English secondary students’ thinking about the status of scientific theories: consistent,comprehensive, coherent and extensively evidenced explanations of aspects of the natural world – or just ‘an idea someone has’

Teaching about the nature of science (NOS) is seen as a priority for science education in many national contexts. The present paper focuses on one central issue in learning about NOS: understanding the nature and status of scientific theories. A key challenge in teaching about NOS is to persuade students that scientific knowledge is generally robust and reliable, yet also in principle always open to challenge and modification. Theories play a central role, as they are a form of conjectural knowledge that over time may be abandoned, replaced, modified, yet sometimes become well established as current best scientific understanding. The present paper reports on findings from interviews with 13–14 year olds in England where target knowledge presents theories as ‘consistent, comprehensive, coherent and extensively evidenced explanations of aspects of the natural world’. Student thinking reflected a two-tier typology of scientific knowledge in which largely unsupported imaginative ideas (‘theories’) became transformed into fairly definitive knowledge (such as laws) through relatively straightforward testing. These results are considered in relation to research into intellectual development which indicates that effective teaching in this area requires careful scaffolding of student learning, but has potential to contribute to supporting intellectual development across the curriculum.     

Design of a student lab program for nanoscience and technology – an intervention study on students’ perceptions of the Nature of Science,the Nature of Scientists and the Nature of Scientific Inquiry

Background: This article describes the design and the evaluation of a student lab program on the topic of nanoscience and technology (NST), mainly focusing on Nanoscience and its applications. The program was designed for students in grades 8–10 and was part of a larger outreach program of the Collaborative Research Center ‘Function by Switching’ at Kiel University. The Model of Educational Reconstruction (MER) served as a framework for the research-based design of the student lab.

Purpose: We aimed to develop an authentic science activity in the area of NST in order to support scientific inquiry learning and to provide a deeper understanding of scientific topics.

Sample: A total of 154 secondary school students from grades 8–10 of seven different secondary schools participated in this study.

Design and methods: A pre-post questionnaire with six subscales on students’ perceptions of the Nature of Science (NOS), Scientific Inquiry (NOSI) and the involved scientists (NOST) in the area of nanoscience and nanotechnology was applied.

Results: Results show that the applied explicit and reflective approach embedded in the nanoscience content significantly improved the participating students’ perceptions of NOS, NOSI and NOST facets. After the lab visit, students’ answers corresponded to a more adequate perception of today’s science and scientists. Some gender differences in learning gains were also detected.

Conclusion: The study served its main purpose which was to investigate a well-balanced strategy to develop authentic out-of-school-learning environments with a focus on NOS/NOSI/NOST. Testing students’ perceptions of the nature of nanoscience provided insights into students’ worlds and served as feedback for the lab program. The outcomes of this study might help to better understand and further develop authentic (nano)science programs in out-of-school settings and science outreach programs.     

力竭运动后大鼠小脑组织中MDA含量和NOS活性变化的研究

通过力竭运动模型 ,分别在运动后即刻、运动后 2h、运动后 12h和运动后 2 4h测定小脑皮层组织中NOS活性和MDA含量水平 ,结果发现运动后 2 4hMDA含量水平都没有显著的变化。但是运动后即刻小脑组织中的NOS活性出现降低 ,并且在运动后 2h左右出现显著的降低 (P <0.0 5),以后逐渐恢复到安静时的水平 ,在 2 4h后有不显著的增强。根据实验结果 ,我们分析认为小脑运动性疲劳的主要原因之一可能与NOS活性的明显降低有密切关系 ,而与脂质过氧化没有直接的关系     

Impacts of contextual and explicit instruction on preservice elementary teachers' understandings of the nature of science

This mixed‐methods investigation compared the relative impacts of instructional approach and context of nature of science instruction on preservice elementary teachers' understandings. The sample consisted of 75 preservice teachers enrolled in four sections of an elementary science methods course. Independent variables included instructional approach to teaching nature of science (implicit vs. explicit) and the context of nature of science instruction (as a stand‐alone topic vs. situated within instruction about global climate change and global warming). These treatments were randomly applied to the four class sections along a 2 × 2 matrix, permitting the comparison of outcomes for each independent variable separately and in combination to those of a control group. Data collection spanned the semester‐long course and included written responses to pre‐ and post‐treatment administrations of the VNOS‐B, semi‐structured interviews, and a variety of classroom artifacts. Qualitative methods were used to analyze the data with the goal of constructing profiles of participants' understandings of the nature of science and of global climate change /global warming (GCC/GW). These profiles were compared across treatments using non‐parametric statistics to assess the relative effectiveness of the four instructional approaches. Results indicated that preservice teachers who experienced explicit instruction about the nature of science made statistically significant gains in their views of nature of science regardless of whether the nature of science instruction was situated within the context of GCC/GW or as a stand‐alone topic. Further, the participants who experienced explicit nature of science instruction as a stand‐alone topic were able to apply their understandings of nature of science appropriately to novel situations and issues. We address the implications of these results for teaching the nature of science in teacher preparation courses. © 2010 Wiley Periodicals, Inc., Inc. J Res Sci Teach 48: 414–436, 2011     

