In this lesson, students will gather evidence for surface weathering, erosion, and deposition by exploring particular locations on an interactive map of geologic features in North America. They will then use the gathered evidence to construct explanations for how these geoscience phenomena shape Earth’s surface features at varying time and spatial scales. Students will come to the conclusion that these processes have occurred throughout Earth’s history and are ongoing today.
Grade Level: 6–8
ESS2.A: Earth’s Materials and Systems
- The planet’s systems interact over scales that range from microscopic to global in size, and they operate over fractions of a second to billions of years. These interactions have shaped Earth’s history and will determine its future. (MS-ESS2-2)
ESS2.C: The Roles of Water in Earth’s Surface Processes
- Water’s movements—both on the land and underground—cause weathering and erosion, which change the land’s surface features and create underground formations. (MS-ESS2-2)
Two 45-minute class periods
- Students will be able to analyze geological features for evidence of surface weathering, erosion, and deposition.
- Students will be able to construct explanations for how different geoscience processes have shaped and continue to shape Earth’s surface.
Prep for Teachers
Before the Lesson
- Arrange to have computer access for students to work individually or in small groups.
- Download and print the Evidence of Geologic Processes handout.
- Download and print the Weird Geological Formations: What’s the Story? handout.
- Begin the lesson by posing the question: Do you think that the natural landscape around you has always looked like it does today? Point out some features in your region for students to think about, such as hills, forests, streams, rivers, mountains, sandy beaches, or rocky coasts. Elicit student responses and why they think the landscape has or has not changed.
- Play the Making North America | Geology of the Manhattan Skyline video, which shows an example of how the heavily developed landscape of New York City appears today and may have appeared in the past. A story lies in the rocks beneath the skyscrapers and in the various outcroppings visible throughout the city. The video introduces the idea of the North American landscape having changed over time and helps place the lesson in the larger context of our planet’s geological change over millions and billions of years.
- Through the video, students will begin to see that the modern landscape has resulted from millions and billions of years of geologic change and that it continues to change. Be sure students realize that the animations of tectonic processes (~03:12–03:34) are conceptualized and highly sped up. Emphasize that processes such as the volcanic islands “bulldozing” mud from the seafloor toward the East Coast of North America occurred over millions of years.
- Before moving on to the Explore section, make sure students are familiar with the geoscience processes of surface weathering, erosion, and deposition. Ask students to identify a local example where each process can be found. Have them share an example that occurred over a relatively short time geologically speaking (minutes, hours, days, months) and an example that occurred over a longer time (years, decades, hundreds/thousands of years and certainly even longer).
- Direct students to the Making North America | Interactive Map. On the main menu, instruct students to select the Explore option, which takes them to a map of North America with many locator “pins.” (Note: The Expedition and Watch options and the Sky Tour video are not needed for the lesson.)
- The media in this interactive map provide context and explanations for how the landscape was formed over time. While there are many sites that can be explored, in order to manage class time, encourage students to focus on the 10 listed below to maintain a focus on weathering, erosion, and deposition.
- Grand Canyon, Arizona
- Joshua Tree National Park, California
- Flatirons, Colorado
- Monument Rocks, Kansas
- Acadia National Park, Maine
- Caprock Canyons, Texas
- Arches National Park, Utah
- Grosvenor Arch, Utah
- Monument Valley, Utah
- Zion, Utah
- Divide the class into small groups of four or five students. Have each group divide the 10 locations among its members so each student explores two to three sites. You may wish to assign locations to students to facilitate the process.
- Distribute the Evidence of Geological Processes handout. Tell students that their task is to observe the high-resolution images and/or videos available at these sites and to document evidence of past weathering, erosion, or deposition of each landscape. Students should review all the media available for each particular location; some places have more images/videos than others. Point out that students can zoom in on the panoramic images in this interactive map considerably, allowing for observations at great detail.
- For this part of the activity, students should explore their assigned locations individually and fill out the table in Part I of the handout with their observations.
- Next, encourage students to make connections about geoscience processes based on the evidence they have gathered and answer the question in Part II of the handout.
- Have students come back together as a group to share their response to Part II of the handout and reference observations of one site as evidence. They should discuss their explanations and evidence as a group. Guide student discussion by asking questions such as the following:
- Using the interactive
- What features or clues did you look for in gathering your evidence for a particular process?
- Geoscience processes
- Which locations showed evidence of weathering and erosion?
- Which locations showed evidence of sediments, rocks, or boulders being moved and deposited far away from their points of origin?
- Time and spatial scales
- Based on media from the interactive map, how long ago did some of these processes occur?
- How long do you think some of these processes took to result in the features you see today?
- How quickly does our landscape change due to weathering, erosion, and deposition?
- How small or large of an area of Earth’s surface did these processes affect? (Think in terms of distance or surface area.)
- General discussion and conclusions
- Were you surprised by any of the changes that some of the locations have undergone in the past?
- Describe how weathering, erosion, and deposition work together as an ongoing process over time to form a cycle of sorts that resulted in many of the landforms we see today.
- Discuss the range of time scales that are represented in the 10 sites. How has weathering, erosion, and deposition played a role in forming the landscape over both long and short time periods?
- Discuss the variability in size of the landscapes and features examined across the 10 sites. How have weathering, erosion, and deposition contributed to the development of very large areas (e.g., an entire region of North America) and shaped features on small landforms (e.g., a particular hill or gully)?
- Is it possible that weathering, erosion, and deposition work at different rates in different places across North America? Give an example or factors that may influence the rate at which these processes change the landscape.
- In what ways are geoscience processes predictable? In what ways are they not?
- Do you think these processes are still occurring today? Why or why not? What is your evidence?
- Do you think Earth’s surface will continue to change? Why or why not?
- What do you think some of the locations will look like in 100 years? In 100 million years?
- Give students some time to synthesize their ideas as a group and to complete Part III of the handout.
- Through the media, students should have been able to see that Earth’s landscape has been shaped by the geological processes of weathering, erosion, movement, and deposition over thousands, millions, and billions of years. From some images, students should be able to infer that these processes are still occurring—such as when a river carries sediments downstream or when wind erodes a cliff face sediment by sediment. Students should be able to articulate that geological processes occur at varying scales of time and space—from less than a second to billions of years, from microscopic to global. They can occur suddenly and rapidly, or so slowly that nothing appears to be happening at all. They can involve tiny grains of sand, entire mountain ranges, or even whole continents. These are processes that continue from the past and are still occurring today. Earth’s surface is always changing and will continue to change over time.
- Challenge students to think of examples of similar processes (weathering, erosion, deposition) in their own neighborhood or region. Have students share their examples. Ask:
- What is the geological feature? Where is it located?
- What are the processes at work?
- At what scale are the processes occurring?
- Do you think that the geological feature will look the same thousands, millions, or billions of years from now? What is your reasoning?
- Wrap up the lesson by having students complete the Weird Geological Formations: What’s the Story? quiz to apply their understanding of the processes that shape Earth’s surface.