# Hands-on ActivitySinkhole Emergency!

### Quick Look

Time Required: 2 hours 30 minutes

(two 75-minute sessions)

Expendable Cost/Group: US \$3.00

Group Size: 3

Activity Dependency: None

Subject Areas: Data Analysis and Probability, Earth and Space, Number and Operations, Problem Solving, Reasoning and Proof

NGSS Performance Expectations:

 3-5-ETS1-1 3-5-ETS1-2 3-5-ETS1-3 4-ESS2-1 4-ESS3-2

This activity requires the resource(s):

### Summary

The ground is collapsing, and we have a problem! How do we handle a sinkhole emergency? In this activity, students are tasked with repairing a sinkhole to prevent it from spreading and getting larger. Using the engineering design process, student groups first research sinkholes and then brainstorm, plan and design the best solution for repairing a sinkhole so that water cannot get through to dissolve additional soft minerals and become bigger. The effectiveness of each group’s design is determined by pouring water into the top of their “repaired sinkhole” to see how much water gets through. Successful designs should prevent water from leaking through.
This engineering curriculum aligns to Next Generation Science Standards (NGSS).

### Engineering Connection

When a sinkhole occurs, civil engineers examine it from top to the bottom to determine the likely cause(s). Often consulting other experts, such as geologists and excavation contractors, civil engineers then consider many methods of stabilization. After deciding the best course of action, the team quickly works to implement the plan. The success of the repair is determined by its ability to hold water. If the repair is not completely successful, the engineers will consider additional methods to ensure stability.

### Learning Objectives

After this activity, students should be able to:

• Explain how internal erosion can lead to sinkholes.
• Considering specific constraints (material types, material amounts, time), create a design that prevents further internal erosion under a sinkhole.
• Apply steps of the engineering design process.

### Educational Standards Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards. All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org). In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

###### NGSS: Next Generation Science Standards - Science
NGSS Performance Expectation

3-5-ETS1-1. Define a simple design problem reflecting a need or a want that includes specified criteria for success and constraints on materials, time, or cost. (Grades 3 - 5)

Do you agree with this alignment?

Click to view other curriculum aligned to this Performance Expectation
This activity focuses on the following Three Dimensional Learning aspects of NGSS:
Science & Engineering Practices Disciplinary Core Ideas Crosscutting Concepts
Define a simple design problem that can be solved through the development of an object, tool, process, or system and includes several criteria for success and constraints on materials, time, or cost.

Alignment agreement:

Possible solutions to a problem are limited by available materials and resources (constraints). The success of a designed solution is determined by considering the desired features of a solution (criteria). Different proposals for solutions can be compared on the basis of how well each one meets the specified criteria for success or how well each takes the constraints into account.

Alignment agreement:

People's needs and wants change over time, as do their demands for new and improved technologies.

Alignment agreement:

NGSS Performance Expectation

3-5-ETS1-2. Generate and compare multiple possible solutions to a problem based on how well each is likely to meet the criteria and constraints of the problem. (Grades 3 - 5)

Do you agree with this alignment?

Click to view other curriculum aligned to this Performance Expectation
This activity focuses on the following Three Dimensional Learning aspects of NGSS:
Science & Engineering Practices Disciplinary Core Ideas Crosscutting Concepts
Generate and compare multiple solutions to a problem based on how well they meet the criteria and constraints of the design problem.

Alignment agreement:

Research on a problem should be carried out before beginning to design a solution. Testing a solution involves investigating how well it performs under a range of likely conditions.

Alignment agreement:

At whatever stage, communicating with peers about proposed solutions is an important part of the design process, and shared ideas can lead to improved designs.

Alignment agreement:

Engineers improve existing technologies or develop new ones to increase their benefits, to decrease known risks, and to meet societal demands.

Alignment agreement:

NGSS Performance Expectation

3-5-ETS1-3. Plan and carry out fair tests in which variables are controlled and failure points are considered to identify aspects of a model or prototype that can be improved. (Grades 3 - 5)

Do you agree with this alignment?

Click to view other curriculum aligned to this Performance Expectation
This activity focuses on the following Three Dimensional Learning aspects of NGSS:
Science & Engineering Practices Disciplinary Core Ideas Crosscutting Concepts
Plan and conduct an investigation collaboratively to produce data to serve as the basis for evidence, using fair tests in which variables are controlled and the number of trials considered.

