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Research in general chemistry laboratory instruction has rarely focused on the impact of the learning environment on the graduate teaching assistants (GTAs). We decided to investigate the effect that facilitating a well established cooperative problem-based chemistry laboratory has on GTAs' epistemological and metacognitive development, and how this may translate into their scientific professional growth. Thirteen new GTAs underwent a day and a half teaching training complemented by weekly staff meetings. They were interviewed after their first semester as GTAs, and the data collected were analyzed utilizing a phenomenological approach. Three dimensions that describe the experience lived by the participants emerged from the analysis: affective engagement, metacognitive engagement, and epistemological reflection. The last two offer a rich description of how the laboratory context promotes GTAs' metacognitive and epistemological development, whereas the former provides understanding about the motivation driving their intellectual engagement. Considering the role of metacognition in research, and that personal epistemology is strongly tied to identity development, and that it shapes expectations and ways of learning, it is our contention that appropriate teaching experiences may contribute to better prepare graduate students for their journey in becoming scientists and to embark on successful research.

Laboratory graduate teaching assistants (GTAs) play a prominent role in undergraduate chemistry education. Although the success of a laboratory program relies significantly on the performance of GTAs, only rarely have they been considered actual partners in instruction or have their experiences in the academic lab been investigated. This paper reports on an embedded multiple case study designed to investigate how chemistry graduate students in two independent and very different learning environments constructed their GTA selfimage and what aspects contributed to this process. Participants in this study included 13 GTAs from an expository-based program and 11 GTAs from an inquiry-based program. Interviews, memos, training artifacts, laboratory manuals, and course syllabi were collected to generate case reports for each program. Findings suggest that GTAs' construction of their selfimage is shaped through the interaction of several factors: prior experiences, training, beliefs about the nature of knowledge and about the nature of academic laboratory work, and involvement in the laboratory setting. Findings from this study encourage laboratory coordinators to reconsider GTA participation in instruction in a new and different light and, when applicable, to look at their training and support from a new angle. Instead of focusing exclusively on what and how to teach, lab coordinators may design training and support programs that also target the factors that influence construction of GTA self-image. A more fruitful experience is attainable for students and GTAs insofar as the graduate students develop a teaching assistant self-image consistent with the specific instructional objectives.

Lewis structures are important for learning chemistry as they serve as an essential link between the structure of chemical compounds and their function. Unfortunately, the creation of valid Lewis structures remains an elusive goal for many students. In recent years, several web-based programs have been created that allow students to receive immediate feedback on the structures that they draw; however, the interface in most of these programs is not naturalistic, and there is a significant learning curve for students. This article describes the development, features, and pilot testing of OrganicPad, an innovative and user-friendly program that has been designed to allow students to draw Lewis structures by using the natural user interface of a Tablet PC.

emergent topics on chemistry education [experimental teaching] emergent topics on chemistry education [experimental teaching]Resumen (Enseñanza de la química experimental: Comprendiendo la experiencia de los Instructores Asistentes en el laboratorio académico)La investigación del aprendizaje en los laboratorios de química se ha enfocado muy poco en las experiencias de los estudiantes de posgrado que fungen como instructores (Instructores Asistentes) y sobre como éstas afectan el aprendizaje. Un estudio fenomenológico fue realizado para explorar el sentido que once IAs asignaron a su tarea de instrucción. La reducción y el análisis fenomenológicos de entrevistas produjeron tres dimensiones fundamentales que describen la experiencia de los IAs: Hacer, Saber y Transferir. El rol percibido de los IAs emergió como el factor que interconecta estas tres dimensiones. Los resultados sugieren que los IAs se ven a sí mismos como proveedores de conocimiento y administradores del tiempo y la seguridad, y que su auto-imagen determina sus decisiones sobre la instrucción y el ambiente de aprendizaje. Los beneficios accesibles para los IAs (dominio de los contenidos, habilidades de comunicación y satisfacción personal) no son exclusivos de la instrucción en el laboratorio. No fueron evidentes los beneficios relacionados con el desarrollo de perspectivas más sofisticadas sobre el conocimiento y la ciencia. En este artículo se discuten implicaciones para la instrucción y el entrenamiento de asistentes.Palabras clave: Instrucción de laboratorio de química, estudiantes de posgrado, instructors asistentes, fenomenología