Master of Science / Department of Physics / Nobel S. Rebello / Over the past 20 years there have been limited efforts to improve students’ interest and knowledge of electronics and to offer students experiences to integrate and apply their knowledge of electronics with experimental physics. None of the reform efforts cited in the literature have performed a careful assessment of student learning and attitudes, and most of them report anecdotal success. These programs share several commonalities. They typically have a capstone project experience in which students apply their knowledge and skills in electronics and instrumentation to a particular context. The KSU Physics Department has embarked on an endeavor to improve the PMI (Physical Measurement and Instrumentation) class taken by physics majors. Capstone project experiences for students in PMI will provide them with an opportunity to revisit experiments they completed in previous courses. They then apply the knowledge and skills in electronics and instrumentation learned at the beginning of the PMI course to automate these experiments. The use of LabVIEW and NI ELVIS provides a range of opportunities to students due to their visual interface and easy learning curve. However, they do have some disadvantages such as speed and resolution when compared to more traditional measurements with oscilloscopes. Three specific capstone experiences have been developed in PMI. These include saturated absorption in Rubidium, the Franck-Hertz experiment, and the speed of light measurement. In each case, students first complete the traditional experiments and then use NI ELVIS and LabVIEW to automate these experiments. Students are provided minimal explicit guidance in completing the capstone projects. These include one-page handouts describing the goals, basic procedures and questions that students have to answer for themselves. Comparing data from traditional experiments and those from automated using LabVIEW and NI ELVIS provides a context in which to discuss the trade-offs between the traditional and automated experiments. Future efforts include the development of more experiments as well as careful assessment of student learning and attitudes as a result of the capstone experiences in the PMI class. This project can potentially inform similar efforts at other institutions in the future.

Doctor of Philosophy / Department of Physics / Nobel S. Rebello / This research project investigates students’ development of problem solving schemata while using strategies that facilitate the process of using solved examples to assist with a new problem (case reuse). Focus group learning interviews were used to explore students’ perceptions and understanding of several problem solving strategies. Individual clinical interviews were conducted and quantitative examination data were collected to assess students’ conceptual understanding, knowledge organization, and problem solving performance on a variety of problem tasks. The study began with a short one-time treatment of two independent, research-based strategies chosen to facilitate case reuse. Exploration of students’ perceptions and use of the strategies lead investigators to select one of the two strategies to be implemented over a full semester of focus group interviews. The strategy chosen was structure mapping. Structure maps are defined as visual representations of quantities and their associations. They were created by experts to model the appropriate mental organization of knowledge elements for a given physical concept. Students were asked to use these maps as they were comfortable while problem solving. Data obtained from this phase of our study (Phase I) offered no evidence of improved problem solving schema. The 11 contact hour study was barely sufficient time for students to become comfortable using the maps. A set of simpler strategies were selected for their more explicit facilitation of analogical reasoning, and were used together during two more semester long focus group treatments (phase II and phase III of this study). These strategies included the use of a step-by-step process aimed at reducing cognitive load associated with mathematical procedure, direct reflection of principles involved in a given set of problems, and the direct comparison of problem pairs designed to be void of surface similarities (similar objects or object orientations) and sharing physical principles (conservation of energy problems). Overall, our results from the final two phases of this project indicate that these strategies are helpful in facilitating student ability to identify important information from given problems. The promising results from our study have significant implications for further research, curriculum material development, and instruction.

Doctor of Philosophy / Department of Physics / Dean A. Zollman / This research presents an investigation of how students dynamically construct knowledge in a new situation. In particular, this work focuses on the contexts of light and optics, and examines the dynamic construction of an understanding of wavefront aberrometry. The study began with clinical interviews designed to elicit students’ prior knowledge about light, basic optics, and vision; the data were analyzed phenomenographically to obtain student models of understanding and examine the possible model variations. The results indicate that students have a significant number of resources in this subject area, though some are incomplete or less useful than others. In subsequent phases, many learning and teaching interviews were conducted to design and test scaffolding procedures that could be of use to students as they constructed their understanding of the given phenomenon. Throughout this work, student responses were analyzed in terms of the resources that were being used through the knowledge construction process. Finally, a modified analysis method is presented and utilized for quantifying what types of concepts students use while constructing their understanding, and how they are able to link varying types of concepts together. Significant implications extend beyond the single context of wavefront aberrometry. Each distinct analysis technique provides further insight to the ways in which students learn across contexts and the ways in which we can scaffold their learning to improve curriculum and instruction.

