Teacher & Student Materials > Quenching a Thirsty Planet
Where is water found?
3 Hours
Students will explore the ways water is stored on Earth and how it is moved through Earth through the Water Cycle.
The students will learn about surface water and groundwater and their role in the water cycle, the development of cities, and the impacts of human intervention. Using examples of the Hoover Dam and High Plains aquifer, the students will work closely with real-world data to draw their own conclusions about the future of water.
A rudimentary understanding that water is moved through Earth through a series of processes (ex. Ocean→ clouds→ rain→ ocean).
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Materials: Teacher Slides: 2.1 Where is water found?
Review the previous lesson set’s objectives by having students discuss with a partner or in their groups the questions on slide 1. Students should make connections to lesson 1.1 about different people having different relationships with water.
Have students share thoughts as time allows
The teacher may need to review what “water stress” means before starting. Water stress is a situation in which the water resources in a region or country are insufficient for its needs.
Class Discussion and
Peer-to-peer discussion
Hold up the gallon of water. If you want, emphasize how heavy a gallon of water is. You can have different students come up to the front to feel it as well.
State to the class:
This is all the water of planet Earth.
This is the water that is seen from space in the oceans that make people call this the blue planet.
This is the glaciers that make up the northern and southern poles and rest atop mountain ranges. This is the rivers, the lakes, the tiny ditches along a rural road filled with water. This is the precipitation from every single rainy day for which you have ever been alive. This is the water in your afterschool sports drink, the water in your faucet used to brush your teeth, the water used by farmers to irrigate their crops, the water required to complete nearly every single task on this planet. Pour the gallon of water into the glass or clear container.
Allow students to predict how much water is available for our use
Measure out 8 tablespoons from the clear container, pour the back into the gallon jug, counting aloud as you go. Hold up the still nearly empty jug and state to the class: this is all the water NOT in the ocean, which is about 3% of all the water on planet Earth. All the rest of this water is what makes our Earth blue, the salty waters of the oceans that separate our continents and communities.
Measure out 1 1⁄2 tablespoons out of the 8 tablespoons from the gallon jug and pour back into the clear container and state to the class:
Unfortunately, about .5% of the Earth’s water is still salt water even though it’s NOT in the ocean, so it’s also not usable by humans. This includes landlocked bodies of water like the Great Salt Lake and the Dead Sea, which can have an even higher salt concentration than the ocean.
We also have something called brackish water, which is a mix of salt and freshwater.
Hold up the even more empty jug, now with just 6 1⁄2 tablespoons, and state to the class:
This means only 2.5% of the Earth’s water is truly fresh water.
Measure out 4 1⁄2 tablespoons out of the 6 1⁄2 tablespoons in the gallon jug, pour back into the clear container, and state to the class:
However, 1.7% of the Earth’s water, although it’s fresh, it ISN’T accessible because it’s frozen as glaciers, trapped underground, or otherwise unavailable to humans.
Hold up the gallon just with only 2 tablespoons left and state to the class:
This is all the water, less than 1% on planet Earth that is fresh AND available to sustain all the human, animal, and plant life that has existed, currently exists and will exist in the future.
Peer-to-peer discussion
Have students point out where they see water. After they point it out, use the animations to have the different places water is found appear. Then point out that they have categories, such as surface water, groundwater, and water in the atmosphere.
This is how water is stored on Earth. Picture it as a 3D model – it’s in the ground, on the surface, and in the air.
If you teach states of matter, slide 13 would be a good spot to make that connection. This slide can be skipped if states of matter are not part of your lesson.
Have students draw what they know of the water cycle. Ask them to think about the ways we know water is stored on Earth.
This can be done on a piece of paper or on a whiteboard as a group.
As a class, build a model of the water cycle. It should be simplistic at this point. The model should be available for the class to refer back to throughout the remainder of the unit.
Build it together so that students have a starting point to work from as they develop the models into more sophisticated representations of the water cycle.
DP: Modeling
We think it can be useful for learners to first build a model as a group on a whiteboard. Whiteboards provide a low-risk, flexible way for learners to work together on a challenging task.
Because these models will be used throughout the unit, it is important to use common language when discussing the model. See the expandable or the terminology in the Information for Planning & Teaching section.
The processes of the water cycle are closely tied to weather.
If weather is not an emphasis in your curriculum, skip these slides.
Materials: 2.1 The Hoover Dam & Lake Mead
This activity requires learners to read and interpret line graphs. If students are unfamiliar, plan additional time to teach or review the components of graphs.
Discuss the role of oceans in the water cycle, weather, climate, and contribution to resources.
If oceans are not a significant part of your curriculum, this section can be skipped. Salinity of oceans will be revisited later in this unit as part of desalination.
This would be a good stopping point depending on how your school structures class periods. The next set of slides starts in a different direction.
