Analyzing difficulties with mole-concept tasks by using familiar analog tasks

This study was conducted to determine which skills and concepts students have that are prerequisites for solving moles problems through the use of analog tasks. Two analogous tests with four forms of each were prepared that corresponded to a conventional moles test. The analogs used were oranges and granules of sugar. Slight variations between test items on various forms permitted comparisons that would indicate specific conceptual and mathematical difficulties that students might have in solving moles problems. Different forms of the two tests were randomly assigned to 332 high school chemistry students of five teachers in four schools in central Indiana. Comparisons of total test score, subtest scores, and the number of students answering an item correctly using appropriate t-test and chi square tests resulted in the following conclusions: (1) the size of the object makes no difference in the problem difficulty; (2) students understand the concepts of mass, volume, and particles equally well; (3) problems requiring two steps are harder than those requiring one step; (4) problems involving scientific notation are more difficult than those that do not; (5) problems involving the multiplication concept are easier than those involving the division concept; (6) problems involving the collective word “bag” are easier to solve than those using the word “billion”; (7) the use of the word “a(n)” makes the problem more difficult than using the number “1”.     

Attention to novel objects during verb learning

Three experiments provided evidence that 3.5- to 4-year-old English-speaking children (N = 72) attend to the appearances of novel objects, not only when they hear a novel noun, but also when they hear a novel verb. Children learning nouns in the context of novel, moving objects attended exclusively to the appearances of objects, even though nouns were also related to the motions of those objects. Children learning verbs attended equally to the appearances of objects and their motions. The latter result contrasted with the results from adults (N = 20), who focused more strongly on motions than on the appearances of objects when learning verbs. When familiar objects were instead employed, child verb learners attended more to motions than to the appearances of objects. Children may attend to novel objects during verb learning because knowledge of an object may be prerequisite to understanding what a verb means in the context of that object.     

A comparison of department chair tasks in Australia and the United States

Virtually every managerial book written lists and expounds upon the tasks, duties, roles and responsibilities of administrators. This paper reports a portion of the findings of the third phase of a study of Australian and U.S. academic department chairs in colleges and universities. In it, we seek to clarify how chairs in the two countries define the tasks that exemplify their role as chair. The driving question behind this inquiry is: Do academic department chairs, independent of country, define their tasks in the same way? And, if so, how might universities in both countries benefit from this knowledge?     

Visualizing spatial tasks: A comparison of computer graphic and full-band video displays

Three spatial tasks were created in two forms, as video and as computer graphics. Both forms of each task were presented to third graders, middle schoolers, and adults preferred working with the video but were more accurate working with computer graphics. Third graders preferred the computer but were equally successful working with both displays. The study suggests that the expectations with which students approach an instructional technology may determine the effectiveness of that technology more than characteristics of the technology in question.     

Cognitive support for learning computer-based tasks using animated demonstration

This study investigated the influence of cognitive support for learning computer-based tasks using animated demonstration (AD) on instructional efficiency. Cognitive support included (1) segmentation and learner control introducing interactive devices that allow content sequencing through a navigational menu, and content pacing through stop and play buttons along with a slide bar for fast forward and rewind; (2) presentation modality and (3) a hybrid approach using a combined format of ADs with static graphics. Instructional efficiency was a combined effect of time-on-task during the learning phase and test performance. Time-on-task was included as a measurement to determine whether this would provide an alternative explanation for the benefits of learner control. Three learner-paced conditions with different types of cognitive support were developed, whereas a system-paced format, created without additional cognitive support, was used as a control condition. The learning task of this study was using graphic vector-based software Bezier tools to trace a cartoon. The results tended to suggest that the combination of different types of cognitive support (i.e. presenting the accompanying explanations as written captions to the learner-paced AD in visual-only instruction or combining learner-paced AD with static graphics in dual-modality instruction) had a positive effect, while learner pacing alone had not a significant positive effect.     

用Excel绘制常微分方程的分支图

用Excel2003绘制了常微分方程Hopf分支,Poincare分支,多重闭轨的分支以及同宿轨线的分支结构图。     

Predicting performance on academic and non-academic tasks: A comparison of adolescents with and without learning disabilities

Previous research suggests that adolescents with learning disabilities (LD) are less accurate in predicting academic performance than normally achieving (NA) adolescents and display a tendency to overestimate their level of performance (e.g., Klassen, 2007). However, no studies have been conducted investigating whether this overestimation is specific to academic contexts or a phenomenon that extends across domains. Ninety-four adolescents (46 LD, 48 NA) predicted their performance on a spelling task and on a ball-throwing task. Results revealed group differences in performance calibration across domains with adolescents with LD showing an overestimation of ability on the spelling and ball-throwing tasks, and NA adolescents demonstrating more precise self-appraisals. Additionally, the accuracy of non-academic performance predictions remained stable with increasing difficulty in the NA group whereas the adolescents with LD demonstrated a decrease in accurate performance prediction as the difficulty level increased.     

