arXiv subjects

Alejandro Gangui

Publications and source records attributed to Alejandro Gangui.

At least 73 records · Page 4Linked to original sources

arXiv2010

Some remarks on a current study involving preservice elementary teachers and some basic astronomical phenomena

Recent studies have shown that not only primary school students but also their future teachers reach science courses with pre-constructed and consistent models of the world surrounding them. These ideas include many misconceptions which turn out to be robust and hence make difficult an appropriate teaching-learning process. We have designed some tools that proved helpful in putting in evidence some of the most frequently used alternative models on a few basic astronomical notions. We have tested these tools with preservice elementary teachers from various normal schools in Buenos Aires and made a first analysis of the results. The collection of data recovered so far shows that some non-scientific conceptions are indeed part of the prospective teachers' (scientific) background and that, therefore, the issue deserves special attention during their formal training.

physics.ed-ph↗

arXiv2009

The National Library of Argentina: exhibiting astronomy-related rare books

Astronomical and cosmological knowledge up to the dawn of modern science was profoundly embedded in myth, religion and superstition. Many of these inventions of the human mind remain today stored in different supports: medieval engravings, illuminated manuscripts, and of course also in old and rare books.

physics.hist-ph↗

arXiv2009

The movement of shadows: a teaching proposal for the secondary school

A didactic sequence of activities on some topics of Astronomy, related mainly with the length and orientation of shadows cast by a gnomon, the movement of shadows during daytime in different seasons of the year, and finding the true astronomical North, is fully developed. It also includes a discussion of observations from different frames of reference and of some topics in the history of science to enrich a debate among students, as well as the construction of a simplified model for the apparent displacement of the Sun, and of a sundial, and their use as resources to discuss some common misconceptions found in students. Multiple suggestions and clear guides are given for teachers of secondary education to implement theses activities in their classes.

physics.ed-ph↗

arXiv2009

Unpublished opening lecture for the course on the theory of relativity in Argentina, 1925

Honorable Rector, Honorable Professors, and Students of this University: In these times of political and economic struggle and nationalistic fragmentation, it is a particular joy for me to see people assembling here to give their attention exclusively to the highest values that are common to us all. I am glad to be in this blessed land before a small circle of people who are interested in topics of science to speak on those issues that, in essence, are the subject of my own meditations.. [abridged].

physics.hist-ph↗

arXiv2009

Einstein's unpublished opening lecture for his course on relativity theory in Argentina, 1925

In 1922 the University of Buenos Aires (UBA) Council approved a motion to send an invitation to Albert Einstein to visit Argentina and give a course of lectures on his theory of relativity. The motion was proposed by Jorge Duclout (1856-1927), who had been educated at the Eidgenossische Technische Hochschule, Zurich (ETH). This proposal was the culmination of a series of initiatives of various Argentine intellectuals interested in the theory of relativity. In a very short time Dr. Mauricio Nirenstein (1877-1935), then the university's administrative secretary, fulfilled all the requirements for the university's invitation to be endorsed and delivered to the sage in Berlin. The visit took place three years later, in March-April 1925. The Argentine press received Einstein with great interest and respect; his early exchanges covered a wide range of topics, including international politics and Jewish matters. Naturally, the journalists were more eager to hear from the eminent pacifist than from the incomprehensible physicist. However, after his initial openness with the press, the situation changed and Einstein restricted his public discourse to topics on theoretical physics, avoiding some controversial political, religious, or philosophical matters that he had freely touched upon in earlier interviews.. [abridged].

physics.hist-ph↗

arXiv2009

Motion of the heavens: a pedagogical proposal for secondary education teachers

First part of a didactic sequence of activities on some topics of Astronomy, related mainly with the day and night cycle and the seasons, including the construction of a simplified solar system model and its use as a resource to discuss some common misconceptions found in students. Multiple suggestions and clear guides are given for teachers of the first two years of secondary education to implement theses activities in their classes.

physics.pop-ph↗

arXiv2009

Precession of the Equinoxes: a pedagogical proposal for secondary education teachers

