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Make a Water Cycle Model

A transparent box with lid at its side. The box is filled with a layer of sand on the right side and a layer of water on the left side. A rock sits on top of the sand layer. On the lid of the box a small bag filled with ice cubes is shown. Above the box part of a heat lamp is shown.

Earth is a planet full of water. 70% of its surface is covered with water in oceans, lakes, rivers, and more. Water on our planet can also be found in the atmosphere and underground. In this lesson, students will explore how water is continually cycled among land, the oceans, and the atmosphere. As students build a physical model of the water cycle, they will be able to simulate and observe evaporation, condensation, precipitation, and other water cycle processes in real-time.

Remote learning: This lesson plan can be adapted to work remotely. The Engage section of the lesson can be done over a video call. Students will need to do their water cycle model experiment individually and independently during the Explore section using the Student Worksheet as a guide and can then share their observations with each other, virtually. A set of materials can be prepared in advance or students can use materials found around the house. End the lesson with a discussion over a video call during the Reflect section.

Learning Objectives

NGSS Alignment

MS-ESS2-4 . Develop a model to describe the cycling of water through Earth's systems driven by energy from the sun and the force of gravity.

Materials needed for the lesson 'Make a Water Cycle'

For educator and each student group of 3–5:

Background Information for Teachers

Earth is a planet full of water. About 70% of the Earth's surface is covered by water, but water is not distributed equally on Earth. 97% of the water is found in the world's oceans; the remaining water is found in glaciers and ice, rivers, lakes, underground, or in the atmosphere. The U.S. Geological Survey (USGS) estimates that Earth's total water supply is about 326 million cubic miles (about 1,359 million cubic km) of water! Most of this water is liquid, but on Earth water can also exist as a solid in the form of ice or snow, and as a gas in the form of water vapor.

The water on Earth is in constant movement. This movement is not limited to Earth's surface, but also includes the atmosphere and the subsurface. The water cycle, also called the hydrologic cycle, describes how water moves within and on Earth and atmosphere and its transition from one state to another. The water cycle is dynamic and involves many different processes that contribute to water being moved from one place to another. Some of these processes are evaporation, condensation, precipitation, transpiration, and infiltration (Figure 1).

Schematic that shows the different process of the water cycle.

A cross-section of a landscape including an ocean, green land, and snowy mountains. The sun is shown above the ocean. Clouds are shown above the land and the ocean. Blue areas depict rivers and lakes on the green land. Grey arrows show the movement of water from the ocean into the atmosphere, back onto the land and within the subsurface. Blue arrows visualize processes such as evaporation, transpiration, surface runoff, or infiltration. Blue dashed lines from the clouds to the ground visualize precipitation.

The Sun is the major driver of the water cycle. Surface waters such as the ocean, lakes, and rivers are heated up by solar energy and thus, some of the liquid water evaporates and becomes water vapor. As warm air rises, that moist air rises to higher altitudes. In the process, it cools down and eventually condenses into water droplets. This process is called condensation . We see these tiny water droplets as clouds in the sky. The tiny water droplets within a cloud merge and become bigger and heavier until they get too heavy and fall down to the ground due to gravity. This process is called precipitation . If temperatures are too cold to keep the water droplets in a liquid state, they crystalize and form snow or ice crystals and fall to the ground as snow or hail. Snow that is deposited on mountains or glaciers can be stored as solid water for thousands of years until it gets warm enough for it to melt again. Ice and snow can also directly transform into water vapor in a process called sublimation . Gravity also causes liquid water to fall on land, and thus get absorbed into the soil through infiltration where it can be stored as groundwater or taken up by plants. Plants release some of the water back into the atmosphere through their leaves in a process called transpiration . Water that does not soak into the ground flows over the land as surface runoff until it enters a river, lake, or the ocean. Again, gravity is the driving force. These water bodies function as storage reservoirs for liquid water. It is from there that the water cycle starts again when the Sun's energy turns the water into water vapor.

