Active Discovery by Students in the General Chemistry Course

Exploring Quantum Concepts in Chemistry: Active Discovery by Students in the General Chemistry Course I. Rationale for the Project General chemistry is a core course for students considering careers in the natural sciences, engineering, medicine, or other technology fields. It is also a critical course for the preparation of an informed 21st Century citizenry to understand the public policy issues of the impact of technology upon society and the environment. The large number of students who take general chemistry makes the content of this course of great importance to the quality of undergraduate education nationally. The relevance and accessibility of the material in the general chemistry course affects many students’ career decisions. Our nation has an economic imperative to train workers for jobs in biotechnology, advanced medical care, the computer and electronics industries, and in the materials sciences. In general, there is a need to encourage students considering careers in the science and technology fields, and to support their mastery of new concepts in chemistry. We propose to develop a new approach to the quantum aspects of the general chemistry course taken by undergraduates majoring in the sciences at American colleges. This approach will emphasize the teaching of quantum concepts as the foundation of modern chemistry and science. It relies on three convergent streams of development in the sciences and education: (1) modern science and technology are becoming ever more reliant on our understanding of the quantum nature of matter; (2) educational research has provided us with new insights into how students develop the deep conceptual understanding necessary for the transfer of learning to new domains; and, (3) the interactive control of computer graphics provides for the exploration and visualization of quantum concepts. The first development provides the need and significance of the proposed project. The second provides the justification for the method of instruction and approach we propose. Finally, computer tools provide the vehicle for our project. Through prior projects and professional activities, the members of the proposed project team are Exploring Quantum Concepts in Chemistry: Project Narrative page 3 already an integrated unit. We have named an Advisory Board of nationally known and geographically distributed chemistry education experts to broaden the intellectual input to the project, as well as improve the visibility and eventual dissemination of our products. To ensure input from faculty at diverse institutions during the project development, we have arranged for consulting support from the New England Board of Higher Education. The proposed work is based on a study that involved the use of software tools specifically designed to enable students to explore visually the quantum aspects of atoms and molecules. These tools, developed for the National Science Foundation funded project Quantum Sciences Across Disciplines project (QSAD), provide a route to elucidation and exploration of quantum ideas that bypasses the barriers presented by traditional approaches based on detailed mathematical analysis. With these tools, quantum concepts emerge for the student in a descriptive language of shape, location, and color. Based on this prior experience, we propose to: · design and implement interactive software for instruction of quantum concepts at a level suitable for science concentrators in general chemistry courses; · design complementary laboratory experiments for testing of quantum concepts; · create and disseminate the supporting text for the materials to be learned, and an instructor’s manual documenting effective instructional strategies; · provide a test bed for the incorporation of new teaching strategies appropriate for medium and large size general chemistry courses using computer software; · begin to offer annual, self-sustaining workshops in the use of our materials for chemistry instructors from two-year and four-year institutions in the final year of the proposed work. 1. The Need to Introduce Quantum Concepts in Chemistry. The year 2000 marked the 100th anniversary of the quantum model. Quantum concepts now underpin our modern understanding of the universe and our ability to control nature for human needs. The crafts of modern chemistry, materials science, and electrical engineering rely on the manipulation of matter at the atomic and molecular level. This is fast becoming true of biology as well. The products are new technologies and experimental probes: new Exploring Quantum Concepts in Chemistry: Project Narrative page 4 polymeric materials, new ceramics, new electronics materials including LEDs and microelectronic circuits, new approaches to computation through electronics, coding, and information processing, and new spectroscopies. This ubiquitous use of the quantum model of matter throughout the sciences and technology will propel it to the center of 21st general chemistry courses. To this end, it is unnecessary to teach the mathematical aspects of quantum chemistry to freshman students. The concepts in the quantum model are few in number, but enormous in consequence. Quantized energy levels, spin, the geometry of electronic orbitals, and the Pauli Principle can all be understood qualitatively and descriptively, and then applied to chemical behavior, extending from the single atom, to small molecules, to polymers, and finally to the properties of materials. 