Vicente A Talanquer
- Professor, Chemistry and Biochemistry-Sci
- Distinguished Professor, Chemistry and Biochemistry
- Ph.D. Chemistry (Physical Chemistry)
- Universidad Nacional Autonoma de Mexico (UNAM), Mexico City, Mexico City, Mexico
- Bulk and interfacial properties of reacting and associating systems
- M.S. Chemistry (Physical Chemistry)
- Universidad Nacional Autonoma de Mexico (UNAM), Mexico City, Mexico City, Mexico
- Sublattice ordered phases of the Griffith’s three component mode
- B.S. Chemistry
- Universidad Nacional Autonoma de Mexico (UNAM), Mexico City, Mexico City, Mexico
- Simple model for an electrolyte
- Distinguished Professor, University of Arizona, Tucson, Arizona (2015 - Ongoing)
- Professor, University of Arizona, Tucson, Arizona (2013 - 2015)
- Associate Professor, University of Arizona, Tucson, Arizona (2000 - 2013)
- Associate Professor B, Universidad Nacional Autonoma de Mexico (1998 - 2000)
- Associate Professor A, Universidad Nacional Autonoma de Mexico (1992 - 1998)
- Assistant Professor, Universidad Nacional Autonoma de Mexico (1988 - 1992)
- Arizona Professor of the Year
- Carnegie Foundation, Winter 2015
- University Distinguished Professor
- University of Arizona, Summer 2015
- Distinguished Achievement in Science Education Award
- College of Science, University of Arizona, Spring 2013
- James Flack Norris Award for Outstanding Achievement in the Teaching of Chemistry
- American Chemical Society (Northeastern Section), Fall 2012
- Henry and Phyllis Koffler Prize in Teaching
- University of Arizona, Spring 2012
- Leicester & Kathryn Sherrill Creative Teaching Award
- University of Arizona, Spring 2007
- Five-Star Teaching Award
- Honors College, University of Arizona, Spring 2006
- Early-Career Teaching Award
- College of Science, University of Arizona, Spring 2004
General Chemistry;Physical Chemistry;Science Teaching;Chemistry Teaching
DissertationCHEM 920 (Spring 2019)
Exchange Chemical InfoCHEM 695B (Spring 2019)
General Chemistry IICHEM 152 (Spring 2019)
ResearchCHEM 900 (Spring 2019)
Chemical Thinking SupplementalCHEM 197B (Fall 2018)
DissertationCHEM 920 (Fall 2018)
Exchange Chemical InfoCHEM 695B (Fall 2018)
General Chemistry ICHEM 151 (Fall 2018)
General Chemistry IICHEM 152 (Fall 2018)
ResearchCHEM 900 (Fall 2018)
DissertationCHEM 920 (Spring 2018)
Exchange Chemical InfoCHEM 695B (Spring 2018)
General Chemistry IICHEM 152 (Spring 2018)
ResearchCHEM 900 (Spring 2018)
DissertationCHEM 920 (Fall 2017)
Exchange Chemical InfoCHEM 695B (Fall 2017)
Independent StudyCHEM 499 (Fall 2017)
Preparatory ChemistryCHEM 100 (Fall 2017)
ResearchCHEM 900 (Fall 2017)
DissertationCHEM 920 (Spring 2017)
Exchange Chemical InfoCHEM 695B (Spring 2017)
General Chemistry IICHEM 152 (Spring 2017)
Plng+Implemnt Sci CurricSTCH 420A (Spring 2017)
ResearchCHEM 900 (Spring 2017)
Central Ideas in Chemical SciCHEM 439A (Fall 2016)
DissertationCHEM 920 (Fall 2016)
Exchange Chemical InfoCHEM 695B (Fall 2016)
Lecture General ChemCHEM 101A (Fall 2016)
Plng+Implemnt Sci CurricSTCH 420A (Fall 2016)
- Talanquer, V., & Irazoque, G. (2014). Ciencias 3, Química. México: Castillo-McMillan.
- Talanquer, V. A. (2018). Exploring mechanistic reasoning in chemistry. In Science Education Research and Practice in Asia-Pacific and Beyond(pp 39-52). The Netherlands: Springer.
- Burd, G. D., Tomanek, D. J., Blowers, P., Bolger, M. S., Cox, J., Elfring, L. K., Grubbs, E. A., Hunter, J., Johns, K. A., Lazos, L., Lysecky, R. L., Milsom, J. A., Novodvorsky, I., Pollard, J. R., Prather, E. E., Talanquer, V. A., Thamvichai, R., Tharp, H. S., & Wallace, C. (2016). Developing faculty cultures for evidence-based teaching practices in STEM: A progress report.. In Transforming Institutions: 21st Century Undergraduate STEM. West Lafayette, IN.: Purdue University Press.
- de Jong, O., & Talanquer, V. A. (2015). Why is it relevant to learn the big ideas in chemistry at school?. In Relevant chemistry education: From theory to practice(pp 11-31). The Netherlands: Sense Publishers.
- Sevian, H., Talanquer, V., Bulte, A., & Stacy, A. (2014). Development of understanding in chemistry. In Topics and trends in current science education, 9th ESERA Conference Selected Contributions(pp 291-306). Dordrecht: Springer.More infoEditors: Bruguičre, C | Tiberghien, A | Clément, P
- Talanquer, V. A. (2014). Conocimiento didáctico del contentido y progresiones de aprendizaje [Pedagogical Content Knowledge and Learning Progressions].. In Conocimiento Didáctico del Contenido: Una Perspectiva Iberoamericana [Pedagogical Content Knowledge: An Iberoamerican Perspective](pp 206-225 (Chapter 8)). Editorial Académica Española.
- Talanquer, V. A. (2014). El rol de las supocisiones implícitas y las estrategias heurísticas en el razonamiento de los estudiantes de química [The role of implicit assumption and heuristic strategies in chemistry students' reasoning]. In A (Eds.) Avances en didáctica de la química: modelos y lenguaje [Advances in chemistry education: models and language](pp 93-105 (Chapter 6)). Ediciones Universitarias de Valparaíso, Valparaíso.
- Talanquer, V. A. (2014). Using qualitative analysis software to facilitate qualitative data analysis.. In Tools of Chemistry Education Research. ACS Symposium Series(pp 83-95 (Chapter 5)). American Chemical Society.
- Talanquer, V. (2013). How do students reason about chemical substances and reactions?. In Concepts of matter in science education. Series Innovations in Science and Technology Education(pp 331-346). Dordrecht: Springer.More infoVolume: 19; Editors: Tsaparlis, G | Sevian, H
- Talanquer, V. (2004). Chapter 1 Statistical mechanics of fluid interfaces. In Interface Science and Technology(pp 1-32).
- Talanquer, V. A. (2018). Chemical rationales: another triplet for chemical thinking. INTERNATIONAL JOURNAL OF SCIENCE EDUCATION, 40(15), 1874-1890.
- Talanquer, V. A. (2018). Construcción y aplicación de un modelo atómico simple a partir de datos experimentales [Construction and application of a simple atomic model from experimental data].. Alambique, 93, 34-40.
- Talanquer, V. A. (2018). Importance of Understanding Fundamental Chemical Mechanisms. JOURNAL OF CHEMICAL EDUCATION, 95(11), 1905-1911.
- Talanquer, V. A. (2018). Progressions in reasoning about structure-property relationships. CHEMISTRY EDUCATION RESEARCH AND PRACTICE, 19(4), 998-1009.
- Talanquer, V. A., & Sjostrom, J. (2018). Eco-reflexive chemical thinking and action.. Current Opinion in Green and Sustainable Chemistry, 13, 16-20.
- Talanquer, V. A., Scalco, K., Kill, K., & Cordeiro, M. (2018). Making sense of phenomena from sequential images versus illustrated text.. Journal of Chemical Education, 95, 347-354.
- Talanquer, V. A. (2017). Coloreando cáscaras de huevo: Una exploración de la extensión y velocidad de las reacciones químicas. Alambique, 90, 37-43.
- Talanquer, V. A. (2017). Concept Inventories: Predicting the Wrong Answer May Boost Performance. JOURNAL OF CHEMICAL EDUCATION, 94(12), 1805-1810.
- Talanquer, V. A. (2017). Enlace químico y estructura: construcción de modelos y explicaciones a partir de datos experimentales. Educacio Quimica, 21, 26-32.
- Talanquer, V. A. (2017). Tres elementos fundamentales en la formación de docentes de ciencias. TED: Tecne, Epsiteme y Didaxis, 41, 183-196.
- Talanquer, V. A., Sevian, H., Clinchot, M., Ngai, C., Huei, R., Lambertz, J., Banks, G., Weinrich, M., & Pelletier, P. (2017). Better formative assessment.. The Science Teacher, March, 69-74.
- Talanquer, V., & Pollard, J. (2017). Reforming a Large Foundational Course: Successes and Challenges. JOURNAL OF CHEMICAL EDUCATION, 94(12), 1844-1851.
- Talanquer, V. A. (2016). Central Ideas in Chemistry: An Alternative Perspective. JOURNAL OF CHEMICAL EDUCATION, 93(1), 3-8.
- Talanquer, V. A. (2016). Physical Chemistry: A Very Short Introduction.. SCIENCE & EDUCATION, 25(7-8), 927-928.
- Weinrich, M. L., & Talanquer, V. (2016). Mapping students' modes of reasoning when thinking about chemical reactions used to make a desired product. CHEMISTRY EDUCATION RESEARCH AND PRACTICE, 17(2), 394-406.
- Banks, G., Clinchot, M., Cullipher, S., Huie, R., Lambertz, J., Lewis, R., Ngai, C., Sevian, H., Szteinberg, G., Talanquer, V., & Weinrich, M. (2015). Uncovering Chemical Thinking in Students' Decision Making: A Fuel-Choice Scenario. JOURNAL OF CHEMICAL EDUCATION, 92(10), 1610-1618.
- Cullipher, S., Sevian, H., & Talanquer, V. (2015). Reasoning about benefits, costs, and risks of chemical substances: mapping different levels of sophistication. CHEMISTRY EDUCATION RESEARCH AND PRACTICE, 16(2), 377-392.
- Heisterkamp, K., & Talanquer, V. A. (2015). Interpreting data: The hybrid mind.. JOURNAL OF CHEMICAL EDUCATION, 92, 1988-1995.
- Talanquer, V. (2015). Threshold Concepts in Chemistry: The Critical Role of Implicit Schemas. JOURNAL OF CHEMICAL EDUCATION, 92(1), 3-9.
- Talanquer, V. A. (2015). Extracción, separación e identficación de sustancias [Extraction, separation, and identification of substances].. Alambique, 82, 17-23.
- Talanquer, V. A. (2015). La importancia de la evaluación formativa [The importance of formative assessment]. EDUCACION QUIMICA, 26, 177-179.
- Talanquer, V. A., Bolger, M. S., & Tomanek, D. J. (2015). Exploring Prospective Teachers’ Assessment Practices: Noticing and Interpreting Student Understanding in the Assessment of Written Work. Journal of Research in Science Teaching, 52(5), 585-609.
- Weinrich, M. L., & Talanquer, V. (2015). Mapping students' conceptual modes when thinking about chemical reactions used to make a desired product. CHEMISTRY EDUCATION RESEARCH AND PRACTICE, 16(3), 561-577.
- Yan, F., & Talanquer, V. (2015). Students' Ideas about How and Why Chemical Reactions Happen: Mapping the conceptual landscape. INTERNATIONAL JOURNAL OF SCIENCE EDUCATION, 37(18), 3066-3092.