An experimental comparison of urban children with suburban children on eight tasks of basic skills

About 1500 children from an inner city school district and a suburban school district were asked to perform eight tasks of basic skills. There were differences in the performances of the children. The differences depended upon the socio-economic background of the children. On many of the skills, third grade urban children were similar to first grade suburban children. It is for this reason that the inner city children in this study were considered disadvantaged and a program of skill development has begun. Inner city children must have experiences that will help them acquire the skills that suburban children have acquired before entering school.     

The effects of preferred representations on some tasks using solid geometrical figures

Privileged (typical, basic-level) representations are cognitive representations in which figurative features play a significant part. We specifically consider studies on the conventional point of view in object perception (Palmer, Rosch, & Chase, 1981). We propose an analysis of solid geometrical problems in the field of typicality theory and more generally in the theoretical field of mental models. Applied to this geometrical domain, the analysis suggests that individual cognitive representations — corresponding with different points of view from which a figure can be seen — are more or less representative examples of the category, that is to say they correspond more or less with the mental model built by the subject in this domain. Task 1 emphasizes the most representative point of view for four solid geometrical figures chosen by the experimenter. Then, we analyse two tasks on each figure from both the typical and non typical points of view. Errors occur most frequently when the geometrical figure is seen from its non typical viewpoints. Particular attention should be paid to this factor in analysing errors made by subjects.     

Conceptualizing teachers' understanding of students' mathematical learning by using assessment tasks*

The study was designed to support teachers on conceptualizing their understanding of students' learning by the use of assessment tasks. A school-based assessment team consisting of the researcher and four third-grade teachers teaching in the same school was set up as a learning context of supporting teachers in developing assessment tasks integral to instruction. The assessment tasks along with students' responses to the task, classroom observations, interviews, routine weekly meetings, teachers' weekly reflective journals, and students' responses to the assessment tasks were the data collected in the study. The teachers' views of using assessment tasks and the generation of assessment tasks were developed in the course of the study. In the process of generating assessment tasks, teachers improved their awareness of students' various solutions and learning difficulties to a specific problem, their awareness of the importance of developing students' critical thinking, and their awareness of where students need to make a remedial instruction. The research reported in the paper was supported by the National Science Council of Taiwan under Grant NSC 90-2521-S134-003-. The opinions expressed in this paper are those of the author and do not necessarily reflect the view of funding agency.     

Developing teacher knowledge using a tool for creating tasks for the classroom

In this paper we illustrate the use of a tool from a teaching programme with one year graduate students. This tool is designed to help them to develop tasks for the classroom. It is described in its three stages, for analysing mathematics, for connecting the curriculum, and for informing in-the-moment shifts. We finally discuss the role of tools in developing a pedagogy for teacher education.     

凡人与大师

凡人对大师说:"我像你一样勤奋努力,也像你一样执著追求,然而我依然是个凡人,而你却成了大师,这是为什么?"大师没有正面回答,而是给他出了一个题目:"假如现在横亘在你我之间是一条河流,你怎样跨越?"     

Context effect in some tasks of comparison of pictures in primary school. Two empirical illustrations

Many works have shown that a child, having to solve a problem, deals with the task according to the significations he gives to the problem-space he is facing and to the social space in which the task is inscribed. This article presents two experimentations dealing more particularly with the social space of solution of a classical task of comparison of identical pictures for which the experimenter asks for a judgement. They show how the introduction of slight contextual changes facilitates the variety of answers produced by 4–5 year-olds and 5–6 year-olds children, and consequently the production of answers centered on the relation of identity between the pictures.     

Confronting prospective teachers' ideas of evolution and scientific inquiry using technology and inquiry‐based tasks

This study addresses the need for research in three areas: (1) teachers' understandings of scientific inquiry; (2) conceptual understandings of evolutionary processes; and (3) technology‐enhanced instruction using an inquiry approach. The purpose of this study was to determine in what ways The Galapagos Finches software–based materials created a context for learning and teaching about the nature of scientific knowledge and evolutionary concepts. The research used a design experiment in which researchers significantly modified a secondary science methods course. The multiple data sources included: audiotaped conversations of two focus pairs of participants as they interacted with the software; written pre‐ and posttests on concepts of natural selection of the 21 prospective teachers; written pre‐ and posttests on views of the nature of science; three e‐mail journal questions; and videotaped class discussions. Findings indicate that prospective teachers initially demonstrated alternative understandings of evolutionary concepts; there were uninformed understandings of the nature of scientific inquiry; there was little correlation between understandings and disciplines; and even the prospective teachers with research experience failed to understand the diverse methods used by scientists. Following the module there was evidence of enhanced understandings through metacognition, and the potential for interactive software to provide promising context for enhancing content understandings. © 2005 Wiley Periodicals, Inc.