2. Students learn best when provided with the opportunity for active exploration. For the past century quantum theory has been at the heart of modern chemistry just as chemistry is at the heart of materials science and medical research. Nevertheless, instruction at a level that deeply engages students in quantum ideas has been largely avoided in general chemistry due to the belief by instructors that the material is too mathematically abstruse. Our experience is that this barrier can be largely removed by using a discoverybased approach relying on interactive tools for the exploration and visualization of quantum behavior. Providing in-depth instruction through the use of a fundamental conceptual model is an approach supported by current research on the science of learning. The Committee on Learning Research and Educational Practice of the National Research Council writes “A key finding in the learning and transfer literature is that organizing information into a conceptual framework allows for greater ‘transfer’; that is, it allows the student to apply what was learned in new situations and to learn related information more quickly” (NRC, 1999). The NRC Committee further writes, “To develop competence in an area of inquiry, students must have opportunities to learn with understanding. Deep understanding of subject matter transforms factual information into usable knowledge.” Our hypothesis is that students provided with well-conceived instruction on the quantum model of chemical behavior will be able to understand better a wide range of chemical properties, spectroscopic Exploring Quantum Concepts in Chemistry: Project Narrative page 5 techniques, and the behavior of materials. 3. The authentic use of computers for general chemistry education. The use of computers for symbolic and virtual graphical representation is now ubiquitous in chemistry research. In a similar manner, we see computer graphics as essential to providing students insight into modern chemistry and science. We further believe that, properly used, computers can offer innovative solutions to the educational problem of how to teach effectively when the student-professor ratio is high. Problems that benefit from the authentic use of the power of software are ones that require individual interactive exploration of otherwise inaccessible concepts. For example, if merely displaying the electronic distribution associated with an atomic orbital were sufficient, then current texts would do an admirable job in teaching quantum concepts, since they all contain such pictures. In fact, these texts are not successful (Shiland, 1997) because students are not able to understand what is being represented. By contrast, the interactivity of properly designed computer software enables students to explore the meaning of what they are observing by varying controlling parameters. Research for the QSAD project in high schools demonstrated that, to successfully introduce a software-based approach to teaching quantum concepts, teachers had to modify their instructional approach to use the software effectively (Robblee et al, 2000). II. Project Objectives Our long-term goal is to devise new instructional techniques to provide general chemistry students with a better and deeper conceptual understanding of the physical world, an understanding that they can transfer to the study of other sciences and technologies, and the knowledge to make informed decisions as citizens. To support this, the scope of the proposed project is specified by our short-term objectives: Objective 1: Create an introduction to the quantum aspects of matter for general chemistry students. We propose to develop materials that, when distributed over the term, will occupy about half of a semester in a one-year general chemistry course. These materials will allow students to explore the basis of our modern understanding of atomic and molecular electronic structure, and then to learn how to use this understanding to explain the properties and dynamic behavior of materials. These behaviors include: the continuum of ionic, polar covalent, and covalent bonding; properties of acids and bases as determined Exploring Quantum Concepts in Chemistry: Project Narrative page 6 by charge distribution; electronegativity; redox reactions; organic synthesis, properties of organic macromolecules of biological interest such as proteins, carbohydrates, and nucleic acids; the properties of inorganic materials such as metals, plastics and ceramics; and the response of such materials to spectroscopic probing with electromagnetic fields. The planned curriculum materials may ultimately be used as a foundation for explaining the remaining topics in the general chemistry sequence. Objective 2: Create software for quantum instruction in general chemistry. Modern science relies heavily upon the use of computers for visual realizations of microscopic theories of physical behavior. From these graphical representations arise a descriptive approach with metaphors and similes to describe the atomic and molecular behaviors that give rise to macroscopically observable effects. This project will develop interactive computer software to provide general chemistry students with a visual and descriptive introduction to the different representations of our understanding of atomic and molecular structure. This software will be written in Java for cross-platform use, and be downloadable from the web. Objective 3: Create an instructional environment that supports a deep understanding of the properties of matter. Lecturing represents one end of a continuum of instructional strategies. It relies upon a transmission model for student learning: the instructor transmits, the student listens. At the other end of the spectrum, the student is the primary actor who discovers new truths with the assistance of a tutor. The reality of general chemistry instruction at major universities is that the student-professor ratio is too high, and the quantity of material too demanding, for the instructor to provide each student with individual attention. It is our intention to investigate intermediate instructional methods for science courses with large enrollments and to provide a model of how to shift instruction from transmission to personal construction through the use of software for computer-based explorations, peer group collaborative instruction, and assignments designed to stimulate student inquiry and discovery. Such a shift in instructional methods is coincident with our objective of teaching for deeper understanding of quantum behavior with the expectation of later transfer of understanding. For this purpose we plan to: (1) design activities and concept questions for students studying in groups in recitation or with trained peer leaders and, when this infeasible, for use in an interactive lecture format (Mazur, 1997); (2) design these activities around investigations of computer simulations of quantum behavior; Exploring Quantum Concepts in Chemistry: Project