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Genetics is the cornerstone of modern biology and understanding genetics is a critical aspect of scientific literacy. Research has shown, however, that many high school graduates lack fundamental understandings in genetics necessary to make informed decisions or to participate in public debates over emerging technologies in molecular genetics. Currently, much of genetics instruction occurs at the high school level. However, recent policy reports suggest that we may need to begin introducing aspects of core concepts in earlier grades and to successively develop students’ understandings of these concepts in subsequent grades. Given the paucity of research about genetics learning at the middle school level, we know very little about what students in earlier grades are capable of reasoning about in this domain. In this paper, we discuss a research study aimed at fostering deeper understandings of molecular genetics at the middle school level. As part of the research we designed a two-week model-based inquiry unit implemented in two 7th grade classrooms (N = 135). We describe our instructional design and report results based on analysis of pre/post assessments and written artifacts of the unit. Our findings suggest that middle school students can develop: (a) a view of genes as productive instructions for proteins, (b) an understanding of the role of proteins in mediating genetic effects, and (c) can use this knowledge to reason about a novel genetic phenomena. However, there were significant differences in the learning gains in both classrooms and we provide speculative explanations of what may have caused these differences.  相似文献   

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This study examined engineering and physical science students' understanding of the electromagnetic induction (EMI) phenomena. It is assumed that significant knowledge of the EMI theory is a basic prerequisite when students have to think about electromagnetic phenomena. To analyse students' conceptions, we have taken into account the fact that individuals build mental representations to help them understand how a physical system works. Individuals use these representations to explain reality, depending on the context and the contents involved. Therefore, we have designed a questionnaire with an emphasis on explanations and an interview, so as to analyse students' reasoning. We found that most of the students failed to distinguish between macroscopic levels described in terms of fields and microscopic levels described in terms of the actions of fields. It is concluded that although the questionnaire and interviews involved a limited range of phenomena, the identified explanations fall into three main categories that can provide information for curriculum development by identifying the strengths and weaknesses of students' conceptions.  相似文献   

4.
In recent years, science education has placed increasing importance on learners' mastery of scientific reasoning. This growing emphasis presents a challenge for both developers and users of assessments. We report on our effort around the conceptualization, development, and testing the validity of an assessment of students' ability to reason around physical dynamic models in Earth Science. Building from the research literature on analogical mapping and informed by the current perspectives on learning progressions, we present a three‐tiered construct describing the increasing sophistication of students' analogical reasoning around the correspondences and non‐correspondences between models and the Earth System: at the level of entities (Level 1), configurations in space or relative motion of entities (Level 2), and the mechanism or cause for observed phenomena (Level 3). Grounded in a construct‐centered design approach, we describe our process for developing assessments in order to examine and validate this construct, including how we selected topics and models, designed items, and developed outcome spaces. We present the specific example of one assessment centered on moon phases, which was administered to 164 8th and 9th grade Earth Science students as a pre/postmeasure. Two hundred ninety‐four responses were analyzed using a Rasch modeling approach. Item difficulties and student proficiency scores were calculated and analyzed regarding their relative performance with respect to the three levels of the construct. The analysis results provided initial evidence in support of the construct as conceived, with students displaying a range of analogical reasoning spanning all three construct levels. It also identified problematic items that merit further examination. Overall, the assessment has provided us the opportunity to better describe and frame the cognitive uses of models by students during learning situations in Earth Science. Implications for instruction and future directions for research in this area are discussed. © 2012 Wiley Periodicals, Inc. J Res Sci Teach 49: 713–743, 2012  相似文献   

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Previous studies have documented the promising results from student-constructed representations, including stop-motion animation (SMA), in supporting mechanistic reasoning (MR), which is considered an essential thinking skill in science education. Our current study presents theoretically and empirically how student-constructed SMA contributes to promoting MR. As a theoretical perspective, we propose a framework hypothesizing the link between elements of MR and the construction nature of SMA, that is, chunking and sequencing. We then examined the extent to which this framework was consistent with a multiple-case study in the domain of static electricity involving five secondary school students constructing and using their own SMA creation for reasoning. In addition, students' reasoning in pre- and postconstruction of an SMA was examined. Our empirical findings confirmed our framework by showing that all students identified the basic elements of MR, that is, entities and activities of entities, when engaging in chunking and sequencing. Chunking played a role in facilitating students to identify entities responsible for electrostatic phenomena, and sequencing seemed to elicit students to specify activities of these entities. The analysis of students' reasoning in pre- and postconstruction of SMA found that student-generated SMA has a potential effect on students' retention of the use of MR. Implications for instruction with SMA construction to support MR are discussed.  相似文献   