For more than 20 years, the states of Georgia, Alabama, and Florida have been involved in discussions, negotiations, and lawsuits over shared water resources in the Southeast region. The main conflict has been over the waters of the Apalachicola-Chattahoochee-Flint (ACF) basin, which is shared by all three states. For this discussion, only look at the Chattahoochee river and discuss, “who owns the water?”
Class Discussion
Explain that water is stored underground in aquifers. Follow along the slides to point out that aquifers store our water too. We access this water source through pumps and wells.
Using the model the class built together as a starting point, have students make a new model adding their new understanding. They will need this model in future assignments.
This is will include an introduction to runoff, so students can identify what it is and its role in the water cycle. It is not important that students understand runoff in depth at this point. It will be more thoroughly explored later in the unit.
DP: Modeling
Building models iterative such as it is designed here is useful because it provides opportunities for students reflect and assess their new knowledge and reconcile what they know now with what they knew before.
Materials: 2.1 High Plains Aquifer & Agriculture
Because groundwater is recharged so slowly and is the primary use of irrigation for large farms, we are using our groundwater source faster than it can recharge, which is expensive for farmers and costly for the Earth. Students will explore this through data.
This activity requires students to read and interpret a bar graph with two variables. Plan additional time to review the components of bar graphs if you believe students will require additional support.
The water cycle, also known as the hydrological cycle, is a fundamental process that continuously circulates water on Earth.
The water cycle involves the three states of water: solid, liquid, and gas. Water can exist as ice, liquid water, or water vapor. These states undergo phase changes depending on temperature. For example, when heat is applied to ice, it melts and becomes liquid water. Similarly, when liquid water is heated, it evaporates and turns into water vapor, which is a gas. Conversely, when water vapor cools, it condenses back into liquid water, forming clouds.
The water cycle consists of several important components. Perhaps most significantly, the water cycle is powered by the sun. Evaporation occurs when the sun’s energy heats up water bodies like oceans, lakes, and rivers, causing water to turn into water vapor and rise into the atmosphere. As the water vapor rises, it cools and condenses into tiny water droplets, forming clouds. These clouds then undergo a process called precipitation, where the water droplets combine and fall back to the Earth’s surface as rain, snow, sleet, or hail.
Another critical aspect of the water cycle is runoff. When precipitation reaches the Earth’s surface, it may flow over the land, collecting in rivers and streams and eventually making its way back to the oceans. This runoff plays a crucial role in maintaining the balance of water on Earth.
The water cycle is influenced by various factors. Temperature, air pressure, humidity, wind, and topography all impact the movement and behavior of water within the cycle. For instance, warmer temperatures increase evaporation rates, while cooler temperatures promote condensation and cloud formation. Wind helps transport water vapor across different regions, affecting precipitation patterns.
A watershed is an area of land where all the water drains into a common outlet, such as a river or lake. Watersheds play a vital role in collecting and distributing water, influencing the movement of water within the cycle. Teachers should emphasize the importance of preserving and protecting watersheds to maintain a sustainable water supply.
Reservoirs, both natural and man-made, play a significant role in the water cycle. Natural reservoirs, such as lakes, ponds, and wetlands, serve as storage areas for water. They collect and hold precipitation, releasing it gradually through evaporation, transpiration by plants, or downstream flow. Man-made reservoirs, such as dams, are constructed to store water for various purposes, including irrigation, hydroelectric power generation, and water supply. These reservoirs help regulate water availability and distribution, especially in regions prone to drought or where water resources are limited.
Additionally, the ocean is a critical component of the water cycle. It acts as a vast reservoir, holding about 97% of the Earth’s water. The ocean contributes to the water cycle through evaporation. As the sun’s energy heats the ocean’s surface, water evaporates, forming water vapor that rises into the atmosphere. This process is a significant source of moisture for the air and precipitation worldwide. The ocean’s role in the water cycle highlights its importance in sustaining life on Earth and maintaining the overall balance of the global water system.
The water cycle affects various aspects of our lives, including weather patterns, ecosystems, agriculture, and human activities such as water management and infrastructure. By highlighting these connections, students can appreciate the significance of the water cycle in their daily lives.
This lesson plan can be adapted to fit a variety of schedules and modified to match your content goals.
If time is short, we recommend modifying the lesson to include two iterations of the water cycle and completing the Hoover Dam & Lake Mead worksheet as a group in class and the High Plains Aquifer and Agriculture as an independent worksheet. The “What if Earth’s water was only one-gallon” simulation and the role of oceans can be cut to save time.
If students require additional support in reading graphs, the lesson will take longer.