- Ngai, C., Sevian, H., & Talanquer, V. (2014). What is this Substance? What Makes it Different? Mapping Progression in Students' Assumptions about Chemical Identity. INTERNATIONAL JOURNAL OF SCIENCE EDUCATION, 36(14), 2438-2461.More infoGiven the diversity of materials in our surroundings, one should expect scientifically literate citizens to have a basic understanding of the core ideas and practices used to analyze chemical substances. In this article, we use the term 'chemical identity' to encapsulate the assumptions, knowledge, and practices upon which chemical analysis relies. We conceive chemical identity as a core crosscutting disciplinary concept which can bring coherence and relevance to chemistry curricula at all educational levels, primary through tertiary. Although chemical identity is not a concept explicitly addressed by traditional chemistry curricula, its understanding can be expected to evolve as students are asked to recognize different types of substances and explore their properties. The goal of this contribution is to characterize students' assumptions about factors that determine chemical identity and to map how core assumptions change with training in the discipline. Our work is based on the review and critical analysis of existing research findings on students' alternative conceptions in chemistry education, and historical and philosophical analyses of chemistry. From this perspective, our analysis contributes to the growing body of research in the area of learning progressions. In particular, it reveals areas in which our understanding of students' ideas about chemical identity is quite robust, but also highlights the existence of major knowledge gaps that should be filled in to better foster student understanding. We provide suggestions in this area and discuss implications for the teaching of chemistry.
- Sevian, H., & Talanquer, V. (2014). Rethinking chemistry: A learning progression on chemical thinking. Chemistry Education Research and Practice, 15(1), 10-23.More infoAbstract: Dominant educational approaches in chemistry focus on the learning of somewhat isolated concepts and ideas about chemical substances and reactions. Reform efforts often seek to engage students in the generation of knowledge through the investigation of chemical phenomena, with emphasis on the development and application of models to build causal explanations and predict outcomes. However, chemistry has been characterized as a technoscience that blends scientific pursuit and technological goals. Besides searching for explanations, our discipline also involves the design of substances and processes to address relevant problems, as well as the evaluation of social, economic, and environmental benefits, costs, and risks associated with chemical knowledge and products. In order to develop authentic curricula, instruction, and assessments that are better aligned with the core goals and practices of chemistry, we need to understand how students' chemical thinking progresses over time. We define chemical thinking as the development and application of chemical knowledge and practices with the main intent of analyzing, synthesizing, and transforming matter for practical purposes. In this paper we present a blueprint of a theoretically sound and evidence-based foundation for an educational framework centered on the idea of chemical thinking. Our investigations are focused on the development of a learning progression that describes likely pathways in the evolution of students' chemical thinking with training in the discipline from grade 8 (age 13-14) through 16 (undergraduate completion). © 2014 The Royal Society of Chemistry.
- Sjostrom, J., & Talanquer, V. (2014). Humanizing Chemistry Education: From Simple Contextualization to Multifaceted Problematization. JOURNAL OF CHEMICAL EDUCATION, 91(8), 1125-1131.More infoChemistry teaching has traditionally been weakly connected to everyday life, technology, society, and history and philosophy of science. This article highlights knowledge areas and perspectives needed by the humanistic (and critical reflexive) chemistry teacher. Different humanistic approaches in chemistry teaching, from simple contextualization to socioscientific orientations to multifaceted problematization, are discussed. The latter is crucial for "critical chemistry teaching", which includes both problematized content knowledge in chemistry and problematized knowledge about chemistry and chemistry education (about the nature of chemistry, its role in society, and the way it is communicated inside and outside the classroom). We illustrate how various facets of chemistry knowledge for teaching can be used to characterize different levels of complexity in the integration of the human element into chemistry education.
- Szteinberg, G., Balicki, S., Banks, G., Clinchot, M., Cullipher, S., Huie, R., Lambertz, J., Lewis, R., Ngai, C., Weinrich, M., Talanquer, V., & Sevian, H. (2014). Collaborative Professional Development in Chemistry Education Research: Bridging the Gap between Research and Practice. JOURNAL OF CHEMICAL EDUCATION, 91(9), 1401-1408.More infoProfessional development that bridges gaps between educational research and practice is needed. However, bridging gaps can be difficult because teachers and educational researchers often belong to different Communities of Practice, as their activities, goals, and Means of achieving those goals often differ. Meaningful collaboration among teachers and educational researchers can create a merged Community of Practice in which both teachers and educational researchers mutually benefit. A collaboration of this type is described that centered on investigating students' abilities to apply chemical thinking when engaged in authentic tasks. We describe the design-based principles behind the collaboration, the work of the collaborative team, and a self-evaluation of results interpreted through a Communities-of-Practice perspective, with primary focus on the teachers' perceptions. Analysis revealed ways in which teachers' assessments shifted toward more research-based practice and ways in which teachers navigated the research process. Implications for affordances and constraints of such collaborations among teachers and educational researchers are discussed.
- Talanquer, V. (2014). Chemistry Education: Ten Heuristics To Tame. JOURNAL OF CHEMICAL EDUCATION, 91(8), 1091-1097.More infoStudents in our chemistry classes often generate shallow responses to our questions and problems. They fail to recognize relevant cues in making judgments and decisions about the properties of chemical substances and processes, and make hasty generalizations that frequently lead them astray. Results from research in the psychology of decision making can help us better understand how students approach chemistry tasks under conditions of limited knowledge, time, or motivation. In this contribution, I describe 10 cognitive heuristics that are often responsible for biases in student thinking. Helping students tame these heuristics may allow us to foster more meaningful learning in chemistry classrooms.
- Talanquer, V. (2014). DBER and STEM Education Reform: Are We Up to the Challenge?. JOURNAL OF RESEARCH IN SCIENCE TEACHING.More infoThe extent and quality of Discipline-Based Education Research (DBER) at the post-secondary level have grown substantially in recent years. Associated research findings are central to current reform efforts to transform science, technology, engineering, and math (STEM) education in colleges and universities across the United States. The increased visibility of DBER efforts creates opportunities and challenges that should be carefully analyzed. In this contribution, I reflect on critical issues that need to be considered and addressed in advancing the fields of DBER, using the articles included in this Special Issue of the Journal of Research in Science Teaching to ground the discussion. (C) 2014 Wiley Periodicals, Inc.
- Talanquer, V. (2014). Simulaciones computacionales para construir y explorer modelos [Computer simulations for building and exploring models]. Alambique, 76, 8-16.
- Talanquer, V. A. (2014). Desarrollando pensamiento químico en contextos sociales y ambientales [Developing chemical thinking in social and environmental contexts].. Educacio Quimica, 17, 4-11.
- Talanquer, V. A. (2014). Razonamiento pedagógico específico sobre el contenido [Specific pedagogical content reasoning].. Educacion Quimica, 25(3), 391-397.
- Talanquer, V., & Sevian, H. (2014). Chemistry in past and new science frameworks and standards: Gains, losses, and missed opportunities. Journal of Chemical Education, 91(1), 24-29.More infoAbstract: Science education frameworks and standards play a central role in the development of curricula and assessments, as well as in guiding teaching practices in grades K-12. Recently, the National Research Council published a new Framework for K-12 Science Education that has guided the development of the Next Generation Science Standards. In this paper, we discuss what we see as critical gains, losses, and missed opportunities in the representation of chemistry in these new documents compared to the previous National Science Education Standards. The goal is to facilitate the comparative analysis of these two documents from a chemistry perspective, and elicit issues that we judge demand greater discussion and reflection among chemistry educators. © 2013 The American Chemical Society and Division of Chemical Education, Inc.
- Haozhi, X. u., & Talanquer, V. (2013). Effect of the level of inquiry of lab experiments on general chemistry students' written reflections. Journal of Chemical Education, 90(1), 21-28.More infoAbstract: The central goal of this exploratory study was to characterize the effects of experiments involving different levels of inquiry on the nature of college students' written reflections about laboratory work. Data were collected in the form of individual lab reports written using a science writing heuristic template by a subset of the students enrolled in the first and second semester of general chemistry at a research-intensive university. Our findings indicate that the level of inquiry of the experiments seems to affect three main areas of students' reflections: knowledge, evaluation, and improvements. In the case of knowledge, our findings were particularly interesting as higher levels of inquiry were associated with a smaller proportion of reflective statements in this area. However, these types of reflections shifted from mostly focusing on factual knowledge to largely concentrating on procedural knowledge and metacognitive knowledge. In general, our results elicit trends and highlight issues that can help instructors and curriculum developers identify strategies to better support and scaffold student thinking in different learning environments. © 2012 The American Chemical Society and Division of Chemical Education, Inc.
- Haozhi, X. u., & Talanquer, V. (2013). Effect of the level of inquiry on student interactions in chemistry laboratories. Journal of Chemical Education, 90(1), 29-36.More infoAbstract: The central goal of our exploratory study was to investigate differences in college chemistry students' interactions during lab experiments with different levels of inquiry. This analysis was approached from three major analytic dimensions: (i) functional analysis; (ii) cognitive processing; and (iii) social processing. According to our results, which were based on the qualitative analysis of direct observations of different groups of students working in general chemistry laboratories, experiments that involved higher levels of inquiry were associated with an increase in the frequency of episodes in which students engaged in proposing ideas versus asking and answering each others' questions. Higher levels of inquiry also favored episodes in which experimental work was approached in a more exploratory (versus procedural) manner. Increased levels of inquiry were also associated with more frequent episodes of domination in which a few students in a group directed the actions of others. In general, our results elicit trends and highlight issues that can help instructors identify strategies to better support and scaffold productive engagement in the laboratory. © 2012 The American Chemical Society and Division of Chemical Education, Inc.
- Maeyer, J., & Talanquer, V. (2013). Making predictions about chemical reactivity: Assumptions and heuristics. Journal of Research in Science Teaching, 50(6), 748-767.More infoAbstract: Diverse implicit cognitive elements seem to support but also constrain reasoning in different domains. Many of these cognitive constraints can be thought of as either implicit assumptions about the nature of things or reasoning heuristics for decision-making. In this study we applied this framework to investigate college students' understanding of structure-property relationships in the context of chemical reactivity. The ability to understand and apply structure-property relationships to explain the behavior of physical, chemical, and biological systems is a core competence that many science and engineering majors are expected to develop. Core findings were derived from semi-structured interviews based on a ranking task. Study participants relied on intuitive, spurious, and valid assumptions about the nature of chemical entities in building their responses. In particular, many of students appeared to conceive chemical reactions as macroscopic reassembling processes thought to be more favored the easier it seemed to break reactants apart or put products together. Students also expressed spurious chemical assumptions based on the misinterpretation and overgeneralization of chemical ideas. Reasoning heuristics for decision-making also played a significant role in the construction of answers to ranking questions. Specifically, interviewees demonstrated strong over-reliance on variable reduction strategies and recognition memory in their reasoning. Our findings reveal the need for educational approaches that more effectively affect the conceptual sophistication and depth of reasoning about structure-property relationships of college students. Our research framework provides a productive approach for the analysis of student reasoning in scientific domains. © 2013 Wiley Periodicals, Inc.
- Talanquer, V. (2013). Chemistry education: Ten facets to shape Us. Journal of Chemical Education, 90(7), 832-838.More infoAbstract: The chemistry knowledge that we want our students to develop is rich, complex, and multifaceted. However, some teachers and instructors at the secondary school and college levels approach it in rather rigid and unidimensional ways. The central goal of this contribution is to describe and discuss 10 different complementary perspectives or "facets" from which chemistry content in introductory courses can be analyzed. This multidimensional view may help chemical educators, particularly those who are new to the profession, enrich their understanding of chemistry as a teaching subject and open the path for diverse reconceptualizations of the chemistry curriculum. © 2013 The American Chemical Society and Division of Chemical Education, Inc.