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Quantitative and qualitative studies of various aspects of the perception of biotechnology were conducted among 469 Slovenian high school students of average age 17 years. Our research aimed to explore relationships among students' pre-knowledge of molecular and human genetics, and their attitudes to four specific biotechnological applications. These applications—Bt corn, genetically modified (GM) salmon, somatic and germ line gene therapy (GT)—were investigated from the viewpoints of usefulness, moral acceptance and risk perception. In addition, patterns and quality of moral reasoning related to the biotechnological applications from the aspect of moral acceptability were examined. Clear gender differences were found regarding the relationship between our students' pre-knowledge of genetics and their attitudes to biotechnological applications. While females with a better genetics background expressed a higher risk perception in the case of GM salmon, their similarly well-educated male colleagues emphasized the risk associated with the use of germ line GT. With all four biotechnological applications, patterns of both rationalistic—deontological and teleological—and intuitive moral reasoning were identified. Students with poorer genetics pre-knowledge applied an intuitive pattern of moral reasoning more frequently than their peers with better pre-knowledge. A pattern of emotive reasoning was detected only in the case of GM salmon. A relatively low quality of students' moral reasoning, as demonstrated by their brief and small number of supporting justifications (explanations), show that there is a strong need for practising skills of argumentation about socio-scientific issues in Slovenian high schools on a much larger scale. The implications for future research and classroom applications are discussed.  相似文献   

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This study, conducted in an inner-city middle school, followed the conceptual changes shown in 25 students' writing over a 12-week science unit. Conceptual changes for 6 target students are reported. Student understanding was assessed regarding the nature of matter and physical change by paper-and-pencil pretest and posttest. The 6 target students were interviewed about the goal concepts before and after instruction. Students' writing during lesson activities provided qualitative data about their understandings of the goal concepts across the science unit. The researcher constructed concept maps from students' written statements and compared the maps across time to assess changes in the schema of core concepts, complexity, and organization as a result of instruction. Target students' changes were studied in detail to determine patterns of conceptual change. After patterns were located in target students' maps, the remaining 19 students' maps were analyzed for similar patterns. The ideas that students identified in their writing showed changes in central concepts, complexity, and organization as the lessons progressed. When instructional events were analyzed in relation to students' demonstrated ideas, understanding of the goal conceptions appeared in students' writing more often when students had opportunities to explain their new ideas orally and in writing.  相似文献   

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Students' perceptions of literacy assessment processes and practices were investigated in two year long case studies undertaken in two English classrooms in two state high schools in Queensland, Australia. A range of qualitative data techniques was used to collect information related to students' previous experiences of assessment in primary school, students' responses to the first and last literacy assessment task of the school year, and their perceptions of assessment at the end of the year. The study showed that students' attitudes, beliefs, practices and understandings about assessment varied both within and across student groups and differences in students' accounts were evident both at the start and end of the school year. The findings highlight the role that students play in actively constructing knowledge about literacy assessment through their prior and current experiences with assessment tasks, and in their interactions with each other.  相似文献   

