Introducing middle school students to engineering principles using educational bridge design software

Journal of Engineering Education, Jul 2000 by Symans, Michael D

ABSTRACT

In an effort to motivate middle school students to consider future careers in engineering, an educational outreach program was developed and implemented during National Engineers Week. The outreach program concentrated on bridge engineering and was presented within one day to the entire eighth grade student population of the local public school system. The program began with a presentation on careers in engineering with a particular emphasis placed on bridge engineering. Fundamental engineering concepts used in bridge design were then explained. The students used these concepts to design a single-span truss bridge using an educational bridge design software program. Finally, a bridge design competition was held in which the students attempted to optimize the design oftheir bridge.

I. INTRODUCTION

National Engineers Week is held each year in February to promote the field of engineering. One method for promoting engineering is to introduce K-12 students to engineering through simple hands-on engineering activities. Although many practicing engineers and academicians are interested in promoting engineering through such activities, it may require considerable effort to develop a meaningful outreach program (for example, see the outreach program described in Reference 1). Furthermore, implementation of an outreach program can be time-consuming. As an aid to those who are interested in developing K-12 engineering outreach programs, this paper describes an outreach program that was developed to introduce middle school students to general engineering principles with an emphasis on bridge engineering. The outreach program can be implemented within the confines of a typical one-hour class and thus may be used to reach many students in a relatively short period of time.

The primary purposes for implementing the outreach program were: 1) to enhance student interest in science and mathematics by demonstrating a real-world application of these subjects, 2) to provide students with an understanding of the kind of work that structural engineers do, and 3) to plant the "seeds" that cause students to consider future careers in engineering.

II. DESCRIPTION OF OUTREACH PROGRAM

The outreach program was presented by the author and three assistants (two graduate students and one undergraduate student) to the entire eighth grade earth science class of the local public school system. Each class consisted of approximately 30 students with a total of six classes. Thus, the program reached about 180 eighth grade students. The program was presented to all six classes during one day, each class being 45 minutes in duration. A web site containing photographs of the program is located at the following URL: http.//www.wsu.edu/~symans/Educ/educ.htm.

The outreach program actually began the day before our visit to the middle school. In an effort to generate interest among the eighth graders in our pending classroom visit, a videotape was provided to the eighth grade earth science teacher to show to each of her classes the day before our visit. The videotape was obtained from Newton's Apple2 and provided an introduction to engineering and explained how engineers are involved in the design of a wide variety of products. The day of our visit began with a presentation on careers in engineering. The presentation was delivered in a topdown hierarchy starting with the different fields of engineering (e.g., chemical, electrical, mechanical and civil), focusing on the branches of civil engineering (e.g., environmental, hydraulic, trans,portation, geotechnical and structural), and then concentrating on structural engineering with particular emphasis given to bridge engineering. The intent of the top-down hierarchy was to provide a context within which to discuss bridge engineering. We wanted students to recognize that bridge engineering was but one example of the kind of engineering that they could one day be practicing.

Once we completed our introduction to bridge engineering, we asked students questions about the videotape they watched prior to our visit. Examples of questions that are suitable for the Newton's Apple2 videotape are: Can a bridge carry more load than it weighs?, Can wind damage a bridge?, What types of bridges are there?, Why would an engineer choose one bridge design over another?. These questions quite naturally led to our discussion on different bridge configurations that engineers use. We explained the primary features of the following types of bridges: beam and girder, truss, arch, suspension, cable-stayed, and floating. We then discussed the different types of loads that act on bridges (e.g., traffic, wind, and earthquake). Next, in preparation for using the bridge design software, we discussed some fundamental engineering design principles for truss bridges. For example, we explained that all truss members are subjected either to tension forces (i.e., forces that pull apart) and compression forces (i.e., forces that push together). Further, we explained that if compression members are subjected to too much force, they are likely to buckle while tension members are likely to yield. The concept of buckling was illustrated quite simply by placing the end of a yardstick on the floor and applying a compressive force to the other end of the yardstick.