Many calls to improve science education in college and university settings have focused on improving instructor pedagogy. Meanwhile, science education at the K-12 level is undergoing significant changes as a result of the emphasis on scientific and engineering practices, crosscutting concepts, and disciplinary core ideas. This framework of “three-dimensional learning” is based on the literature about how people learn science and how we can help students put their knowledge to use. Recently, similar changes are underway in higher education by incorporating three-dimensional learning into college science courses. As these transformations move forward, it will become important to assess three-dimensional learning both to align assessments with the learning environment, and to assess the extent of the transformations. In this paper we introduce the Three-Dimensional Learning Assessment Protocol (3D-LAP), which is designed to characterize and support the development of assessment tasks in biology, chemistry, and physics that align with transformation efforts. We describe the development process used by our interdisciplinary team, discuss the validity and reliability of the protocol, and provide evidence that the protocol can distinguish between assessments that have the potential to elicit evidence of three-dimensional learning and those that do not.

Acid−base chemistry is central to a wide range of reactions. If students are able to understand how and why acid− base reactions occur, it should provide a basis for reasoning about a host of other reactions. Here, we report the development of a method to characterize student reasoning about acid−base reactions based on their description of what happens during the reaction, how it happens, and why it happens. We show that we can reliably place student responses into categories that reflect the model of acid−base reactivity used and whether the students invoke an electrostatic causal argument. However, the quality of student responses is highly dependent on the structure of the task prompt, which must be structured to provide students with enough information for them to understand what is needed. In general, students who construct responses that invoke a causal mechanistic Lewis model are more likely to draw appropriate curved arrow reaction mechanisms.

Because Lewis structures provide a direct connection between molecular structure and properties, the ability to construct and use them is an integral component of many chemistry courses. Although a great deal of time and effort has been dedicated to development of “foolproof” rules, students still have problems with the skill. What is more, many students fail to connect the skill with the reasons for learning it. In fact, it appears that conventional instructional practices involved in teaching Lewis structures are in direct conflict with much of what we know about how people learn. In support of this assertion, we present the results of a mixed-methods study designed to investigate how students at all levels draw Lewis structures, and how students perceive the utility of Lewis structures. We offer suggestions for alternative methods of developing this skill in order to provide students with an approach to meaningful learning.

The connection between the molecular-level structure of a substance and its macroscopic properties is a fundamental concept in chemistry. Students in college-level general and organic chemistry courses were interviewed to investigate how they used structure-property relationships to predict properties such as melting and boiling points. Although student difficulties in this area are well documented, they are usually classified as individual misconceptions. However our studies showed that student problems appear to arise from a complex interplay of problems involving a number of different sources: (1) models of phases/ phase change, (2) use of representations, (3) language and terminology, and (4) use of heuristics in student reasoning. No two students used the same sets of ideas to perform the task at hand, and while we did see some recurrences of a single idea or heuristic, the ways that students combined them were different. We believe that, at least for high-level complex tasks such as determining structure-property relationships, student understanding is best understood as a set of loosely connected ideas, skills, and heuristics that are not well integrated. These are not single "misconceptions" that can be reconstructed in isolation. What is clear is that students who have done everything we ask of them, and who have earned high grades in chemistry courses are unable to address a core concept in chemistry. Typical assessments often mask the difficulties that students have with core concepts, since many students may correctly answer a question using heuristics, but have faulty reasoning. We recommend that instruction should include a scaffolded progression of ideas, and opportunities to construct and connect their understanding that will allow students to construct a more coherent framework from which to make predictions about the behavior of matter. # 2013 Wiley Periodicals, Inc. J Res Sci Teach 50: 2013

The ability to use representations of molecular structure to predict the macroscopic properties of a substance is central to the development of a robust understanding of chemistry. Intermolecular forces (IMFs) play an important role in this process because they provide a mechanism for how and why molecules interact. In this study, we investigate student thinking about IMFs (that is, hydrogen bonding, dipole–dipole interactions, and London dispersion forces) by asking general chemistry college students to both describe their understanding in writing and to draw representations of IMFs. Analysis of student drawings shows that most students in our study did not have a stable, coherent understanding of IMFs as interactions between molecules. At least 55% of the students in our study unambiguously represented each IMF an interaction or bond within a single molecule , while only 10–30% of students represented each IMF as an interaction between molecules. Furthermore, the majority of students (59%) were not consistent in the way that they represented the different IMFs (as within or between). That is, their representations varied depending on the IMF. Student written descriptions of intermolecular forces were typically quite ambiguous, meaning that it was not possible to determine from the student description alone whether the student understood IMFs as bonds or interactions. It was only when the student’s representation was consulted that we could determine whether a particular student had an appropriate understanding of IMFs. We believe that in situations where spatial information is crucial, free-form drawn representations are more likely to provide meaningful insight into student thinking.

The study presented here is a follow-up to a previous report in which we investigated how general-chemistry students in a transformed curriculum reason about simple acid–base reactions. In the present study, we use and adapt the previously developed coding scheme for a longitudinal study in which we follow students from general chemistry through organic chemistry. We find that (i) generally, the manner in which students reason about acid–base reactions increases in sophistication over the course of a two-semester sequence of organic chemistry; (ii) there is little difference in reasoning between students at the end of a transformed general-chemistry course and a similar cohort at the beginning of organic chemistry; (iii) the nature of a student’s general-chemistry experience has a profound effect on the sophistication of their reasoning in that students from a transformed general-chemistry course are more likely to provide causal mechanistic explanations for simple acid–base reactions than students with other general-chemistry experiences; and (iv) the type of acid–base reaction that the students discuss impacts the type of reasoning they exhibit. We find that when asked to explain a Lewis acid–base reaction, students are less likely to invoke electrostatic ideas.

Previously, we found that: (i) many students were unable to construct representations of simple molecular structures; (ii) a majority of students fail to make the important connection between these representations and macroscopic properties of the material; and (iii) they were unable to decode the information contained in such representations. Assuming that lack of an understanding of the purpose of such representations inhibited students’ meaningful learning, we have worked to address this “representation problem” explicitly in the context of a novel introductory general chemistry curriculum: Chemistry, Life, the Universe, and Everything (CLUE). CLUE includes a learning progression to help students master the relationships between molecular structure and bulk properties. Two methods were used to assess student learning: OrganicPad, a tablet-PC program that can recognize, record, and grade student free-form naturalistic structure drawings; and the Implicit Information from Lewis Structures Instrument (IILSI), a validated survey that asks students to identify the kinds of information they believe can be deduced from Lewis structures. A comparison of two statistically equivalent cohorts of students revealed that CLUE students show marked improvements (effect size, r = 0.6), over control students in their ability to construct structures. CLUE students were also significantly better at decoding the information that these structures contain. We present evidence that the improvements observed are due to the design and implementation of the specific learning progression rather than instructor effects.

In this paper we discuss how and why core ideas can serve as the framework upon which chemistry curricula and assessment items are developed. While there are a number of projects that have specified "big ideas" or "anchoring concepts", the ways that these ideas are subsequently developed may inadvertently lead to fragmentation of knowledge, rather than construction of a coherent, contextualized framework. We present four core ideas that emerged as a consequence of a transformation effort at our institution and discuss the relationships between core ideas and more recognizable topics in the context of a general chemistry course. We show how commonly taught topics can be supported and developed on the basis of the core ideas and discuss why this approach can lead to a more expertlike framework upon which students can build their future understanding.