9,205 research outputs found
Assessing the Effectiveness of a Computer Simulation in Introductory Undergraduate Environments
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
Raman Scattering Signatures of Kitaev Spin Liquids in A IrO Iridates
We study theoretically the Raman scattering response in the
gapless quantum spin liquid phase of the Kitaev-Heisenberg model. The dominant
polarization-independent contribution reflects the density of
states of the emergent Majorana fermions in the ground-state flux-sector. The
integrability-breaking Heisenberg exchange generates a second contribution,
whose dominant part has the form of a quantum quench
corresponding to an abrupt insertion of four gauge fluxes. This results
in a weakly polarization dependent response with a sharp peak at the energy of
the flux excitation accompanied by broad features, which can be related to
Majorana fermions in the presence of the perturbed gauge field. We discuss the
experimental situation and explore more generally the influence of
integrability breaking for Kitaev spin liquid response functions.Comment: 9 pages including supp. ma
Analytic Criteria for Power Exhaust in Divertors due to Impurity Radiation
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
A New Instrument For Measuring Student Beliefs About Physics and Learning Physics: The Colorado Learning Attitudes About Science Survey
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
The Design and Validation of the Colorado Learning Attitudes about Science Survey
The Colorado Learning Attitudes about Science Survey (CLASS) is a new instrument designed to measure various facets of student attitudes and beliefs about learning physics. This instrument extends previous work by probing additional facets of student attitudes and beliefs. It has been written to be suitably worded for students in a variety of different courses. This paper introduces the CLASS and its design and validation studies, which include analyzing results from over 2400 students, interviews and factor analyses. Methodology used to determine categories and how to analyze the robustness of categories for probing various facets of student learning are also described. This paper serves as the foundation for the results and conclusions from the analysis of our survey dat
Correlating Student Beliefs With Student Learning Using The Colorado Learning Attitudes about Science Survey
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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