In today's Daily Do, What do you mean we could run out of water? (a.k.a. How can we run out of water?), students engage in science and engineering practices and use cause-and-effect as a thinking tool to make sense of the phenomenon of running out of a seemingly ubiquitous natural resource—water. Students figure out that this phenomenon is also a human-caused problem to be solved. While students could complete this task independently, we encourage students to work virtually with peers or in the home with family members.

Daily Do Playlist—Natural Resources: Water

How can we run out of water? is a stand-alone task. However, it can be taught as part of an instructional sequence in which students coherently build the science idea that fresh water resources are limited and are distributed unevenly around the planet. In this third and final lesson on the playlist, students explore their own water usage to help them understand fresh water is a limited resource.

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Begin by asking students to think about how they use water. Individually, have students make a list of all the ways they use water. Next, have them share their ideas with a partner or small group. Next, prompt students to think about where the water they use comes from. When students are finished, engage them in a whole-group discussion to share their ideas.

Students will likely share they use water for many different things, including drinking, washing, and watering (to name just a few). However, many students do not know where their water comes from, and answers here will vary greatly. Some students may just say, "the faucet," and others may suggest it comes from a nearby lake, river, or ocean.

Now that students have begun to think about water and where it comes from, ask them to consider the following questions:

• Do you think water is used to make other things you use?
• Can you use water from anywhere to drink, wash, and make things?
• Could we ever run out of the water we need?

Give students time to discuss their ideas in small groups, then have students share their thoughts around the proposed questions with the class. As students share, record their thoughts on the board or some chart paper.

Tell students that to give them a better idea of how we use water and where it comes from, you have a short video clip for them to watch. As students watch the H₂0: The Molecule That Made Us—Virtual Water video, have them document what they notice and wonder.

Ask students to share what they noticed. Students may share the following observations:

• It takes water to grow things that we eat.
• It takes water to grow things, like cotton, that we use to make clothes.
• We use a lot of water to make stuff.
• Sometimes we use all the water.

Then ask students to share their questions, which may include these:

• Why does it take so much water to make stuff?
• Where does the water come from?
• What is a water footprint?
• Does everyone have a water footprint?
• Will the lake ever come back?
• Why didn't rain water keep filling the lake?

Transition students to thinking about where the water is before it arrives where we need it. From the video, they know that some water comes from lakes, but where else does it come from? After some sharing of ideas, ask students if just any kind of water can be used for things like drinking, bathing, watering plants, etc., and have them share their thinking. Answers here will vary, but allow all ideas to be shared without judgment.

Tell students you have another short video about water that you would like them to watch that will help them answer some of their questions. Prompt students to again write down anything they notice or questions that arise. Play the H20: The Molecule That Made Us—Cracks in the Earth video (below).

Discussion Guidance. Use these discussions as formative assessment opportunities to see what your students know and/or don't know about water, how it is used, and where it comes from. At this point, it is not necessary to correct any misconceptions or incomplete ideas about water, as students will be given opportunities to change their thinking around water during the rest of the Daily Do lesson.

After showing the video, ask students to share any new questions they may have about what they watched. Student questions may include these:

• Why do we need to grow things in the desert?
• How can using water make the ground sink?
• What does he [Sangen] mean that we are running out?
• Can't we just use ocean water for stuff?

Say, "It sounds like we have a lot of questions about the water we use and where it comes from." Explain that you have a bundle of information for them to explore to gather data about water so they will be able to answer some of their questions.

Have students join their group and assign a different resource to each group member to read or explore. If you are completing this Daily Do with students in a distance-learning environment, consider using this Google Slides Jigsaw template. Make a copy for each student group, and instruct them to summarize their learning from each resource for their peers. Encourage students to use the comment feature to discuss similarities and differences among their resources, and the conclusions they can draw from all four resources.

• How much water do we use? U.S. Water Use from 1950–2015 (interactive map). Students explore this interactive map to see how much water humans use for different activities, including manufacturing, farming, etc.
• Saline Water and Salinity. Students read about salinity and what humans can and cannot use salt water for.
• Land Subsidence. Students read about how land is sinking in some places due to overuse of ground water.
• H₂O: The Molecule That Made Us—What's Your Water Footprint?. Students read about the water footprint of different foods and objects/materials we use and the effect on the ground water supply.

Have students share what they learned from their assigned reading/interactive with the rest of the group. Then have groups create a poster of what they have learned about where our water comes from, what we use it for, and the effects that using water have on the planet. Have students present their posters to the class when they are completed.

Guidance. This activity can be done in several different ways. Another option could be to assign each group the same resource and have them create a poster to share the information with the rest of the class. These resources differ in reading complexity, allowing multiple access points.

Transition to evaluating how our thinking about water has changed since the beginning of the lesson. What questions did we have that we are now able to answer through our research? We have figured out the following:

• The majority of the water we use is fresh water.
• Salt water makes up most of the water on Earth, but very little is used for making the things humans use.
• Salt water has different salinity levels.
• Fresh water is found in different places, but a lot is stored underground.
• We are using groundwater faster than it can be replaced, and this is causing some cities and other places to sink and the ground to crack open.
• Everything has a water footprint (the amount of water it takes to make that item).
• In some places, humans have used so much water from lakes and rivers that they have completely dried up.

Next, have students explore the What's Your Water Footprint? calculator to determine their water footprint. Before they start, have them predict their water footprint based on what they have figured out so far.

When students are done exploring their water footprint, have a whole-group discussion about what they figured out about their water footprint. Prompt students by asking, "Are you surprised by your water footprint?" and encouraging them to share their thinking.

Have students consider the implications of their water usage by asking them the following questions:

• How do you think our water usage affects the availability of this natural resource?
• Are there things we can do to reduce our water usage?
• Do you think it's necessary to reduce water usage at this point in time?

Students can work individually or in small groups to formulate their ideas. Then have them share their ideas in a whole-group discussion.

Additional Guidance. Human impact on Earth's systems is becoming increasingly more noticeable. The consumption of fresh water across the globe has altered the biosphere in many different ways. This lesson introduces students to the idea that fresh water is a natural resource that we need to watch and manage carefully to ensure it lasts.

To continue learning about this topic, have students investigate the availability of fresh water worldwide.