Heat Transfer, Entropy Pose Problems

Inquiry-based activities can help overcome undergraduate engineering students’ misconceptions

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The Institution of Chemical Engineers (IChemE), Rugby, U.K., annually awards 14 medals that recognize chemical engineers for their contributions to the profession. One of them, the Hutchison medal, commemorates past-president Sir Kenneth Hutchison and is awarded to authors of practical, wide-ranging, philosophical or thought-provoking papers that stimulate debate among chemical engineers.

 The 2010 medal was recently awarded to Professor Michael Prince and Associate Professor Margot Vigeant, Department of Chemical Engineering, and co-author Dr. Katharyn Nottis, Department of Education, all from Bucknell University, Lewisburg, Pa.. Their paper, “A preliminary study on the effectiveness of inquiry-based activities for addressing misconceptions of undergraduate engineering students,” was published in the IChemE journal Education for Chemical Engineers in July 2009 (pp. 29–410).

The authors say they chose this topic because of growing recognition among educators that students frequently enter classrooms with preconceptions that may filter new learning and thereby interfere with their ability to master critical engineering concepts. They add that the importance of engaging student preconceptions features prominently in such works as the 2000 National Research Council’s study on how people learn.

Preconceptions may interfere with students’ ability to master critical engineering concepts.

While there’s growing awareness of this problem, the authors say that many teachers could still be surprised at the extent to which students in their courses, even those who do well on exams, can fail to grasp important concepts between heat, energy and temperature, and certain concepts involving entropy and the second law of thermodynamics.  Two misconceptions that had been identified in previous research were selected for the study.

The first is that students often couldn’t distinguish between factors that affect the rate of heat transfer and those that affect the amount of energy transferred in a given physical situation. For example, students generally believed that factors that increase the rate of heat transfer always increase the amount of heat transferred and vice versa.

The second is confusion about the impact of entropy on real-world processes. For example, students believed that heat could be converted to work with 100% efficiency if friction and heat losses to the surroundings were eliminated.

“Confusion on both of these points persisted even when students had successfully completed relevant coursework, strongly indicating that these are robust misconceptions,” note the authors.

Students in the study were asked to participate in various inquiry-based activities aimed at addressing these misconceptions. First, they were put into teams and asked to predict what would happen in a number of scenarios. They were then given physical experiments and/or computer simulations to test their predictions, and then were asked to discuss how their thinking had changed if their predictions didn’t match reality.

All questions were conceptual in nature, using technology where appropriate. After the activities, students were asked to step back and generalize what they had learned from the experiments and in some cases were asked to extend that knowledge to a novel application to determine if the learning was transferable to a new situation.

Overall, these inquiry-based activities improved performance on questions that directly addressed the activity content in 40 out of 42 cases, significantly so for 20 of them. Long-term gains (after 10 weeks) were also seen in the end-of-semester post-test on 27 out of 29 cases, significantly so for 12 of them.

Looking at the results, the fraction of students answering individual questions correctly went up as often as it went down without activities. After implementing activities, the number of students correctly answering questions at both sites increased 75 times out of 80 on post- and long-term post results, and only decreased three times.

“Taken in total, the study offers evidence that suggests that inquiry-based activities can be used to help repair persistent engineering misconceptions held by undergraduate engineering students,” say the authors.

Initial data are preliminary, based primarily on results from a single institution and for a limited number of targeted misconceptions and activities. Moreover, caution the authors, the results depend heavily on a single measure of conceptual understanding.

“However, the preliminary results are encouraging. While the idea of using concept inventories and concept questions is becoming more widespread throughout engineering, an accessible source of inquiry-based activities with demonstrated effectiveness has not existed until this point. By making these activities widely available, we hope to enable other interested faculty to incorporate them into their courses,” they conclude.

Step-by-step instructions for these activities, written both as a faculty manual and student handouts, are available from the authors (prince@bucknell.edu, mvigeant@bucknell.edu, knottis@bucknell.edu).


Seán Ottewell is Chemical Processing's Editor at Large. You can e-mail him at sottewell@putman.net

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