Doctor of Philosophy / Department of Physics / Nobel S. Rebello / Research that investigates the dynamics of knowledge construction by students as they model phenomena at the microscopic level has not been extensively conducted in physics and science education in general. This research wherein I investigated the dynamics of knowledge construction of students in the context of microscopic friction is an attempt to do so. The study commenced with an investigation of the variations in the existing models of students about microscopic friction (phase I of the study). Clinical interviews were conducted with introductory physics students in order to elicit their models. A phenomenographic approach of data analysis was employed to establish the variations in students’ models. Results show that students’ mental models of friction at the atomic level are dominated by their macroscopic experiences. Friction at the atomic level according to most students is due to mechanical interactions (interlocking or rubbing of atoms). Can we build on these macroscopic ideas of students in order to help them construct more scientific explanations of friction at the atomic level? The second phase of the research was an investigation of the dynamics of knowledge construction of students as they constructed models of friction at the atomic level while building on their prior ideas. Individual as well as group teaching interviews were conducted with introductory physics students in order to investigate students learning trajectories and the processes they undergo as they created new models of friction at the atomic level. Results show that the span, zone of proximal development and the epistemological orientations of the students greatly influenced the extent to which they utilize scaffolding afforded to them during the model-building process. Moreover, results show that students undergo the process of incorporation and displacement during their model construction and reconstruction. In the third phase, an instructional material geared towards helping students develop more scientific explanations of microscopic friction was developed and pilot-tested. Overall, the results of the study have significant implications for further research, in improving instruction, and curriculum material development.

Doctor of Philosophy / Department of Physics / Dean A. Zollman / A series of teaching activities using physical models was developed to present some portions of physics of Positron Emission Tomography (PET) and investigate students’ understanding and transfer of learning in physics to a medical technology. A teaching interview protocol consistent with a qualitative research methodology was developed and administered to the students enrolled in an algebra-based introductory level physics course. 16 students participated in individual interviews and another 21 students participated in the group sessions. The major objectives of the teaching interviews were to investigate students’ transfer of physics learning from their prior experiences to the provided physical models, from one model to the other and from the models to the PET problems. The study adapted phenomenological research methodology in analyzing students’ use of cognitive resources and cognitive strategies during knowledge construction and reconstruction. A resource based transfer model framed under the cognitive theory of learning and consistent with contemporary views of transfer was used to describe the transfer of physics learning. Results of the study indicated both appropriate and inappropriate use of the students’ prior conceptual resources in novel contexts. Scaffolding and questioning were found to be effective in activating appropriate and suppressing the inappropriate resources. The physical models used as analogies were found useful in transferring physics learning to understand image construction in PET. Positive transfer was possible when the models were introduced in an appropriate sequence. The results of the study indicate the occurrence of three types of non-scaffolded transfer – spontaneous, semi spontaneous and non-spontaneous. The research found connections between sequencing of hints and phrasing of information in activating students’ different conceptual resources. A qualitative investigation based on Vygotsky’s Zone of Proximal Development (ZPD) has been completed in two contexts – one involving an instructor and the other involving peers. Significant expansion of the students’ ZPD occurred through peer interaction. The results indicate that the appropriate sequencing of learning activities and group interactions can promote learning. Additional research in transfer of physics learning from macroscopic phenomena to microscopic phenomena are warranted by the conclusions of this work.

Doctor of Philosophy / Department of Physics / Nobel S. Rebello / Conventional wisdom has long advised that students’ learning is best supported by interaction with physical manipulative. Thus, in the physics laboratory, students typically spend their time conducting experiments with physical equipment. However, computer simulations offer a tempting alternative to traditional physical experiments. In a virtual experiment, using a computer simulation, students can gather data quickly, and measurement errors and frictional effects can be explicitly controlled. This research investigates the relative support for students’ learning offered by physical and virtual experimentation in the context of simple machines. Specifically, I have investigated students’ learning as supported by experimentation with physical and virtual manipulative from three different angles-- what do students learn, how do students learn, and what do students think about their learning. The results indicate that the virtual manipulative better supported students’ understanding of work and potential energy than the physical manipulative did. Specifically, in responding to data analysis questions, students who used the virtual manipulative before the physical manipulative were more likely to describe work as constant across different lengths of frictionless inclined planes (or pulley systems) and were more likely to adequately compare work and potential energy, whereas students who used the physical manipulative first were more likely to talk about work and potential energy separately. On the other hand, no strong support was found to indicate that the physical manipulative better supported students’ understanding of a specific concept. In addition, students’ responses to the survey questions indicate that students tend to value data from a computer simulation more than from a physical experiment. The interview analysis indicates that the virtual environment better supported the students to create new ideas than the physical environment did. These results suggest that the traditional wisdom that students learn best from physical experiments is not necessarily true. Thus, researchers should continue to investigate how to best interweave students’ experiences with physical and virtual manipulatives. In addition, it may be useful for curriculum designers and instructors to spend more of their efforts designing learning experiences that make use of virtual manipulatives.

