«Scenes and Labs Supporting Online Chemistry David Yaron+, Karen L. Evans* and Michael Karabinos+ + Department of Chemistry, Carnegie Mellon ...»
Paper Presented at the 83rd Annual AERA National Conference, April 2003
Scenes and Labs Supporting Online Chemistry
David Yaron+, Karen L. Evans* and Michael Karabinos+
Department of Chemistry, Carnegie Mellon University
Learning Research and Development Center, University of Pittsburgh
Nature of introductory chemistry
This project is creating and disseminating online activities for introductory level chemistry
that are designed to support and integrate into traditional college chemistry courses. Such courses typically consist of a large lecture, regular homework (graded or ungraded), and weekly or biweekly hands-on laboratories. Our activities complement the current paper-andpencil homework by allowing students to engage in authentic [Chinn & Malhotra. 2002] chemistry activities, with the educational goals of increasing the cognitive flexibility with which new information is held, and supporting transfer of new information into a variety of distinct situations. These goals are met through simulations such as our virtual laboratory (http://ir.chem.cmu.edu/) that allow for varied practice to increase flexibility, and through scenario-based activities that make the applicability of the knowledge explicit and provide incontext learning [Yaron et al, 2001a].
Chemistry is a central science. It plays a crucial role in most aspects of modern science and technology, from biotechnology to the creation of new materials and medicines. Because much of the excitement of modern chemistry is how it brings deeper insight and power to bear on issues in the environment, medicine, forensics, and space sciences, it is reasonable to expect additional motivational benefits from scenarios that highlight this broad applicability.
Learning challenges and interventions Learning challenges Given that chemistry concepts are
and initially are difficult to attach to real world experience, high school and college chemistry courses have evolved a standard set of paperand-pencil manipulations (dimensional analysis, balancing equations, stoichiometry, and Lewis dot structures) canonized in the exercises of textbooks. Traditional high school chemistry courses emphasize development of these notational tools as a basis from which the ‘real stuff’ can be approached. However, these tools are taught in the absence of activities Scenes and labs supporting online chemistry 1 of 12 Paper Presented at the 83rd Annual AERA National Conference, April 2003 that show their underlying utility. While these tools might be considered the underlying procedural knowledge base, they become inert bits of knowledge that are extremely difficult for students to access. The difficulty in applying these procedures occurs at two levels. One is within the formal chemical domain, where it is often difficult to connect a paper-and-pencil procedure to an actual chemical process (use in chemistry). The other level is the application of a procedure to complex real settings (transfer to the real world). More fundamentally, the traditional educational approach strips out the very essence of science–that of inquiry–and leaves behind a confusing bag of tricks. The following two sections discuss the interventions we are developing to address these challenges.
Figure 1: The virtual lab (http://ir.chem.cmu.edu/) provides a flexible learning enviromment in which students can design and perform their own experiments. The panel on the right shows multiple representations of the contents of a solution, which would not be possible in a physical lab.
Use in chemistry: The Virtual Lab
Our virtual lab is aimed at supporting ways in which students can see “use in chemistry”.
This learning challenge is similar to that observed in physics education, where the mathematical problem solving emphasized in traditional courses has been shown to convey little conceptual understanding [Hestenes, 1992; Pushkin, 1998]. The conceptual physics movement has achieved significant improvements in students' conceptual understanding by Scenes and labs supporting online chemistry 2 of 12 Paper Presented at the 83rd Annual AERA National Conference, April 2003 complementing traditional mathematical problem solving, such as using Kirchoff's laws to calculate properties of electronic circuits, with activities that emphasize conceptual problem solving, such as predicting the relative brightness of light bulbs arranged in various configurations [McDermott et al, 2000]. Most traditional chemistry courses continue to focus on mathematical problem solving and could likely benefit from a shift to conceptual teaching.
However, construction of conceptual problem solving activities for chemistry is as challenging as that faced by physicists due to the abstract nature of chemistry and its occurrence at multiple time and length scales.
Our virtual lab supports conceptual instruction by providing a set of manipulatives that enable a new type of interaction with chemical phenomena [Yaron et al, 2000]. Students can design and quickly carry out their own experiments, and see representations of the chemistry that go well beyond that possible in a physical lab. When instructors replace some of the existing end of chapter exercises with virtual lab experiences, the virtual lab provides additional representations to serve as a bridge between the traditional paper-and-pencil activities from the textbook and actual chemical phenomena. Note that the goal of the virtual lab is not to replace the physical laboratory. Rather, it is to help students connect their paperand-pencil work to actual chemical phenomena by enabling varied practice that promotes flexibility and making such connections more explicit and increasing applicability.
Classroom observations, involving 30-35 students working alone or as pairs solving virtual lab problems, have been used to gain insight into student interactions with various types of activities in the virtual lab. These observations have informed the design of our activities and allowed us to formulate targets to be addressed by more controlled experiments. Students at both the high school and college level take about 5 minutes to become sufficiently familiar with the user interface that their focus shifts to acheiving the chemistry goals set forth by the assignment.
Converting a traditional problem solving activity to a virtual lab activity on the same concept often reveals something interesting about student difficulties. Consider, for instance, the traditional problem, “When 10ml of 1M A was mixed with 10ml of 1M B, the temperature went up by 10 degrees. What is the heat of the reaction between A and B?” Many students who are proficient in such calculations are still unable to design a virtual lab experiment in response to the prompt “Construct an experiment to measure the heat of reaction between A and B?”. This student difficulty reveals that the traditional problem fails to place this procedure in a context that conveys its utility. So although students can perform the
procedure, this procedure is not activated in response to appropriate prompts. Since the virtual lab supports experimental design activities, it enables a type of practice that may reinforce activation of such procedural knowledge.
