Posing questions about an article might improve one's knowledge-a cognitive function, or monitor one's thought processes-a metacognitive function. This study focuses on guided question posing while using a metacognitive strategy by 12th grade honors chemistry students. We investigated the ways by which the metacognitive strategy affected students' skills to pose complex questions and to analyze them according to a specially designed taxonomy. Our learning unit, Case-based computerized laboratories, emphasizes learning through chemical case studies, accompanied by tasks, that call for posing questions to which the answer cannot be found in the text. Teachers equipped their students with a metacognitive strategy for assessing the quality of their own questions and characterizing them according to a three-component taxonomy: content, thinking level, and chemistry understanding levels. The participants were 793 experimental and 138 comparison chemistry students. Research instruments included interviews and case-basedquestionnaires. Interviews with students revealed that using the metacognitive strategy the students had been taught, they were capable of analyzing the questions they generated with the taxonomy. The questionnaires showed that students significantly improved their question posing skill, as well as the complexity level of the questions they posed. A significant difference was found in favor of the experimental group students. Stimulating students to generate complex questions with a metacognitive strategy in mind enabled them to be aware of their own cognitive process and to self-regulate it with respect to the learning task.

A new learning unit in chemistry, Case-based Computerized Laboratories (CCL) and Computerized Molecular Modeling (CMM) was developed at the Technion. The CCL and CMM curriculum integrates computerized hands on experiments and molecular modeling with an emphasis on scientific inquiry and case studies. Our research aimed at investigating the effect of the CCL and CMM learning environment on students' higherorder thinking skills of question posing, inquiry, and modeling. The experimental group included 614 honors 12th grade chemistry students from high schools in Israel who studied according to this learning unit. The comparison group consisted of 155 12th grade chemistry honors students who studied other chemistry programs. Pre-and post-tests questionnaires were used to assess students' higher-order thinking skills. Students' responses were analyzed using content analysis rubrics and their statistical analysis. Our findings indicated that the scores of the experimental group students improved significantly in question posing, inquiry and modeling skills from the pre-test to the post-test. The net gain scores of the experimental group students were significantly higher than those of their comparison peers in all three examined skills. In modeling skills, experimental group students significantly improved their achievements in making the transfer from 3D models to structural formulae, but only about half of them were able to transfer from formulae to 3D models. By presenting a case-based chemistry assessment tool and content analysis of students' responses in this paper, we enable teachers and educators to analyze their students' higherorder thinking skills both qualitatively and quantitatively.

No abstract

No abstract

Much knowledge in chemistry exists at a molecular level, inaccessible to direct perception. Chemistry instruction should therefore include multiple visual representations, such as molecular models and symbols. This study describes the implementation and assessment of a learning unit designed for 12th grade chemistry honors students. The organic chemistry part of the unit was taught in a Computerized Molecular Modeling (CMM) learning environment, where students explored daily life organic molecules through assignments and two CMM software packages. The research objective was to investigate the effect of the CMM learning unit on students' modeling skill and sub-skills, including (a) drawing and transferring between a molecular formula, a structural formula, and a model, and (b) transferring between symbols/models and microscopic, macroscopic, and process chemistry understanding levels. About 600 12th grade chemistry students who studied the CMM unit responded to a reflection questionnaire, and were assessed for their modeling skill and sub-skills via pre-and post-case-based questionnaires. Students indicated that the CMM environment contributed to their understanding of the four chemistry understanding levels and the links among them. Students significantly improved their scores in the five modeling sub-skills. As the complexity of the modeling assignments increased, the number of students who responded correctly and fully decreased. We present a hierarchy of modeling sub-skills, starting with understanding symbols and molecular structures, and ending with mastering the four chemistry understanding levels. We recommend that chemical educators use case-based tools to assess their students' modeling skill and validate the initial hierarchy with a different set of questions.