geography and cultural influence.

, is a glacial

Glacier : A large, slow-moving mass of ice on land, which influences the availability of fresh water

glacial retreat : Glacial retreat is the process of glaciers melting faster than their ice can be replaced by new snow or ice, which can lead to reduced freshwater resources.

glaciers : Massive, slowly moving bodies of ice that can form streams or pools as they melt.

valley
. The famous Matterhorn

Matterhorn : A mountain in the Alps on the border between Switzerland and Italy, known for its distinctive and iconic pyramid shape.

, a peak on the Alps

Alps : A major mountain range in Europe, stretching across eight countries including Switzerland and Italy.

between Switzerland

Switzerland : A country in Central Europe known for its neutrality, Alpine landscapes, and well-developed financial sector.

and Italy

Italy : A country in Southern Europe known for its rich history, art, and cuisine.

, was carved as glaciers

Glacier : A large, slow-moving mass of ice on land, which influences the availability of fresh water

glaciers : Massive, slowly moving bodies of ice that can form streams or pools as they melt.

collided and squeezed up the earth

Earth : The third planet from the Sun, which has water in solid, liquid, and gas forms and is the main focus of the water cycle

between them. Canada

Canada : A country in North America known for its natural beauty, multicultural population, and being the second largest country in the world by area.

's "Big Rock

Big Rock : A large glacial erratic located in Alberta, Canada, deposited by a glacier.

" is one of the world's largest " glacial

glacial retreat : Glacial retreat is the process of glaciers melting faster than their ice can be replaced by new snow or ice, which can lead to reduced freshwater resources.

glaciers : Massive, slowly moving bodies of ice that can form streams or pools as they melt.

erratics
," boulders left behind as a glacier

Glacier : A large, slow-moving mass of ice on land, which influences the availability of fresh water

glaciers : Massive, slowly moving bodies of ice that can form streams or pools as they melt.

advances or retreats.

Glacial

glacial retreat : Glacial retreat is the process of glaciers melting faster than their ice can be replaced by new snow or ice, which can lead to reduced freshwater resources.

melt can also create landforms

landforms : Natural physical features of the Earth's surface, such as valleys, mountains, and plateaus.

. The Great Lakes

Great Lakes : A group of five large freshwater lakes in North America, located on the border between the United States and Canada: Lake Superior, Lake Michigan, Lake Huron, Lake Erie, and Lake Ontario.

, for example, are part of the landscape of the Midwest

Midwest : A region in the United States that includes states like Illinois, Indiana, Iowa, Kansas, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota, and Wisconsin.

of the United States and Canada

Canada : A country in North America known for its natural beauty, multicultural population, and being the second largest country in the world by area.

. The Great Lakes

Great Lakes : A group of five large freshwater lakes in North America, located on the border between the United States and Canada: Lake Superior, Lake Michigan, Lake Huron, Lake Erie, and Lake Ontario.

were created as an enormous ice

ice : Solid form of water. On Earth, it is primarily found in glaciers, ice sheets, and ice caps.

ice sheets : Large masses of glacial land ice extending more than 50,000 square kilometers (19,300 square miles).

ice caps : Smaller than ice sheets, covering an area of less than 50,000 square kilometers.

Antarctic ice sheet : A massive ice sheet covering Antarctica, containing the majority of the world's fresh water.

sheet melted and retreated, leaving liquid pools.

The process of erosion

erosion : The process by which natural forces like water, wind, or ice wear away rocks and soil.

and the movement of runoff

runoff : Runoff is the movement of water, usually from precipitation, that flows over the land's surface towards bodies of water like rivers or oceans.

also create varied landscapes across Earth

Earth : The third planet from the Sun, which has water in solid, liquid, and gas forms and is the main focus of the water cycle

's surface. Erosion is the process by which earth is worn away by liquid water, wind, or ice

ice : Solid form of water. On Earth, it is primarily found in glaciers, ice sheets, and ice caps.

.

Erosion

erosion : The process by which natural forces like water, wind, or ice wear away rocks and soil.

can include the movement of runoff

runoff : Runoff is the movement of water, usually from precipitation, that flows over the land's surface towards bodies of water like rivers or oceans.

. The flow of water can help carve enormous canyons, for example. These canyons can be carved by rivers on high plateaus (such as the Grand Canyon

Grand Canyon : A massive canyon carved by the Colorado River in Arizona, USA, known for its incredible depth and colorful landscapes.

, on the Colorado Plateau

Colorado Plateau : A large, high desert region in the United States, covering parts of Colorado, Utah, Arizona, and New Mexico.

in the U.S. state of Arizona

Arizona : A state in the southwestern region of the United States, known for its deserts and the Grand Canyon.