Narrative page 7 (3) coordinate laboratory experiments with study group assignments and computer explorations. Objective 4: Gather data on the effectiveness of our software and instructional methods for teaching students quantum concepts. In support of the above objectives, Professors Garik and Kelley, the project evaluator, with the assistance of a graduate student, will investigate carefully how students’ conceptions of quantum behavior are built, how students transfer these concepts to other topics in chemistry, and what the impact is of the novel instructional formats. An outcome of this process will be a Quantum Concept Inventory, akin to the Force Concept Inventory of misconceptions in mechanics (Hestenes, Wells & Swackhamer, 1992). This will serve as a guide for instructors engaged in modern science and technology education to assess their students’ backgrounds. Objective 5: Design materials for national use. We will design our materials and methods with the input of instructors of general chemistry at other institutions. We are especially interested in involving community college faculty. Through workshops with consulting professors during the first and second summers, and responding to their needs, we will prepare for national dissemination. Specifically to support this objective, we have designed our project to include (1) an Advisory Board of nationally recognized chemistry educators who are geographically distributed; and (2) enlisted the services of the New England Board of Higher Education to support our recruitment of instructors representing a spectrum of higher education institutions for our project. Finally, we will design a survey to be distributed to general chemistry instructors nationwide. This survey will be aimed at polling the instructors' attitudes towards quantum concepts in general chemistry. Objective 6: Design materials for web dissemination. To provide for the widest accessibility of our materials for both instructors and students, all materials will be designed for easy internet access and with the eventual goal of supporting distance learning. We will rely upon instructors/consultants invited to our summer workshops to provide us with feedback on the web presentation of our materials. Exploring Quantum Concepts in Chemistry: Project Narrative page 8 III. Project Significance 1. We are proposing to move the content and methods of instruction for general chemistry toward what the chemistry course of the year 2050 must look like by developing new methods of teaching quantum science concepts. 2. Our project instructional methods will be aimed at supporting in-depth inquiry by students enrolled in science courses of varying sizes, both large and small. 3. At the completion of the project we plan to have in place novel instructional materials and methods that can be used at other institutions. The instructional tools and supporting materials will be available over the web; the instructional methods will be disseminated through annual self-supporting workshops. The web site will be constructed to support and encourage use of our materials from a distance. IV. Background Software for a Descriptive Introduction to Electronic Structure This proposal is based on our prior project Quantum Science Across Disciplines (QSAD) funded by the National Science Foundation (NSF REC-9554198; 5/1/96 -- 4/30/99; 5/1/99 -- 4/30/01 no-cost extension) to investigate methods for teaching quantum science to high school and undergraduate students using interactive graphical computer software. Professors Garik (PI) and Dill (co-PI) collaborated on this project. At Boston University Professor Dill piloted lecture presentations and selected software with his students in the context of general chemistry, and Professor Garik used the software in his integrated sciences course for pre-service elementary school teachers. In high schools we investigated how teachers taught with our materials and what their students learned. The interactive Java software visualization tools we created bypass mathematical analysis to support real time interactivity with simulations designed for students to learn the basic concepts of energy levels, transitions between energy levels, the electron cloud model, the nature of molecular bonds, and the structure and charge distributions of important molecules. Multiple representations (2-d and 3-d) are offered to assist students’ understanding of scale and structure. With these tools, quantum concepts and electronic behavior emerge in a descriptive language of shape, location, and color. Graphics are Exploring Quantum Concepts in Chemistry: Project Narrative page 9 commercial quality. Examples are in the Appendix (also http://qsad.bu.edu). The QSAD Quantum Explorers (Atomic, Bond, Diatomic, Polyatomic, and Spectrum Explorers) are ready for use as a component of the proposed project. Currently the calculations are based on Extended Hückel molecular theory for computing molecular orbitals and Roothan-Hartree-Fock atomic orbitals for display purposes. These computations are fast and accurate enough to preserve the trends of the Periodic Table. The Quantum Science Across Disciplines project was a proof of concept that software for teaching quantum concepts to novices can be created. However, the QSAD software by itself lacks the structured environment and detailed supporting materials necessary to make it usable by a wide audience of students and instructors. The project proposed here is to extend in an informed manner the QSAD software through the development of instructional material and techniques appropriate for undergraduate education. In this process, some of the existing QSAD software will need to be modified or significantly extended in order for the materials to serve the foundational role envisioned. QSAD Lessons Relevant to this Proposal 1. We studied high school chemistry students in classes using the QSAD software, and compared them to students taught with a traditional approach. Concept maps were used to explore the students’ understanding. For our assessment, special attention was paid to student explanations of the relationships among eight concepts: bonding, color, electronic structure, energy, molecular geometry, periodic trends, polarity and solubility. The