Alignment agreement:

Tests are often designed to identify failure points or difficulties, which suggest the elements of the design that need to be improved.

Alignment agreement:

Different solutions need to be tested in order to determine which of them best solves the problem, given the criteria and the constraints.

Alignment agreement:

NGSS Performance Expectation

4-ESS2-1. Make observations and/or measurements to provide evidence of the effects of weathering or the rate of erosion by water, ice, wind, or vegetation. (Grade 4)

Do you agree with this alignment?

Click to view other curriculum aligned to this Performance Expectation
This activity focuses on the following Three Dimensional Learning aspects of NGSS:
Science & Engineering Practices Disciplinary Core Ideas Crosscutting Concepts
Make observations and/or measurements to produce data to serve as the basis for evidence for an explanation of a phenomenon.

Alignment agreement:

Rainfall helps to shape the land and affects the types of living things found in a region. Water, ice, wind, living organisms, and gravity break rocks, soils, and sediments into smaller particles and move them around.

Alignment agreement:

Living things affect the physical characteristics of their regions.

Alignment agreement:

Cause and effect relationships are routinely identified, tested, and used to explain change.

Alignment agreement:

NGSS Performance Expectation

4-ESS3-2. Generate and compare multiple solutions to reduce the impacts of natural Earth processes on humans. (Grade 4)

Do you agree with this alignment?

Click to view other curriculum aligned to this Performance Expectation
This activity focuses on the following Three Dimensional Learning aspects of NGSS:
Science & Engineering Practices Disciplinary Core Ideas Crosscutting Concepts
Generate and compare multiple solutions to a problem based on how well they meet the criteria and constraints of the design solution.

Alignment agreement:

A variety of hazards result from natural processes (e.g., earthquakes, tsunamis, volcanic eruptions). Humans cannot eliminate the hazards but can take steps to reduce their impacts.

Alignment agreement:

Testing a solution involves investigating how well it performs under a range of likely conditions.

Alignment agreement:

Cause and effect relationships are routinely identified, tested, and used to explain change.

Alignment agreement:

Engineers improve existing technologies or develop new ones to increase their benefits, to decrease known risks, and to meet societal demands.

Alignment agreement:

###### Florida - Science
• Identify the physical properties of common earth-forming minerals, including hardness, color, luster, cleavage, and streak color, and recognize the role of minerals in the formation of rocks. (Grade 4) More Details

Do you agree with this alignment?

• Describe the basic differences between physical weathering (breaking down of rock by wind, water, ice, temperature change, and plants) and erosion (movement of rock by gravity, wind, water, and ice). (Grade 4) More Details

Do you agree with this alignment?

• Identify resources available in Florida (water, phosphate, oil, limestone, silicon, wind, and solar energy). (Grade 4) More Details

Do you agree with this alignment?

Suggest an alignment not listed above

### Materials List

Each group needs:

For the entire class to share:

• digital kitchen scale
• tap water
• markers/crayons/colored pencils
• 2 large plastic containers for each material provided
• design materials of choice:
• air-dry clay
• kinetic sand
• soil
• pebbles
• dead leaves (gather from outside)
• computers/devices
• printer paper
• books/articles/media on sinkholes (see Multimedia Support or Technology Integration section below)

### Pre-Req Knowledge

Students should be familiar with weathering and erosion concepts.

### Introduction/Motivation

Sinkholes are a common geographical feature, particularly in Florida. What experiences with sinkholes do you have? (Let students share their experiences). For example, there is a sinkhole called Devil’s Millhopper in, Florida watch: “Museums in the Parks: Devil’s Millhopper Geological State Park” (4:23) by Florida Museum on YouTube. Is this sinkhole dangerous? This sinkhole has created a beautiful ecosystem and a great place for archaeologists to find artifacts that help them to further understand the people that lived there long ago. This one isn’t dangerous, but do you think all sinkholes are harmless? How could a sinkhole be dangerous? This news clip of sinkholes in Central Florida is from 2018 "Sinkholes Appearing in Florida After Heavy Rain" (1:51) by NBC News on YouTube. How does the impact of these sinkholes differ from the impact of Devil’s Millhopper? (Possible answers: Expect students to mention how Devil’s Millhopper provides a home for lots of plants and animals, an archaeologically significant site, and beauty for human pleasure. In contrast, they may discuss the loss of property like homes and businesses, destroyed roadways, costs of repair, and possible injuries or fatalities.)