The horizontal movement of water in the water cycle happens both in the atmosphere through clouds being moved around the globe by air currents, and through water flow on land as surface runoff or as waterflow in rivers or underground. Although water in the water cycle is constantly moving and continuously transforming from one state to another, no water ever disappears! The water that exists on our planet today is the same water that existed on our planet a thousand or a million years ago! The natural cycling of water is one of the most important processes on Earth, as it provides all living organisms with a continuous supply of fresh water. The water cycle also plays a significant role in the weather patterns on our planet, as it contributes to weather events such as precipitation or cloud formation. Without the water naturally recycling itself, life on Earth would not be possible!

In this lesson, students will explore some of the processes that are part of the water cycle in more detail. They will build a miniature landscape, including a water body inside a closed plastic box, and then use a heat lamp to mimic the Sun. In their model, students will be able to observe evaporation, condensation, precipitation, infiltration, and surface runoff in real-time. Based on their observations, students will be able to conclude that the water cycle is propelled by the Sun and gravity.

Prep Work (15 minutes)

Engage (15 minutes), explore (60 minutes), reflect (45 minutes), make career connections, lesson plan variations, explore our science videos.

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Evaporation and the Water Cycle Completed

Evaporation is the process that changes liquid water to gaseous water (water vapor). Water moves from the Earth’s surface to the atmosphere via evaporation.

• Water Science School HOME • The Water Cycle •

Water cycle components » Atmosphere · Condensation · Evaporation · Evapotranspiration · Freshwater lakes and rivers · Groundwater flow · Groundwater storage · Ice and snow · Infiltration · Oceans · Precipitation · Snowmelt · Springs · Streamflow · Sublimation · Surface runoff

Water evaporating from a power-plant cooling tower.

What is evaporation and why does it occur?

Evaporation occurs when energy (heat) forces the bonds that hold water molecules together to break. When you’re boiling water on the stove, you’re adding heat to liquid water. This added heat breaks the bonds, causing the water to shift from its liquid state to its gaseous state (water vapor), which we know as steam.

Water easily evaporates at its boiling point (212° F, 100° C) but evaporates much more slowly at its freezing point because of the heat energy required to evaporate the water.

The opposite of evaporation is condensation. Condensation is the process of water vapor turning back into liquid water. Condensation occurs when saturated air is cooled, such as on the outside of a glass of ice water.

Drippy fact graphic. Drippy stands off to the left, while fact is in black text on right.

Evaporation drives the water cycle

Most of the moisture in the atmosphere (about 90%) came from water evaporating from oceans, seas, lakes, and rivers. (And because over 70% of Earth’s surface is covered by oceans, they contribute a lot to the overall volume of water evaporating into the atmosphere.) The rest of the moisture in the atmosphere came from plant transpiration and (a very small amount) from sublimation.

On a global scale, the amount of water evaporating is about the same as the amount of water delivered to the Earth as precipitation.

This does vary geographically, though. Evaporation is more prevalent over the oceans than precipitation, while over the land, precipitation routinely exceeds evaporation. Most of the water that evaporates from the oceans falls back into the oceans as precipitation. Only about 10 percent of the water evaporated from the oceans is transported over land and falls as precipitation. Once evaporated, a water molecule spends about 10 days in the air. The process of evaporation is so great that without precipitation runoff , and groundwater discharge from aquifers , oceans would become nearly empty.

Salty stands off to the left holding a salt shaker. Text is on the right side.

People make use of evaporation

One way to produce table salt is to evaporate saline water in evaporation ponds, a technique used by people for thousands of years.

Seawater contains other valuable minerals that are easily obtained due to evaporation. Water from the Dead Sea is ideal for the extraction of not only table salt, but also magnesium, potash, and bromine. The Dead Sea is actually a lake, located in the Middle East within a closed watershed and without any means of outflow. This closed basin system is abnormal for most lakes. Water primarily leaves the lake by evaporating, resulting in upwards of 1,300 - 1,600 millimeters of evaporated water per year in this desert area! The result is that the waters of the Dead Sea have the highest salinity and density of any sea in the world, too high to support life.

