11,641 research outputs found
Reforming a large lecture modern physics course for engineering majors using a PER-based design
We have reformed a large lecture modern physics course for engineering majors
by radically changing both the content and the learning techniques implemented
in lecture and homework. Traditionally this course has been taught in a manner
similar to the equivalent course for physics majors, focusing on mathematical
solutions of abstract problems. Based on interviews with physics and
engineering professors, we developed a syllabus and learning goals focused on
content that was more useful to our actual student population: engineering
majors. The content of this course emphasized reasoning development, model
building, and connections to real world applications. In addition we
implemented a variety of PER-based learning techniques, including peer
instruction, collaborative homework sessions, and interactive simulations. We
have assessed the effectiveness of reforms in this course using pre/post
surveys on both content and beliefs. We have found significant improvements in
both content knowledge and beliefs compared with the same course before
implementing these reforms and a corresponding course for physics majors.Comment: To be published in the Proceedings of the Physics Education Research
Conference 200
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
Black Holes in Higher-Derivative Gravity
Extensions of Einstein gravity with higher-order derivative terms arise in
string theory and other effective theories, as well as being of interest in
their own right. In this paper we study static black-hole solutions in the
example of Einstein gravity with additional quadratic curvature terms. A
Lichnerowicz-type theorem simplifies the analysis by establishing that they
must have vanishing Ricci scalar curvature. By numerical methods we then
demonstrate the existence of further black-hole solutions over and above the
Schwarzschild solution. We discuss some of their thermodynamic properties, and
show that they obey the first law of thermodynamics.Comment: Typos corrected, discussion added, figure changed. 4 pages, 6 figure
Lichnerowicz Modes and Black Hole Families in Ricci Quadratic Gravity
A new branch of black hole solutions occurs along with the standard
Schwarzschild branch in -dimensional extensions of general relativity
including terms quadratic in the Ricci tensor. The standard and new branches
cross at a point determined by a static negative-eigenvalue eigenfunction of
the Lichnerowicz operator, analogous to the Gross-Perry-Yaffe eigenfunction for
the Schwarzschild solution in standard dimensional general relativity.
This static eigenfunction has two r\^oles: both as a perturbation away from
Schwarzschild along the new black-hole branch and also as a threshold unstable
mode lying at the edge of a domain of Gregory-Laflamme-type instability of the
Schwarzschild solution for small-radius black holes. A thermodynamic analogy
with the Gubser and Mitra conjecture on the relation between quantum
thermodynamic and classical dynamical instabilities leads to a suggestion that
there may be a switch of stability properties between the old and new
black-hole branches for small black holes with radii below the branch crossing
point.Comment: 33 pages, 8 figure
Spherically Symmetric Solutions in Higher-Derivative Gravity
Extensions of Einstein gravity with quadratic curvature terms in the action
arise in most effective theories of quantised gravity, including string theory.
This article explores the set of static, spherically symmetric and
asymptotically flat solutions of this class of theories. An important element
in the analysis is the careful treatment of a Lichnerowicz-type `no-hair'
theorem. From a Frobenius analysis of the asymptotic small-radius behaviour,
the solution space is found to split into three asymptotic families, one of
which contains the classic Schwarzschild solution. These three families are
carefully analysed to determine the corresponding numbers of free parameters in
each. One solution family is capable of arising from coupling to a
distributional shell of matter near the origin; this family can then match on
to an asymptotically flat solution at spatial infinity without encountering a
horizon. Another family, with horizons, contains the Schwarzschild solution but
includes also non-Schwarzschild black holes. The third family of solutions
obtained from the Frobenius analysis is nonsingular and corresponds to `vacuum'
solutions. In addition to the three families identified from near-origin
behaviour, there are solutions that may be identified as `wormholes', which can
match symmetrically on to another sheet of spacetime at finite radius.Comment: 57 pages, 6 figures; version appearing in journal; minor corrections
and clarifications to v
Mapping the dynamic interactions between vortex species in highly anisotropic superconductors
Here we use highly sensitive magnetisation measurements performed using a
Hall probe sensor on single crystals of highly anisotropic high temperature
superconductors to study the dynamic interactions
between the two species of vortices that exist in such superconductors. We
observe a remarkable and clearly delineated high temperature regime that
mirrors the underlying vortex phase diagram. Our results map out the parameter
space over which these dynamic interaction processes can be used to create
vortex ratchets, pumps and other fluxonic devices.Comment: 7 pages, 3 figures, to be published in Supercond. Sci. Techno
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
A Study of Educational Simulations Part I - Engagement and Learning
Interactive computer simulations with complex representations and sophisticated graphics are a relatively new addition to the classroom, and research in this area is limited. We have conducted over 200 individual student interviews during which the students described what they were thinking as they interacted with simulations. These interviews were conducted as part of the research and design of simulations for the Physics Education Technology (PhET) project. PhET is an ongoing project that has developed over 60 simulations for use in teaching physics, chemistry, and physical science. These interviews are a rich source of information about how students interact with computer simulations and what makes an educationally effective simulation. We have observed that simulations can be highly engaging and educationally effective, but only if the student's interaction with the simulation is directed by the student's own questioning. Here we describe our design process, what features are effective for engaging students in educationally productive interactions and the underlying principles which support our empirically developed guidelines. In a companion paper we describe in detail the design features used to create an intuitive simulation for students to use
Developing and Researching PhET simulations for Teaching Quantum Mechanics
Quantum mechanics is difficult to learn because it is counterintuitive, hard
to visualize, mathematically challenging, and abstract. The Physics Education
Technology (PhET) Project, known for its interactive computer simulations for
teaching and learning physics, now includes 18 simulations on quantum mechanics
designed to improve learning of this difficult subject. Our simulations include
several key features to help students build mental models and intuitions about
quantum mechanics: visual representations of abstract concepts and microscopic
processes that cannot be directly observed, interactive environments that
directly couple students' actions to animations, connections to everyday life,
and efficient calculations so students can focus on the concepts rather than
the math. Like all PhET simulations, these are developed using the results of
education research and feedback from educators, and are tested in student
interviews and classroom studies. This article provides an overview of the PhET
quantum simulations and their development. We also describe research
demonstrating their effectiveness and share some insights about student
thinking that we have gained from our research on quantum simulations.Comment: accepted by American Journal of Physics; v2 includes an additional
study, more explanation of research behind claims, clearer wording, and more
reference
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