1,720,961 research outputs found
Static properties of a spool on an incline: An IBSE lecture proposal
No full textThe static equilibrium properties of a spool, resting on an incline and subject
to the tension exerted by a string wrapped around the core cylinder, are
studied by means of Newtonian mechanics. The overall behaviour of this
system is imagined to be similar to that of a doggie kept on a leash. Starting
from the well-known mechanical properties of the spool on a horizontal
plane, this analogy is used to construct an inquiry-based-learning lecture
adopting the BSCS 5E instructional model. In this approach the static
properties of the spool on the incline are used to conceive an Extend phase
A physical point of view on the arithmetic and geometric mean inequality
No full textWe propose a simple experiment designed to justify the arithmetic and geometric mean inequality by means of the laws of thermodynamics. The experiment consists in measuring the entropy variation Δ S in the thermodynamic irreversible process of cooling a metal in water. By considering the metal and water as a single isolated system, the arithmetic and geometric theorem is seen to hold by noticing that Δ S is positive for this irreversible transformation. These interdisciplinary activities may be used to reinforce basic concepts in thermodynamics in high school or first-year college students
The dynamics of water micro-particles in air
No full textThe dynamics of water micro-particles in air can be studied by introducing a viscous force in the equations of the motion, in addition to the weight of the particle and the buoyance force. In this work, by taking account of the buoyance force, the range of the micro-particle is calculated as a function of the angle at which it is released. An analytic-numerical procedure to find the angle giving the maximum range is indicated. The effect of a convective air flow is finally studied
Real-world phenomena as useful tools in physics teaching
No full textDelightful real-world phenomena may capture the attention of students and may trigger their curiosity. The rolling of a food can on a conveyor belt in a grocery store, the observation of the optimal angle in a shotput contest or of the way a sprinter runs, the appearance of a coloured line on a CD or a DVD under white light, the spectacular dance of sun glints on the shallow waters by the seashore are all phenomena which can be proposed to high-school or undergraduate college students in the "engagement" phase of a lecture in which the Inquiry-Based Learning approach is used. In this work we propose these examples along with a brief justification, based on elementary physics principles, of the observed phenomena
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Interacting charges and the classical electron radius
No full textThe equation of the motion of a point charge q repelled by a fixed point-like charge Q is derived and studied. In solving this problem useful concepts in classical and relativistic kinematics, in Newtonian mechanics and in non-linear ordinary differential equations are revised. The validity of the approximations is discussed from the physical point of view. In particular the classical electron radius emerges naturally from the requirement that the initial distance is large enough for the non-relativistic approximation to be valid. The relevance of this topic for undergraduate physics teaching is pointed out
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Training teachers: Explorative activities measuring Planck's constant
No full textIn recent years, Modern Physics has been included in the curricula of Italian secondary schools, so that many teachers are asking for specific didactical tools to allow their students to acquire the right skills to deal with final examinations. The Physics Department at University of Salerno (Italy) is, therefore, planning PLS (Piano Lauree Scientifiche / Scientific Degree Project) training courses to give some valid educational paths through new didactical strategies for Physics learning. Introducing quantum mechanics by experimental set-ups with commonly used materials is a rather interesting and challenging task. In fact, this practice allows teacher attending the course to reproduce the same experiments in their own class. Moreover, by using readily available material for the experimental set-up, a soft approach to Modern Physics can be achieved. In the present work, we propose the analysis of an experiment: the measurement of Planck's constant, one of the most important fundamental quantities in Modern Physics, by means of Light Emitting Diodes (LEDs). The properties of LEDs can be explained by means of elementary quantum mechanics concepts. As a consequence, when describing the quantum behaviour of these commonly used physical systems, Planck's constant needs to be considered. Therefore, to illustrate one possible way of measuring Planck's constant to high-school students, we can make use of the current-voltage (I-V) characteristics of a LED. In fact, by opportunely interpreting the measured I-V curves of these systems, by means of a linear fitting the value of Planck's constant can be obtained
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