- Talanquer, V. (2013). Learning progressions: Promise and potential. Educacion Quimica, 24(4), 362-364.More infoAbstract: The educational construct of Learning Progression (LP) is becoming central in research and curriculum development in science education in the US. Learning progressions are models that describe how students' understanding of central concepts or ideas becomes more sophisticated over time. To date, only a few learning progressions have been developed and validated in critical science areas. In this issue of Educación Química, leaders and pioneers in LP research and development across the world describe and discuss their efforts to expand and strengthen our understanding of learning progressions in chemistry. © Universidad Nacional Autónoma de México.
- Talanquer, V. (2013). School Chemistry: The Need for Transgression. Science and Education, 22(7), 1757-1773.More infoAbstract: Studies of the philosophy of chemistry over the past 15 years suggest that chemistry is a hybrid science which mixes scientific pursuits with technological applications. Dominant universal characterizations of the nature of science thus fail to capture the essence of the discipline. The central goal of this position paper is to encourage reflection about the extent to which dominant views about quality science education based on universal views of scientific practices may constrain school chemistry. In particular, we discuss how these predominant ideas restrict the development of chemistry curricula and instructional approaches that may better support the learning of the ideas and practices that studies of the philosophy of chemistry suggest are at the core of the discipline. Our analysis suggests that philosophical studies about the nature of chemistry invite us to transgress traditional educational boundaries between science and technology, inquiry and design, content and process, and to reconceptualize school chemistry as a paradigmatic techno scientific subject. To support these changes, chemical education researchers should expand the scope of their investigations to better understand how students and teachers reason about and engage in more authentic ways of chemical thinking and doing. © 2011 Springer Science+Business Media B.V.
- Talanquer, V. (2013). When atoms want. Journal of Chemical Education, 90(11), 1419-1424.More infoAbstract: Chemistry students and teachers often explain the chemical reactivity of atoms, molecules, and chemical substances in terms of purposes or needs (e.g., atoms want or need to gain, lose, or share electrons in order to become more stable). These teleological explanations seem to have pedagogical value as they help students understand and use abstract chemical models. They may, however, become a roadblock in developing mechanistic understandings of the structure and properties of chemical systems. I explore the explanatory preferences of college students with different levels of training in chemistry to determine the extent to which they prefer teleological explanations over causal explanations. Major results revealed a strong preference at all the targeted educational levels for explanations that invoke intentionality as a driver for chemical reactivity. I discuss the educational implications of these findings and invite chemistry educators to reflect on these issues. © 2013 The American Chemical Society and Division of Chemical Education, Inc.
- Talanquer, V., Tomanek, D., & Novodvorsky, I. (2013). Assessing students' understanding of inquiry: What do prospective science teachers notice?. Journal of Research in Science Teaching, 50(2), 189-208.More infoAbstract: The theoretical construct of teacher noticing has allowed mathematics teacher educators to examine teacher thinking and practice by looking at the range of activities that teachers notice in the classroom. Guided by this approach to the study of teacher thinking, the central goal of this exploratory study was to identify what prospective science teachers notice when evaluating evidence of student understanding in another teacher's inquiry-based unit. Our results are based on the qualitative analysis of 43 prospective teachers' evaluations of assessment evidence presented to them in the form of a video case and associated written artifacts. Analysis of our data revealed two major categories of elements, Task-General and Task-Specific, noticed by our study participants. Task-General elements included attention to learning objectives, independent student work, and presentation issues and they often served to guide or qualify the specific inquiry skills that were evaluated. Task-Specific elements included the noticing of students' abilities to perform different components of an investigation. In general, study participants paid attention to important general and specific aspects of student work in the context of inquiry. However, they showed preferential attention to those process skills associated with designing an investigation versus those practices related to the analysis of data and generation of conclusions. Additionally, their interpretations of assessment outcomes were largely focused on the demonstration of general science process skills; much less attention was paid to the analysis of the epistemological validity or scientific plausibility of students' ideas. Our results provide insights into the design of meaningful learning experiences for prospective teachers that elicit, challenge, and enrich their conceptions of student understanding in the context of inquiry. © 2013 Wiley Periodicals, Inc.
- Young, K. K., & Talanquer, V. (2013). Effect of different types of small-group activities on students' conversations. Journal of Chemical Education, 90(9), 1123-1129.More infoAbstract: Teaching reform efforts in chemistry education often involve engaging students in small-group activities of different types. This study focused on the analysis of how activity type affected the nature of group conversations. In particular, we analyzed the small-group conversations of students enrolled in a chemistry course for nonscience majors. Group work in this course was designed and facilitated by preservice teachers enrolled in a science teaching methods class. Our results suggest that the types of activities in which students were engaged influenced the extent to which group talk focused on content-related issues. In particular, activities that asked students to compare and contrast different systems, different ideas, or predicted and actual behaviors were often associated with higher student engagement in constructing, transforming, and applying knowledge to make sense of concepts and ideas discussed in class. © 2013 The American Chemical Society and Division of Chemical Education, Inc.
- Christian, K., & Talanquer, V. (2012). Content-Related Interactions in Self-initiated Study Groups. International Journal of Science Education, 34(14), 2231-2255.More infoAbstract: The central goal of the present exploratory study was to investigate the nature of the content-related interactions in study groups independently organized by college organic chemistry students. We were particularly interested in the identification of the different factors that affected the emergence of opportunities for students to co-construct understanding and engage in higher levels of cognitive processing. Our results are based on the analysis of in situ observations of 34 self-initiated study sessions involving over a 100 students in three academic semesters. The investigation revealed three major types of social regulation processes, teaching, tutoring, and co-construction in the observed study sessions. However, the extent to which students engaged in each of them varied widely from one session to another. This variability was mostly determined by the specific composition of the study groups and the nature of the study tasks in which they were engaged. Decisions about how to organize the study session, the relative content knowledge and conceptual understanding expressed by the participants, as well as the cognitive level of the problems that guided group work had a strong impact on the nature of student interactions. Nevertheless, group talk in the observed study groups was mostly focused on low-level cognitive processes. The results of our work provide insights on how to better support students' productive engagement in study groups. © 2012 Copyright Taylor and Francis Group, LLC.
- Christian, K., & Talanquer, V. (2012). Modes of reasoning in self-initiated study groups in chemistry. Chemistry Education Research and Practice, 13(3), 286-295.More infoAbstract: Characterizing the modes of reasoning typically applied by students to solve different types of chemistry problems is of central importance for the design of instructional strategies that can better support their learning of specific content. Thus, the central goal of this study was to identify dominant modes of reasoning expressed by college chemistry students while working in self-initiated study groups. We were particularly interested in exploring potential relationships between modes of reasoning, content focus of group discussions, and levels of cognitive processing. Our study was based on the analysis of student conversations in 34 study sessions of 14 study groups involving over 100 students enrolled in the first semester of college organic chemistry. Our analysis indicated that most of the content-related conversations in the study could be categorized as involving at least one of four major reasoning modes: Model-based reasoning, case-based reasoning, rule-based reasoning, and symbol-based reasoning. In general, group talk was largely focused on issues of representation and structure which preferentially invoked rule-based reasoning; discussions about chemical reactions heavily relied on case-based reasoning. Overall, model-based reasoning was minimally applied. In general, over 70% of the content-related conversations corresponded to lower levels of cognitive processing. Rule-based thinking and case-based thinking were often based on students remembering and applying knowledge. Although model-based reasoning was used scarcely, it more frequently led to higher levels of cognitive processing. The results of our work provide insights into how to modify instruction to better support students' reasoning inside and outside the classroom. This journal is © The Royal Society of Chemistry.
- Cullipher, S., Sevian, H., & Talanquer, V. (2012). A learning progression approach to studying benefits, costs and risks in chemical design. La Chimica Nella Scuola, 34(3), 344-51.
- Garritz, A., & Talanquer, V. (2012). Emergent topics in chemistry education: Nature of chemistry and learning progressions. Educacion Quimica, 23(3), 328-330.More infoAbstract: We have decided to open the section "Emergent topics in Chemistry Education" to update our readers on the most relevant topics in Chemical Education. Chemistry education has changed and will continue doing so because of the emergence of new educational interests. It is thus necessary that we become aware of these new ideas to improve both our teaching and educational research. In this editorial piece we include a brief description of two of the Emergent Topics selected for years 2012 and 2013 as especial themes for our Journal: Nature of Chemistry and Learning Progressions.
- Martínez, A., Valdés, J., Talanquer, V., & Chamizo, J. (2012). Estructura de la materia: De saberes y pensares [Structure of matter: Knowing and thinking]. Educación Química, 23, 361-369.
- Talanquer, V. (2012). Chemistry education: Ten dichotomies we live by. Journal of Chemical Education, 89(11), 1340-1344.More infoAbstract: Modern thought in chemical education seems to be shaped by a set of dichotomies that are useful in identifying and highlighting problems, as well as in generating and communicating novel ideas. However, these binary oppositions may also constrain our thinking. Among these dichotomies, we draw attention to 10 different oppositions including, among others, the pairs abstract/concrete, algorithmic/conceptual, and symbolic/microscopic. The central goal of this contribution is to reflect on the scope and limitations of common dichotomic conceptualizations of critical elements of chemical education. The major motivation is to invite chemical educators to critically analyze ideas or beliefs that we often take for granted. © 2012 The American Chemical Society and Division of Chemical Education, Inc.
- McClary, L., & Talanquer, V. (2011). College chemistry students' mental models of acids and acid strength. Journal of Research in Science Teaching, 48(4), 396-413.More infoAbstract: The central goal of this study was to characterize the mental models of acids and acid strength expressed by advanced college chemistry students when engaged in prediction, explanation, and justification tasks that asked them to rank chemical compounds based on their relative acid strength. For that purpose we completed a qualitative research study involving students enrolled in different types of organic chemistry course sections at our university. Our analysis led to the identification of four distinct mental models, some of which resembled scientific models of acids and acid strength. However, the distinct models are better characterized as synthetic models that combined assumptions from one or more scientific models with intuitive beliefs about factors that determine the properties of chemical substances. For many students in our sample, mental models served more as tools for heuristic decision-making based on intuitively appealing, but many times mistaken, concept associations rather than as cognitive tools to generate explanations. Although many research participants used a single general mental model to complete all of the interview tasks, the presence of specific problem features or changes in the nature of the task (e.g., prediction vs. explanation) prompted several students to change their mental model or to add a different mental representation. Our study indicates that properly diversifying and sequencing the types of academic tasks in which students are asked to participate could better foster meaningful learning as different types of cognitive resources may be activated by different students, and thus shared, analyzed, and discussed. © 2011 Wiley Periodicals, Inc.
