Lab 1: Where's the Water?

The lab activity described here was created by Betsy Youngman of Phoenix Country Day School and LuAnn Dahlman of TERC for the EarthLabs project.

Summary and Learning Objectives

Using data on the world's water distribution, students calculate the percentage of water that is available to humans and examine graphics that illustrate the distribution. Students develop a sense of where the world's water is located and how it moves through the Earth system.

After completing this investigation, students will be able to:
  • Interpret graphics of world water consumption and distribution.
  • Use data to calculate percentages of water distribution.
  • Translate data into a hands-on demonstration (an optional task).
  • Interpret maps, charts, and other info-graphics.
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Context for Use

This is the introductory lab in a sequence of lessons on drought: it sets the tone of the topic's importance for subsequent lessons. The lesson has a section that requires calculation of percentages; these can be solved with a calculator or spreadsheet program. The activity can be completed individually, in small groups, or as a whole class. The entire lesson should take 1-2 class periods.

Estimated Time Required:
Part A: 30 minutes
Part B: 15 minutes
Part C: 30 minutes

Activity Overview and Teaching Materials

In Part A, Students begin their study of drought by reading a statement from the World Water Council about the importance of water to life. They also examine a unique cartogram that depicts water consumption around the world. Provided with this table of data on global water distribution (Excel 2007 (.xlsx) 11kB Aug6 18), students use a spreadsheet program or a calculator to learn what a small portion of the world's water is readily available for human use. Part A also suggests an optional hands-on activity to kinesthetically reinforce the relative lack of freely available freshwater resources.

In Part B, students consider the quantity of water that moves through hydrologic cycle and approximate residence times that it spends in each step of the cycle.

In Part C, students explore the concept of freshwater and population distribution, raising the issue of water scarcity. The lab concludes with students exploring a report and Website published by the journal, Scientific American.

Printable Materials

You may want to provide a hard copy of the activity sheet (Acrobat (PDF) 27kB Aug3 08) on which students can record their answers. A

of the activity sheet and suggested answers is also available. Educators are encouraged to customize the questions and add new ones to meet specific learning goals in your location.

Teaching Notes and Tips

The importance of freshwater to survival, as well as its relative scarcity, are the most important points of this lab. You might heighten student interest in this topic by giving this description of a water distribution demonstration (Microsoft Word 2007 (.docx) 16kB Aug7 18) to a pair or small group of your more animated students and assigning them to practice and present the demonstration as a 5-minute follow up to the lab.

The calculate section could be assigned for completion without a calculator as a way to encourage students to practice using their manual quantitative skills.

Graphics about the global availability of freshwater at Vital Water Graphics, United Nations Environment Programme may be useful for stimulating follow-up discussions or for assessing student understanding.

Assessment

As an alternate assessment, students can make their own info-graphics to share with the class. Students can choose from amongst the issues raised in this lesson.

Challenging students to come up with a creative illustration for the optional hands-on demonstration would also make an excellent performance assessment.

State and National Science Teaching Standards

Additional Resources

Background Information

Pedagogic Considerations

This lesson presents numerically intensive information in a range of ways that can resonate with different learning modalities. Using a variety of presentation styles can make the information more accessible to diverse learners.

Content Extension

Once students begin to see the collision of water resources availability and population distribution and growth, they may want to share news articles. Engaging students in discussions on current events related to drought would be a powerful addition to this lesson.