As we saw from the news clip, sinkholes form when water causes internal erosion. Internal erosion is caused by water seeping under the top layers of the earth and dissolving the bedrock. In Florida, our bedrock is mostly limestone. Based on the news story, it seems like sinkholes happen quite often. Why do we not see very large sinkholes all over the place in Florida? (Have students discuss and lead the class to conclude that experts make sure it doesn’t continue to get worse).

When a sinkhole forms, civil engineers, often with the help of geologists, will determine the risk of the sinkhole spreading. If they think it won’t spread, they typically leave it alone. If the sinkhole is at risk for dangerous spreading, a process called “stabilization” happens. The experts will explore the sinkhole to determine the severity and cause, decide on the best method of repair, and test out their work with water.

Today, you are going to work as civil engineers to stabilize a sinkhole that has opened in a field near the school. Everyone is safe, but it was determined that it needs to be repaired as soon as possible to prevent the hole from spreading and becoming dangerous and destructive. You, as civil engineers, will follow the engineering design process to develop an effective solution for stabilization of the sinkhole. Let’s get to work saving our school and community!

### Procedure

Background

A sinkhole is a natural depression or hole in the ground. In the United States, they are most common in the Southeast because of the karst terrain. Karst terrain is made up of soluble bedrock, most often limestone. When water seeps through the soil, the limestone dissolves and forms cavities. This internal erosion is caused by water that is most likely acidic from its contact with decaying plants and animals and absorption of carbon dioxide from the soil. This is considered erosion, and not weathering, because the sediment is being dissolved or moved. Weathering refers to the breaking down of a source, such as rock, mineral, or soil into sediment, while erosion removes sediment from the source.

There are three types of natural sinkhole formations: dissolution, cover-subsidence, and cover-collapse. Dissolution sinkholes are slowly formed when water seeps through cracks in the bedrock, dissolving it. Cover-subsidence sinkholes are small and gradually forming. They are caused by water dissolving a void in the limestone bedrock and the sediment above sinking with it. Cover-collapse sinkholes occur suddenly when the layers are internally eroded to a point of thinness that cannot hold any longer. Artificial sinkholes are caused by human activities such as drilling, mining, building, over-pumping groundwater, and changing surface water flow.

There are many methods for stabilizing a sinkhole before major damage occurs. These include filling, underpinning, compaction grouting, and geopolymer injection. In the case of a cover-collapse sinkhole, however, it is often too late to use stabilization methods. Repairing a deep sinkhole is done by a filling process that starts with civil engineers and/or geologists inspecting the size and cause of the sinkhole before excavating loose sediment. The goal of sinkhole repair is to prevent the spread and make the land usable again by preventing water from seeping into the bedrock while still being absorbent. Most often, the sinkhole is filled with a concrete base, a middle layer of clay sand, and a top layer of soil. Landscaping can also help to maintain stabilization.

Before the Activity

• Make copies of the Sinkhole Emergency Workbook and the Sinkhole Emergency Post-Assessment, one for each student.
• Prepare research materials and devices. You may want to provide students with a digital menu for accessing specific material choices on devices. Hardcopy research materials should be in a central location.
• Set up each group’s station with a beaker and funnel.
• Put each of the choice materials (Kinetic sand, air-dry clay, soil, pebbles, etc.) into a large plastic container and place in a central location. (Note: This is the class stock of materials.)
• Set out the small-medium containers near the stock containers. Groups will choose which container size they use for each of their materials.
• Place the scale with the other shared materials for convenient weighing.
• Fill a large container with water. A pitcher or watering may also be used.
• Decide on the most effective method to group your students.

