Opening the black box : investigating the impact of engineering design on mechanistic problem solving and mechanistic understanding
Keywords: Education.

The goal of this dissertation was to better understand how working on projects in makerspaces might affect the development of students' skills and knowledge. However, because makerspaces support an enormous variety of activities, it was necessary to restrict the focus to a specific type of activity and a specific set of outcomes. The activity was building mechanistic systems through the engineering design process, and the outcomes of interest were the development of mechanistic problem-solving skills and the construction of mechanistic understanding. In the first study, high-school students took part in a year-long digital fabrication course in a makerspace. Over the course of the study, they worked on two long-term projects using the engineering design process. Both of the projects involved designing a single object that consisted of many interacting parts, and completing the projects required progressive refinement over the course of multiple iterations of the engineering design cycle. In the second project in the course, the students worked together to design and build a mechanistic system, the Rube Goldberg machine. After taking part in the course, the students received significantly higher scores on a set a hands-on problems involving mechanisms, and a fine-grained analysis of their problem-solving approaches indicated that they had become significantly more like expert mechanical engineers. This study suggested that designing and developing complex systems over multiple iterations of the engineering design process supported the development of mechanistic problem-solving skills in the high-school students. The second study was designed to learn more about how building a mechanistic system through the engineering design process might support the construction of mechanistic knowledge. This study used a 2x2 factorial design to understand the impact of different aspects of the engineering design process---problem-centered making and reflection---on specific dimensions of mechanistic understanding. Students in this study were tasked with building a LEGO pendulum clock, and they all had access to a webpage containing text, diagrams, and videos about how pendulum clocks worked. The two factors in this study were problem-centered making [building the clock with step-by-step instructions vs. having to figure out how to build the clock using information on the webpage] and reflection [self-explaining the text on the webpage vs. not self-explaining]. Crossing these factors resulted in four groups: Read, Build, Explain, and Build+Explain. By comparing these groups on a set of posttest questions designed to measure different dimensions of mechanistic understanding, it was possible to learn more about how each of these activities supported learning about the pendulum-clock mechanism. The first finding was that problem-centered making and self-explaining each supported learning about distinct dimensions of mechanistic knowledge. The students who self-explained learned more about what the purposes of the parts in the clock, and scored higher on a set of questions designed to assess declarative knowledge about the clock. The students who worked on the building problem (as opposed to the students who simply rebuilt the clock using instructions) learned more about the structural organization of the parts in the clock. However, neither of these activities was superior at supporting the construction of causal knowledge about the parts in the clock. The second finding was that the students in the Build+Explain group who engaged in both activities learned significantly more about the causal relations between components in the clock than any of the other groups. Additionally, this group of students were significantly more likely to transfer their knowledge to infer how an analogous, novel mechanism worked. These findings suggested that the combination of problem-centered making and reflection was most effective at supporting the construction of complete, transferable knowledge about a mechanism. Together, the studies in this dissertation suggest that building mechanisms through a problem-centered, reflective process may support the development of mechanistic problem-solving skills as well as the construction of mechanistic understanding. This work has implications for researchers who are interested in how people learn about mechanisms, and for practitioners who are interested in supporting students in learning about how things work. Future work is needed to better understand the mechanisms through which skill and knowledge develop during the process of problem-centered, reflective making. These findings point to future directions for research, including the investigation of educational engineering design processes and the use of virtual, problem-centered, reflective making activities to support learning about a larger number of mechanistic systems