- McClary, L., & Talanquer, V. (2011). Heuristic reasoning in chemistry: Making decisions about acid strength. International Journal of Science Education, 33(10), 1433-1454.More infoAbstract: The characterization of students' reasoning strategies is of central importance in the development of instructional strategies that foster meaningful learning. In particular, the identification of shortcut reasoning procedures (heuristics) used by students to reduce cognitive load can help us devise strategies to facilitate the development of more analytical ways of thinking. The central goal of this qualitative study was thus to investigate heuristic reasoning as used by organic chemistry college students, focusing our attention on their ability to predict the relative acid strength of chemical compounds represented using explicit composition and structural features (i.e., structural formulas). Our results indicated that many study participants relied heavily on one or more of the following heuristics to make most of their decisions: reduction, representativeness, and lexicographic. Despite having visual access to reach structural information about the substances included in each ranking task, many students relied on isolated composition features to make their decisions. However, the specific characteristics of the tasks seemed to trigger heuristic reasoning in different ways. Although the use of heuristics allowed students to simplify some components of the ranking tasks and generate correct responses, it often led them astray. Very few study participants predicted the correct trends based on scientifically acceptable arguments. Our results suggest the need for instructional interventions that explicitly develop college chemistry students' abilities to monitor their thinking and evaluate the effectiveness of analytical versus heuristic reasoning strategies in different contexts. © 2011 Taylor & Francis.
- Talanquer, V. (2011). Macro, submicro, and symbolic: The many faces of the chemistry "triplet". International Journal of Science Education, 33(2), 179-195.More infoAbstract: The idea that chemical knowledge can be represented in three main ways: macro, submicro, and symbolic (chemistry triplet) has become paradigmatic in chemistry and science education. It has served both as the base of theoretical frameworks that guide research in chemical education and as a central idea in various curriculum projects. However, this triplet relationship has been the subject of different adaptations and reinterpretations that sometimes lead to confusion and misunderstanding, which complicates the analysis of the triplet's nature and scope. Thus, the central goal of this paper is to describe some of the existing views of the triplet relationship in chemistry and science education and critically analyse their underlying assumptions. We also propose a general structure of our chemistry knowledge intended to better situate the chemistry triplet in relationship with the different types, scales, dimensions, and approaches that seem to characterise such knowledge. Our proposed model may be useful in the analysis, evaluation, and reflection of educational research results and teaching practices centred on the triplet relationship. © 2011 Taylor & Francis.
- Talanquer, V. A. (2011). El papel de las ideas previas en el aprendizaje de la química [The role of prior knowledge in chemistry learning].. Alambique, 69, 35-41.
- Davila, K., & Talanquer, V. (2010). Classifying End-of-Chapter Questions and Problems for Selected General Chemistry Textbooks Used in the United States. JOURNAL OF CHEMICAL EDUCATION, 87(1), 97-101.
- Dávila, K., & Talanquer, V. (2010). Classifying end-of-chapter questions and problems for selected general chemistry textbooks used in the United States. Journal of Chemical Education, 87(1), 97-101.
- Maeyer, J., & Talanquer, V. (2010). The role of intuitive heuristics in students' thinking: Ranking chemical substances. Science Education, 94(6), 963-984.More infoAbstract: The characterization of students' cognitive biases is of central importance in the development of curriculum and teaching strategies that better support student learning in science. In particular, the identification of shortcut reasoning procedures (heuristics) used by students to reduce cognitive load can help us devise strategies to foster the development of more analytical ways of thinking. The central goal of this study was thus to investigate the reasoning heuristics used by undergraduate chemistry students when solving a traditional academic task (ranking chemical substances based on the relative value of a physical or chemical property). For this purpose, a mixed-methods research study was completed based on quantitative results collected using a ranking-task questionnaire and qualitative data gathered through semistructured interviews. Our results revealed that many study participants relied frequently on one or more of the following heuristics to make their decisions: recognition, representativeness, one-reason decision making, and arbitrary trend. These heuristics allowed students to generate answers in the absence of requisite knowledge; unfortunately, they often led students astray. Our results suggest the need to create more opportunities for college chemistry students to monitor their thinking, develop and apply analytical ways of reasoning, and evaluate the effectiveness of shortcut reasoning procedures in different contexts. © 2010 Wiley Periodicals, Inc.
- Talanquer, V. (2010). Exploring dominant types of explanations built by general chemistry students. International Journal of Science Education, 32(18), 2393-2412.More infoAbstract: The central goal of our study was to explore the nature of the explanations generated by science and engineering majors with basic training in chemistry to account for the colligative properties of solutions. The work was motivated by our broader interest in the characterisation of the dominant types of explanations that science college students use to make sense of phenomena under conditions of limited time and limited explicit knowledge about a topic. Explanations were collected in written form using two different quizzes that students completed under time constraints at the end of a two-semester general chemistry course. Our study revealed that students' ability to generate causal/mechanical explanations depended on the nature of the task. In general, students were more inclined or able to generate mechanistic explanations to account for boiling-point elevation and freezing-point depression than to make sense of osmotic flow. The analysis of the types of causal explanations built by the study participants suggests that students may be biased towards some causal models or explanatory modes characterised as causal-additive and causal-static in our work. A large proportion of the students built non-causal teleological explanations to account for osmotic flow. None of the participants in our study used a dynamic model of matter as the basis for their explanations of any of the relevant phenomena; the idea of an underlying random process that is taking place at all times giving rise to emergent properties and behaviours was completely absent from their intuitive reasoning under conditions of limited time and knowledge. © 2010 Taylor & Francis.
- Talanquer, V. (2010). Intuitive Thinking in Chemistry: Implicit Assumptions and Heuristics. ENSENANZA DE LAS CIENCIAS, 28(2), 165-174.More infoThe central goal of this work is to illustrate the extent to which science students' reasoning is constrained by a) implicit assumptions about the properties and behavior of the relevant entities in the domain, and b) shortcut reasoning procedures (heuristics) in order to build explanations, generate inferences, and make predictions and decisions with limited time and knowledge. Results from our research consistently suggest that, even at college level, students' thinking is largely controlled by these types of cognitive constraints. Solving problems, generating explanations, or building inferences seems to involve the activation or instantiation of a spectrum of constraints, from domain-general to domain-specific, from implicit to explicit, which may act in complementary or competitive ways. The goal is not necessarily to achieve conceptual coherence, but rather local explanatory coherence during a specific task in a determined context. The characterization of students' intuitive thinking is thus of central importance in the development of curriculum and teaching strategies that better support student learning in science, as well as in the design of assessment tools to gather valid evidence of student understanding.
- Talanquer, V. A. (2010). Construyendo puentes conceptuales entre las varias escalas y dimensiones de los modelos químicos [Building conceptual bridges between the different scales and dimensions of chemical models].. Educacio Quimica, 5, 11-18.
- Talanquer, V., & Pollard, J. (2010). Let's teach how we think instead of what we know. Chemistry Education Research and Practice, 11(2), 74-83.More infoAbstract: Despite multiple calls for reform, the curriculum for first-year college chemistry at many universities across the world is still mostly fact-based and encyclopedic, built upon a collection of isolated topics, oriented too much towards the perceived needs of chemistry majors, focused too much on abstract concepts and algorithmic problem solving, and detached from the practices, ways of thinking, and applications of both chemistry research and chemistry education research in the 21st century. This paper describes an alternative way of conceptualizing the introductory chemistry curriculum for science and engineering majors by shifting the focus from learning chemistry as a body of knowledge to understanding chemistry as a way of thinking. Starting in 2007, we have worked on the development and implementation of a new curriculum intended to: promote deeper conceptual understanding of a minimum core of fundamental ideas instead of superficial coverage of multiple topics; connect core ideas between the course units by following well-defined learning progressions; introduce students to modern ways of thinking and problem-solving in chemistry; and involve students in realistic decision-making and problem-solving activities. © The Royal Society of Chemistry 2010.
- Talanquer, V., Novodvorsky, I., & Tomanek, D. (2010). Factors influencing entering teacher candidates' preferences for instructional activities: A glimpse into their orientations towards teaching. International Journal of Science Education, 32(10), 1389-1406.More infoAbstract: The present study was designed to identify and characterize the major factors that influence entering science teacher candidates' preferences for different types of instructional activities, and to analyze what these factors suggest about teacher candidates' orientations towards science teaching. The study involved prospective teachers enrolled in the introductory science teaching course in an undergraduate science teacher preparation program. Our analysis was based on data collected using a teaching and learning beliefs questionnaire, together with structured interviews. Our results indicate that entering science teacher candidates have strong preferences for a few activity types. The most influential factors driving entering science teacher candidates' selections were the potential of the instructional activities to motivate students, be relevant to students' personal lives, result in transfer of skills to non-science situations, actively involve students in goal-directed learning, and implement curriculum that represents what students need to know. This set of influencing factors suggests that entering science teacher candidates' orientations towards teaching are likely driven by one or more of these three central teaching goals: (1) motivating students, (2) developing science process skills, and (3) engaging students in structured science activities. These goals, and the associated beliefs about students, teaching, and learning, can be expected to favor the development or enactment of three major orientations towards teaching in this population of future science teachers: "motivating students," "process," and "activity-driven." © 2010 Taylor & Francis.
- Talanquer, V. (2009). On cognitive constraints and learning progressions: The case of "structure of matter". International Journal of Science Education, 31(15), 2123-2136.More infoAbstract: Based on the analysis of available research on students' alternative conceptions about the particulate nature of matter, we identified basic implicit assumptions that seem to constrain students' ideas and reasoning on this topic at various learning stages. Although many of these assumptions are interrelated, some of them seem to change or lose/gain strength independently from one another. Overlapping or competing presuppositions about the structure, properties, and dynamics of matter may be able to coexist at any given level, particularly at intermediate stages of expertise. Our results allowed us to suggest common paths in the transition from naïve through novice to expert along relevant dimensions related to the structure and properties of chemical substances. The identification of these cognitive constraints provides a useful framework that educators can use to better understand and even predict many of their students' learning difficulties. It can also assist in the design and organisation of learning experiences and assessment tools that recognise and take advantage of the most likely trajectories towards expertise (learning progressions) followed by many students. © 2009 Taylor & Francis.
- Talanquer, V. A. (2009). De escuelas, docentes y TICs [Of schools, teachers, and ICTs]. Educacion Quimica, 346-351, 20.
- Talanquer, V. A. (2009). Química; ¿Quién eres, a dónde vas y cómo te alcanzamos? [Chemistry: Who are you? Where are you going? How do we catch up with you?]. Educacion Quimica, 20, 220-226.
- Stains, M., & Talanquer, V. (2008). Classification of chemical reactions: Stages of expertise. Journal of Research in Science Teaching, 45(7), 771-793.More infoAbstract: In this study we explore the strategies that undergraduate and graduate chemistry students use when engaged in classification tasks involving symbolic and microscopic (particulate) representations of different chemical reactions. We were specifically interested in characterizing the basic features to which students pay attention when classifying chemical reactions at the symbolic and microscopic levels. We identified the categories that students create when classifying chemical reactions, and compared the performance in simple classification tasks of students with different levels of preparation in the discipline. Our results suggest that advanced levels of expertise in chemical classification do not necessarily evolve in a linear and continuous way with academic training; a significant proportion of undergraduate students, regardless of their level of preparation in chemistry, based their classification schemes on the identification of surface features and failed to create chemically meaningful classes, Students' ability to identify chemically meaningful groups was strongly influenced by their recent learning experiences and their graduate work in chemistry. The level of expertise and the type of chemical representation influenced the number and types of categories created, the nature of the features used to build a class, and the role that these features played during the classification process. Although all of the participants in our study expressed similar levels of unfamiliarity with the microscopic images of chemical reactions, advanced students were more adept at using the available representational features to build chemical meaning. © 2007 Wiley Periodicals, Inc.