(Source: Overview of Middle East Water Resources, Middle East Water Data Banks Project ) .

Evaporative cooling: Cheap air conditioning!

Because energy is required to break the bonds holding water molecules together, evaporation removes heat from the environment, leading to a net cooling. Think of when a physician wipes an alcohol pad on your arm before giving you an injection – your arm feels cold. That’s because the alcohol rapidly evaporates from the surface of your skin, and with it some heat from the surface of your arm.

In climates where the humidity is low and the temperatures are hot, an evaporative cooler can lower the air temperature by 20 degrees F., while it increases humidity. As this map shows, evaporative coolers work best in the dry areas of the United States (red areas marked A) and can work somewhat in the blue areas marked B. But in section C, in the humid eastern U.S., normal air conditioners must be used.

Evaporative coolers are really quite simple devices, at least compared to air conditioners, because they pull in the dry, hot outdoor air and pass it through an evaporative pad that is kept wet by a supply of water. In a home device, a fan draws the air through the pad causing the water in the pad to evaporate, resulting in cooler air which is then pumped through the house. Much less energy is used as compared to an air conditioner.

Below are other science topics associated with the water cycle.

Precipitation and the Water Cycle

People recreating on the Chattahoochee River in Atlanta.

Streamflow and the Water Cycle

Snowmelt Runoff and the Water Cycle

Frozen carbon dioxide (dry ice) sublimates directly into a vapor.

Sublimation and the Water Cycle

Surface-water-gley developed in glacial till, Northern Ireland.

Infiltration and the Water Cycle

Lenticular clouds over hills in New Zealand.

The Atmosphere and the Water Cycle

Image: Stormwater Runoff in Rapid City, SD

Surface Runoff and the Water Cycle

Clouds, caused by condensed evaporation, above a field

Condensation and the Water Cycle

Springs and the Water Cycle

Satellite image of the North Pole area showing massive amounts of water stored as ice.

Ice, Snow, and Glaciers and the Water Cycle

Groundwater flowing from cracks in a wall of the Grand Canyon.

Groundwater Flow and the Water Cycle

Groundwater Storage and the Water Cycle

water cycle

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Read a brief summary of this topic

water cycle , also called hydrologic cycle , cycle that involves the continuous circulation of water in the Earth - atmosphere system. Of the many processes involved in the water cycle, the most important are evaporation , transpiration , condensation , precipitation , and runoff . Although the total amount of water within the cycle remains essentially constant, its distribution among the various processes is continually changing.

A brief treatment of the water cycle follows. For full treatment, see hydrosphere: The water cycle .

Evaporation , one of the major processes in the cycle, is the transfer of water from the surface of the Earth to the atmosphere. By evaporation, water in the liquid state is transferred to the gaseous , or vapour, state. This transfer occurs when some molecules in a water mass have attained sufficient kinetic energy to eject themselves from the water surface. The main factors affecting evaporation are temperature , humidity , wind speed, and solar radiation . The direct measurement of evaporation, though desirable, is difficult and possible only at point locations. The principal source of water vapour is the oceans , but evaporation also occurs in soils , snow , and ice . Evaporation from snow and ice, the direct conversion from solid to vapour, is known as sublimation. Transpiration is the evaporation of water through minute pores, or stomata, in the leaves of plants . For practical purposes, transpiration and the evaporation from all water, soils, snow, ice, vegetation, and other surfaces are lumped together and called evapotranspiration , or total evaporation.

Follow water as it cycles through the air, land, lakes and rivers, and oceans

Water vapour is the primary form of atmospheric moisture. Although its storage in the atmosphere is comparatively small, water vapour is extremely important in forming the moisture supply for dew , frost , fog , clouds , and precipitation. Practically all water vapour in the atmosphere is confined to the troposphere (the region below 6 to 8 miles [10 to 13 km] altitude).

The transition process from the vapour state to the liquid state is called condensation . Condensation may take place as soon as the air contains more water vapour than it can receive from a free water surface through evaporation at the prevailing temperature. This condition occurs as the consequence of either cooling or the mixing of air masses of different temperatures. By condensation, water vapour in the atmosphere is released to form precipitation .