With the Students

Day 1

1. Pass out the Sinkhole Emergency Workbook for each student to record their notes, data, and answers throughout the activity.
2. Review the basic steps of the engineering design process, listing them on the board as they are discussed. (Ask, Research, Brainstorm, Plan, Design, Build, Test, Improve.) Record the question with the “Ask” step: What is the best way to repair a sinkhole?
3. Explain to students that they will be using provided materials to fill a funnel to test their design. Ensure students understand their constraints:
• The materials provided are air-dry clay, kinetic sand, pebbles, soil, and dead leaves.
• They may only use three materials from the selection provided.
• The repair should prevent water from leaking through the bottom of the funnel while not causing puddling at the top.
• The design must weigh 200 g (excluding the mass of funnel and beaker).
4. Divide the class into groups of three or four students each.
5. Provide the groups with access to the research materials. (Consider using a menu of resources to ensure quick and easy access to the resources.) As groups research, they should take note of information that could help them solve the problem.
6. Have groups gather back together and share out any information they learned.
7. Have students spend time brainstorming independently before having a group brainstorming discussion.
8. Have groups reorganize and brainstorm as a group. Each group should narrow down their ideas and plan their first design. Make sure the groups decide on the materials they want to use, how much of each material they will use, and how each material will be arranged in the sinkhole. In their notes, each student should justify their design for their group.
9. One student from each group should weigh and record the mass of their funnel and beaker in grams. (This will be used to subtract from the final mass.)
10. The members of each group can take turns weighing out the materials in their containers. Make sure they zero out/tare the scale with the empty container before filling.
11. Give students 5-10 minutes to build their repair inside of their funnel. Once finished, they should weigh their funnel and repair and then subtract the mass of their empty funnel and beaker to make sure the final mass of the materials is 200 g.
12. To test their repair, one team member slowly pours 50 mL of water into their design. The most successful design will keep all or most of the water from seeping through the bottom, while not having a puddle form on the surface of the repair, after 2 minutes.

Day 2

1. Prepare the same as Day 1.
2. Lead a discussion of the successes and failures from Day 1’s tests.
3. Have students individually brainstorm how their group could improve their design.
4. Have groups discuss and plan an improved design to address any problems they may have had on Day 1.
5. Have groups build their redesign and test it the same way as on Day 1.
6. Have groups work together to analyze their data and make any conclusions about the success of their designs.
7. Have each student design a small poster or slide to display each design’s justification, results, and conclusions.
8. Have students split into new groups that consist of at least one student from each of the engineering groups. They should each share both of their designs’ justifications, results, and conclusions.
9. Have each student fill out the Sinkhole Emergency Post-Assessment.

### Vocabulary/Definitions

bedrock: The solid rock that exists at some depth below the ground surface. Bedrock is rock "in place", as opposed to material that has been transported from another location by weathering and erosion.

dissolve: To chemically disintegrate, destroy, make disappear mineral or rock.

erosion: The action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited.

internal erosion: The formation of voids within a soil caused by the removal of material by seepage.

karst: A type of land formation, usually with many caves formed through the dissolving of limestone by underground drainage.

limestone: A common type of carbonate sedimentary rock that is partially soluble, especially in acid, and therefore forms many erosional landforms.

sediment: A naturally occurring material that is broken down by processes of weathering and erosion.

sinkhole: A depression or hole in the ground caused by some form of collapse of the surface layer.

stabilization: The process of fixing a sinkhole to prevent its spread.

weathering: The deterioration of rocks, soils, and minerals as well as wood and artificial materials through contact with water, atmospheric gases, and biological organisms.

### Assessment

Pre-Activity Assessment

Brainstorm: After playing the news clip, have students discuss possible answers to the questions below in pairs or small groups. Remind students that they are not expected to be right, just participate in thinking and discussing. (If needed, remind the class of the expectations for kind and productive conversations with classmates.)

• How can the impact of sinkholes be harmful or negative?
• Do we see sinkholes everywhere? Why or why not?
• What should we do when a sinkhole happens?

Activity Embedded (Formative) Assessment

Record Keeping: Each student will be responsible for keeping records of ideas, notes, diagrams, plans, data, observations, and reflections on the Sinkhole Emergency Workbook.

Discussion: As students work through the activity, check in with groups and the class as a whole to promote discussion based around the engineering design process and the Sinkhole Emergency Workbook.

Post-Activity (Summative) Assessment

Jigsaw Presentation: Have students split into new groups that consist of at least one student from each of the engineering groups. They should each share both of their designs’ justifications, results, and conclusions.

