Neutron spectrum from 252Cf spontaneous fission

Includes bibliography.Measurements have been made of the neutron spectrum from the spontaneous fission of 252Cf in the restframe of the fragment by simultaneous observation of the neutron time-of-flight and the fragment velocity. The fragments were detected by means of thin film plastic scintillators in which the scintillation pulse-height response was verified to be a linear function of fragment velocity. The measurements of the neutron spectrum in the restframe of the fragment are compared with previous work and are found to deviate significantly from the predicted observations of the simple form of the evaporation model

Differential cross section for neutron-proton radiative capture at En=63.4 MeV

Bibliography: pages 120-128.The angular distribution of photons from n-p radiative capture of 63.4 MeV neutrons has been measured using a new technique in which both the photon and the deuteron were detected simultaneously and the deuteron identified using pulse shape discrimination. Data taken at eight n-ϒ angles (45°-150°) were transformed to deuteron photodisintegration cross sections at the equivalent laboratory energy, Eᵧ = 33.9 MeV. The data were analysed in combination with independent measurements of the 0° and 180° cross sections. Legendre polynomial coefficients obtained from the analysis are consistent with other measurements in this energy range as well as with values reported from global fits. The measurements deviate marginally from predictions based on potential model calculations using the Bonn r-space and Paris potentials

The introductory astronomy course at the University of Cape Town: probing student perspectives

We report on research carried out to improve teaching and student engagement in the introductory astronomy course at the University of Cape Town. This course is taken by a diverse range of students, including many from educationally disadvantaged backgrounds. We describe the development of an instrument, the Introductory Astronomy Questionnaire (IAQ), which we administered as pre- and post-tests to students enrolled in the course. The instrument comprised a small number of questions which probed three areas of interest: student motivation and expectations, astronomy content, and worldview. Amongst our findings were that learning gains were made in several conceptual areas, and that students appeared to develop a more nuanced view of the nature of astronomy. There was some evidence that the course had a positive impact on students' worldviews, particularly their attitudes towards science. We also identified a promising predictor of course success that could in future be used to identify students requiring special teaching intervention.Comment: 19 pages, 2 figures. Accepted for publication in Physical Review Special Topics - Physics Educatio

Effectiveness of a GUM-compliant course for teaching measurement in the introductory physics laboratory

An evaluation of a course aimed at developing university students' understanding of the nature of scientific measurement and uncertainty is described. The course materials follow the framework for metrology as recommended in the Guide to the Expression of Uncertainty in Measurement (GUM). The evaluation of the course is based on responses to written questionnaires administered to a cohort of 76 first year physics students both pre- and post-instruction, which were interpreted in terms of 'point' or 'set' reasoning. These findings are compared with responses from a control group of 70 students who completed a similar laboratory course apart from the use of traditional approaches to measurement and data analysis. The results suggest that the GUM framework, together with the specific teaching strategies described, provides opportunities for more effective learning of measurement and uncertainty in the introductory laboratory

Knowledge of astronomical scale: Measurement and evaluation

Having an appreciation for astronomical scale is essential for understanding the foundations of astronomy. However, a key obstacle in developing this understanding is the lack of direct ways to acquire this knowledge. Personal experience may even be detrimental, given that our direct experience is of the Earth as something extremely large, whereas stars, for example, appear as tiny pinpricks of light. As a first step to address this issue, it is necessary to assess people’s knowledge of astronomical scale to identify common misconceptions and evaluate the effectiveness of educational interventions. Previous instruments have generally only included a few questions about scale—mostly through multiple choice—limiting the number of objects simultaneously probed to three and often not probing all possible rankings. To measure people’s knowledge of astronomical scale, we developed an instrument that allows for easy collection, analysis and presentation of data ranking multiple astronomical objects. I will present this instrument and the results from three different samples before and after astronomy instruction: middle school students (N = 922), pre-service science teachers (N = 41) and visitors to a public guided astronomy night viewing tour (N > 500)

Learning as acquiring a discursive identity through participation in a community: improving student learning in engineering education

This is an Accepted Manuscript of an article published by Taylor & Francis in African Journal of Research in Mathematics Science and Technology Education on 2009, available online: http://www.tandfonline.com/10.1080/03043790902989457.In this paper, we propose that learning in engineering involves taking on the discourse of an engineering community, which is intimately bound up with the identity of being a member of that community. This leads to the notion of discursive identity, which emphasises that students' identities are constituted through engaging in discourse. This view of learning implies that success in engineering studies needs to be defined with particular reference to the sorts of identities that students develop and how these relate to identities in the world of work. In order to achieve successful learning in engineering, we need to recognise the multiple identities held by our students, provide an authentic range of engineering-related activities through which students can develop engineering identities and make more explicit key aspects of the discourse of engineering of which lecturers are tacitly aware. We include three vignettes to illustrate how some of the authors of this paper (from across three different institutions) have applied this perspective of learning in their teaching practice

Effects of a course in research methods on scientific thinking among psychology students

This study followed a quasi-experimental design to determine the effect of a course in research methods on undergraduate students’ ability to reason scientifically. Two classes of students in their first and second year of study were asked to participate in the study. The second year class (n = 171) was taught a course in research methods, while the first year class (n = 201) was taught a course in research methods. An instrument consisting of a series of vignettes was administered to all students at the beginning and at the end of the quarter in which these courses were taught. Total scores on the instrument were used to determine the extent of scientific thinking. Analysis of variance showed a non-significant difference between the groups at pretest and a significant difference (p < 0.05) at post test. These results were interpreted to mean that the research methods course was responsible for increasing students’ level of scientific thinking

Contexts, footholds and sense-making in DC circuits

Contexts, footholds and sense-making in DC circuits Physics Education Research Conference, Philadelphia, PA, 1-2 August 201

DC circuits: I. Evidence for fine grained contextual dependence*

This is the first part of a broader study, exploring the contextual variations of the responses of 149 first year (non-physics major) university students at two South African universities in Cape Town. The data analysis was done in terms of the (i) forced choice responses (FCR), (ii) free written responses and (iii) personal interviews. This paper presents the development of the instrument (aspects of circuits questionnaire, or ACQ) used in the exploratory study and the results obtained from the FCR analysis of 60 students. The results showed that the student responses are triggered by the context framed by the questions and the results obtained from investigations using light bulbs cannot be generalised and may be reinterpreted

DC circuits: II. Identification of foothold ideas in DC circuits

This is the second part of a broader investigation which explores the reasons behind the contextual variations in student responses at a fine-grained level. In the previous article (John 2017 Eur. J. Phys. 38 015701) it was established that the students' responses are highly context dependent at a fine-grained level. This article presents the reason for the contextual variations of student responses from their free written responses. The result indicates that students who are being triggered by the productive resources during the engagement with the task will arrive at the correct (canonical) conclusion and those triggered by the unproductive resources will arrive at an incorrect conclusion. We identified the productive foothold ideas in a simple DC circuit with a single resistive element