Example of how four 45-minute class periods could be organized:
| Day | Activity | Potential Modifications |
|---|---|---|
| Day 1 | Class Discussion Teacher Simulation How water is stored and moves through Earth with Water Cycle Model version 1 (Slides 1-28) | If states of matter is an important part of your curriculum, they can be added in at slide 13. |
| Day 2 | The Hoover Dam & Lake Mead | If the role of oceans’ impact on weather, climate, and other resources is not an important part of your curriculum, slides 35-60 can be cut. |
| Day 3 | Oceans as Reservoirs (Slides 31-61) | Slide 62 is a discussion question that can be used to start a new class period or be removed. Can start the worksheet during class time, but learners will most likely not be able to finish it. If learners require additional support in reading bar graphs with multiple variables, plan for additional time. |
| Day 4 | How water is stored and moves through Earth with Water Cycle Model version 2 (Slides 62-77) Assign High Plains Aquifer and Agriculture as homework | 1 hour |
Students will have experiences with the water cycle in a variety of ways. If they live in a rural environment, runoff might have flooded some roads, or flash flood warnings might have been issued on their cell phones. Students might have grown up near a river or lake and have observed its changing conditions over time. They might have participated in water-related activities, such as swimming, fishing, or boating, which provide insights into water quality and recreational uses. Students may have valuable local knowledge about water sources, such as wells, springs, or aquifers, which are not widely known or documented. Or teachers can ask students to go home and ask family members or community elders about how local waterways have changed over time.
Teachers can use and build from students’ knowledge during class discussions to piece together a cohesive understanding of the water cycle and how water sources change over time due to a variety of factors.
Modeling is highly beneficial for young learners as it helps them develop a deeper understanding of complex concepts and phenomena in a simplified and visual manner.
Conceptual Understanding: Scientific models provide a visual representation of abstract ideas, making them more tangible and accessible for young learners. Models help children develop a conceptual understanding of how things work and how different components are interconnected.
Predictive and Explanatory Power: Models allow young learners to make predictions and explanations based on their observations and understanding. By manipulating the model and observing the outcomes, children can develop hypotheses and test their ideas, fostering critical thinking skills.
Simplification and Visualization: Models simplify complex concepts by breaking them down into manageable parts. This simplification makes it easier for young learners to grasp the underlying principles and relationships, providing a foundation for future scientific inquiry.
Modeling Iteratively means creating and refining models through a cyclical process of development and improvement. Rather than attempting to create a perfect model right from the start, iterative modeling involves continuous revision and refinement based on feedback, new data, or changing understanding. Iterative modeling allows for incremental improvements over time. By building models in iterations, you can incorporate new information, insights, and feedback into subsequent versions, leading to more accurate and robust representations of the system being modeled.
Terminology related to scientific modeling:
We do not expect students to use this terminology; rather, we provide it here to establish common terms that we will use when referring to modeling.
Entities versus Processes: Entities refer to the objects, elements, or components within a system, while processes represent the interactions or transformations that occur between these entities. Understanding both entities and processes is essential for creating accurate and comprehensive scientific models.
Input versus Output: In a scientific model, inputs are the factors or conditions that enter the system and affect its behavior, while outputs are the results or outcomes that emerge from the system. Differentiating between inputs and outputs helps young learners identify the cause-and-effect relationships within a model.
Driver: The driver in a scientific model is the factor or element that has the most significant influence on the behavior or outcome of the system. Identifying the driver helps young learners focus on the critical components and understand their impact on the overall model.
Meta-level: The meta-level refers to the higher-level understanding and analysis of a scientific model. It involves examining the relationships, patterns, and connections within the model itself. By considering the meta-level, young learners can gain a deeper comprehension of the underlying principles and concepts embedded within the model.
For the water cycle:
Entities: In the water cycle model, the entities are the different components involved in the cycle. These include bodies of water (such as oceans, rivers, and lakes), the atmosphere, land surfaces, and living organisms (plants and animals).
Processes: The water cycle model illustrates the processes that occur within the system. These processes include evaporation, condensation, precipitation, and transpiration.
Inputs: The inputs in the water cycle model are the factors that enter the system. The primary input is the energy from the sun, which drives the water cycle. Sunlight provides the heat energy necessary for evaporation to occur.
Outputs: The outputs in the water cycle model are the results or outcomes of the processes. The main outputs are precipitation in the form of rain, snow, or hail, which falls from the atmosphere to the Earth’s surface.
Driver: The driver in the water cycle model is the sun. It provides the energy required for evaporation to happen, initiating the movement of water through the cycle.
Meta-level: At the meta-level, we can analyze the water cycle model as a whole and understand the relationships and patterns within it. We can analyze the water cycle model and understand the relationships and patterns within it, taking into account the effects of increased agriculture and urbanization. We consider how these changes brought about by increased agriculture and urbanization impact the water cycle’s dynamics, altering the inputs, outputs, and overall functioning of the system. It highlights the need to understand the consequences of human activities on the water cycle and the importance of sustainable water management practices to ensure the continued availability and quality of water resources.
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