Second part of a didactic sequence of activities on some topics of Astronomy, related mainly with the real shape of the Earth, the gravitational interactions between our planet and other celestial bodies, and the resulting movement of the rotational axis of the Earth, leading to the precession of the equinoctial points. All elements are given for the construction of a simplified Sun-Earth system model, with a zodiacal band surrounding it, in order to show in a pedagogical manner how precession involves a shift of the zodiacal constellations in time.

physics.pop-ph↗

arXiv2008

First echoes of relativity in Argentine astronomy

We consider the attitude of astronomers in Argentina in connection with the new problems posed by relativity theory, before and after GR was presented. We begin considering the sequence of "technical" publications that appeared and use it to attempt to identify who were the relativity leaders and authors in the Argentina scientific community of the 1910-1920s. Among them there are natives of Argentina, permanent resident scientists, and occasional foreign visitors. They are either academic scientists, or high school teachers; we leave aside the {\it philosophers} and the {\it aficionados}. We discuss the scientific facts and publications they handled, the modernity of their information and the "language" they use to transmit their ideas. Finally, we consider astronomers proper; first Charles Perrine, an astronomer interested in astrophysics, contracted by the government of Argentina in the USA as director of its main observatory. He became interested in testing the possible deflection of light rays by the Sun towards 1912; his Argentine expedition was the first to attempt that test. Perhaps Perrine was not so much interested in relativity as in testing the particular astronomical effects it predicted. In any case, he attempted the test with the acquiescence and financial support of the Argentine state, and as a leading member of its official scientific elite. We contrast his very specific and strictly scientific efforts with those of our second astronomer, José Ubach, SJ, a secondary school teacher of science at a leading Buenos Aires Catholic school who reported in response to Eddington's expedition. Finally, our third astronomer is Félix Aguilar, who made an effort to contribute to the public understanding of Einstein's theories in 1924, when Einstein's visit to Argentina had become a certainty. [abridged]

physics.hist-ph↗

arXiv2008

Situational diagnosis for preservice elementary teachers on some basic astronomical phenomena

The present situation of the teaching-learning relationship in astronomy is rarely investigated in our country. This is so, even when it is widely recognized that astronomy is an integral discipline, at the crossroads of advances in physics, geology, chemistry, etc. In this project we aim at contributing with the situational diagnosis in topics of astronomy of preservice elementary teachers, and to try and develop didactic tools that better collaborate with their formal education. We work with an open written questionnaire, designed to put in evidence some of the most frequently used models on a few basic astronomical notions. We here describe the main questions included in the test, and show our first results and some conclusions after having addressed the questionnaire to a number of preservice elementary teachers.

physics.ed-ph↗

arXiv2008

Dante, astrology and astronomy

Some verses of Dante Alighieri suggest his astrological sign and his probable date of birth. This leads us to reflect on the different methods, increasingly divergent, with which sciences as opposed to beliefs approach reality.

physics.hist-ph↗

arXiv2008

Astronomy at school: present situation and future perspectives

Both the basic educational contents for students and study programs for science teachers include several topics in physics and astronomy, from the simplest ones to others as advanced as nuclear fusion to explain stellar evolution and space-time geometry for an approach to modern cosmology. In all these subjects, and most often in the simplest ones, alternative conceptions emerge, as both groups reach science course with preconstructed and consistent models of the universe surrounding them. In this work we present a series of basic questionings that make us reflect on the present situation of the teaching-learning relationship in astronomy within the framework of formal education. We then briefly explain our project aiming at finding the real learning situation of both students and prospective primary-school teachers in astronomical topics and, from the expected results of it, we point towards the need to develop didactic tools that could contribute to improve formal education in astronomy issues.

physics.ed-ph↗

arXiv2008

The "inedito" of Einstein and his 1925 visit to Buenos Aires

In an article published by Mauricio Nirenstein in 1925, a few months after the visit of Albert Einstein to Argentina, the author wrote various comments and references relative to the scientist's visit. In particular, Nirenstein mentioned a personal conversation he had with Einstein in which the sage expressed many interesting ideas on the epistemology of physical sciences. In a note to that article, it was indicated that Einstein would have left in the hands of Nirenstein some notes of a speech he wanted to deliver at the University of Buenos Aires. From 1931 onwards there appeared in a few journals of this city, different versions of what became known as the "inedito" of Einstein. In this paper we discuss both the facts and the individuals. We analyse briefly the "inedito" and we compare it with the two introductory lectures Einstein delivered at the University of Buenos Aires and at the Faculty of Science.

