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Do students know what they know?

Exploring the accuracy of students’ self-assessments
Beth A. Lindsey and Megan L. Nagel
We have conducted an investigation into how well students in introductory science classes (both physics and chemistry) are able to predict which questions they will or will not be able to answer correctly on an upcoming assessment. An examination of the data at the level of students’ overall scores reveals results consistent with the Dunning-Kruger effect, in which low-performing students tend to overestimate their abilities, while high-performing students estimate their abilities more accurately. Similar results have been widely reported in the science education literature. Breaking results out by students’ responses to individual questions, however, reveals that students of all ability levels have difficulty distinguishing questions which they are able to answer correctly from those that they are not able to answer correctly. These results have implications for the future study and reporting of students’ metacognitive abilities.
Read more at journals.aps.org

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A Pedagogical Model of Static Friction

frictionWhile dry Coulombic friction is an elementary topic in any standard introductory course in mechanics, the critical distinction between the kinetic and static friction forces is something that is both hard to teach and to learn.
In this paper, I describe a geometric model of static friction that may help introductory students to both understand and apply the Coulomb static friction approximation….
Read more at http://arxiv.org/pdf/1507.04015v1.pdf

Measuring the speed of light and the moon distance with an occultation of Mars by the Moon

a Citizen Astronomy Campaign

Zuluaga et al
In July 5th 2014 an occultation of Mars by the Moon was visible in South America.
Citizen scientists and professional astronomers in Colombia, Venezuela and Chile performed a set of simple observations of the phenomenon aimed to measure the speed of light and lunar distance.
This initiative is part of the so called “Aristarchus Campaign”, a citizen astronomy project aimed to reproduce observations and measurements made by astronomers of the past.
Participants in the campaign used simple astronomical instruments (binoculars or small telescopes) and other electronic gadgets (cell-phones and digital cameras) to measure occultation times and to take high resolution videos and pictures.
In this paper we describe the results of the Aristarchus Campaign.
We compiled 9 sets of observations from sites separated by distances as large as 2,500 km. We achieve at measuring the speed of light in vacuum and lunar distance with uncertainties of few percent.
The goal of the Aristarchus Campaigns is not to provide improved values of well-known astronomical and physical quantities, but to demonstrate how the public could be engaged in scientific endeavors using simple instrumentation and readily available technological devices.
These initiatives could benefit amateur communities in developing countries increasing their awareness towards their actual capabilities for collaboratively obtaining useful astronomical data.
This kind of exercises would prepare them for facing future and more advanced observational campaigns where their role could be crucial.
Read nore at http://arxiv.org/abs/1506.00346

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A brief history of physics education in the United States

HS physicsIn order to provide insight into current physics teaching practices and recommended reforms, we outline the history of physics education in the United States—and the accompanying pedagogical issues and debates—over the period 1860–2014. We identify key events, personalities, and issues for each of ten separate time periods, comparing and contrasting the outlooks and viewpoints of the different eras.

This discussion should help physics educators to (1) become aware of previous research in physics education and of the major efforts to transform physics instruction that have taken place in the U.S., (2) place the national reform movements of today, as well as current physics education research, in the context of past efforts, and (3) evaluate the effectiveness of various education transformation efforts of the past, so as better to determine what reform methods might have the greatest chances of success in the future…
… Read more at physicseducation.net

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An Exploration of the Limits of the Maxwell-Boltzmann Distribution

The probability distribution of speeds is given in terms of the dimensionless variable x = v/vp, where vp is the most probable speed.

The probability distribution of speeds is given in terms of the dimensionless variable x = v/vp, where vp is the most probable speed.

Yi-Chi Yvette Wu, L. H. Ford
Selected aspects of the Maxwell-Boltzmann for molecular speeds are discussed, with special attention to physical effects of the low speed and high speed limits. We use simple approaches to study several topics which could be included in introductory courses, but are usually only discussed in more advanced or specialized courses…
… Read more at http://arxiv.org/pdf/1410.6965v1.pdf