control and experimental groups showed marked increase in forming propositions in five areas: bonding to electronic structure, electronic structure to periodic trends, molecular geometry to polarity, polarity to solubility, and color to energy. However, the experimental classes improved their ability to explain the relationship between five additional pairs of chemical concepts including: bonding to energy, bonding to polarity, bonding to molecular geometry, and polarity to molecular geometry and solubility (Hurwitz, Abegg, Garik & Nasr, 2000). (2) We worked intensively with chemistry teachers (Robblee et al, 2000). We found that the greatest learning benefits occurred in classrooms where teachers fostered student inquiry using group investigations centered on the software. These teachers reported that their students offered new, more sophisticated explanations for single, double, and triple bonds after using the software; identified the Exploring Quantum Concepts in Chemistry: Project Narrative page 10 cause of electronegativity in terms of energy levels and ionization energies as opposed to arguing teleologically that electronegativity arises from how close the atom is to having a complete valence shell; and, discussed how bonding orbitals shield nuclei from repelling each other, while antibonding orbitals expose nuclei to each other and so are less energetically favorable for binding a molecule. The explanations students offered can be accounted for by the visual images of atoms and molecules, which the software provides. (3) We conducted in-depth pre- and post-interviews with high school students (Eshach & Garik, 2001, 2002a). These interviews provide us with insights necessary to assess baseline understanding and post-instruction learning for formative analysis of our proposed materials. From these interviews we constructed a detailed understanding of students' conceptual difficulties with quantum ideas. These range from their personal constructions of mental images intended to reconcile the model of the Bohr atom with an electron in orbit with the electron cloud model; to recurrent misconceptions held by students regarding the concepts of energy levels, unoccupied orbitals, and molecular bonds; and, deficits and misconceptions of prerequisite content such as Newton's Laws, electrostatic forces, and concepts of probability. We have further unpublished data from interviews with undergraduates. (4) We conducted interviews with experts in order to learn how they (practicing chemists and physicists) think about quantum phenomena (Eshach & Garik, 2002b). The rich set of analogies and metaphors that we documented, and their use of multiple models, has enriched our perspective on how to design curriculum materials. (5) We have assessed student understanding of quantum concepts, and related concepts, in the general chemistry course at Boston University. This past semester we administered pre- and postquestionnaires to all students taking the on-sequence general chemistry course for science concentrators. Students were queried on fundamental prerequisite concepts (wave, energy, and force concepts), information they may have brought from high school (meaning of quantum numbers; location of electron in hydrogen atom). The organization of the questionnaire was based on the work referred to above (Eshach & Garik, 2001), and instructors’ input. Because of the multi-instructor format of the general chemistry course, the outcome of this learning assessment is mixed, and provides a baseline, not an Exploring Quantum Concepts in Chemistry: Project Narrative page 11 evaluation of QSAD materials. (6) Professors Dill and Garik have piloted the QSAD materials at Boston University. Prior to the QSAD project, Professor Dill developed lecture notes, required for the course, on quantum concepts for use with the general chemistry class (Dill, 1998). With the QSAD software, Professor Dill has extended the range of this quantum instruction. Each of the last two years, he taught the students in his lecture section (about 250) how to sketch wave functions manually for an arbitrary potential by identifying the kinetic energy with the wave function’s curvature. Once students mastered the drawing of wave functions (which they did!), they used the Shooter, a QSAD applet designed by Prof. Dill, to solve the Schrödinger equation by varying the energy and observing whether the resulting curve matches the boundary conditions for the potential. This year Professor Hoffman and Mr. Crosby also used the Shooter for demonstration purposes in the honors chemistry course. Professor Garik teaches an integrated sciences course for pre-service elementary school teachers. These students use the QSAD software to investigate the geometry of atomic orbitals, covalent and ionic bonding, and spectroscopic transitions. (Students in this class were appalled to learn that the Bohr model did not describe chemical behavior and demanded to know why so much of their high school instruction and their college text dwelled on this model.) Linked to these software activities are spectroscopy labs. Related software materials: Software packages, like Spartan by Wavefunction, Inc., have been adapted for upper level college courses. The interfaces of these professional programs are not appropriate for introductory instruction. The NSF Visual Quantum Mechanics project at Kansas State University (Dean Zollman, PI) introduces physics students in college courses, and high school teachers and students, to quantum concepts. The project Practical Quantum Mechanics (E.F. Redish, PI, University of Maryland) is for engineering majors at the junior and senior level who have had a prior course in calculus-based physics. We have shared QSAD software with both groups. The difference between a physics and a general chemistry approach makes our efforts distinct. The Maryland group found the level of our materials inappropriate for upper division engineering students. Professor William Vining (University of Massachusetts, Amherst), who has had FIPSE and NSF support for his computer tutoring program for general chemistry, is interested in using our materials with his students (see letter of support). Exploring Quantum Concepts in Chemistry: Project Narrative page 12