9.
Science includes more than just concepts and facts, but also encompasses scientific ways of thinking and reasoning. Students' cultural and linguistic backgrounds influence the knowledge they bring to the classroom, which impacts their degree of comfort with scientific practices. Consequently, the goal of this study was to investigate 5th grade students' views of explanation, argument, and evidence across three contexts—what scientists do, what happens in science classrooms, and what happens in everyday life. The study also focused on how students' abilities to engage in one practice, argumentation, changed over the school year. Multiple data sources were analyzed: pre‐ and post‐student interviews, videotapes of classroom instruction, and student writing. The results from the beginning of the school year suggest that students' views of explanation, argument, and evidence, varied across the three contexts with students most likely to respond “I don't know” when talking about their science classroom. Students had resources to draw from both in their everyday knowledge and knowledge of scientists, but were unclear how to use those resources in their science classroom. Students' understandings of explanation, argument, and evidence for scientists and for science class changed over the course of the school year, while their everyday meanings remained more constant. This suggests that instruction can support students in developing stronger understanding of these scientific practices, while still maintaining distinct understandings for their everyday lives. Finally, the students wrote stronger scientific arguments by the end of the school year in terms of the structure of an argument, though the accuracy, appropriateness, and sufficiency of the arguments varied depending on the specific learning or assessment task. This indicates that elementary students are able to write scientific arguments, yet they need support to apply this practice to new and more complex contexts and content areas. © 2011 Wiley Periodicals, Inc. J Res Sci Teach 48: 793–823, 2011  相似文献   

10.
The hypothesis that an early adolescent brain growth plateau and spurt exists and that this plateau and spurt influence students' ability to reason scientifically and to learn theoretical science concepts was tested. In theory, maturation of the prefrontal lobes during early adolescence allows for improvements in students' abilities to inhibit task‐irrelevant information and coordinate task‐relevant information, which along with both physical and social experience influences scientific reasoning ability and the ability to reject scientific misconceptions and accept scientific conceptions. Two hundred ten students ages 13–16 years enrolled in four Korean secondary schools were administered tests of four prefrontal lobe activities, a test of scientific reasoning ability, and a test of air pressure concepts derived from kinetic‐molecular theory. A series of 14 lessons designed to teach the concepts were then taught. The concepts test was then readministered following instruction. As predicted, among the 13‐ and 14‐year‐olds, performance on the prefrontal lobe measures remained similar or regressed. Performance then improved considerably among the 15‐ and 16‐year‐olds. Also as expected, the measures of prefrontal lobe activity correlated highly with scientific reasoning ability. In turn, prefrontal lobe activity and scientific reasoning ability predicted concept gains and posttest performance. A principal components analysis showed that the study variables had two main components, which were interpreted as an inhibiting and a representing component. Therefore, theoretical concept acquisition was interpreted as a process involving both the inhibition of task‐irrelevant information (i.e., the rejection of intuitively derived misconceptions) and the representation of task‐relevant information (i.e, complex hypothetico‐deductive arguments and counterintuitive scientific conceptions about nonobservable entities). © 2000 John Wiley & Sons, Inc. J Res Sci Teach 37: 44–62, 2000  相似文献   

11.
The literature provides confounding information with regard to questions about whether students in high school can engage in meaningful argumentation about socio‐scientific issues and whether this process improves their conceptual understanding of science. The purpose of this research was to explore the impact of classroom‐based argumentation on high school students' argumentation skills, informal reasoning, and conceptual understanding of genetics. The research was conducted as a case study in one school with an embedded quasi‐experimental design with two Grade 10 classes (n = 46) forming the argumentation group and two Grade 10 classes (n = 46) forming the comparison group. The teacher of the argumentation group participated in professional learning and explicitly taught argumentation skills to the students in his classes during one, 50‐minute lesson and involved them in whole‐class argumentation about socio‐scientific issues in a further two lessons. Data were generated through a detailed, written pre‐ and post‐instruction student survey. The findings showed that the argumentation group, but not the comparison group, improved significantly in the complexity and quality of their arguments and gave more explanations showing rational informal reasoning. Both groups improved significantly in their genetics understanding, but the improvement of the argumentation group was significantly better than the comparison group. The importance of the findings are that after only a short intervention of three lessons, improvements in the structure and complexity of students' arguments, the degree of rational informal reasoning, and students' conceptual understanding of science can occur. © 2010 Wiley Periodicals, Inc. J Res Sci Teach 47: 952–977, 2010  相似文献   

