Physics: Permafrost

Penny Rowe, NorthWest Research Associates; and Steven Neshyba, University of Puget Sound
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Summary

Students learn what permafrost is, the implications of permafrost thawing due to climate change, and how to calculate heat diffusion through permafrost. Student activities include watching a video about permafrost, checking out a journal article, and downloading, plotting and analyzing permafrost data. They learn about how permafrost temperature changes with depth underground, seasonally, and annually, and calculate heat flow through permafrost.

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Learning Goals

Students download and analyze permafrost data and determine how heat diffuses through it. This analysis is scaffolded by a Computational Guided Inquiry (CGI) module, which for this activity takes the form of a set of Jupyter Notebooks that students use to conduct inquiry in the role of a scientist by making calculations and producing and examining plots. Critical thinking and active inquiry is promoted by open-ended responses to prompts (Pause for Analysis questions). Specific learning goals are as follows:

  1. Learn what permafrost is, how it responds to a warming climate, and why it matters.
  2. Examine changes in permafrost temperature over the course of an annual cycle.
  3. Develop skill in analyzing heat flow through a permafrost layer, using a numerical derivative technique.
  4. Examine change in permafrost temperature and heat flow over 4 years.

Context for Use

This activity is designed to be used in a lower-level Physics or Engineering Physics course. Students must have in-class access to computers with internet access and with Jupyter Notebook installed. A computer lab with pre-loaded software can be used or, as in successful pilots, students can download the software onto personal laptops before class (instructions are provided). Problems can be mitigated by having students work in pairs and having an extra laptop or two available equipped with the software as needed. The activity has successfully been taught in a lab section of 20 students and is also appropriate for teaching up to as many as 30 students over several class periods. Application in large classes can be fostered by additional support, if available; e.g. through teaching assistants. The activity typically takes about 3 hours and includes homework assignments. No previous computational or coding experience is required. The instructor will give an introductory lecture to the physics concepts, assign pre-module homework, guide the students in working through the module, and facilitate group discussions.

Description and Teaching Materials

Overview

In this module, students will work actively with polar data through computer programming in Jupyter with Python. The instructions and notebook are designed so that no prior coding experience is necessary on the part of the student or instructor. The notebook and all other materials needed to implement the activity are provided below. Digital backups of data used are included in case online data is moved or removed. The following describes materials, instructor preparation, and the workflow of student activities.

Take a quick look at how the Permafrost module looks in Jupyter. (This is a static image. For the interactive version, see the instructions and materials below).

Materials

  • Student setup guides (Zip Archive 1.2MB Apr29 20). After unzipping, this includes:
    • finding_moving_files_mac.docx, finding_moving_files_pc.docx: File management on your computer
    • installing_running_jupyter_mac.docx, installing_running_jupyter_pc.docx
    • Introduction_to_python3.ipynb: Python3 tutorial, to be run in Jupyter Notebook
  • Student Permafrost Module (Zip Archive 311kB Apr28 20): After unzipping, this includes:
    • Permafrost.ipynb: Jupyter Notebook for students
    • T1.txt, T2.txt, T3.txt, temperature profiles of permafrost.png: Ancillary files that need to be in the same folder as the notebook.
  • : After unzipping, this includes:
    • Permafrost_key.ipynb: Completed Jupyter Notebook
    • permafrost_answers_rubric.docx: Answers to questions and suggested rubric. Although suggested scores are given for all questions, the instructor may choose to grade only selected questions.
    • T1.txt, T2.txt, T3.txt, temperature profiles of permafrost.png: Ancillary files that need to be in the same folder as the notebook.
    • Borehole_740-Nome...timeserie.csv: Digital backup of file students download, which needs to be in the same folder as the notebook.

Instructor Preparation

  1. Download the materials above and unzip all zipped files.
  2. Work through the student tasks in the workflow below.
  3. Compare the completed notebooks to the provided keys and read the question answers in the rubric (see Assessment).
  4. Modify the notebooks as desired and/or include only a portion of them.

Workflow

  1. Students work through the setup guides. They follow the instructions for installing Jupyter on a Mac or PC and work through Introduction_to_python3.ipynb in Jupyter. (Alternatively, the instructor ensures the software is available in a computer lab that will be used.) Students then follow instructions for finding and moving files on a Mac or PC. These tasks have been found to bog down class time for students who are not experienced in them, so we suggest assigning them as homework and reserving some class time afterward to follow up as needed.
  2. The instructor gives the students the files within the Student Permafrost Module. To work through the notebook, students will need to keep these files together in the same directory.
  3. The instructor may choose to demonstrate any of the above tasks on an overhead display before or after the students attempt it as a homework assignment, or have the students follow along with the instructor in class.
  4. The students complete the pre-class activities described in permafrost.ipynb. They can view the activities by opening the file in Jupyter Notebook; it can also be viewed as a static image of permafrost.ipynb.
  5. The instructor gives a lecture explaining that the class will now apply physics concepts covered in class to a real-world example: heat diffusion through permafrost. The relevant material is provided in the introduction to permafrost.ipynb.
  6. Students watch the 13-minute video Permafrost – What is it? from the Alfred Wegener Institute. (The link is also provided in permafrost.ipynb).
  7. Working at a computer singly or in pairs, students complete the permafrost.ipynb module. The instructor walks around the class, helping as needed.
  8. After students finish, the instructor may choose to have students meet in small groups to discuss their answers to questions (e.g. think-pair-share) for 5 minutes.
  9. The instructor gathers the class back up into a group. Students may present think-pair-share responses. The instructor discusses student responses, using the , and wraps up the activity by linking the student work back to the original goals (approximately 10 minutes).

Teaching Notes and Tips

Digital Backups

Data archived online is sometimes moved or removed, or students may have difficult accessing it. In case of this possibility, we have included the permafrost data that students download (Borehole_740-Nome...timeserie.csv) in the Assessment zip folder. We suggest having this file available (e.g. on a thumb drive) during class in case it is needed.

Computer lab vs personal laptops

While students can use a computer lab or work on individual laptops, we suggest the latter. Installing Jupyter Notebooks on laptops is straightforward, gives the students a valuable experience, and allows them to complete work at home, if needed. Furthermore, the student has the computational tool available to them after completion of the activity.

Assessment

Successful completion of the CGI module is expected to be indicative of meeting the learning objectives. Assessment includes in-class assessment of the module as students work as well as grading of completed notebooks and Pause for Analysis responses. Assessment materials are included in the Assessment zip folder, and include:

  • Permafrost_key.ipynb: Completed Jupyter Notebook
  • permafrost_answers_rubric.docx: Answers to questions and suggested rubric. Although suggested scores are given for all questions, the instructor may choose to grade only selected questions.

References and Resources

Climate change videos:

  • Climate Change: Lines of Evidence, from the National Academies of Science, Engineering and Medicine. Options include a 26 minute video or any of 7 videos of about 4 minutes each. To allow for varying levels of available class time, video content was ranked as follows, from most to least relevant:
    • Chapter 1: From the 18 second mark to the 1 minute mark
    • Chapter 3
    • Chapter 5 (8 minutes total).
    • Chapters 1-5 (about 20 minutes).

References

  • Jupyter Notebook
  • Python version 3
  • References and resources contained within the Jupyter Notebook, permafrost.ipynb, include figures from the literature as well as use of web sites and are attributed within the notebook.