Master of Science / Department of Mechanical and Nuclear Engineering / Youqi Wang / Electrospinning is one of the most versatile methods used to fabricate nanofibers. Sub micron and nano level fibers can be continuously produced with the help of an external electric field induced on the polymer melt. These nanofibers can be used in a large variety of applications such as biosensors, three dimensional tissue scaffolds, composites, electronic devices, etc. A unique feature of electrospinning is its ability to work with different fiber assemblies. This helps in making application specific changes and also increases the quality and performance of the fibers. PEO (polyethylene oxide) and electrostrictive graft elastomer (an electroactive polymer developed by NASA) were used in our experiments which focus on controlling the shape and alignment of the fibers. Electroactive polymers (EAP’s) are seen as the basis for future artificial muscles because of their ability to deform when external voltage is applied and quickly recover to their original form when the polarity of the applied voltage is reversed. Hence, aligned fibers of the electrostrictive graft elastomer were produced to mimic the alignment in human muscle fibers. Alignment of fibers is the main objective of this research and was facilitated using vacuum technology. The research was basically divided into three phases, starting with checking of the repeatability of the previously developed techniques using polyethylene oxide. Next, the electrostrictive graft elastomer was spun using the electrospinning techniques and was checked for alignment using the Coaxial Electrode method and PLC controlled secondary electric field method. Finally, a vacuum chamber was designed and built with new components and the elastomer was tested for improved alignment in vacuum using the PLC controlled secondary electric field method.

Doctor of Philosophy / Department of Physics / Nobel S. Rebello / Many introductory calculus-based physics students have difficulties when solving physics problems involving calculus. This study investigates students’ retention and transfer from calculus to physics. While retention is the ability to recall your knowledge at a later point in time, transfer of learning is defined as the ability to apply what one has learned in one situation to a different situation. In this dissertation we propose a theoretical framework to assess students’ transfer of learning in the context of problem solving. We define two kinds of transfer – horizontal transfer and vertical transfer. Horizontal transfer involves applying previously learned ideas in a problem. Vertical transfer involves constructing new ideas to solve the problem. Students need to employ both horizontal and vertical transfer when they solve any problem. This framework evolves through this research and provides a lens that enables us to examine horizontal and vertical transfer. Additionally, this proposed framework offers researchers a vocabulary to describe and assess transfer of learning in any problem solving context. We use a combination of qualitative and quantitative methods to examine transfer in the context of problem solving. The participants in this study were students enrolled in a second-semester physics course taken by future engineers and physicists, calculus instructors and physics instructors. A total of 416 students’ exam sheets were collected and reviewed. Statistical methods were used to analyze the quantitative data. A total of 28 students and nine instructors were interviewed. The video and audio recordings were transcribed and analyzed in light of the aforementioned theoretical framework. A major finding from this study is that a majority of students possess the requisite calculus skills, yet have several difficulties in applying them in the context of physics. These difficulties included: deciding the appropriate variable and limits of integration; not being clear about the criteria to determine whether calculus is applicable in a given physics problem, and others. This study also provides a detailed understanding of students’ difficulties in terms of our theoretical framework. Instructional strategies are suggested at the end to facilitate the transfer from calculus to physics.

Doctor of Philosophy / Department of Physics / Brett D. Esry / The Efimov effect plays a central role in few-body systems at ultracold temperature and has thus accelerated a lot of studies on its manifestation in the collisional stability of the quantum degenerate gases. Near broad Feshbach resonances, Efimov physics has been studied both theoretically and experimentally through the zero-energy scattering observables. We have extended the theoretical studies of Efimov physics to a much broader extent. In particular, we have investigated the three-body Efimov physics near narrow Feshbach resonances and have also identified the Efimov features beyond the zero temperature limit. We have found, near a narrow Feshbach resonance, the non-trivial contribution from both of the resonance width and the short-range physics to the three-body recombination and vibrational dimer relaxation. Remarkably, the collisional stability of the Feshbach molecules are found to be opposite to that near the broad resonances: an increased stability for molecules made by bosons and a decreased stability for those made by fermions. The universal physics observed near the narrow Feshbach resonances is further found not to be limited to the zero temperature observables. We have found that the general features of Efimov physics and those pertaining to a narrow resonance are manifested in different energy ranges above zero temperature. This opens the opportunity to observe Efimov physics by changing the collisional energy while keeping the atomic interaction fixed. The landscape of the universal Efimov physics is thus delineated in both of the interaction and the energy domain. We have also investigated Efimov physics in heteronuclear four-body systems where the complexity can be reduced by approximations. In particular, we have proposed ways for controllable production of the Efimov tri-atomic molecules by three-body or four-body recombinations involving four atoms. We have also confirmed the existence of four-body Efimov effect in a system of three heavy particles and one light particle, which has resolved a decade-long controversy on this topic. Finally, we have studied the collisional properties of four identical bosons in 1D, which is important to the experiments on the quantum gases confined in the 1D optical lattices.