No more "plug and chug"

Aug 5, 2004

Instructional method supported by the National Science Foundation (NSF) aids engineering thermodynamics students in solving real life engineering problems.

Some of them sigh during the first day of class. Some shake their heads, or mutter to themselves as they sit idly in their chair, listening to Karim Nasr introduce the problem-based learning (PBL) method employed in his MECH-320: Thermodynamics course.

Most Kettering engineering students have experience on how to 'plug' a value into an equation and 'chug' out an answer when attempting to resolve an engineering problem. Getting these students to look differently at an engineering problem without immediately reaching for their calculators and using the old 'plug and chug' method, however, has proven to be both challenging and rewarding for Mechanical Engineering (ME) Associate Professor Karim Nasr and students in his course.

The majority of engineering professors in higher education use subject-based learning (SBL) to teach course material and case studies. This method typically relies on several attributes, which include the instructor presenting facts to students, a learning structure defined by the sequence of material presented in a text book, and a discussion of questions based on who, what, where, and when. This traditional and often successful model of knowledge transmission centers primarily on the teacher and what they want students to learn and accomplish from lectures.

But about two years ago, Nasr began considering new ways to help students better learn the concepts and theories presented in his engineering thermodynamics course, which examines the first and second laws of thermodynamics and their application to energy transformations. With Kettering's educational focus geared toward helping students immediately apply what they learn to their cooperative jobs, Nasr conducted research into problem-based learning, an instructional approach that promotes active learning, supports knowledge development, integrates disciplines and naturally combines classroom learning with real-life applications. After formulating a pilot course for incorporating PBL into the classroom, Nasr and Associate Professor of ME Bassem Ramadan then authored a proposal that won a two-year grant of $96,421 from the National Science Foundation to further implement PBL into the classroom and evaluate the outcome of this instructional approach. Soon, Ramadan will add a new dimension to the course by introducing just-in-time animations of system components and their performance. He relies on the power of Computational Fluid Dynamics to simulate flows through components for the purpose of enhanced visualization.

"Students at Kettering are used to the 'plug and chug' method associated with the traditional model of teaching engineering," Nasr explained. "By the time they enroll in my thermodynamics class, they have knowledge of physics, chemistry and calculus, and have undergone training to solve text book problems by plugging a value into an equation and chugging out an answer."

But PBL is a very different instructional model, he said. With this approach, students play a more pivotal role in their education and learn to rely on analyses, synthesis and evaluation. This also means that students must overcome their dependence on formula, accept the notion that a solution to a problem might be days away instead of minutes, and be ready and willing to work on highly complex problems with interconnected concepts. Specifically, PBL requires students to begin thinking about how to solve a problem at the start of the class instead of at the middle or end, which is often the case under the SBL model. The traditional approach relies on the analysis of facts and concepts presented by the professor to help students arrive at a solution. But with PBL, the motivation for solving an engineering problem becomes what Nasr described as "an automatic part of the solution" that closely emulates the real-world engineering environment of industry today.

Additionally, students working in a PBL class environment uncover fundamental concepts and principals just in time as they plan, formulate and solve the problem. Nasr said that students are often excited by the challenge and relevancy of solving real-life problems, and in the engineering realm, this serves as a significant motivational tool to which the sustainability of student attention is fixed. As a result, PBL develops independence in students, promotes creativity, critical thinking and life-long learning.

Currently, the structure of the problem-based engineering thermodynamics (PBET) course revolves around a layout of five modules:

  • Module I: Spark/Compressions Ignition Engines;
  • Module II: Steam Power Plants;
  • Module III: Tower Gas Turbines;
  • Module IV: Vapor Compression Refrigeration; and
  • Module V: Transient problems.

For each module, students address a complex, well-designed problem to solve using just-in-time discovery of principles in a cooperative learning environment. These authentic problems serve as a starting point for students to investigate possible solutions and identify objectives to work toward. Thus, students lead discussions and discover concepts as needed, utilizing fundamental theories and principles with help from the instructor, whose role is that of a guide. Students also engage in a cooperative comprehensive design project during the second half of the class.

As students work toward the discovery of solutions to problems, they produce several resources to help extend and cement what they learned. One of these products is a concept table that features a layout of thermodynamic terms, a description of what the terms mean to each student written in their own words and supporting equations. Additionally, students, working in groups, build on their concept tables by creating concept maps that help develop critical thinking skills and help them become "concept-driven as opposed to being formula-drive," Nasr said.

To assess the quality of this approach and whether or not students find it valuable, Nasr uses several tools, such as a senior from outside the class who serves as an observer and keeps a log of classroom activities and problem areas. Other assessment and evaluation tools include the following:

  • professor review of homework;
  • a team project, where teams of three students consider a four-week project that covers a thermodynamic issue that expands their research and work beyond the traditional course topics;
  • a PBL-focused questionnaire to gather student reaction to the instructional approach and course subject modules; and
  • a common formal exam for PBL and SBL students, which compares student performance on this outcomes-based exam.

Thus far, the results are quite encouraging. Although students find the PBL approach to be extremely challenging, many believe it is well suited for what they expect to encounter in their careers as engineers. When asked in a recent survey if they prefer PBL to the traditional approach, more than 73 percent reported that they agreed with this statement. Some of their comments further support the idea that this instructional approach "makes students understand the concepts so they can apply them to any situation rather than memorizing information and equations," one student wrote.

"For PBL to work effectively," Nasr concluded, "professors must be competent in the area of instruction to facilitate learning and there must be ample time for problem development and solution evolution, since students have become self-directed learners-this is key."

Dr. Ramadan will implement the PBL instructional approach in teaching thermodynamics this coming year and other professors have shown interest in this method as well. In the near future, Nasr and Ramadan will feature their development work in a paper titled "Development and Implementation of Problem-Based Learning Modules for Engineering Thermodynamics" at the 2004 American Society of Mechanical Engineers International Mechanical Engineering Congress and Exposition scheduled for Nov. 13-29 in Anaheim, Calif.

To learn more about this project, contact Associate Professor Karim Nasr at (810) 762-7876, or via e-mail at

Written by Gary J. Erwin