5. Erosion and Deposition

Lesson at a glance: Students will explore erosion and deposition using models and natural examples.

Goal: Students will be able to identify the connection between the water cycle, erosion, deposition and landforms.

Oregon Content Standards:

Science

6.2 Interaction and Change: The related parts within a system interact and change.

6.2E.1 Explain the water cycle and the relationship to landforms and weather.

6.3 Scientific Inquiry: Scientific inquiry is the investigation of the natural world based on observations and science principles that includes proposing questions or hypotheses, and developing procedures for questioning, collecting, analyzing, and interpreting accurate and relevant data to produce justifiable evidence-based explanations.

Ocean Literacy: Essential Principles and Fundamental Concepts

1. The Earth has one big ocean with many features.

1.f. The ocean is an integral part of the water cycle and is connected to all of the earth’s water reservoirs via evaporation and precipitation processes.

3. The ocean is a major influence on weather and climate.

3.b. The ocean absorbs much of the solar radiation reaching Earth. The ocean loses heat by evaporation. This heat loss drives atmospheric circulation when, after it is released into the atmosphere as water vapor, it condenses and forms rain. Condensation of water evaporated from warm seas provides energy for hurricanes and cyclones.

Materials:

  • Watershed model bins (5 students per bin)
  • Spray bottles
  • Fans or straws
  • Cups
  • Water

Time: ­­­­3 hours 15 minutes class times ( Can be broken down into 3 days)

Activity:

Engage (5 min):

Show the students a picture of the Grand Canyon and/or using Google Earth. Ask students how that valley got to be so deep? Begin to identify misconceptions.

Explore (30 min):

Give student groups a watershed model bin. Ask them to use the tools (representing water, wind, movement of the earth, people, animals, etc.) and watershed model bin to try and create a valley.

Have them make notes in their science notebooks as to what they tried, their successes, etc.

Explain (20 min):

As a class, discuss what they found through their exploration. What factors seemed to be most successful at deepening a valley? How did the sand in the watershed bin react to each factor? What is the most likely factor to carve out valleys? The movement of the Earth is responsible for the development of mountains but water shapes the earth after mountain building events and carves out valleys. (Glaciers can also carve valleys.)

As water flows through and over rocks, it causes erosion. Erosion is the process of materials being removed by a force. Explain that erosion happens at many different rates from precipitation from the water cycle.

Ellaborate (60 min):

Ask students to write how precipitation may cause rapid erosion? Ask students a situation where precipitation causes slow erosion? Have them write in their science notebook their hypotheses on how erosion rates may be affected by precipitation patterns. Students should create detailed descriptions of how they will test these different weather patterns effects on erosion rates in their science notebooks. Also, students should create a data table to record their observations.

Have the students test these hypotheses by continuing to experiment with the watershed model. If there are time constraints, assign different groups different things to test. (i.e. heavy precipitation over a short period of time, moderate precipitation over a long period of time, slow precipitation and/or snow melt, different slopes of valley, etc.)

Have the students write down their observations in their science notebooks and assess whether their hypotheses were correct.

Explain (30 min):

Have students describe which weather patterns caused the most rapid and/or slow erosion rates as a class. Complete a class data chart comparing the different erosion rates during different weather patterns.

Ask the students what happened to the material that was eroded? In a watershed, where would that material go? Explain that materials that have eroded are carried through the watershed. When the water slows down, deposition occurs. Deposition is the process of materials being left in a new environment from where they originated.

Ellaborate (30 min):

Have students view a map of a watershed, have them highlight areas that they think deposition would occur.

Students should write in their science journal where deposition would occur.

Evaluate (20 min):

Have students reflect in their science journal to the following prompt:

“How does the water cycle affect the shape of our land?”