- Talanquer, V. (2008). Students' predictions about the sensory properties of chemical compounds: Additive versus emergent frameworks. Science Education, 92(1), 96-114.More infoAbstract: We investigated general chemistry students' intuitive ideas about the expected properties of the products of a chemical reaction. In particular, we analyzed college chemistry students' predictions about the color, smell, and taste of the products of chemical reactions represented at the molecular level. The study was designed to explore the extent to which novice learners intuitively use an additive framework to predict the properties of the product, rather than an approach that recognizes the emergent nature of the properties of chemical compounds. To this end, we used a mixed-methods research approach based on answers to multiple-choice questions and individual interviews with students enrolled in the first year of an introductory general chemistry course for science and engineering majors. Our results indicate that most students at this level rely on an additive heuristic to predict the properties of chemical compounds, overlooking the possibility of emergent properties resulting from the interaction of the atoms that compose the system. Chemistry instructors and chemical educators thus need to intentionally design learning opportunities for students to recognize and differentiate additive and emergent properties in a variety of contexts. © 2007 Wiley Periodicals, Inc.
- Tomanek, D., Talanquer, V., & Novodvorsky, I. (2008). What do science teachers consider when selecting formative assessment tasks?. Journal of Research in Science Teaching, 45(10), 1113-1130.More infoAbstract: The purpose of this qualitative exploratory study was to identify factors that influenced prospective and experienced secondary level science teachers' reasoning as they evaluated or selected tasks to formatively assess their students' understanding of scientific concepts. The analysis of the coded written responses revealed two categories of factors that influenced the teachers' reasoning: (1) characteristics of the task and (2) characteristics of students or the curriculum. Characteristics of the task related to qualities of the task regardless of the learning environment in which it would be used, such as the level of student thinking demanded by a task. Characteristics of the students and the curriculum related to the learning environment in which an assessment task would be implemented, such as students' abilities to complete the task. Both prospective and experienced teachers' task evaluations were influenced by the same factors related to the characteristics of the task, although their interpretations of the meaning of each factor varied, In addition, experienced teachers' task evaluations were more likely than prospective teachers to be influenced by factors related to characteristics of students and the curriculum. The findings are discussed as a conceptual framework that presents the identified factors along three different dimensions: (1) the influence of task, student, and curriculum characteristics, (2) the influence of expectations for success, and (3) the influence of teaching experience. © 2008 Wiley Periodicals.
- Husowitz, B., & Talanquer, V. (2007). Filling and emptying transitions in cylindrical channels: A density functional approach. JOURNAL OF CHEMICAL PHYSICS, 126(22).More infoThe authors use density functional theory in a square gradient approximation to investigate capillary condensation and evaporation in cylindrical channels of finite lengths. The model allows them to systematically explore the effect of the pore's length, width, and surface fields on the location of the transition between "empty" (vapor-filled) and "full" (liquid-filled) states. In general, their results indicate that decreasing the length of the channel drastically reduces the range of pore widths where a transition between liquidlike and vaporlike configurations may be observed. For the wide pores, the transition occurs at very low pressures where the liquid is no longer stable, while for the narrow pores, the transition is hindered by the solid-fluid interactions that favor the vapor phase in lyophobic pores. For the limited range of sizes where the transition can occur, the authors' results confirm the existence of two competing minima that may explain the density oscillations observed in a computer simulation of nanochannels. Comparisons between these results with those generated using a phenomenological model based on the capillary approximation indicate that this simplified approach yields fairly good predictions for medium size pores. However, the capillary approach fails to properly describe the properties of the very small and very large pores. (c) 2007 American Institute of Physics.
- Husowitz, B., & Talanquer, V. (2007). Solvent density inhomogeneities and solvation free energies in supercritical diatomic fluids: A density functional approach. JOURNAL OF CHEMICAL PHYSICS, 126(5).More infoDensity functional theory is used to explore the solvation properties of a spherical solute immersed in a supercritical diatomic fluid. The solute is modeled as a hard core Yukawa particle surrounded by a diatomic Lennard-Jones fluid represented by two fused tangent spheres using an interaction site approximation. The authors' approach is particularly suitable for thoroughly exploring the effect of different interaction parameters, such as solute-solvent interaction strength and range, solvent-solvent long-range interactions, and particle size, on the local solvent structure and the solvation free energy under supercritical conditions. Their results indicate that the behavior of the local coordination number in homonuclear diatomic fluids follows trends similar to those reported in previous studies for monatomic fluids. The local density augmentation is particularly sensitive to changes in solute size and is affected to a lesser degree by variations in the solute-solvent interaction strength and range. The associated solvation free energies exhibit a nonmonotonous behavior as a function of density for systems with weak solute-solvent interactions. The authors' results suggest that solute-solvent interaction anisotropies have a major influence on the nature and extent of local solvent density inhomogeneities and on the value of the solvation free energies in supercritical solutions of heteronuclear molecules. (c) 2007 American Institute of Physics.
- Satins, M., & Talanquer, V. A. (2007). A2: Element or Compound?. Journal of Chemical Education, 84, 880-884.
- Stains, M., & Talanquer, V. (2007). Classification of chemical substances using particulate representations of matter: An analysis of student thinking. International Journal of Science Education, 29(5), 643-661.More infoAbstract: We applied a mixed-method research design to investigate the patterns of reasoning used by novice undergraduate chemistry students to classify chemical substances as elements, compounds, or mixtures based on their particulate representations. We were interested in the identification of the representational features that students use to build a classification system, and in the characterization of the thinking processes that they follow to group substances in different classes. Students in our study used structural and chemical composition features to classify chemical substances into elements, compounds, and mixtures. Many of the students' classification errors resulted from strong mental associations between concepts (e.g., atom-element, molecule-compound) or from lack of conceptual differentiation (e.g., compound-mixture). Strong concept associations led novice students to reduce the number of relevant features used to differentiate between substances, while the inability to discriminate between two concepts (conceptual undifferentiation) led them to pay too much attention to irrelevant features during the classification tasks. Comparisons of the responses to classification tasks of students with different levels of expertise in chemistry indicate that some of these naïve patterns of reasoning may be strengthened by, rather than weakened by, training in the discipline.
- Talanquer, V. (2007). Explanations and teleology in chemistry education. International Journal of Science Education, 29(7), 853-870.More infoAbstract: It has been commonly assumed that teleological explanations are unnecessary and have no place in the physical sciences. However, there are indications that teleology is fairly common in the instructional explanations of teachers and students in chemistry classrooms. In this study we explore the role and nature of teleological explanations and the conditions that seem to warrant their use in chemistry education. We also analyse the learning implications of developing explanations of chemical phenomena within a teleological stance. Our study is based on the qualitative analysis of the instructional explanations presented in traditional chemistry textbooks used in the United States. Our results indicate that teleological explanations are in fact present in these textbooks and help provide an explanatory reason for the occurrence of chemical transformations. Their use is tightly linked to the existence of a rule, principle, or law that governs the behaviour of a chemical system, and that explicitly or implicitly implies the minimisation or maximisation of some intrinsic property. This law or principle tends to provide a sense of preferred direction in the evolution of a transformation. Although teleological explanations seem to have heuristic pedagogical value in chemistry education, they may also lead students to develop alternative conceptions and unwarranted overgeneralisations.
- Talanquer, V. A. (2007). Nucleation of Self-Associating Fluids: Free versus Activated Association.. Journal of Physical Chemistry B, 111, 3438.
- Talanquer, V. A., Morgan, D., Maeyer, J., & Young, K. (2007). Linking general education and science teacher preparation. Journal of College Science Teaching.
- Talanquer, V., Tomanek, D., & Novodvorsky, I. (2007). Revealing student teachers' thinking through dilemma analysis. Journal of Science Teacher Education, 18(3), 399-421.More infoAbstract: We explore the potential of dilemma analysis as an assessment tool to reveal student teachers' thinking and concerns about their practice. For this purpose we analyze the dilemma analyses completed by 22 student teachers enrolled in our science teacher preparation program over a period of four semesters. Student teachers' dilemmas fall into two main groups: dilemmas about student performance and dilemmas associated with instructional decisions. These dilemmas reveal a variety of concerns that student teachers have about their work. In particular, concerns about lack of student motivation and its consequences on performance and instruction play a central role in student teachers' thinking. The recognition of common patterns of thought in our student teacher thinking has made us reflect on and re-evaluate important components of the curriculum in our science teacher preparation program. © Springer Science+Business Media, Inc. 2007.
- Talanquer, V. (2006). Commonsense chemistry: A model for understanding students' alternative conceptions. Journal of Chemical Education, 83(5), 811-816.More infoAbstract: A discussion of the results of a research project guided by the assumption that a common explanatory framework does exist and it can be described by analyzing the research literature on alternative conceptions in chemistry is presented. The goal of this research project is to build a model of a typical "naive" student in an introductory chemistry classroom in a Western society. The intention is to develop a useful framework that chemistry teachers and instructors can use to better understand and even predict many of their students' ideas, and implement instructional strategies that promote learning and understanding. A description on the theoretical and empirical work guiding the analysis of students' conceptions about chemical substances and phenomena, and the development of the proposed explanatory framework is described. Lastly, this work utilizes well-established results in chemical education research to develop tools and models that can help improve teacher thinking and practice.
- Talanquer, V. (2006). Phase transitions in DNA-linked nanoparticle assemblies: A decorated-lattice model. Journal of Chemical Physics, 125(19).More infoPMID: 17129144;Abstract: We use decorated-lattice models to explore the phase behavior of two types of DNA-linked colloidal mixtures: systems with identical nanoparticles functionalized with two different DNA strands (mixture Aab) and mixtures involving two types of particles each one functionalized with a different DNA strand (mixture Aa-Ab). The model allows us to derive the properties of the mixtures from the well-known behavior of underlying spin- n Ising models with temperature and activity dependent effective interactions. The predicted evolution of the dissolution profiles for the colloidal assemblies as a function of temperature and number of single DNA strands on a nanoparticle M is in qualitative agreement with that observed in real systems. According to our model, the temperature at which the assemblies dissolve can be expected to increase with increasing M only for concentrations of colloids below a certain threshold. For more concentrated solutions, the dissolution temperature is a decreasing function of M. Linker-mediated interactions between Aa and Ab particles in the Aa-Ab mixture render the phase separation involving disordered aggregates metastable with respect to a phase transition between a solvent-rich and an ordered phase. The stability of the DNA-linked assembly is enhanced by the ordering of the colloidal network and the ordered aggregates dissolve at higher temperatures. Our results may explain the contrasting evolution of the dissolution temperatures with increasing probe size in Aab and Aa-Ab mixtures as observed experimentally. © 2006 American Institute of Physics.
- Talanquer, V. (2006). Reclaiming the central role of equations of state in thermodynamics. Journal of Chemical Education, 83(1), 127-131.More infoAbstract: Equations of state are key elements in the study of the thermodynamic behavior of physical systems. They describe the relationships between relevant extensive and intensive parameters for any given system and are useful tools for prediction. An equation of state is normally defined as the relationship between temperature (T), pressure (P), and volume (V) in a given system and is limited to the case of gases or liquids. The derivation, analysis, and discussion of equations of state relies on the use of "response coefficients" that can be measured experimentally and on the systematic manipulation of simple thermodynamic relationships. The use of response coefficient such as the compressibility of a fluid or the magnetic susceptibility of a paramagnetic solid to derive an equation of state highlights the importance of experimental work geared towards the measurement of these types of physical properties.