physics.hist-ph↗

arXiv2008

The cosmology of the Divine Comedy

Since the time of ancient civilizations, cosmology had a privileged place within the various artistic and literary manifestations. The Divine Comedy by Dante Alighieri, one of the masterpieces in literature and thought of the Western World, is organized on the image of the cosmos of the XIII century, which is analyzed in this article.

physics.hist-ph↗

arXiv2007

El universo de Einstein: 1905 - annus mirabilis - 2005

Year 2005 was the World Year of Physics, and it was commemorated worldwide as the 100th anniversary of Albert Einstein's legendary works in which the foundations of at least three areas of modern physics were laid: statistical mechanics, quantum mechanics and special relativity. These works turned year 1905 in what deservedly was called the "miraculous year" (annus mirabilis) of Einstein. However, the influence of this great mind was not limited to science. As it is well known, his fingerprint remains engraved in many aspects of our daily life. Because of that, in this work we have tried to cover almost all the subjects in which Einstein was involved during the last century and, of course, try and reveal the future projection his actions will have in this new century that has just begun. Among the subjects covered in the volume one can find the possible connection between Einstein and the artistic vanguard movement, his religiosity, his days in Argentina, the Nobel Prize, the Einstein-Freud correspondence, his pacifism and the nuclear energy, science and politics under the Second Empire and the Weimar Republic, and even a description of his patents and experiments, the studies performed to search for "built-in" features in his brain and the doubts many had regarding whether Einstein was a genius or a crank. Also included are essays on Einstein and Borges, philosophy and relativity, Mach's principle, the relation among science, arts and humanities, and, closer to Einstein's own theoretical research, the twin paradox, chance and quantum mechanics, the arrow of time, gravitational lenses, string theory, holography and black holes, gravitomagnetism, superconductivity, gravitational waves, the photoelectric effect and the alternative theories for gravitation.

physics.hist-ph↗

arXiv2005

Albert Einstein visits Argentina

This is a detailed, day by day, account of Albert Einstein's activities, both social and scientific, during his 30-day stay in Argentina in 1925, including his lectures on relativity at the various local universities and his visit to the National Academy of Sciences, as follows from his personal Diary of the trip to South-America and other contemporary documents.

physics.hist-ph↗

arXiv2003

Cosmology from Topological Defects

The potential role of cosmic topological defects has raised interest in the astrophysical community for many years now. In this set of notes, we give an introduction to the subject of cosmic topological defects and some of their possible observable signatures. We begin with a review of the basics of general defect formation and evolution, we briefly comment on some general features of conducting cosmic strings and vorton formation, as well as on the possible role of defects as dark energy, to end up with cosmic structure formation from defects and some specific imprints in the cosmic microwave background radiation from simulated cosmic strings. A detailed, pedagogical explanation of the mechanism underlying the tiny level of polarization discovered in the cosmic microwave background by the DASI collaboration (and recently confirmed by WMAP) is also given, and a first rough comparison with some predictions from defects is provided.

astro-ph↗

arXiv2003

A Preposterous Universe

Recent announcements that the Cosmic Microwave Background (CMB) - the faint remnant of the Big Bang - is polarized have caused a stir among cosmologists. Such polarization has long been predicted but could not be detected, until the recent DASI and WMAP detections. The polarization is a signature of the motion of the primordial seeds that led to the galaxies and large-scale structure of the Universe observed today. Earlier measurements of tiny temperature fluctuations in the CMB have been used to infer the sizes of the primordial seeds. The polarization signature should help to determine the fundamental parameters of cosmology and to explain how large-scale structure arose [Highwire abstract].

astro-ph↗

arXiv2003

Early Universe Sources for Cosmic Microwave Background Non-Gaussianity

In the framework of inflationary models with non-vacuum initial states for cosmological perturbations, we study non-Gaussian signatures on the cosmic microwave background radiation produced by a broken-scale-invariant model which incorporates a feature at a privileged scale in the primordial power spectrum.

astro-ph↗