Precipitation that falls to the Earth is distributed in four main ways: some is returned to the atmosphere by evaporation, some may be intercepted by vegetation and then evaporated from the surface of leaves , some percolates into the soil by infiltration, and the remainder flows directly as surface runoff into the sea. Some of the infiltrated precipitation may later percolate into streams as groundwater runoff. Direct measurement of runoff is made by stream gauges and plotted against time on hydrographs.

Most groundwater is derived from precipitation that has percolated through the soil. Groundwater flow rates, compared with those of surface water, are very slow and variable, ranging from a few millimetres to a few metres a day. Groundwater movement is studied by tracer techniques and remote sensing.

Ice also plays a role in the water cycle. Ice and snow on the Earth’s surface occur in various forms such as frost, sea ice , and glacier ice. When soil moisture freezes, ice also occurs beneath the Earth’s surface, forming permafrost in tundra climates . About 18,000 years ago glaciers and ice caps covered approximately one-third of the Earth’s land surface. Today about 12 percent of the land surface remains covered by ice masses.

Illustration of a question mark that links to the Climate Kids Big Questions menu.

What Is the Water Cycle?

Water can be found all over Earth in the ocean, on land and in the atmosphere. The water cycle is the path that all water follows as it moves around our planet.

Credit: NASA/JPL-Caltech Data source: NASA's Earth Observatory

On Earth, you can find water in all three states of matter: solid , liquid and gas . Liquid water is found in Earth’s oceans, rivers, lakes, streams—and even in the soil and underground. Solid ice is found in glaciers , snow, and at the North and South Poles . Water vapor—a gas—is found in Earth’s atmosphere.

How does water travel from a glacier to the ocean to a cloud? That’s where the water cycle comes in.

The Water Cycle

Credit: NASA/JPL-Caltech

The Sun’s heat causes glaciers and snow to melt into liquid water. This water goes into oceans, lakes and streams. Water from melting snow and ice also goes into the soil. There, it supplies water for plants and the groundwater that we drink.

Snow falling on a glacier during winter months usually replaces any water that melts away in the summer. However, due to Earth’s overall warming , most glaciers today are losing more ice than they regain, causing them to shrink over time.

How does water get into the atmosphere? There are two main ways this happens:

Warm water vapor rises up through Earth’s atmosphere. As the water vapor rises higher and higher, the cool air of the atmosphere causes the water vapor to turn back into liquid water, creating clouds. This process is called condensation .

When a cloud becomes full of liquid water, it falls from the sky as rain or snow—also known as precipitation . Rain and snow then fill lakes and streams, and the process starts all over again.

Clouds, like these over the savannah in Nairobi, Kenya, form when water vapor in the atmosphere condenses back into liquid water. Credit: Department of State

Why Do We Care About the Water Cycle?

We care about the water cycle because water is necessary for all living things. NASA satellites orbiting Earth right now are helping us to understand what is happening with water on our planet.

an illustration of a green plant sprout growing out of the soil

Water in the Soil

Humans need water to drink, and to water the plants that grow our food. NASA has a satellite called SMAP —short for Soil Moisture Active Passive —that measures how much water is in the top 2 inches (5 cm) of Earth’s soil . This can help us understand the relationship between water in the soil and severe weather conditions, such as droughts.

an illustration of water vapor droplets floating in the atmosphere

Water in the Atmosphere

NASA’s CloudSat mission studies water in our atmosphere in the form of clouds. CloudSat gathers information about clouds and how they play a role in Earth’s climate. Also, the international satellite called the Global Precipitation Measurement Mission (GPM) observes when, where and how much it rains and snows on Earth.

an illustration of a dolphin jumping out of ocean waves

Water in the Oceans

As Earth’s climate becomes warmer, land ice at the North and South Poles starts melting. The water then flows into the ocean, causing sea level to rise. NASA’s Jason-3 mission—short for Joint Altimetry Satellite Oceanography Network-3 —orbits Earth collecting information about sea level and ocean temperature. This helps track how the ocean responds to Earth’s changing climate.