- Husowitz, B., & Talanquer, V. (2005). Nucleation on cylindrical plates: Sharp transitions and double barriers. Journal of Chemical Physics, 122(19).More infoAbstract: We apply methods of density-functional theory in statistical mechanics to study the properties of droplets and bubbles formed on a single cylindrical plate or between two such disks immersed in a metastable fluid. Our approach allows us to analyze the properties of different types of aggregates and investigate the effect of disk size, disk separation, and solid-fluid interactions on the dynamics of a liquid-vapor phase transition. The finite size of disks induces nucleation phenomena that are not observed in the cases of either a planar wall or a slit pore. Heterogeneous nucleation on a single disk is characterized by the existence of two distinct types of critical nuclei that control the phase-transition dynamics at different supersaturations. Asymmetric droplets or bubbles formed on one side of the disk are the preferred nucleation path at high supersaturations. However, these types of aggregates become unstable close to the binodal, where they abruptly collapse into nuclei that engulf the cylindrical plates. Droplet or bubble nucleation in between two disks may occur through a free-energy barrier with one or two maxima depending on the value of the system parameters and the supersaturation. Metastable droplets or bubbles corresponding to local minima of the free energy are observed forming between two plates only after density fluctuations in the system achieve a critical size. These types of aggregates only exist for cylindrical plates larger than a minimum size given a fixed distance between the disks. The stability of these droplets and bubbles decreases when the plates are separated. © 2005 American Institute of Physics.
- Talanquer, V. (2005). Nucleation in a simple model for protein solutions with anisotropic interactions. Journal of Chemical Physics, 122(8).More infoAbstract: A lattice analog of density functional theory is used to explore the structural and thermodynamic properties of critical nuclei in mixtures of particles with attractive anisotropic interactions. Protein molecules are assumed to occupy the sites on a regular cubic lattice, with effective directional interactions that mimic hydrogen bonding and the solvation forces induced by water. Interaction parameters are chosen to qualitatively reproduce the phase behavior of protein solutions. Our model predicts that critical nuclei of the solidlike phase have nonspherical shapes, and that their specific geometry depends on the nature of the anisotropic interactions. Molecules tend to align in distinctive ways in the core and in the interfacial region of these critical clusters, and the width and structure of the interface are highly affected by the presence of a metastable fluid-fluid critical point. Close to the critical region, the height of the barrier to nucleation is strongly reduced; this effect is enhanced by increasing the anisotropy of the intermolecular interactions. Unlike systems with short-range isotropic interactions, nucleation in our model is initiated by highly ordered clusters in which the order-disorder transition is confined to the interfacial region.
- Talanquer, V. (2005). Phase behavior of self-associating fluids with weaker dispersion interactions between bonded particles. Journal of Chemical Physics, 122(15).More infoAbstract: In this study, we explore the global phase behavior of a simple model for self-associating fluids where association reduces the strength of the dispersion interactions between bonded particles. Recent research shows that this type of behavior likely explains the thermodynamic properties of strongly polar fluids and certain micellar solutions. Based on Wertheim's theory of associating liquids [M. S. Wertheim, J. Stat. Phys. 42, 459 (1986); 42, 477 (1986)], our model takes into account the effect that dissimilar particle interactions have on the equilibrium constant for self-association in the system. We find that weaker interactions between bonded molecules tend to favor the dissociation of chains at any temperature and density. This effect stabilizes a monomeric liquid phase at high densities, enriching the global phase behavior of the system. In particular, for systems in which the energy of mixing between bonded and unbonded species is positive, we find a triple point involving a vapor, a dense phase of chain aggregates, and a monomeric liquid. Phase coexistence between the vapor and the monomeric fluid is always more stable at temperatures above the triple point, but a highly associated fluid may exist as a metastable phase under these conditions. The presence of this metastable phase may explain the characteristic nucleation behavior of the liquid phase in strongly dipolar fluids. © 2005 American Institute of Physics.
- Husowitz, B., & Talanquer, V. (2004). Nucleation in cylindrical capillaries. Journal of Chemical Physics, 121(16), 8021-8028.More infoPMID: 15485266;Abstract: The properties of a critical nuclei for the liquid-vapor transition of van der Waals fluids in cylindrical capillaries were analyzed using local density functional theory. The proposed model was used to investigate the effect of pore size, surface field, and supersaturation on the behavior of the system. The calculations predicted the existence of at least three different pathways for the nucleation of droplets and bubbles in these confined fluids. It was found that the morphological transition between these different structures is driven by the existence of states of zero compressibility in the capillary.
- Talanquer, V., & Oxtoby, D. W. (2003). Formation of droplets on nonvolatile soluble particles. Journal of Chemical Physics, 119(17), 9121-9128.More infoAbstract: The structural and thermodynamic properties of droplets formed on soluble and partialy soluble particles composed of a fluid with an extremely low volatility were studied using density functional theory. The required supersaturation for activated nucleation was found to increase as the size of the soluble particle decreases. The solubility transition was found to exhibit various similarities with the deliquescence process of water soluble salts.
- Talanquer, V., & Oxtoby, D. W. (2003). Nucleation of pores in amphiphile bilayers. Journal of Chemical Physics, 118(2), 872-877.More infoAbstract: A simple model which shows both the value and the limitations of classical nucleation theory as a description for pore formation in membranes was employed. On the one hand, the free energies of larger pores can be fit to classical nucleation theory (CNT) expressions, giving explicit predictions from density functional theory for the surface tensions and line tensions in terms of the interaction parameters in the theory. On the other hand, for sufficiently small pores, the macroscopic approximations implicit in CNT break down because of rearrangement on the molecular scale.
- Talanquer, V., Novodvorsky, I., Slater, T. F., & Tomanek, D. (2003). A Stronger Role for Science Departments in the Preparation of Future Chemistry Teachers. Journal of Chemical Education, 80(10), 1168-1171.More infoAbstract: The role of science departments in the preparation of future chemistry teachers was presented. In regard with it, the program developed and implemented by the University of Arizona's College of Science (CoS) for preparing science teacher was also discussed. The program offered the unique opportunity for students to learn to teach science in an environment where courses were focused on central issues related to teaching and learning of science.
- Tomanek, D., Talanquer, V., Novodvorsky, I., & Slater, T. F. (2003). Responding to the call for change: The new College of Science TeacherPreparation Program at the University of Arizona. Cell Biology Education, 2(1), 29-34.More infoPMID: 12822038;PMCID: PMC152778;
- TALANQUER, . (2002). A MICROCOMPUTER SIMULATION OF THE LIESEGANG PHENOMENA. JOURNAL OF CHEMICAL EDUCATION, 71(1), 58-62.
- Talanquer, V. (2002). Nucleation in gas-liquid transitions. Journal of Chemical Education, 79(7), 877-.
- Padilla, K., & Talanquer, V. (2001). Heterogeneous nucleation on aerosol particles. Journal of Chemical Physics, 114(3), 1319-1325.More infoAbstract: The heterogeneous nucleation of supersaturated vapors on spherical aerosol like substrates was analyzed using density functional theory in statistical mechanisms. The classical nucleation theory was found to be inadequate in describing the condensation of droplets on very small particles at high supersaturations. The results were compared with those for the condensation of supersaturated vapors on submicrometer particles.
- Talanquer, V., & Oxtoby, D. W. (2001). Nucleation in a slit pore. Journal of Chemical Physics, 114(6), 2793-2801.More infoAbstract: Density functional theory was studied for the nucleation of the gas-liquid transition. The kinetics of nucleation showed that the critical nucleus can be attached to one of the planes. It can bridge the two planes too. It was observed that the microscopic capillarity approximation provides a qualitative picture. Simulations of phase transitions were used for comparisons.
- Talanquer, V., Cunningham, C., & Oxtoby, D. W. (2001). Bubble nucleation in binary mixtures: A semiempirical approach. Journal of Chemical Physics, 114(15), 6759-6762.More infoAbstract: The interaction forces between water and the four gases (hydrogen, nitrogen, oxygen, and carbon dioxide) were modeled using Lennard-Jones potentials. A positive slope of critical supersaturation with temperature for hydrogen was observed. Results of the study are fully consistent with the experimental trends.
- Talanquer, V., & Oxtoby, D. W. (2000). Density-functional approach to nucleation in micellar solutions. Journal of Chemical Physics, 113(16), 7013-7021.More infoAbstract: The goal of this paper is to develop a theoretical model suitable for strong as well as weak amphiphiles, in which the explicit dual character of the amphiphile molecules is introduced by modeling them with two different force centers connected by a bond. The paper describes the basic model used, and gives the results of calculations for equilibrium phase behavior, planar interfaces, micelles, and vesicles. Focus is made in particular on possible transition states between stable and metastable structures and on nucleation.
- Talanquer, V., & Oxtoby, D. W. (2000). Gas-liquid nucleation in associating fluids. Journal of Chemical Physics, 112(2), 851-856.More infoAbstract: The density functional approach to nucleation is extended to the study of the condensation of associating fluids. We use Wertheim theory for associating liquids in a system of spherical interacting molecules with single association sites. Our calculations show that classical nucleation theory largely underestimates the height of the nucleation barrier in this kind of system, but most of that error can be corrected through the classical model of Katz, Saltsburg, and Reiss for nucleation in associated vapors. © 2000 American Institute of Physics.
- Napari, I., Laaksonen, A., Talanquer, V., & Oxtoby, D. W. (1999). A density functional study of liquid-liquid interfaces in partially miscible systems. Journal of Chemical Physics, 110(12), 5906-5912.More infoAbstract: Liquid-liquid interfaces and nucleation in partially miscible Lennard-Jones (LJ) mixtures are considered using density functional theory. We present phase diagrams, interfacial liquid-vapor and liquid-liquid profiles, and gas-liquid as well as liquid-liquid surface tensions for two types of mixtures having different mixing rules for the LJ energy parameter. A simple local density approximation does not give oscillatory behavior at the liquid-liquid interface, but a more realistic weighted density approximation does show this behavior. Both approaches also give a total density minimum near the interface, comparable to that found in molecular dynamics and integral equation studies. Finally, we calculate the density profiles and free energies for critical nuclei in liquid-liquid phase separation. © 1999 American Institute of Physics.
- Talanquer, V., & Oxtoby, D. W. (1999). A simple off-lattice model for microemulsions. Faraday Discussions, 112, 91-101.More infoAbstract: We have developed a simple off-lattice density functional theory and applied it to ternary water-oil-amphiphile mixtures. Our approach is based on mean field free energy functionals calculated from hard-sphere perturbation theory, to which is added a contribution arising from molecular association between the water-like and the amphiphilic species. This latter term is treated using the Wertheim theory for associating liquid mixtures, and it gives rise to a re-entrant binary phase diagram in a very natural way. The resulting ternary phase diagrams resemble experimental data both qualitatively and quantitatively. We also calculate the structure and free energy of interfaces between phases in this system, and show that the presence of amphiphile dramatically lowers the surface tension between the water-rich and oil-rich phases. This simple model contains many of the features of real microemulsion systems, and can be extended to study lamellar and other complex phases.
- Talanquer, V., & Oxtoby, D. W. (1998). Crystal nucleation in the presence of a metastable critical point. Journal of Chemical Physics, 109(1), 223-227.More infoAbstract: Density functional theory is applied to the study of crystal nucleation in the presence of a metastable critical point. A phenomenological model for fluids with short range interactions is developed to study the influence of critical density fluctuations on the structure of the critical nucleus and the height of the barrier to nucleation. Our results show dramatic changes in the nature of crystal nucleation near the metastable critical point, with nucleation rates increasing several orders of magnitude; this behavior has important consequences for nucleation of colloids and proteins from solution. A nonmonotonic dependence of the critical cluster size on supersaturation is observed under these conditions. © 1998 American Institute of Physics.
