This class activity was designed to follow the Problem Solving Studio (PSS) format developed at Georgia Tech (described in one of the linked cards). As the instructor, you would provide the backstory and then ask an open-ended question. Students will work in pairs to develop a solution through asking questions of the instructor(s) and the instructors asking students clarifying questions. These problems often work best when targeted to a bit of troublesome knowledge or a misconception. This problem is designed to target 1) the ability to accurately draw a boundary around a system, and 2) making reasonable assumptions to solve a problem.

Why PSS?

In school, we typically provide students textbook problems which provide all of the “given” information in the problem statement. However, open ended problems encountered in the real-world often require students to determine on their own what information is needed to create a solution and what appropriate values for various inputs are. This card was developed to provide a low stakes way to help students become more comfortable with ill-defined problems and get them to flex their system definition muscles.

Most chances students get to participate in open-ended problems occur either 1) through large semester long projects or 2) in smaller projects toward the end of the semester. This problem was specifically designed to be used in the first few weeks of a Thermodynamics class to incorporate open-ended thinking early in the semester. This helps to set the stage and provide scaffolding for advanced thinking later in the semester.

Timeframe: In this activity, students will spend ~ 2 hours to grapple with defining their system and justifying their assumptions as they determine what contributes to room air temperature. If you only have 50 or 90 minutes, check out the instructor notes for ways to modify the problem to fit a shorter time frame.

Pre-Class Prep: The key to indoor climate control is understanding heat sources (and sinks)! I have provided information about my college’s gym that you could use, but your fitness center should be able to provide you information on the equipment, size, and number of people in your gym over a given week. You’ll want to print out each individual piece of information on a slip of paper to provide to students as they work.

Student Motivation: You can start class by asking students to vote on the best times to go to the gym. They will likely have different answers based on what equipment or classes they like to attend. Once they are thinking about the number of people in the gym, introduce the problem statement.

Problem Statement: Research has shown that the ideal indoor temperature for exercising is between 68 and 72°F, but we all know that the gym has varying numbers of people working out throughout the day (and throughout the semester)! Will the gym need to be heated or cooled? How do you determine what size heating or A/C unit should be installed in a building like this where the loads vary so dramatically?

Problem Solving Studio: As students are working on the problem, engage them and ask open ended questions to elicit their thinking. They will likely have information based questions for which you can provide them information slips (you can also do this if they are seeming stuck). Try to avoid asking closed-ended questions or leading question such as, "What do you think we could assume about the pressure of air where we are near sea level", but instead try to ask opened ended questions such as, "I see you don't have a pressure written down, what is your plan to deal with that?"

Class Conclusion: As class is wrapping up, most students should have finished the problem. To make sure to close the loop, you should ask the class to fill out the Critical Incident Questionnaire so you can get information on how the session went. This also can lead you to do a debrief at the start of the next class session for both the key content and the process. I have also included a reflective homework asking students to restate and clarify their thought process.