10,534 research outputs found

    Towards characterizing the relationship between students' interest in and their beliefs about physics

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    We examine the relationships between students' self-reported interest and their responses to a physics beliefs survey. Results from the Colorado Learning Attitudes about Science Survey (CLASS v3), collected in a large calculusbased introductory mechanics course (N=391), were used to characterize students' beliefs about physics and learning physics at the beginning and end of the semester. Additionally students were asked at the end of the semester to rate their interest in physics, how it has changed, and why. We find a correlation between surveyed beliefs and self-rated interest (R=0.65). At the end of the term, students with more expert-like beliefs as measured by the 'Overall' CLASS score also rate themselves as more interested in physics. An analysis of students' reasons for why their interest changed showed that a sizable fraction of students cited reasons tied to beliefs about physics or learning physics as probed by the CLASS survey. The leading reason for increased interest was the connection between physics and the real world

    Assessing the Effectiveness of a Computer Simulation in Introductory Undergraduate Environments

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    We present studies documenting the effectiveness of using a computer simulation, specifically the Circuit Construction Kit (CCK) developed as part of the Physics Education Technology Project (PhET) [1, 2], in two environments: an interactive college lecture and an inquiry-based laboratory. In the first study conducted in lecture, we compared students viewing CCK to viewing a traditional demonstration during Peer Instruction [3]. Students viewing CCK had a 47% larger relative gain (11% absolute gain) on measures of conceptual understanding compared to traditional demonstrations. These results led us to study the impact of the simulation's explicit representation for visualizing current flow in a laboratory environment, where we removed this feature for a subset of students. Students using CCK with or without the explicit visualization of current performed similarly to each other on common exam questions. Although the majority of students in both groups favored the use of CCK over real circuit equipment, the students who used CCK without the explicit current model favored the simulation more than the other grou

    Praxis Mapping: A methodology for evaluating the political impacts of international projects

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    This report describes the participatory development of a process we have used to consider the political implications of a climate justice project we worked on together from 2010 to 2013, called Strengthening the role of civil society in water sector governance towards climate change adaptation in African cities – Durban, Maputo, Nairobi (see http://ccaa.irisyorku.ca). This project was funded by the International Development Research Centre (IDRC) and the U.K. Department for International Development (DFID) through their Climate Change Adaptation in Africa programme.This research was supported by the International Development Research Centr

    Analytic Criteria for Power Exhaust in Divertors due to Impurity Radiation

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    Present divertor concepts for next step experiments such ITER and TPX rely upon impurity and hydrogen radiation to transfer the energy from the edge plasma to the main chamber and divertor chamber walls. The efficiency of these processes depends strongly on the heat flux, the impurity species, and the connection length. Using a database for impurity radiation rates constructed from the ADPAK code package, we have developed criteria for the required impurity fraction, impurity species, connection length and electron temperature and density at the mid-plane. Consistent with previous work, we find that the impurity radiation from coronal equilibrium rates is, in general, not adequate to exhaust the highest expected heating powers in present and future experiments. As suggested by others, we examine the effects of enhancing the radiation rates with charge exchange recombination and impurity recycling, and develop criteria for the minimum neutral fraction and impurity recycling rate that is required to exhaust a specified power. We also use this criteria to find the optimum impurity for divertor power exhaust.Comment: Preprint for the 11th PSI meeting, Adobe pdf with 14 figures, 15 page

    An improved continuous compositional-spread technique based on pulsed-laser deposition and applicable to large substrate areas

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    A new method for continuous compositional-spread (CCS) thin-film fabrication based on pulsed-laser deposition (PLD) is introduced. This approach is based on a translation of the substrate heater and the synchronized firing of the excimer laser, with the deposition occurring through a slit-shaped aperture. Alloying is achieved during film growth (possible at elevated temperature) by the repeated sequential deposition of sub-monolayer amounts. Our approach overcomes serious shortcomings in previous in-situ implementations of CCS based on sputtering or PLD, in particular the variations of thickness across the compositional spread and the differing deposition energetics as function of position. While moving-shutter techniques are appropriate for PLD-approaches yielding complete spreads on small substrates (i.e. small as compared to distances over which the deposition parameters in PLD vary, typically about 1 cm), our method can be used to fabricate samples that are large enough for individual compositions to be analyzed by conventional techniques, including temperature-dependent measurements of resistivity and dielectric and magnetic and properties (i.e. SQUID magnetometry). Initial results are shown for spreads of (Sr,Ca)RuO3_3.Comment: 6 pages, 8 figures, accepted for publication in Rev. Sci. Instru

    A New Instrument For Measuring Student Beliefs About Physics and Learning Physics: The Colorado Learning Attitudes About Science Survey

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    The Colorado Learning Attitudes about Science Survey (CLASS) is a new instrument designed to measure student beliefs about physics and about learning physics. This instrument extends previous work by probing additional aspects of student beliefs and by using wording suitable for students in a wide variety of physics courses. The CLASS has been validated using interviews, reliability studies, and extensive statistical analyses of responses from over 5000 students. In addition, a new methodology for determining useful and statistically robust categories of student beliefs has been developed. This paper serves as the foundation for an extensive study of how student beliefs impact and are impacted by their educational experiences. For example, this survey measures: that most teaching practices cause substantial drops in student scores; that a student's likelihood of becoming a physics major correlates with their 'Personal Interest' score; and that, for a majority of student populations, women's scores in some categories, including 'Personal Interest' and 'Real World Connections', are significantly different than men's scores

    An Integrated Passive Phase-Shift Keying Modulator for Biomedical Implants With Power Telemetry Over a Single Inductive Link

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    This paper presents a passive phase-shift keying (PPSK) modulator for uplink data transmission for biomedical implants with simultaneous power and data transmission over a single 13.56 MHz inductive link. The PPSK modulator provides a data rate up to 1.35 Mbps with a modulation index between 3% and 38% for a variation of the coupling coefficient between 0.05 and 0.26. This modulation scheme is particularly suited for biomedical implants that have high power demand and low coupling coefficients. The PPSK modulator operates in conjunction with on-off-keying downlink communication. The same inductive link is used to provide up to 100 mW of power to a multi-channel stimulator. The majority of the system on the implant side was implemented as an application specific integrated circuit (ASIC), fabricated in 0.6-[Formula: see text] high voltage CMOS technology. The theory of PPSK modulation, simulated and measured performance evaluation, and comparison with other state-of-the-art impedance modulation techniques is presented. The measured bit error rate around critical coupling at 1.35 Mbps is below 6 ×10(-8)

    Correlating Student Beliefs With Student Learning Using The Colorado Learning Attitudes about Science Survey

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    A number of instruments have been designed to probe the variety of attitudes, beliefs, expectations, and epistemological frames taught in our introductory physics courses. Using a newly developed instrument -- the Colorado Learning Attitudes about Science Survey (CLASS)[1] -- we examine the relationship between students' beliefs about physics and other educational outcomes, such as conceptual learning and student retention. We report results from surveys of over 750 students in a variety of courses, including several courses modified to promote favorable beliefs about physics. We find positive correlations between particular student beliefs and conceptual learning gains, and between student retention and favorable beliefs in select categories. We also note the influence of teaching practices on student beliefs
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