- Talanquer, V. (1997). A new phenomenological approach to gas-liquid nucleation based on the scaling properties of the critical nucleus. Journal of Chemical Physics, 106(23), 9957-9960.More infoAbstract: The scaling properties of the critical nucleus, as proposed recently by McGraw and Laaksonen, are analyzed in the context of density functional results for simple Lennard-Jones systems. A simple phenomenological approach with no adjustable parameters is introduced to test the validity of these scaling relations in describing the nucleation behavior of nonpolar and weakly polar vapors. © 1997 American Institute of Physics.
- Talanquer, V., & Oxtoby, D. W. (1997). Nucleation in the presence of an amphiphile: A density functional approach. Journal of Chemical Physics, 106(9), 3673-3680.More infoAbstract: Density functional theory is applied to the study of gas-to-liquid nucleation in binary and ternary mixtures with one amphiphilic component. The theory allows the evaluation of density profiles and molecular orientation distributions in the critical nucleus. The predicted cluster compositions for binary and ternary systems resemble qualitatively the experimental behavior for water-n-alcohol and water-n-butanol-n-nonane mixtures, respectively. © 1997 American Institute of Physics.
- Carrillo, E., Talanquer, V., & Costas, M. (1996). Wetting transition at the liquid-air interface of methanol-alkane mixtures. Journal of Physical Chemistry, 100(14), 5888-5891.More infoAbstract: Wetting transition (Tw) and consolute (CT) temperatures close to the upper critical solution temperature (UCST) have been determined for methanol + n-alkane mixtures where n = 6-12. Tw and the CT were also measured for noninteger n values, i.e., for mixtures of methanol + a binary mixture of two normal alkanes. The liquid-vapor surface tension (σLV) and the liquid-liquid interfacial tension (σLL) were measured at 25°C. For all mixtures studied the methanol rich-phase is denser than the alkane rich-phase. It is found that while the CT increases continuously, the Tw first increases and then decreases as a function of n. This is the first time that, for a homologous series of mixtures, this behavior has been found. For 6 ≤ n ≤ 8.25 the observed wetting transition was from partial wetting to nonwetting (the alkane rich-phase intrudes between the methanol rich-phase and the vapor) while for 8.5 ≤ n ≤ 12 the transition was from partial to total wetting (the methanol-rich phase intrudes between the alkane rich-phase and the vapor). Both the change of Tw and the inversion in the nature of the wetting phase with n are in qualitative agreement with the predictions of a recently developed mean-field model where a normalized parameter b, whose calculation involves σLV and σLL, plays the role of n in the experiments. © 1996 American Chemical Society.
- Talanquer, V., & Oxtoby, D. W. (1996). Critical clusters in binary mixtures: A density functional approach. Journal of Chemical Physics, 104(5), 1993-1999.More infoAbstract: We apply a square-gradient density functional theory to study the nucleation of the gas-to-liquid transition for nonideal binary mixtures. For weakly nonideal mixtures, we predict deviations from ideal behavior in the compositions and free energies of critical nuclei. When the nonideality becomes large enough to allow miscibility gaps, some qualitatively new features arise. We find regions in phase space in which more than one critical nucleus can form, as well as cases in which the critical nucleus itself begins to phase separate, forming a structure of cylindrical symmetry in which the two ends are enriched in the two components of the mixture. © 1996 American Institute of Physics.
- Talanquer, V., & Oxtoby, D. W. (1996). Nucleation on a solid substrate: A density functional approach. Journal of Chemical Physics, 104(4), 1483-1492.More infoAbstract: We extend the density functional approach to the statistical mechanics of inhomogeneous fluids to calculate the rate of heterogeneous nucleation of the gas-to-liquid transition by a planar solid substrate. Comparison with classical nucleation theory (extended to incorporate the line tension that results from three-phase contact) reveals the inadequacy of the latter approaches as the spinodal is approached. Wetting and drying transitions have a large effect on the usefulness of classical theory. Free energies of formation for critical heterogeneous nuclei and their shapes and density profiles are calculated from density functional theory. © 1996 American Institute of Physics.
- Laaksonen, A., Talanquer, V., & Oxtoby, D. W. (1995). Nucleation: Measurements, theory, and atmospheric applications. Annual Review of Physical Chemistry, 46(1), 489-524.More infoAbstract: New experiments have succeeded in measuring actual rates of nucleation and are revealing the shortcomings of classical nucleation theory, which assumes that the molecular-scale regions of the new phase may be treated using bulk thermodynamics and planar surface free energies. In response to these developments, new theories have been developed that incorporate information about molecular interactions in a more realistic fashion. This article reviews recent experimental and theoretical advances in the study of nucleation of liquids from the vapor and of crystals from the melt, with particular emphasis on phenomena that relate to particle formation in the atmosphere.
- Nyquist, R. M., Talanquer, V., & Oxtoby, D. W. (1995). Density functional theory of nucleation: A semiempirical approach. The Journal of Chemical Physics, 103(3), 1175-1179.More infoAbstract: We present a semiempirical approach to the density functional theory of gas-liquid nucleation, in which the same experimental properties used in classical nucleation theory (equilibrium vapor pressure, liquid density, and surface tension) are used to fit three adjustable parameters in the intermolecular potential. This approach allows direct comparison of nucleation rates with experimental data. Agreement with results on nonane from three different experimental groups is reasonable, although the comparison clearly reveals the scatter in those results and suggests that further experimental measurements by different groups on the same systems would be very valuable. For water and the n-alcohols, this version of density functional theory gives results quite close to classical nucleation theory, implying that it is not a good approximation to describe polar fluids by effective spherically symmetric potentials. © 1995 American Institute of Physics.
- Talanquer, V. (1995). Density functional analysis of phenomenological theories of gas-liquid nucleation. Journal of Physical Chemistry, 99(9), 2865-2874.More infoAbstract: We employ density functional theory to explore the range of validity of phenomenological approaches to the study of gas-liquid nucleation. We consider the Dillmann-Meier theory of nucleation and the diffuse interface theory developed by Gránásy. By using density functional theory to calculate cluster properties such as the variation of free energy with cluster size or the local enthalpy or entropy profiles, we find that the success of these models in fitting experimental data is at least in part fortuitous. On the basis of our analysis, we identify relevant model variables and propose new parametrizations that are more consistent with our density functional calculations. © 1995 American Chemical Society.
- Talanquer, V., & Oxtoby, D. W. (1995). Heterogeneous nucleation of molecular and dipolar fluids. Physica A: Statistical Mechanics and its Applications, 220(1-2), 74-84.More infoAbstract: We present a summary of the main properties of an interaction site model for heterogeneous nucleation of molecular and dipolar fluids on charged hard spheres. Density functional theory is used to calculate the work of formation of critical nuclei formed on small spherical particles. Nucleation rates depend on the size and charge of the central seed. Sign preferences lead to rates of nucleation that differ by several orders of magnitude. © 1995.
- Talanquer, V., & Oxtoby, D. W. (1995). Nucleation in molecular and dipolar fluids: Interaction site model. The Journal of Chemical Physics, 103(9), 3686-3695.More infoAbstract: We consider the effect of molecular anisotropy and dipole moment on the rate of homogeneous and heterogeneous nucleation of molecular and dipolar fluids. Density functional theory is applied to an interaction site model of molecules composed of two tangent or fused hard spheres interacting through Lennard-Jones and coulombic potentials. Interfacial properties are conditioned by entropy vs energy competition. For nucleation on a charged hard sphere, the calculated rates depend strongly on the size and charge of the central seed. Preferred surface orientations of the dipolar molecules are responsible for nucleation rates differing by several orders of magnitude for charges of different sign. © 1995 American Institute of Physics.
- Talanquer, V., & Oxtoby, D. W. (1995). Nucleation of bubbles in binary fluids. The Journal of Chemical Physics, 102(5), 2156-2164.More infoAbstract: We have applied density functional methods to predict the nucleation rates of bubbles in superheated, stretched, or supersaturated binary fluid mixtures. Our model uses Lennard-Jones mixtures, with mixing rules chosen to allow either ideal or nonideal solution behavior. Deviations from the predictions of classical nucleation theory are in general quite large, with the locus of observable bubble nucleation (the kinetic stability limit) following the spinodal (the thermodynamic stability limit) reasonably closely. Comparisons are made with a variety of experiments, and puzzling earlier results are explained, such as the increase in solubility of some gases with temperature at the kinetic stability limit. Further experiments are needed to explore the variety of behavior predicted by the present calculations. © 1995 American Institute of Physics.
- Pérez, C., Roquero, P., & Talanquer, V. (1994). Wetting properties of simple binary mixtures and systems with one self-associating component. The Journal of Chemical Physics, 100(8), 5913-5921.More infoAbstract: The presence of additional chemical equilibria in an otherwise simple system can induce unexpected phase behavior. We analyze the effect of this phenomenon on the wetting properties of binary mixtures with one self-associating component. As a first step we characterize the global wetting phase diagram of a mean-field lattice model for a simple binary system. We evaluate its reliability in generating an adequate topological description of bulk critical and wetting transition manifolds. These results serve as a basis to study the influence of self-association. We find that under appropriate conditions the appearance of new species in solution can lead to irregular wetting behavior such as "reentrant" wetting and "dewetting. " © 1994 American Institute of Physics.
- Talanquer, V. (1994). A microcomputer simulation of the liesegang phenomena. Journal of Chemical Education, 71(1), 58-62.
- Talanquer, V., & Oxtoby, D. W. (1994). Dynamical density functional theory of gas-liquid nucleation. The Journal of Chemical Physics, 100(7), 5190-5200.More infoAbstract: We present a consistent dynamical nucleation theory based on density functional theory. By considering the properties of stable droplets in closed volumes, the height and shape of the barrier to nucleation are calculated. Contributions from fluctuations in the center of mass of the nucleating cluster are taken into account. Forward and backward rates for cluster dynamics are obtained, and nucleation rates are then evaluated under steady-state conditions. We test the quantitative effects of several shortcuts to calculating nucleation rates. The predictions of the full theory presented here show very modest changes from those of the simpler nonclassical theory proposed earlier by Oxtoby and co-workers. © 1994 American Institute of Physics.
- Talanquer, V., & Oxtoby, D. W. (1993). Nucleation in dipolar fluids: Stockmayer fluids. The Journal of Chemical Physics, 99(6), 4670-4679.More infoAbstract: We have used density functional theory to begin the study of nucleation in dipolar fluids. The simplest case of a system composed of Stockmayer molecules has been considered. Under a Weeks-Chandler-Andersen perturbation scheme we obtain the corresponding bulk phase diagram and interfacial properties of planar and spherical liquid-vapor interfaces. Molecules tend to align perpendicular to the interface on the liquid side of small droplets, but the overall effect of this on free energies is negligible. The resulting nonclassical effects on nucleation rates are, hence, close to those found in nonpolar Lennard-Jones fluids. © 1993 American Institute of Physics.
- Talanquer, V. (1992). Global phase diagram for reacting systems. The Journal of Chemical Physics, 96(7), 5408-5421.More infoAbstract: The global phase diagram of a chemically reactive system is described for a model which can be thought of as the "regular-solution" model of a ternary mixture. We consider the particular addition reaction X + Y → Z and analyze the significant features of the phase diagrams which result from the intersection of the chemical equilibrium surface and the phase coexistence manifolds for all possible values of the energy parameters. Based on the nature of molecular interactions, six different general kinds of mixtures can be identified where interesting phenomena such as triple and quadruple points, closed-loop phase coexistence curves, lower and upper areatropy, and critical areatropy appear as a consequence of chemical and phase equilibrium interaction. © 1992 American Institute of Physics.
