Authentic Lessons for 21st Century Learning

Erosion: Beauty or Beast?

Science

K20 Center, Patricia Turner, Jean Cate, Michelle Rahn | Published: May 26th, 2022 by K20 Center

  • Grade Level Grade Level
  • Subject Subject
  • Course Course
  • Time Frame Time Frame 2-3 class period(s)
  • Duration More 120 minutes

Summary

Students explore water erosion and investigate erosion and weathering in different types of soil. Funding provided by Agriculture and Food Research Initiative Competitive Grant no. 2013-69002-23146 from the ​USDA National Institute of Food and Agriculture.

Essential Question(s)

What makes the land/Earth surface around us change, move, and wear away?

Snapshot

Engage

Students observe earth materials, such as gravel, large-grained sand or pebbles, fine-grain sand, and silt or clay, and discuss similarities and differences.

Explore

Students investigate how soil and rock particles are moved from one place to another.

Explain

Students explain the processes of erosion and weathering by writing summary statements, then read a story and watch a video about erosion and weathering.

Extend

Students investigate which soil types allow greater erosion and look for examples of erosion around their school or school community. Fifth grade students research and propose solutions.

Evaluate

Students explain how their understanding of erosion and weathering have changed as well as provide evidence for their erosion claims.

Materials

  • Article (attached; teacher use)

  • Card Sort (attached; optional; 1 per small group)

  • 25 6-8 oz. paper or plastic cups

  • Samples of different type of soil, such as Gravel (limestone); Sand with large pebbles or grains; Fine sand; Fine silt/clay, to fill up cups for each group

  • 15 trays (9x13) approximately

  • 5 spray bottles filled with water

  • 25 straws

  • 5 large ice cubes

  • Class set of safety goggles

  • Small wooden paddle or large craft sticks

  • Collect different types of soil from your area, such as sandy loam, clay-like soil, topsoil, silt, or soil with vegetation.

Engage

For each group or table, prepare 4 paper cups with one with gravel, one with large grain sand with pebbles, one with fine-grain sand, and one with soil with silt or clay. Ask the essential question of the class: What makes the land/earth around us change, move, and wear away? Responses may include ice and snow.

Tell students to decide a characteristic to use to place the earth samples in a particular order. Then, tell students to place the cups of earth materials in order using their observations of characteristic.

Have students make notes of their observations of the physical properties of the rocks and soils in the cups in their science journals. They should note properties, such as size, shape and color, noting the similarities and differences. See Figure 1.

Figure 1. Observing soil properties.

As a group students will provide evidence as to how and why they ordered the cups. Ask: What was the rule for the way you sorted these? What properties did you notice? Listen carefully to how they support their reasoning for the ordering of the earth materials. As students are explaining their thinking, record key thoughts and words on chart paper or board using a webbing strategy. See sample in Figure 2.

Figure 2. Organizing the Earth's materials.

Explore

For the Card Sort activity, pass out the attached handout to small groups and have students complete cut the cards out. This formative assessment examines students’ thinking before they are introduced to the formal concepts of weathering and erosion. Tell students that each of the cards describes a way that can change rocks, soil, or sediments. Have students discuss the similarities and differences between the cards, but do not provide them with the names of the processes. Encourage students to sort their cards into various categories that describe a similar way that rock, sand, or sediment was changed. Students can name their groups. Have students share their categories for the similar types of changes and listen carefully for evidence of initial ideas about weathering, erosion and deposition even though they may not use the terminology. Have students look for similarities in grouping with the initial activity using the cups of materials. These activities help build a connection between students’ initial ideas and the formal concepts and vocabulary of weathering and erosion.

To begin the Explore section, set up these stations at each table and ask students to prepare their science journals by adding a table similar to Figure 3. Have students rotate through each station about every 5 minutes (for larger classes, you may set up duplicate stations). Remind students to wear their goggles and to remember science safety rules.

Figure 3. Table for recording observations.

Station 1: Provide a 9x13 tray with sand and a spray bottle filled with water. The nozzle of the spray bottle should be set so that the water comes out in a stream, rather than a spray. This will allow for some of the sand to be displaced, imitating erosion. At Station #1, put a card sign that says: Spray water over the sand and observe what happens to the sand. Draw what you observe and write what you noticed in your science journal.

Station 2: Provide a 9x13 tray filled with sand and a large ice cube on top of the sand. At Station #2, put a card sign that says: Observe what happens to the sand where the ice is. Push the ices cube(s) through the sand, imitating glacial erosion. Record your observations in your science journal. Before moving to the next station, move the sand and ice cube back to where they were when you arrived.

Station 3: Set up a small plastic clear aquarium filled with sand built up only on one side, add two cups of water. At Station #3, put a card sign that says: Use the large craft stick to simulate water waves. Record your observations in your journal. Before moving to the next station, move the sand and ice cube back to where they were when you arrived.

Station 4: Provide a tray filled with sand and enough straws for each student group. At station #4 make a card sign that says: Be sure to wear your safety goggles. Then, gently blow air across the sand from one end to the other. Draw and write about your observations in your science journal.

As you monitor, ask questions of your students during the station rotations, such as: How do you think rainfall shapes the landscape? How might different angles of a slope in the downhill movement of water affect the rate of erosion? How might different soil types erode from the flowing of water at different rates? How might vegetation affect the movement of water over land surfaces?

Explain

Have students discuss in their groups what they observed at each station. Then, ask them to write a summary sentence in their science journal for each station. Summary statements may include: When water ran over the sand, it moved. Ask students how the changes in each station were similar and different. Ask them to offer an explanation for the changes.

Have the class read, together or individually, Erosion by Virginia Castleman, or a similar book. If using the book Erosion read pages 4 through 7 and page 11. (Note: This is a great time to share with students that nonfiction books have the unique feature that the reader can enter the book at any point to get information.) Then ask students to write a group definition of water erosion using their own words and include two examples from the text and or the stations. Repeat with the definition of weathering, if students were able to observe the breakdown of rocks. (To add to students’ understanding of weathering, you may want to have students rub two limestone rocks together to make a small sand pile to show how they easily are broken down. Another way to have students experience weathering, is to have students observe and draw the edges of a few pieces of small sandstone, then place them in a plastic bottle or tube with a lid and some water. Have students vigorously shake the tube for a few minutes, then remove the sandstones and dry them off. Have students draw the edges after the shaking. Edges should be smoother and students should be able to observe some sand particles in the plastic bottle or tube.) Student responses: Responses should include water erosion occurs when water flows over the ground or winds blows over the ground and takes other loose weathered material with it. The weathering is the natural break down of rocks into particles.

Next, have students watch the Bill Nye Erosion video clip.

After watching the video about soil erosion, have your students add to their definitions and examples using the Examples and Non-Examples strategies. Ask questions such as: What did you find out about the changes of the earth’s surfaces? What happened with the large block of mineral salt in the video? What do you think Bill Nye was trying to model when he froze the bottle of water? Bill Nye uses the word changing often in this video, what does changing have to do with erosion?

Bring back the card sort that was used as a formative assessment. Have students sort the cards into two groups: examples of erosion and non-examples of erosion. Have groups share their reasoning; don’t forget to ask how they would describe the non-examples of erosion. Listen carefully and make note of any examples that may need further discussion and explanation. See Figure 4.