Lab 2: What's a Watershed?
The lab activity described here was created by Betsy Youngman of Phoenix Country Day School and LuAnn Dahlman of TERC for the EarthLabs project. The hands-on activity in Part A is adapted from similar lessons by Windows to the Universe and California's Project WILD.
Activity Summary and Learning Objectives
Students build a physical model to explore watershed features, then use Google Earth software to tie the model to a real place. By exploring several layers of map-based images and data, students develop an appreciation of the complexity of a watershed and river system in the context of a both a local and national scale.After completing this investigation, students will be able to:
- Build a physical model of a watershed.
- Identify watershed features such as drainage divides, rivers, tributary.
- Predict streamflow patterns based on landform features.
- Use Google Earth to view watershed features.
- Discover their own watershed.
- Describe land cover and population changes within a watershed.
Context for Use
This activity builds background knowledge necessary for understanding drought. The physical model and Google Earth-based exploration of watershed data help students grasp how surface water moves across the landscape. The activity requires simple lab or household materials for Part A and the computer lab for Part B. Both parts lend themselves well to small group work. There are no prerequisite skills needed for the activity, but it may take longer if this is the first time students have used Google Earth. The activity can stand alone from the drought unit as an introduction to rivers.
Estimate of Time Required: Part A: 45 minutes; Part B: 45 to 90 minutes, depending on students' previous experience with Google Earth.
Activity Overview and Teaching Materials
In part A, small groups of students build physical models to demonstrate the concepts of watersheds and drainage divides. Each group of 2 to 4 students will need the following materials.
- Large aluminum roasting pan or paint tray
- Stack of tissue paper or newspapers
- Masking Tape
- Sheet of white plastic, slightly larger than the pan (a trash compactor bag cut into single sheet works well)
- Spray bottle
- Blue food coloring
- Absorbent cloth or paper towels
- 2 different colors of permanent markers
- Blocks of wood or a notebook to lift one end of your tray
In Part B, students use Google Earth and watershed data from USGS EDNA Watershed Atlas site to look for correlations between watershed features and landforms. They also explore population density and land cover change in a watershed of their choice. Students conclude by preparing an illustrated description of a watershed.
Google Earth is a freely available virtual globe program. It displays satellite images, aerial photographs, and graphic layers on personal computers by serving them over the Internet. Advanced versions of Google Earth are available for purchase, but this activity uses the free version.
If student computers don't have Google Earth installed, they can download and install the free program from the Google Earth download page.
You may want to provide a hard copy of the activity sheet (Acrobat (PDF) 45kB Aug3 08) on which students can record their answers. A word processing document (Microsoft Word 29kB Aug3 08) of the activity sheet that includes 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 watershed models are easily built and explored in one class period. There are suggested materials to use, but there is much flexibility in the design. If you do not have squirt bottles or baking pans suggest to students to bring them in from home. Give students several days or a week's notice so that they can empty and clean an appropriate container.
Google Earth is an amazing and engaging program. Allow students sufficient time for exploration within the program will help them use it in subsequent lessons. Encourage students to access Google Earth's online User's Guide to understand how various tools and features work.
Also note that the EDNA watershed data sets from the USGS are rich sources of information for multiple investigations. Performing a practice run through the steps students will follow will help you anticipate questions that students may have.
If multiple computers are downloading or using Google Earth simultaneously, a lab may experience issues with limited bandwidth. Installation is recommended prior to student use. It is also recommended that this activity not be students' first exposure to Google Earth as there is a strong likelihood that they will be distracted by wanting to explore the program by checking out familiar places and experimenting with the tool's many features.
To assess student understanding in Part A, you may ask students to draw a diagram of their watershed model and label all significant features. Additional insight into student understanding can be gained by examining their answers to the Stop and Think questions.
State and National Science Teaching Standards
Applicable California Science Teaching Standards
Earth Science - California Geology
9. The geology of California underlies the state's wealth of natural resources as well as its natural hazards. As a basis for understanding this concept:
- 3. Students know the importance of water to society, the origins of California 's fresh water, and the relationship between supply and need.
g. Recognize the usefulness and limitations of models and theories as scientific representations of reality.
- Select and use appropriate tools and technology (such as computer-linked probes, spreadsheets, and graphing calculators) to perform tests, collect data, analyze relationships, and display data.
Applicable Massachusetts Science and Technology Standards (PDF - 1.3 Mb)
Earth and Space Science - Earth Processes and Cycles
- 3.4 Water flows into and through a watershed.
Applicable New York Core Curricula
Physical Setting/Earth Science (PDF - 135 Kb)
STANDARD 4 - Students will understand and apply scientific concepts, principles, and theories pertaining to the physical setting and living environment and recognize the historical development of ideas in science.
- Key Idea 2. Many of the phenomena that we observe on Earth involve interactions among components of air, water, and land.
- 2.1u A watershed is the area drained by a stream and its tributaries.
STANDARD 6 — Interconnectedness: Common Themes. Students will understand the relationships and common themes that connect mathematics, science, and technology and apply the themes to these and other areas of learning.
- Key Idea 2. Models are simplified representations of objects, structures, or systems used in analysis, explanation, interpretation, or design.
Applicable North Carolina Earth and Space Science Standards
4.06 Evaluate changes in local bodies of water and/or watershed over time:.
Applicable Texas Essential Knowledge and Skills (TEKS)112.49. Geology, Meteorology, and Oceanography.
(10) Science concepts. The student knows the interactions that occur in a watershed. The student is expected to identify the characteristics of a local watershed.
Applicable National Science Education Standards (SRI)
Science as Inquiry (12ASI)
Abilities necessary to do scientific inquiry
- 12ASI1.3 Use technology and mathematics to improve investigations and communications. A variety of technologies, such as hand tools, measuring instruments, and calculators, should be an integral component of scientific investigations. The use of computers for the collection, analysis, and display of data is also a part of this standard. Mathematics plays an essential role in all aspects of an inquiry. For example, measurement is used for posing questions, formulas are used for developing explanations, and charts and graphs are used for communicating results.
- 12ASI1.4 Formulate and revise scientific explanations and models using logic and evidence. Student inquiries should culminate in formulating an explanation or model. Models should be physical, conceptual, and mathematical. In the process of answering the questions, the students should engage in discussions and arguments that result in the revision of their explanations. These discussions should be based on scientific knowledge, the use of logic, and evidence from their investigation.
Understandings about Science and Technology
- 12EST2.2 Science often advances with the introduction of new technologies. Solving technological problems often results in new scientific knowledge. New technologies often extend the current levels of scientific understanding and introduce new areas of research.