Day 1: The Water Cycle
Begin the lesson by projecting the Water Cycle Diagram (S-8-8-3_Water Cycle Diagram.doc). Give students copies of the Water Cycle Diagram and have them write the process or a description of what is happening at each stage of the water cycle, labeled A–E.
Read aloud Follow a Drop through the Water Cycle (S-8-8-3_Follow a Drop.doc or http://ga.water.usgs.gov/edu/followadrip.html). Stop periodically to have students identify the stage of the water cycle on the Water Cycle Diagram. It may be helpful for students who are visual learners to give them a copy of Follow a Drop through the Water Cycle.
Hand out The Water Cycle worksheet (S-8-8-3_The Water Cycle and KEY.doc). Have students complete the worksheet independently or in pairs.
Day 2: Modeling Watersheds and Wetlands
Write the definition of watershed on the board. Explain to students that every house, school, and neighborhood is part of a watershed. Say to students, “I want you to copy the definition of watershed on your worksheet. In the space next to it, I want you to draw a picture of what you believe a watershed would look like based on the definition.” As students work, walk around and check for students’ understanding.
Watershed Activity (Model)
After students complete their worksheets, take the class outside to an open area. Inform students that as a class, they will be creating a model of a watershed. As you travel outside, be sure to bring newspaper, a white plastic tablecloth, five spray bottles filled with water, food coloring, five sponges, and students’ science notebooks. Once outside:
- Hand out pieces of newspaper. Be sure that each student has a sheet of newspaper. Ask students to crumple their sheets of newspaper. The crumpled sheets of newspaper should then be placed on the ground.
- Place the white plastic tablecloth over the crumpled newspaper. Make sure that the edges of the tablecloth are flat against the ground. Inform students that the covered crumpled newspaper represents mountains.
- As students stand around the edges, have them predict where water would go if rain were to fall on the land. Have students share their ideas with a partner.
- Next, begin passing around your five spray bottles and give each student a turn with spraying water on the tablecloth.
- As the water flows off the tablecloth, have students observe where the water is going.
- Use this opportunity to engage the class in a discussion about watersheds.
- Ask students questions such as, “How does the water cycle link to our watershed?” “Where do you see the water collecting?” “Based on this simulation, when it rains in our area, where does the water collect, and where does it go?” Use these questions to guide the discussion and to give more information on watersheds.
Explain to students that wetlands act as the transitional area and filtering systems between the land and water. Many types of wetlands exist, including fresh and salt water marshes, bogs, estuaries, swamps, retention ponds, vernal pools, and river banks (flood plains). Show students images of various wetlands (S-8-8-3_Types of Wetlands.doc).
- Select five students and give each of them a sponge.
- Say to students, “If these sponges are acting as wetlands, where can they be placed on our watershed model?” Allow for student responses and have the five students place the sponges in five different locations on the watershed.
- Give each of the five students a spray bottle and have them stand by their sponge.
- Say to students, “The first time we sprayed the water, we predicted how the water would flow. We also learned that the land the water traveled upon was part of our watershed. Now we are going to observe the purpose of wetlands. How do you think the water will flow this time with the wetlands in place?” Allow time for student responses.
- Have the five students with the water bottles begin spraying their section of the watershed, starting at the mountain top.
- Ask students what they believe the job of wetlands is as they watch the water flow and collect. Students’ responses will vary, but explain to students wetlands serve as a reservoir and even out the fluctuating water levels, soaking up excess water during wet times and releasing stored water during dry times. Wetlands act as a buffer zone between dry land and bodies of water. Wetlands help trap pollutants and silt. Define silt and explain that if too much silt enters waterways, it can block the flow of water. Also, less oxygen is available, and it can harm or kill aquatic organisms.
- Next, pass the food coloring to each of five students with a spray bottle. As students are adding food coloring to their spray bottles, ask the class, “If pesticides somehow tainted the watershed, what do you believe would be the role of the wetlands?” Allow time for student suggestions.