NASA is also tracking how Earth’s water moves all around our planet. This is the work of the GRACE-FO —or Gravity Recovery and Climate Experiment-Follow On —mission. It tracks the movement of water from one month to the next, and can even measure changes in deep groundwater hundreds of feet below Earth’s surface.

NASA’s Aqua satellite also collects a large amount of information about Earth’s water cycle, including water in the oceans, clouds, sea ice, land ice and snow cover.

Related NASA Missions

Evaporation

Evaporation is the process by which a liquid turns into a gas. It is also one of the three main steps in the global water cycle.

Earth Science, Meteorology, Geography

Evaporation on a Farm

Water evaporates from a sugar beet field after a summer shower in Borger, Netherlands. Evaporation is a key step in the water cycle.

Photograph by Buiten-Beeld/Alamy Stock Photo

Evaporation happens when a liquid turns into a gas. It can be easily visualized when rain puddles “disappear” on a hot day or when wet clothes dry in the sun. In these examples, the liquid water is not actually vanishing—it is evaporating into a gas, called water vapor .

Evaporation happens on a global scale. Alongside condensation and precipitation , evaporation is one of the three main steps in the Earth’s water cycle . Evaporation accounts for 90 percent of the moisture in the Earth’s atmosphere ; the other 10 percent is due to plant transpiration .

Substances can exist in three main states: solid, liquid, and gas. Evaporation is just one way a substance, like water, can change between these states. Melting and freezing are two other ways. When liquid water reaches a low enough temperature, it freezes and becomes a solid—ice. When solid water is exposed to enough heat, it will melt and return to a liquid. As that liquid water is further heated, it evaporates and becomes a gas—water vapor.

These changes between states (melting, freezing, and evaporating) happen because as the temperature either increases or decreases, the molecules in a substance begin to speed up or slow down. In a solid, the molecules are tightly packed and only vibrate against each other. In a liquid, the molecules move freely, but stay close together. In a gas, they move around wildly and have a great deal of space between them.

In the water cycle, evaporation occurs when sunlight warms the surface of the water. The heat from the sun makes the water molecules move faster and faster, until they move so fast they escape as a gas. Once evaporated, a molecule of water vapor spends about ten days in the air.

As water vapor rises higher in the atmosphere, it begins to cool back down. When it is cool enough, the water vapor condenses and returns to liquid water. These water droplets eventually gather to form clouds and precipitation.

Evaporation from the oceans is vital to the production of fresh water. Because more than 70 percent of the Earth’s surface is covered by oceans, they are the major source of water in the atmosphere. When that water evaporates, the salt is left behind. The fresh-water vapor then condenses into clouds, many of which drift over land. Precipitation from those clouds fills lakes, rivers, and streams with fresh water.

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The Water Cycle

Below, you'll find some helpful information and links to experiments and resources about the water cycle for use in the classroom or at home. We hope these resources help you introduce the importance of clean, safe water to your students.

The Water Project is dedicated to providing clean, safe water to people in the developing world who suffer needlessly without it. We hope you'll introduce our work to your students or classmates.

The Water Cycle - What is It?

Help build wells in Kenya, Africa Schools

Evaporation

All Dried Up A simple experiment showing how evaporation rates are different based on the amount of light a cup of water receives.

The Case of the Disappearing Water (PDF) This lesson includes a story about a missing person where one of the few clues is a cup of water that has partially evaporated. Students must conduct an experiment to see how long it takes for the given amount of water to evaporate in order to find out where the missing person is located. While meant for grades 4-6, the story could easily be rewritten for older grades as a "forensic science" case.

Water Purification by Evaporation and Condensation (PDF) An activity to illustrate how the water cycle helps to purify water.

Condensation

Make a Cloud in a Bottle Highlighting the concepts of air pressure and temperature in cloud making, this experiment uses a burnt match and some water to create a cloud inside of a plastic bottle. Due to the use of matches an adult is necessary.