Observation of students interacting with challenge problems has also revealed unanticipated errors, and these errors may form the basis for instructional design. For instance, students were given solutions of four chemicals (A, B, C, and D) and asked to design and perform experiments to determine the reaction between them (i.e. A + 2B -- 3C + D). The intent was to give practice in determining the stoichiometric coefficients (1, 2, 3, and 1 for the example reaction). However, almost all students mis-interpreted the results of their experiments in a way that revealed a fundamental misunderstanding of the limiting reagent concept. (When they mixed A with B, they found that A remained in the solution. From this, they concluded that A must be a product and wrote the reaction as A + B -- C + D + A. In actuality, A remains in solution not because it is a product, but because it is an excess reagent.) Such errors provide a basis for an elicit-confront-resolve educational strategy [McDermott, 2000], in which an incorrect prediction is elicited from the student, confronted by pointing out its logical inconsistency and then resolved with the goal of giving the student a deeper conceptual understanding.
Observations of, and artifacts from, students performing challenge problems have also revealed that many students are able to develop sophisticated problem solving strategies, beyond the level the instructors anticipated based on these students algebraic problem solving skills. For instance, when posed with a complex problem involving multiple interacting chemical equilibria (a weak acid dye binding to DNA), half of the students discovered that the phenomena was pH dependent, realized it could be controlled by a buffer, and then designed an acid-base titration that would allow them to determine the appropriate buffer without doing explicit calculations. This approach clearly demonstrates a deep conceptual understanding of acid-base chemistry and highlights the potential of the virtual lab to support and assess conceptual learning.
The University of British Columbia has compared our virtual lab, which provides a flexible and open-ended learning environment, to a more constrained virtual lab [Jones and Tasker, 2001], in which students are offered more limited choices. Both were used as pre-lab exercises to prepare students for a physical laboratory experiment. Their informal observations suggested that students who use our more flexible virtual lab were better prepared for the physical laboratory [Nussbaum 2002].
Transfer to the real world: Scenario based activities The second learning challenge mentioned above is helping students understand the applicability of their knowledge to a real world setting. Our instructional approach here is to embed the procedural knowledge in a scenario that highlights its utility.
Our design of scenarios was and will be guided by the concept map of Figure 2. This map was developed jointly by research professors in chemistry (first author) and in education, an instructional designer (third author), and a high school chemistry teacher (second author).
The design of such a map was motivated by the sense that part of the difficulty in learning chemistry stems from the bottom up organization of chemistry content that has become reified in the curricular cannon. The design process was based on review of recent chemical research, chemistry articles from the New York Times and Scientific American News Scan columns, National Science Education Standards for Chemistry, and various chemistry textbooks. The design process was recursive and the product is dynamic since it can be revised in response to future changes in the domain. A more detailed account is presented at this conference by the second author (session 31.032, Science Learning and Instruction New Member Poster Session Hyatt Exhibityion Hall)
The top of the concept map presents the three subdomains that comprise modern chemistry:
explaining phenomena, analyzing substances to determine their chemical makeup, and synthesizing new types of chemical substances. Underlying these three subdomains is the Toolbox, a collection of procedures and models that are applied selectively as needed to develop explanations, conduct analyses, or direct syntheses.
While articles from the scientific press and Nobel Laureates’ prize work in chemistry for the past 50 years were nearly equally distributed among the three subdomains, the content standards and textbooks focused almost exclusively on the Toolbox and the Explain subdomain. This reveals a substantial disconnect between what is taught and what the field actually encompasses. Because the Toolbox underlies the subdomains of chemistry, educators have tried to build a solid base; but chemists work through a particular subdomain by linking the demands of the problem at hand to the appropriate tools needed for execution of a solution. Use of a particular tool is embedded within the context of the problem itself. When instruction focuses exclusively on the Toolbox, learning will be disconnected from
intellectual and practical use. We know that such inert knowledge will rarely be available or usable, let alone memorable. The goal of our scenarios is to move toward authentic chemistry activities that mirror the work of those in the discipline. Scenarios allow us to place the skills of the traditional course in appropriate contexts. Gradual incorporation of such materials in a course creates a smooth pathway to educational reform.
Our CreateStudio tools enable instructors to modify and create scenario-based learning activities by combining the virtual laboratory and other simulation and visualization tools with multimedia [Yaron et al., 2001b, Yaron et al 2002]. A powerful approach is to use CreateStudio's multimedia components to create virtual worlds that students explore to collect samples for analysis in the virtual lab. For instance, a hot spot can be placed on an image that, when clicked, causes a solution to appear in the virtual lab.
Although the structure of many courses assumes otherwise, we believe that students can reap the benefits of working on real-world, contextualized applications before they master most of the basic notational procedures, in part through the use of simulations. In the absence of technology, paper-and-pencil problems involving real-world phenomena – not just cover stories – can lead to assignments that are interesting, but overly complex or too demanding on working memory for students [Sweller, 1988; Kotovsky, Hayes and Simon, 1985]. By offloading some tasks to the computer, we enable students to focus on the issue of current pedagogical interest. This approach is used in our Mixed Reception activity, to allow students to use concepts covered in the first few weeks of a high school course to solve a murder mystery. In our Mission Critical Chemistry activity, students use simulations to calculate rocket trajectories, such that they can focus on development of new fuels for a mission to Mars.