A plant trip provides subjects for team projects and lecture exampies in a sophomore chemical engineering course, thus becoming a unifying "theme" for the course. The "theme" structure is intended to improve student mastery of course material by helping students relate different course topics to one another via real equipment and processes. Here, performance in a subsequent junior chemical engineering course by students from the "theme course" is compared with performance by students who took the sophomore course in a traditional lecture-homework-exam format. Theme course graduates claim better retention of concepts from the sophomore course, though their scores on exam questions testing their knowledge, comprehension, and application of these concepts did not differ significantly from that of students from the traditional course. Theme course graduates did earn higher grades in the junior course, due to better performance on exam questions requiring higher level skills such as analysis, synthesis, and evaluation. Students were enthusiastic about the course structure, and expressed excitement about learning from "real life." Thus the "theme" structure results in early student success in the skills necessary for engineering design, and generates student enthusiasm for engineering.

I. INTRODUCTION

When faculty discuss student learning, three problems are cited frequently. (1) Learning is "compartmentalized;" students work through material section by section, but fail to connect this week's material to last week's. (2) "Retention" of subject matter is poor; students leave one course and are apparently unable to recall that material in the next. (3) Students lack a "feel" for engineering, a mental picture of equipment and its operation. Upon reading "Natural gas is burned in a plant to generate steam," several undergraduates assumed this steam was the combustion product rather than imagining a boiler. Discussion with colleagues reveals these problems are not unique to Ohio University.

Plant trips can make engineering "real" to students. However, some faculty resist taking younger students on plant trips because "they won't understand anything." When people study music, they listen to great performers. Why do we expect our students to master the instruments before they see professionals perform? Still, it is prudent to question whether the learning value of a plant trip balances the students' loss of instructional time, perhaps in several courses. The learning value of a plant trip may increase if the trip is part of the course, not a single event.

A plant trip provides a unifying theme for the sophomore-level "Energy Balances" course at Ohio University (taught by V. Young). This paper discusses student reaction to the "Theme class" and evaluates the performance of Theme class graduates relative to graduates from a traditional lecture-homework-exam format class in "Thermodynamics" (taught by B. Stuart), a subsequent course that builds on concepts learned in Energy Balances. Differences in student-instructor rapport or class size may affect the results; these factors are not the focus of this investigation.

II. RESULTS AND DISCUSSION

A. The Students

Thirty-six students enrolled in Energy Balances in Spring 1997, fifteen in the author's "Theme" section and twenty-one in the "Traditional" section taught by another instructor. Lowman' defines a class of fewer than 16 as "very small" and 16-35 as "small." The effect of class size is neglected here.

Academic ability of students entering the course was assessed by overall and engineering grade point average (GPA) and was similarly distributed in the two sections (table 1). Each section included three students with GPAs above 3.5 and two below 2.5. Engineering GPAs are typically based on three courses for these students. All had just finished the "Material Balances" course, taught by two different instructors using the same text. Students from the two Material Balances sections were distributed between the two Energy Balances sections.

Final grade distributions in the two sections were also similar (figure 1). One student in the Theme section did not earn the required C to progress to Thermodynamics; this was not one of the students entering with a GPA below 2.5. All students in the Traditional class earned at least a C. Twenty-eight of these students completed Thermodynamics the following fall.

B. The Energy Balances Course

Subject matter focused on chapters 7-9 of Felder and Rousseau,2 and exams based on textbook problems were the major factor in determining course grades. Chapters 1-6 of this text are the basis of the prerequisite Material Balances course. Students in the Traditional section had textbook problems for homework. In the Theme section, textbook problems were not assigned, but students were quizzed weekly on worked examples and "Ask Yourself" questions from the text. Text problems were worked in recitation for both sections. A plant trip (Huntsman Chemical's polystyrene production facility in Belpre, Ohio) was announced to both sections and took place in the third week of class; participation was not graded. Only two students from the Traditional section attended. All but one student from the Theme section attended. The remainder of the course description deals only with the Theme section; the reader is presumably familiar with traditional lecture-homework-exam class format.