从EDN1、NOS2A基因筛选预测HiHiLo训练效果的分子标记

目的:拟从EDN1及NOS2A基因的多态性位点中筛选出与HiHiLo(高住高练低训)训练效果相关的分子标记,为帮助制定个性化的低氧训练方案提供理论参考。方法:采用Association-Study研究方法,测定、分析了72名我国北方地区汉族健康男性青年30天HiHi-Lo训练前后有氧运动能力、心功能变化率与EDN1、NOS2A基因多态性的关联性。HiHiLo训练方案包括每晚10h低氧环境(14.3%～14.8%含氧量)暴露、每周3次30 min75%VO2max强度的低氧运动和日常的体育锻炼。有氧运动能力指标包括递增负荷功率车运动中测定的最大耗氧量、固定负荷血乳酸以及低氧训练中的血氧饱和度,心功能指标包括彩色多普勒测定的安静及三级固定负荷(50 W→100 W→150 W)功率车运动3min后的心脏结构与功能指标。基因多态性选取了EDN1基因外显子SNP/rs5370、rs1800997和3’端rs4714383,NOS2A基因启动子区STR(CCTTT)n和内含子SNP/rs2248814。结果:1)经过30天HiHiLo训练后,EDN1基因SNP/rs1800997的3A/3A基因型人群在安静状态下左心室心肌收缩力提高程度显著优于含4A等位基因的基因型人群,SNP/rs4714383的CC基因型人群运动中左心室泵功能改善程度显著优于含T等位基因的基因型人群;2)NOS2A基因STR(CCTTT)n上2个等位基因n值之和与VO2max提高率显著正相关,SNP/rs2779249的GT基因型人群固定负荷运动中心脏机能节省化水平提高的程度显著大于GG基因型人群。结论:在我国北方汉族男性人群中,EDN1基因SNP/rs1800997、rs4714383和rs2779249的3A/3A、CC和GT基因型携带者HiHiLo训练后心功能提高效果较好;NOS2A基因STR(CCTTT)n基因座上2个等位基因n值均较大的基因型携带者HiHiLo训练后VO2max提高效果较好。     

The effect of reflective discussions following inquiry‐based laboratory activities on students' views of nature of science

This research investigated the effect of reflective discussions following inquiry‐based laboratory activities on students' views of the tentative, empirical, subjective, and social aspects of nature of science (NOS). Thirty‐eight grade six students from a Lebanese school participated in the study. The study used a pretest–posttest control‐group design and focused on collecting mainly qualitative data. During each laboratory session, students worked in groups of two. Later, experimental group students answered open‐ended questions about NOS then engaged in reflective discussions about NOS. Control group students answered open‐ended questions about the content of the laboratory activities then participated in discussions of results of these activities. Data sources included an open‐ended questionnaire used as pre‐ and posttest, answers to the open‐ended questions that experimental group students answered individually during every session, transcribed videotapes of the reflective discussions of the experimental group, and semi‐structured interviews. Results indicated that explicit and reflective discussions following inquiry‐based laboratory activities enhanced students' views of the target NOS aspects more than implicit inquiry‐based instruction. Moreover, implicit inquiry‐based instruction did not substantially enhance the students' target NOS views. This study also identified five major challenges that students faced in their attempts to change their NOS views. © 2010 Wiley Periodicals, Inc. J Res Sci Teach 47: 1229–1252, 2010     

College students' perceptions of the theory of evolution

Although a well‐corroborated scientific theory, the theory of evolution has continued to cause dilemmas for some individuals who have not easily been able to accommodate the concepts of this theory within their “cognitive culture.” The reason lies in the overlap of some ideas that the theory advocates with other social, epistemological, and religious beliefs. This study describes how 11 college biology students who completed a course on the theory of evolution perceive the relationship among their epistemological beliefs about science, their beliefs about religion, and their perception of nature and causality and their position regarding the theory of evolution. It also compares the different positions of the students to that of the course instructor. Questionnaires and semistructured interviews were used to collect data. Qualitative methods were used to analyze the data and identify the various positions of the students and course instructor. The students' positions ranged from complete acceptance to complete rejection of the theory of evolution. The results suggest that students' personal beliefs should not be dismissed or underestimated when teaching the theory of evolution. © 2008 Wiley Periodicals, Inc. J Res Sci Teach 45: 395–419, 2008     

The development of seventh graders' views of nature of science

This study investigated the development in students' nature of science (NOS) views in the context of an explicit inquiry‐oriented instructional approach. Participants were 18 seventh‐grade students who were taught by a teacher with “appropriate” knowledge about NOS. The intervention spanned about 3 months. During this time, students were engaged in three inquiry‐oriented activities that were followed by reflective discussions of NOS. The study emphasized the tentative, empirical, inferential, and creative aspects of NOS. An open‐ended questionnaire, in conjunction with semi‐structured interviews, was used to assess students' views before, during, and after the intervention. Before instruction, the majority of students held naïve views of the four NOS aspects. During instruction, the students acquired more informed and “intermediary” views of the NOS aspects. By the end of the intervention, the students' views of the NOS aspects had developed further still into informed and “intermediary.” These findings suggest a developmental model in which students' views develop along a continuum during which they pass through intermediary views to reach more informed views. Implications for teaching and learning of NOS are discussed. © 2007 Wiley Periodicals, Inc. J Res Sci Teach 45: 470–496, 2008     

有氧训练及热应激对运动大鼠肾脏组织NO、NOS及自由基代谢的影响

目的：探讨有氧耐力训练对运动热应激大鼠肾脏组织NO、NOS及自由基代谢的影响。方法：对大鼠进行为期6w的递增负荷运动训练，并在运动末次施加热应激，测定大鼠肾脏组织NO、NOS、MDA和SOD含量或活性。结果：（1）运动加热应激使大鼠肾脏组织NO、NOS、iNOS和MDA显著高于安静组和急性运动组，SOD和SOD／MDA显著低于安静组和急性运动组；（2）训练安静组与安静对照组相比，MDA均显著下降，NO、NOS均显著上升；（3）训练后运动热应激大鼠肾脏组织NO、NOS、iNOS、MDA显著下降，SOD显著上升。结论：（1）在热环境下运动，机体NO、NOS和自由基代谢增加，抗氧化酶活性下降；（2）在常温下进行有氧耐力训练练，可以适当提高机体的耐热性，降低运动热应激对机体的损伤。