Erosion Model Inquiry Beth Parsons and Kara Allan Overview: (75-90 minutes) This lesson is the third lesson in a five-day mini-unit on erosion. It is a model inquiry that asks students to reflect on the uses of scientific models, and then apply their understanding by using a model in their own investigation. The lesson also focuses on specific vocabulary use in context. During this lesson students will work in small groups (3-5 students) to build a model watershed. The model represents both a forested and deforested slope. Students enact the model by raining on the two slopes using a plastic cup with holes. Students make observations before and after enacting the model to note how deforestation affects erosion patterns and the possible impacts on the watershed. Grade: 6th Grade (can be modified for other grades) Focus Questions: (1) What is deforestation? (2) How does deforestation impact erosion? (3) How does increased erosion impact the watershed? Standards:

• Oregon 6.2E.1 Explain the water cycle and its relationship to landforms and weather. • Ocean Literacy Principle 2c: The ocean and life in the ocean shape the features of the

Earth: Erosion – the wearing away of rock soil and other biotic and abiotic earth materials – occurs in coastal areas as wind, waves, and currents in rivers and the ocean move sediments.

• Ocean Literacy Principle 3d: The ocean is a major influence on weather and climate: Most rain that falls on land originally evaporated from the tropical ocean.

Vocabulary:

erosion weathering deforestation fluid denudation sediment watershed deposition transportation

Materials:

Erosion Inquiry Outline Procedure steps for model set up Lasagna pan (1 per group) 35-40 3-inch pieces of pipe cleaners Package of playdough (1 per group) 1-inch stack of postcard sized foam sheets (1 per group) 1 cup of soil (per group) Cup with small holes poked into the bottom (1 per group)

Cup for pouring water (1 per group) Water Clock or stopwatches

Model Set-up

1. Place entire lump of playdough (bedrock) in the center of the lasagna pan (watershed) on top of the foam layers (lithosphere).

2. Cover the playdough with soil (top soil), packing the soil around the playdough. 3. On half of the mound, stick pipe cleaners (trees) closely together in rows to cover the

entire half (forested side). Stick pipe cleaners into the mound far enough to reach the playdough.

4. Pour enough water to cover the bottom of the lasagna pan without going past the foam layer.

5. To enact model, fill solid cup with water. Hold the “holed” cup over the mound. Pour water into the “holed” cup, letting water fall over entire mound for 15-20 seconds. Don’t over-rain the model!

Activity Engagement: (10 min) Pose the question, “What is deforestation?” to students in small groups. Allow groups time to discuss, and then have each group share their definition. Pose the question, “What is a scientific model and why do we use them?” to small groups. Allow groups time to discuss, and then share their thinking. Exploration: (15-20 min) Explain to students how to construct their watershed model. Allow groups time to construct their model. Have students discuss what the model parts represent. Each student should sketch and label a diagram of the model on their lab outline. Have students make hypotheses about the way deforestation might affect erosion patterns (what will happen when the model is enacted). Explanation: (15 min) Have students discuss and record observations of the model prior to “rainstorm.” Have students enact model by creating a “rainstorm” using the plastic cup with holes in it. Allow water to rain on the model for 15-20 seconds (depends on hole size). Have students discuss and record observations of the model after the “rainstorm.” Elaboration: (20 min) Allow groups time to do a walking tour of the other groups’ models. Ask students to note differences and similarities between models, and consider possible explanations for theses similarities and differences.

After the walking tour, have a whole group discussion about what students noticed and their possible explanations. Encourage students to use scientific language and unit specific vocabulary in their observations and explanations. Evaluation: (10 min) Have students independently draw conclusions about what they observed in their models. Conclusions should be written on their lab outlines. Then allow additional time for students to answer the application question on the lab sheet, “What could an affect of deforestation be on watersheds?” If time allows, have students share their responses.

Name______________________________

Erosion Inquiry

Question: How will deforestation affect erosion patterns? Hypothesis: ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ Observations: ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ Conclusion: ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________

What could an effect of deforestation be on watersheds? ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________