Precipitation

The Rainmaker This experiment uses a burner to heat water and a cookie tray of ice cubes above it to show how water vapor turns into precipitation like rain.

Collection (and Conservation)

Leaky Faucets Matter This activity challenges students to be more aware of leaks in their house by showing just how much water can be lost through a single leaky faucet over time.

** PLEASE NOTE: All of the links in the "Resources" section of our website are provided for your convenience. The Water Project, Inc. does not endorse any of the linked content. The owners and creators of the content on these third-party sites are solely responsible for that content. If you have concerns about any of these links, please note its URL and contact us here .

IMAGES

The Water Cycle
Hydrological Cycle
The Water Cycle: Collection, Condensation, Precipitation, Evaporation, Learning Videos For Children
Hydrologic cycle diagram
Hydrologic Cycle
The evaporation stage of the water cycle

VIDEO

ChemistryByPk # Water cycle # made by students of ICSE
Evaporation of Water
January 7, 2023
The Water Cycle
Evaporation #shorts
World Geography: Chapter 2 The Physical World

COMMENTS

11 Activities to Teach Water Cycle Science
6. Rising Sea Levels. The polar ice caps store the second largest amount of water on Earth. (Oceans store the most.) The water in the ice caps is in a frozen state and not in motion as part of the water cycle. However, as temperatures increase with global warming, there is melting at the polar ice caps.
Make a Water Cycle Model | Lesson Plan - Science Buddies
In this lesson, students will explore how water is continually cycled among land, the oceans, and the atmosphere. As students build a physical model of the water cycle, they will be able to simulate and observe evaporation, condensation, precipitation, and other water cycle processes in real-time. Remote learning: This lesson plan can be ...
Evaporation and the Water Cycle | U.S. Geological ... - USGS.gov
Just as the water you wash your car with runs off down the driveway as you work, the rain that Mother Nature covers the landscape with runs off downhill, too (due to gravity). Runoff is an important component of the natural water cycle. Note: This section of the Water Science School discusses the Earth's "natural" water cycle...
water cycle - Encyclopedia Britannica | Britannica
Of the many processes involved in the water cycle, the most important are evaporation, transpiration, condensation, precipitation, and runoff. Although the total amount of water within the cycle remains essentially constant, its distribution among the various processes is continually changing. A brief treatment of the water cycle follows.
Exploring the Water Cycle Teacher’s Guide - NASA
1. Hand out the Water Cycle Capture Sheet. Students will use this throughout the rest of the lesson. 2. Show the water cycle video (slide 5). Students should be labeling their blank diagrams as they watch. This version of the water cycle is more complex than the one on their capture sheets. Students only need to copy the terms from the word bank.
What Is the Water Cycle? | NASA Climate Kids
The water cycle is the path that all water follows as it moves around Earth in different states. Liquid water is found in oceans, rivers, lakes—and even underground. Solid ice is found in glaciers, snow, and at the North and South Poles. Water vapor—a gas—is found in Earth’s atmosphere. Water can be found all over Earth in the ocean, on ...
Evaporation - National Geographic Society
Evaporation is a key step in the water cycle. Evaporation happens when a liquid turns into a gas. It can be easily visualized when rain puddles “disappear” on a hot day or when wet clothes dry in the sun. In these examples, the liquid water is not actually vanishing—it is evaporating into a gas, called water vapor.
The Water Cycle - Experiments and ... - The Water Project
A flash animated activity that lets you control the water cycle as you learn. (FLASH Required) Create a mini water cycle using a bowl, a mug, some plastic wrap and a rubber band to show how evaporation, condensation and precipitation occur in a closed system. Learn what happens when the water cycle doesn't work for people.
Water Cycle Reading and Writing - Teacher Package
The Water Cycle In this illustration of the water cycle, precipitation falls to earth (1) and enters streams flowing seaward as runoff (2) or infiltrates into the ground (3). Groundwater feeds streams and lakes and is taken up by plants (4), from which it transpires into the atmosphere as water vapor. Evaporation from the sea (5) and other surface