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This study examined senior high school students' cognitive orientation toward scientific or social information, designated as information preference, and associated preferential reasoning modes when presented with an environmental issue concerning nuclear energy usage. The association of the information preference variable with some academic and personal background attributes of the participants was also examined. A questionnaire, preference survey test and interview methods were used to gather the data. Students' preference test scores fell within -0.66 to 2 on a scale of -4 (social orientation) to 4 (scientific orientation). Statistical analyses showed that students' performance in science was a good predictor of the information preference exhibited by students. Interview content analysis showed that students' preferences and reasoning modes were mutually consistent. Particularly, subjects of neutral preference, whose preference scores fell between 0 and 1, displayed a reasoning mode that is considerably integrated containing references to both scientific and socially relevant content.  相似文献   

14.
Although molecular-level details are part of the upper-secondary biology curriculum in most countries, many studies report that students fail to connect molecular knowledge to phenomena at the level of cells, organs and organisms. Recent studies suggest that students lack a framework to reason about complex systems to make this connection. In this paper, we present a framework that could help students to reason back and forth between cells and molecules. It represents both the general type of explanation in molecular biology and the research strategies scientists use to find these explanations. We base this framework on recent work in the philosophy of science that characterizes explanations in molecular biology as mechanistic explanations. Mechanistic explanations describe a phenomenon in terms of the entities involved, the activities displayed and the way these entities and activities are organized. We conclude that to describe cellular phenomena scientists use entities and activities at multiple levels between cells and molecules. In molecular biological research, scientists use heuristics based on these intermediate levels to construct mechanistic explanations. They subdivide a cellular activity into hypothetical lower-level activities (top-down approaches) and they predict and test the organization of macromolecules into functional modules that play a role in higher-level activities (bottom-up approaches). We suggest including molecular mechanistic reasoning in biology education and we identify criteria for designing such education. Education using molecular mechanistic reasoning can build on common intuitive reasoning about mechanisms. The heuristics that scientists use can help students to apply this intuitive notion to the levels in between molecules and cells.  相似文献   

15.
Learning progressions are theoretical models that describe learning of scientific ideas and practices over time. These hypothetical progressions need to be tested and refined in order to productively inform instruction and assessment. In this paper, we report our attempts to revise a learning progression in genetics. In particular, we focused on two constructs that embody core ideas in classical genetics and one molecular construct. The revisions are based on analysis of pre‐ and postinterview data obtained from sixty 11th grade students before and after they engaged in a 10‐week unit that addressed these concepts. We found that while many of the students held ideas that aligned with the progression, there were several distinct dimensions of student reasoning that were not captured and led to substantial revisions of the constructs including: (a) the splitting of the construct dealing with meiosis (E) into two subconstructs (E1‐physical passage of genetic information and E2 – the role of sex cells), (b) the addition of new levels to constructs dealing with the universal nature and organization of the genetic code (A) and construct (F). For Construct A, the lower levels were expanded to include ideas about the localization of DNA in cells and to include ideas about the composition of DNA that were not captured in the progression. Revisions to Construct F included the expansion of existing levels and the addition of modes of inheritance such as codominance and incomplete dominance. The research we present offers insights about a methodological approach that can be used to test and refine progressions, as well as insights about student learning in genetics as we further describe and expand the stepping‐stone ideas in the progression and discuss further the multidimensional nature of learning progressions.  相似文献   

16.
Recently, a growing awareness of the relationship between assessment and learning has resulted in several major critiques of existing practice and proposals for reform in science education at national and regional levels. One initiative advocates the use of carefully constructed performance tasks that give students opportunities to demonstrate their understanding as they would in the world outside of school. The purpose of this study was to explore relationships among school students' (n = 189) acquisition of meaningful understandings of protein synthesis. Students were tested before and after protein synthesis instruction using a multiple choice assessment format and an open‐ended assessment format. The assessment instrument was designed to measure students' interrelated understanding of protein synthesis. An independent t‐test analysis was conducted on the posttests to measure retention of factual information and gender differences. Analysis of student‐generated analogies also revealed unique patterns in students' understandings of this topic. This research provides information for educators on students' acquisition of meaningful understandings of protein synthesis and has many implications for educators. © 1999 John Wiley & Sons, Inc. J Res Sci Teach 36: 1–22, 1999.  相似文献   