- Robledo, A., Varea, C., & Talanquer, V. (1991). Curvature interfacial transitions in amphiphile monolayers and their possible relation to the onset of micelle formation. Physical Review A, 43(10), 5736-5739.More infoAbstract: We describe two types of curvature-related interfacial transitions occuring in soluble amphiphile monolayers under compression. The first type corresponds to the buckling of areas with sizes up to the monolayers de GenresTaupin persistence length squared, and starts to occur when the interfacial tension is about one-half its bare value. The second type corresponds to the transformation of the simply connected monolayer into either a dispersion of droplets or an interconnected bicontinuous structure. The resulting type of volume-spanning state is determined by the sign of the saddle-splay bending constant © 1991 The American Physical Society.
- Talanquer, V., Varea, C., & Robledo, A. (1989). Global phase diagram for binary alloys with one magnetic component. Physical Review B, 39(10), 7030-7038.More infoAbstract: We describe the global mean-field phase diagram for a binary alloy that contains one magnetic component. We obtain 12 types of system phase diagrams, each of which displays a different interaction of chemical (segregration or ordering) and magnetic (ferromagnetic or antiferromagnetic) long-range order. Our results follow from the known features of the phase diagrams along the symmetric sections of Griffithss three-component (spin-1) model when both uniform and sublattice ordered states are considered. The multiple-phase coexistence and associated multicritical states of the spin-1 model appear in alloy language linked to previously unknown features such as first-order magnetic to paramagnetic transitions within chemically ordered phases, phase segregation among two magnetically ordered states, and first-order field-induced transitions. © 1989 The American Physical Society.
- Talanquer, V., Varea, C., & Robledo, A. (1989). Sublattice-ordered phases in a lattice model for a micellar solution. Physical Review B, 39(10), 7039-7044.More infoAbstract: We describe the mean-field global phase diagram for a Widom-type lattice mixture of bifunctional molecules ab and AA with general finite interactions. Our results follow from the known features of the phase diagrams along the symmetric sections of Griffithss three-component (spin-1) model when both uniform and sublattice-ordered states are considered. The properties of the mixture are analogous to those of a binary alloy with one magnetic component. We find first- and second-order transitions between uniform fluid states and five different types of ordered phases. © 1989 The American Physical Society.
- Talanquer, V., Varea, C., & Robledo, A. (1989). Sublattice-ordered phases of Griffiths's three-component model. Physical Review B, 39(10), 7016-7029.More infoAbstract: We describe the essential features of the mean-field phase diagram for the spin-1 Ising model with general nearest-neighbor interaction when sublattice ordering is made explicit. The phase diagram (in five-dimensional field space) can be classified into 84 zones where uniform with ordered phase coexistence is identified and multicritical behavior is determined. This generalized Ising model was studied extensively, in its ferromagnetic version, by Furman, Dattagupta, and Griffiths towards the end of the last decade. Here we complement that study with the antiferromagnetic phase behavior associated with the same model. Two different mappings between uniform and ordered phase existence conditions facilitated our task and indicated the interconnections that exist between ferromagnetic and antiferromagnetic properties in the model. Known features, like the shield region, appear reproduced in other energy-parameter locations, but also new features occur, such as additional tricritical and fourth-order critical lines connected by sixth-order critical points. © 1989 The American Physical Society.
- Talanquer, V. A. (2018, Fall). Reconceptualizing the Chemistry Curriculum to Foster Chemical Thinking. Faculty Seminar. Arizona State University.
- Talanquer, V. A. (2018, Spring). What does it take to develop Chemical Thinking?. Ragsdale Colloquium. University of Utah.
- Talanquer, V. A. (2018, Summer). Assessing for chemical thinking. IUPAC International Conference of Chemistry Education. Sydney, Australia: IUPAC.
- Talanquer, V. A. (2018, Summer). Understanding student reasoning to foster chemical thinking. Faculty Seminar. University of New South Wales.
- Talanquer, V. A. (2018, Summer). ¿Qué formas de pensamiento químico demanda el mundo actual? [What types of chemical thinking demands the modern world?]. Anniversary Educacion Quimica. Facultad de Quimica, UNAM. Mexico City.
- Talanquer, V. A. (2017, Fall). Chemical Thinking: A fresh look at the General Chemistry curriculum.. Faculty Seminar. Athens, GA: University of Georgia.
- Talanquer, V. A. (2017, Fall). Educar con Ambición. IV Congresso Internacional de Educação Científica e Tecnológica. Santo Angelo, Brazil: Universidade Regional Integrada do Alto Uriguai.
- Talanquer, V. A. (2017, Fall). Exploring and Promoting Chemical Thinking. Faculty Seminar. Stony Brook, NY: Stony Brook University.
- Talanquer, V. A. (2017, Spring). Exploring reasoning to construct thinking.. La Mattina Lecture Series. Durham, NH: University of New Hampshire.
- Talanquer, V. A. (2017, Spring). Exploring student reasoning to support better teaching.. Faculty Seminar. Ann Arbor,, MI: University of Michigan.
- Talanquer, V. A. (2017, Spring). Secuencias y progresiones de aprendizaje. XV Encuentro de Educación Química. Valparaiso, Chile: Pontificia Universidad Católica de Valparaíso.
- Talanquer, V. A. (2017, Spring). ¿Cómo se piensa en Química?. XV Encuentro de Educación Química. Valparaiso, Chile: Pontificia Universidad Católica de Valparaíso.
- Talanquer, V. A. (2016, April 14). Exploring student reasoning to support better teaching.. Invited Talk- University of Massachusetts-Armherst. University of Massachusetts-Armherst: University of Massachusetts-Armherst.
- Talanquer, V. A. (2016, December 7). Strategies and challenges in the development of chemical thinking.. Invited Talk-Purdue University. Department of Chemistry, Purdue University.
- Talanquer, V. A. (2016, February 9). Exploring mechanistic reasoning in chemistry.. Invited Talk- Michigan State University. Michigan State University: Michigan State University.
- Talanquer, V. A. (2016, June 2). ¿Porqué se nos complica la ciencia? [Why does science seems difficult?]. Invited Presentation, School of Chemistry, UNAM. Mexico. School of Chemistry, UNAM. Mexico: School of Chemistry, UNAM. Mexico.
- Talanquer, V. A. (2016, November 18). Exploring student reasoning to support better teaching. Invited Talk- Portland State University. Department of Chemistry, Portland State University: Portland State University.
- Talanquer, V. A. (2016, October 12). Tres elementos fundamentales en la formación de docentes de ciencias [Three core elements in science teacher preparation].. VII Congreso Internacional de Formación de Profesores de Ciencias (Colombia). Bogota, Colombia: Universidad Pedagogica Nacional de Colombia.
- Talanquer, V. A. (2016, September 29). ¿Qué formas de pensar debemos desarrollar en nuestros estudiantes de química? [What types of reasoning should we foster in the chemistry classroom?]. 51 Congreso Mexicano de Química (Mexican Chemical Society). Pachuca, Mexico: Pachuca Mexico.
- Talanquer, V. A. (2015, April). Let’s focus on chemical thinking. Invited Presentation UC-Davis. University of California-Davis: University of California-Davis.
- Talanquer, V. A. (2015, December). Exploring student reasoning to support better teaching. Invited plenary speaker at 42nd National Convention of the South African Chemical Institute. Durban, South Africa: South African Chemical Institute.
- Talanquer, V. A. (2015, October). Cómo piensan nuestros alumnos? [How do our students’ think?]. Invited plenary speaker at 50°Congreso Mexicano de Química. Queretaro, Mexico: Sociedad Quimica de Mexico.
- Blowers, P., Burd, G. D., Bolger, M. S., Johns, K. A., Lazos, L., Lysecky, R. L., Milsom, J. A., Novodvorsky, I., Pollard, J. R., Prather, E. E., Talanquer, V. A., Thamvichai, R., Tharp, H. S., Wallace, C. S., Cox, J., Elfring, L., Grubbs, E., & Hunter, J. (2014, Oct). Developing Faculty Cultures for Evidence-Based Teaching Practices in STEM: A Progress Report. Transforming Institution: 21st Century STEM Undergraduate Education Conference. Indianapolis, IN: AAU-STEM.
- Talanquer, V. (2014, March). Strategies for analyzing qualitative data with qualitative analysis software. Invited Presentation 247th ACS National MeetingDallas, TX.
- Talanquer, V. A. (2014, July). Exploring student reasoning in chemistry. Invited plenary speaker at European Conference on Research in Chemistry Education. University of Jyvaskyla, Findland: University of Jyvaskyla, Findland.
- Talanquer, V. A. (2014, March). Taking the lead in the preparation of prospective chemistry teachers. Invited Presentation President Session 247th ACS Meeting. Dallas, TX.
- Talanquer, V. A. (2014, May). How do our students think?. Invited Presentation at North Dakota State University. Fargo.
- Talanquer, V. A. (2014, November). Exploring student reasoning. Invited plenary speaker at International Science Education Conference.. Singapore: National Institute of Science Education..
- Talanquer, V. A. (2014, October). How do students think?. Invited Presentation Wake Forest University. Wake Forest University: Wake Forest University.
- Talanquer, V. A. (2013, June). Enseńanza de la Química [Teaching Chemistry]. Invited Presentation Seminario Internacional “La modificación curricular de la ENP, desafíos y perspectivas para la innovación educativa”. Mexico City, Mexico: Escuela Nacional Preparatoria, UNAM.More infoOther Information: Video Conference
- Talanquer, V. A. (2013, June). Exploring Changes in Students' Thinking about Central Ideas in Chemical Design. Invited Presentation Gordon Research Conference on Chemistry Education Research and Practice. Newport, RI: Salve Regina University.
- Talanquer, V. A. (2013, October). What do our students learn?. Invited Presentation at University of Wisconsin. Madison.
- Talanquer, V. A. (2013, September). Cómo piensan nuestros alumnos? [How do our students’ think?]. Invited Presentation VI Reunión de Educadores de Química en Argentina. Bahía Blanca, Argentina.
- Talanquer, V. A. (2012, February). Exploring how chemistry students’ think. Invited Presentation at University of Nebraska, LincolnDepartment of Chemistry. University of Nebraska, Lincoln.
- Talanquer, V. A. (2012, May). How do students reason about chemical substances and reactions?. Invited Presentation at University of Iowa.
- Talanquer, V. A. (2012, November). Enseńar Química: Lucha contra la intuición. [Teaching Chemistry: Fighting Intuition]. Invited Presentation Benemérita Universidad Autónoma de Puebla. Puebla, México.
- Talanquer, V. A. (2012, November). Let’s teach how we think instead of what we know. Invited Presentation 199th 2YC3 (Two-Year College Chemistry Consortium). Yuma, AZ: Arizona Western College.
- Talanquer, V. A. (2012, November). Pensando en Química [Thinking on Chemistry]. Invited Presentation 10th Biennial National Conference of Natural Science Teachers. Toluca, México.More infoDates: 03/30-04/02
- Prather, E. E., Wallace, C. S., Milsom, D., Johns, K., Manne, S., Tomanek, D., Novodvorsky, I., Burd, G. D., Elfring, L., & Talanquer, V. A. (2014, October/Fall). Active Learning Strategies that Promote Group Problem Solving and Increased Student Success in Large Enrollment Science Courses. University of Arizona Education Expo. University of Arizona.
- Pollard, J. R., & Talanquer, V. A. (2016, August). Chemical Thinking Workshop at the Biannual Conference on Chemical Education- University of Northern Colorado.