Post-Assessment: On the Sinkhole Emergency Post-Assessment, students will write a paragraph explaining the importance of stabilizing a sinkhole as soon as possible.

Making Sense Assessment: Have students reflect on the science concepts they explored and/or the science and engineering skills they used by completing the Making Sense Assessment.

### Investigating Questions

• How do sinkholes form? (Answer: Sinkholes form when water seeps through the topsoil and the bedrock (limestone) dissolves, forming cavities.)
• What are some possible effects of sinkholes? (Answer: Sinkholes can cause the collapse of ground structures and damage infrastructure, leading to costly repairs. Sinkholes can also cause changes in the ecosystem.)
• How can we repair a sinkhole with local resources? (Answer: We can repair a sinkhole using local resources such as clay and gravel to plug a sinkhole.)
• What does the data show us about our design(s)? (Possible answer: Our data shows that we have found an effective method of sinkhole repair, but it does not properly absorb the surface water. We will need to revise our design to fix this issue.)
• Why is it important to stabilize a sinkhole as soon as possible? (Answer: A sinkhole should be stabilized as soon as possible so it does not spread or collapse. Because of internal erosion occurring under the surface, you cannot be sure how quickly or much a sinkhole has spread. The longer we wait to repair it, the more severe and labor some the repair will need to be. Quick action can help prevent possible damage to homes, businesses, roadways, and lives caused by a sinkhole.)

### Safety Issues

• Students should wash their hands in between handling materials to avoid contamination.
• Dispose of materials appropriately, making sure nothing but water goes down the drain.

### Troubleshooting Tips

• You may need to adjust the target mass of the design, depending on your supplies.

### Activity Extensions

• To test the sustainability of their repair, have students repeat the water test with the design over the course of several days. After a set number of days (3-5), measure the final volume of water in the beaker and examine any damage or changes to the appearance of their design.
• Try the activity again with materials the students find outside at school (i.e., leaves, grass, soil, sand, rocks, etc.). They should still be required to stay within a maximum mass, but they do not need to weigh out the individual materials. They also can use an unlimited number of different materials.
• Have students write a letter to a fellow civil engineer explaining how they repaired the sinkhole. They should include the amount of each material as percentages, which they will convert from fractions.

### Activity Scaling

• For younger students, decide on the three best materials to use as a class. With everyone using the same materials, the students can focus their design on the placement of materials.
• For older students, increase the access to materials. Have groups choose any three orderable materials they want to use within a budget. They will complete a cost-benefit analysis to justify the purchases.

• Recommended books/articles/media on sinkholes for student research:
• Sinkholes (Devastating Disasters) by Nadia Higgins (available free online through Epic! and for hardcopy purchase here)
• Sinkholes (Disaster Zone) by Vanessa Black (available free online through Epic! and for hardcopy purchase here)
• The Science of a Sinkhole by Robin Koontz (available free online through Epic!)
• Sinkholes (A True Book: Extreme Earth) by Ann O. Squire (available for purchase here)
• “How Do Sinkholes Form?” by Practical Engineering on YouTube
• “How Do MASSIVE Sinkholes Form?” by Life Noggin on YouTube

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### References

Dougherty, Percy H., and Perlow, Michael, Jr. “The Macungie Sinkhole, Lehigh Valley, Pennsylvania: Cause and Repair.” Environmental Geology and Water Sciences. (1988) Vol 12, No. 2, pp. 89-98. 10.1007/BF02574793.

Fellenstein, Stephanie. Popular Mechanics. Posted December 2, 2021. Hearst Magazine Media, Inc. https://www.popularmechanics.com/adventure/outdoors/tips/a9192/why-sinkholes-appear-and-how-to-fix-them-15704756/

### Contributors

Morgan Dallaportas

### Supporting Program

Multidisciplinary Research Experiences for Teachers of Elementary Grades, Herbert Wertheim College of Engineering, University of Florida

### Acknowledgements

This curriculum was based upon work supported by the National Science Foundation under RET grant no. EEC 1711543— Engineering for Biology: Multidisciplinary Research Experiences for Teachers in Elementary Grades (MRET) through the College of Engineering at the University of Florida. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.