Groundwater Contamination Prediction

Nicole LaDue, Northern Illinois University
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Summary

Formative assessment questions using a classroom response system ("clickers") can be used to reveal students' spatial understanding. Students are shown this diagram and told, "A storm event releases chemicals stored at the farm that end up in the groundwater. Click on the well that is most likely to be contaminated."

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Context

Audience

Students in an introductory-level geoscience course

Skills and concepts that students must have mastered

Students need to know that groundwater flows down-gradient, need to know what kinds of sediments are (im)permeable, and need to understand the effects of permeability on groundwater flow.

How the activity is situated in the course

This activity is used as a formative assessment question following a lecture or activity about groundwater flow. Displaying the results after administering the question provides students and instructor immediate feedback about how well students understand groundwater movement.

Goals

Content/concepts goals for this activity

The goals of this activity are:

  • to evaluate if students can identify the direction that groundwater will flow given a water table of varying depth (conceptual skill)
  • to integrate information from the topography and subsurface structure to predict where groundwater will flow (spatial skill)

Higher order thinking skills goals for this activity

Students will make a spatial prediction, receive feedback, and modify their prediction based on the feedback.

Other skills goals for this activity

Not applicable

Description and Teaching Materials

Several student response systems (clickers) offer a response option where you can upload an image and students can respond by clicking directly on the image. The system will generate a heat map of the responses. After teaching students about groundwater flow through lecture, videos, or an activity, use this question as a low stakes (low/no point-value) evaluation of their understanding. Revealing the results to students will show whether there is general consensus on one answer or more than one answer. For example, in the heat map of students' responses shown here, students' answers converged on each of the three wells, indicating that some students do not understand which direction groundwater will flow in this scenario and others do not understand that the shale forms an impermeable barrier. Using a technology-enhanced formative assessment (TEFA) approach, if the pattern of responses lacks consensus, engage the students in peer discussion about the answer (Beatty & Gerace, 2009). Allow students to "revote" for their answer after a brief discussion. If there is not convergence on the scientifically accurate answer, then engage in re-teaching the concept.

Science of Learning: Why It Works

There is accumulating evidence that engaging in spatial prediction and receiving feedback about the nature of one's errors leads to improved spatial reasoning (Gagnier et al. 2017; Resnick et al., 2017). Making a prediction, receiving feedback, and learning from the mismatch between the expected and actual outcomes is a process studied in cognitive science called the delta-rule model of learning (Rescorla and Wagner, 1972). Modern models of learning from the education research literature focuses on Piaget's concept of accommodation, where people will adjust their mental models as a consequence of the the feedback (Dole and Sinatra, 1998). Examples from research on geology concepts show us that students' build more scientifically accurate mental models after engaging in prediction and feedback. Gagnier et al. (2017) engaged students in making predictions about the interior of a geologic structure using block diagrams. The cycle of prediction and feedback facilitated students improved performance on a test of penetrative thinking. Resnick et al. (2017) engaged students in making predictions about the geologic time scale using a classroom response system (clickers). Students answered multiple-choice questions about the position of geologic events on a typical diagram of the geologic time scale. The spatial prediction clicker questions were as effective as, and more efficient than a hands-on meter stick activity at building a scientifically accurate linear conception of geologic time. Building on this research, we propose that the technique described below is a useful approach to identify students' spatial conceptions associated with various geologic phenomena (LaDue et al., 2021; LaDue and Shipley, 2018).

Teaching Notes and Tips

I use this activity to assess student understanding immediately after lecturing about groundwater flow. Feedback and discussion can be used to help students arrive at the scientific answer to this question. First, engage students in a pair-share discussion about what makes each of the three wells different from one another (e.g., elevation, depth, distance from the Farm, direction from the Farm). After those four options have emerged from discussion, have students rank the importance of those attributes as it relates to the problem. This discussion may be sufficient to guide students to the correct answer. Engage students in re-voting and if there is still a divergence in answers, do another pair-share and ask students to convince one another of their answer before re-voting a 3rd time.

Through discussion with colleagues, we found that the original diagram was asking two questions about groundwater: 1. Can students identify a confined aquifer? and 2. Do students recognize how groundwater moves? Four alternate diagrams were created to help distinguish between these concepts and scaffold student reasoning. Questions we asked for these diagram were: "The septic tank under the house leaks for a month before being repaired. Click where you expect the pollution will be found in the groundwater."; or "The septic tank under the house leaks for a month before being repaired. Click on the well that is most likely to be contaminated." Our reasoning for creating each diagram variation can be found in their captions.





Assessment

This question is useful for students to self-assess where their answer fits relative to other students in the class. Top Hat displays student responses in a heat map image that highlights the most common answers. In most systems it is possible to designate a region for the correct answer, but receiving a right-wrong answer is likely less useful than engaging students in peer discussion if the students' responses do not converge on one region.

References and Resources

Resources: There are several systems that offer click-on-diagram questions. The one we used is: https://tophat.com

References

Beatty, I. D., & Gerace, W. J. (2009). Technology-enhanced formative assessment: A research-based pedagogy for teaching science with classroom response technology. Journal of Science Education and Technology, 18(2), 146-162.

Dole, J. A., & Sinatra, G. M. (1998). Reconceptalizing change in the cognitive construction of knowledge. Educational psychologist, 33(2-3), 109-128.

Gagnier, K. M., Atit, K., Ormand, C. J., & Shipley, T. F. (2017). Comprehending 3D diagrams: Sketching to support spatial reasoning. Topics in cognitive science, 9(4), 883-901.

LaDue, N. D., Ackerman, J. R., Blaum, D., & Shipley, T. F. (2021). Assessing Water Literacy: Undergraduate Student Conceptions of Groundwater and Surface Water Flow. Water, 13(5), 622.

LaDue, N.D. and Shipley, T.F. (2018). Click-on-Diagram Questions: A New Tool to Study Conceptions using Classroom Response Systems. Journal of Science Education and Technology, 27(6), 492-507.

Rescorla, R. A., & Wagner, A. R. (1972). A theory of Pavlovian conditioning: Variations in the effectiveness of reinforcement and nonreinforcement. Classical conditioning II: Current research and theory, 2, 64-99.

Resnick, I., Newcombe, N. S., & Shipley, T. F. (2017). Dealing with big numbers: Representation and understanding of magnitudes outside of human experience. Cognitive science, 41(4), 1020-1041.