17.
This study explored the understandings of data and measurement that school students draw upon, and the ways that they reason from data, when carrying out a practical science inquiry task. The two practical tasks used in the study each involved investigations of the relationships between two independent variables (IVs) and a dependent variable (DV); in both tasks, one IV covaried with the DV, whereas the other did not. Each was undertaken by 10 students, aged 10, 12, and 14 years (total n = 60 students), working individually. Their actions were video‐recorded for analysis. In a subsequent interview, each student was asked to discuss and interpret data collected by two other students, undertaking a similar (but different) practical task, shown on a video‐recording. An analysis of the sample students' performance on the practical tasks and their interview responses showed few differences across task contexts, or with age, in students' reasoning, but significant differences in performance when investigating situations of covariation and non‐covariation. Few students in the sample displayed sufficient understanding of measurement error to deal effectively with the latter. Investigations of non‐covariation cases revealed, much more clearly than investigations of covariation cases, the students' ideas about data and measurement, and their ways of reasoning from data. Such investigations therefore provide particularly valuable contexts for teaching and research. © 2004 Wiley Periodicals, Inc. J Res Sci Teach 41: 748–769, 2004  相似文献   

18.
“Complex systems” is a general-purpose reasoning scheme, used in a wide range of disciplines to make sense of systems with many similar entities. In this paper, we examine the generality of this approach in learning chemistry. Students' reasoning in chemistry in terms of emergent complex systems is explored for two curricula: a normative and a complexity-based one, so that the interaction could be examined under both the conditions. A quasi-experimental pretest-intervention-posttest comparison group design was used to explore student's learning, complemented with interview data. The experimental group (n = 47) studied the topic of gases with a complexity-based curriculum. A comparison group (n = 45) studied with a normative curriculum for the same duration. Students' answers to questionnaires were coded with a complexity-based approach that included levels (distinguishing micro- and macro-levels), stochastic particle behaviors, the emergence of macro-level patterns from micro-level behaviors, and the source of control in the system. It was found that students' reasoning about chemistry concepts in terms of complex systems falls into three distinct and coherent mental models. A sophisticated mental model included most of the above-described complexity features, while the nonsophisticated model included none. The intermediate model is typified by distinguishing between levels, but not by stochastic and emergent behaviors. The nonsophisticated mental model was used mostly in the pretest. In the posttest, the experimental group used the intermediate and sophisticated models; while the comparison group used the nonsophisticated and intermediate models. Discussion approaches the topics of the generality of the complex systems approach; and the unique forms of reasoning that a complexity approach may contribute to learning science.  相似文献   

19.
Since the work of Watson and Crick in the mid-1950s, the science of genetics has become increasingly molecular. The development of recombinant DNA technologies by the agricultural and pharmaceutical industries led to the introduction of genetically modified organisms (GMOs). By the end of the twentieth century, reports of animal cloning and recent completion of the Human Genome Project (HGP), as well techniques developed for DNA fingerprinting, gene therapy and others, raised important ethical and social issues about the applications of such technologies. For citizens to understand these issues, appropriate genetics education is needed in schools. A good foundation in genetics also requires knowledge and understanding of topics such as structure and function of cells, cell division, and reproduction. Studies at the international level report poor understanding by students of genetics and genetic technologies, with widespread misconceptions at various levels. Similar studies were nearly absent in India. In this study, I examine Indian higher secondary students' understanding of genetic information related to cells and transmission of genetic information during reproduction. Although preliminary in nature, the results provide cause for concern over the status of genetics education in India. The nature of students' conceptual understandings and possible reasons for the observed lack of understanding are discussed.  相似文献   

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The purpose of this study was to identify and characterize students' understandings about the concept of burning. Naturalistic data-collecting strategies used in this study included participant observation and interviewing. Twenty eighth graders were interviewed using the “interview-about-events” technique, a variation of the Piagetian interview. The interviews were audiotape recorded, transcribed, and analyzed using the process of analytic induction. The analysis showed that students' understandings about burning were fragmented, inconsistent, and at variance with scientific knowledge. These understandings are analyzed using Olson's (1977) characterization of common sense and scientific knowledge.  相似文献   

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