- Ask students to spray the watershed again, although this time, ask two of the “spray bottle” students to remove their “wetland sponges.” Then have all five students spray their watersheds.
- Have students observe the differences between the areas of watershed that had wetlands and those that did not. Have students brainstorm the role of the wetlands in regards to pollutants. Student responses will vary, but students should observe that the wetlands soak up much of the “polluted water.” The parts of the watershed without wetlands have more pollution.
- Have students draw a T-chart in their science notebooks. Students should show the differences between parts of the watersheds that had wetlands during the “pesticide spill” and the parts of the watershed that did not have wetlands.
Watershed WITHOUT Wetlands
Watershed WITH Wetlands
More pollutants such as pesticides enter streams and rivers.
Increased silt in waterways.
Protected from flooding
Fewer pollutants enter streams and rivers.
Less silt in waterways.
Day 3: Identifying the Local Watershed
Review the concept of watersheds as systems and explain the following:
- Water that is not evaporated or absorbed into the soil drains from the land by way of watersheds. Watersheds are the natural sloping land water follows as it drains off the land.
- Watersheds can be as small as a puddle or many miles wide.
- Pennsylvania watersheds connect with larger watersheds in the United States to empty into the oceans.
- There are six major watersheds in Pennsylvania: Lake Erie, Ohio, Susquehanna, Potomac, Genesee, and the Delaware. (List them on the board.)
Conduct a whole-class activity to identify and find out more about the local watershed. Use one of the following Web sites:
Project the Web site so all students can see it and hand out a copy of Our Watershed (S-8-8-3_Our Watershed and KEY.doc). First identify the local watershed and then click on its name to find out more about it. Read through the information on the Web site and take student volunteers to give answers to the questions on the worksheet.
After students have learned more information about their local watershed, inform them you will be taking them on a watershed walk. Ask students to bring their science notebooks and a writing utensil.
- Once the class is outside, say to students, “Where do you think water would collect in puddles or pools after it rains?” Take suggestions from students. Next ask students, “Where do you think the water might run after it rains? What is the path that you think the water would take?”
- Use suggestions that students give to create a watershed walk for your class. Based on the responses students give, follow the direction the class believes water would travel after it rains.
- Have students create a map of the school, including the path they think water would flow after it rains.
- As students are working on their maps, ask them, “What are some pollutants you see along this path that the water might come in contact with?” Allow for student responses. Students may see trash, paper cups, paper, etc., while participating in this watershed walk.
- Ask students, “Based on the pollutants that we see, how could this affect the purity of our water?” Students answers will vary, but they should reply by saying that if the water is traveling in an area that is heavily polluted, it taints the water. This tainted water affects the organisms that live in it and use it to survive.
- Say to students, “I want you to think of ways we could prevent our watershed from becoming polluted.” Ask students for suggestions. Use this as an opportunity for brainstorming and a class discussion. Have one student act as a recorder, to write down all the suggestions given by the class.
After completing the activity outside, bring the class back into the room. As a closing activity, ask students to write a meaningful sentence using one or two of the following terms: water cycle, watershed, wetland. The sentence should reflect something new students learned during this lesson (e.g., “Our school is in the Susquehanna watershed, and there is a wetland area near the stream behind the school”).
- Give students about three minutes to quietly write their sentences.
- After the three minutes, ask students to turn to a partner and share their sentences.
- Have them work together to write one new sentence.
- Have students share their sentences.
- Students needing opportunities for additional learning can create a flashcard for the term watershed. Using an index card, one side of the index card should have the term watershed. On the opposite side, students (1) draw a picture to help remember what a watershed is, (2) use the word watershed in a sentence, and (3) write down a linking word that reminds them of what a watershed is.
- Provide students with a word bank to use for Part II, The Water Cycle worksheet.
- Have students make a circular flowchart of the water cycle, with a raindrop shape for each stage of the cycle.
- Students going beyond the standards can work in small groups to research how wetlands served as a buffer against Hurricane Katrina. Have students present the information in essay format. As students complete the assignment, students share the information with the rest of the class.