). They can also be carved by currents deep in the ocean (such as the Monterey Canyon, in the Pacific

Ocean : A large body of saltwater that covers most of Earth’s surface, significant in the water cycle

Pacific Ocean : The largest and deepest ocean, covering more than 30% of the Earth's surface and located between Asia, Australia, the Americas, and Antarctica.

Ocean off the coast of the U.S. state of California

California : A state in the western United States, known for its diverse geography and cultural influence.

).

Reservoirs and Residence Time

Reservoir

reservoir : A natural or artificial place where water is collected and stored for use, such as an aquifer or a body of water.

s are simply where water exists at any point in the water cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

. An underground aquifer can store liquid water, for example. The ocean

Ocean : A large body of saltwater that covers most of Earth’s surface, significant in the water cycle

is a reservoir. Ice sheets

ice : Solid form of water. On Earth, it is primarily found in glaciers, ice sheets, and ice caps.

ice sheets : Large masses of glacial land ice extending more than 50,000 square kilometers (19,300 square miles).

are reservoirs. The atmosphere itself is a reservoir of water vapor

vapor : The gaseous state of water, which is part of the continuous water cycle including solid and liquid states.

.

Residence time

residence time : The average time a water molecule spends in a reservoir in the water cycle.

is the amount of time a water molecule spends in one reservoir

reservoir : A natural or artificial place where water is collected and stored for use, such as an aquifer or a body of water.

. For instance, the residence time

residence time : The average time a water molecule spends in a reservoir in the water cycle.

of "fossil water," ancient groundwater reservoir

reservoir : A natural or artificial place where water is collected and stored for use, such as an aquifer or a body of water.

s, can be thousands of years.

Residence time for water in the Antarctic ice sheet is about 17,000 years

residence time : The average time a water molecule spends in a reservoir in the water cycle.

Residence time in Antarctic ice sheet is about 17,000 years : Water molecules spend a long time in the form of ice, influencing global water distribution and climate.

Antarctic ice sheet : A massive ice sheet covering Antarctica, containing the majority of the world's fresh water.

. That means that a molecule of water will stay as ice for about that amount of time.

The residence time for water in the ocean is much shorter—about 3,200 years

Residence time in the ocean is about 3,200 years : Water remains in the ocean for a shorter period compared to glaciers, affecting ocean circulation and climate systems.

.

The residence time of water in the atmosphere is the shortest of all—about nine days

Residence time in the atmosphere is about nine days : Water moves quickly through the atmosphere, impacting weather patterns and climate variability.

.

Calculating residence time

residence time : The average time a water molecule spends in a reservoir in the water cycle.

can be an important tool for developers and engineers. Engineers may consult a reservoir

reservoir : A natural or artificial place where water is collected and stored for use, such as an aquifer or a body of water.

's residence time when evaluating how quickly a pollutant will spread through the reservoir

reservoir : A natural or artificial place where water is collected and stored for use, such as an aquifer or a body of water.

, for instance. Residence time may also influence how communities use an aquifer.

Fast Fact

Breaking the Cycle
The water cycle

water cycle : The water cycle is the continuous process by which water is circulated throughout the Earth and its atmosphere. It involves the processes of evaporation, condensation, precipitation, and collection.

can change. Glacial retreat is the process in

we are experiencing the fastest rate of glacial retreat in recorded history : This suggests that glaciers are melting at an unprecedented rate, which is likely due to global warming and has serious implications for fresh water availability.

glacial retreat : Glacial retreat is the process of glaciers melting faster than their ice can be replaced by new snow or ice, which can lead to reduced freshwater resources.

which glaciers

Glacier : A large, slow-moving mass of ice on land, which influences the availability of fresh water

glaciers : Massive, slowly moving bodies of ice that can form streams or pools as they melt.

melt faster than their ice

ice : Solid form of water. On Earth, it is primarily found in glaciers, ice sheets, and ice caps.

can be replaced by precipitation

Precipitation : Any form of water, like rain or snow, that falls from the atmosphere to the surface of Earth

. Glacial retreat limits the amount of fresh water available on Earth

Earth : The third planet from the Sun, which has water in solid, liquid, and gas forms and is the main focus of the water cycle

. We are experiencing the fastest rate of glacial retreat in recorded history.
Articles & Profiles
National Geographic: Spring Rains Darken Saturn's Moon Titan

Titan : Saturn's largest moon, mentioned in the context of changing weather patterns

Website
USGS: Water Cycle Components
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Editor
Jeannie Ever

Jeannie Evers : An editor for Emdash Editing, associated with the document content

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Producer
National Geographic Society
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Last Updated

October 19, 2023

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