Smartphones as experimental tools to measure acoustical and mechanical properties of vibrating rods

Modern smartphones have calculation and sensor capabilities that make them suitable for use as versatile and reliable measurement devices in simple teaching experiments. In this work a smartphone is used, together with low cost materials, in an experiment to measure the frequencies emitted by vibrating rods of different materials, shapes and lengths. The results obtained with the smartphone have been compared with theoretical calculations and the agreement is good. Alternatively, physics students can perform the experiment described here and use their results to determine the dependencies of the obtained frequencies on the rod characteristics. In this way they will also practice research methods that they will probably use in their professional life

Smartphones on the air track. Examples and difficulties

In this paper we describe a classical experiment with an air track in which smartphones are used as experimental devices to obtain physical data. The proposed experiment allows users to easily observe and measure relationships between physical magnitudes, conservation of momentum in collisions and friction effects on movement by utilizing the users’ own mobile devices

El laboratorio en el bolsillo: Aprendiendo física con tu smartphone

La enseñanza de la física está fuertemente basada en el trabajo experimental de los alumnos. El trabajo en el laboratorio les permite aprender el uso de material y técnicas experimentales o de análisis, pero también las limitaciones de las leyes teóricas y de los datos obtenidos en el laboratorio. Se trata, entonces, de un trabajo fundamental para un aprendizaje y comprensión más completos de la física y debe entonces reforzarse, tanto desde un punto de vista práctico como haciéndolo más atractivo y motivando el trabajo autónomo de los alumnos. En muchas situaciones, sin embargo, razones presupuestarias o de número de alumnos limitan las posibilidades de trabajo experimental de los estudiantes. En este artículo divulgativo mostramos cómo los teléfonos móviles, que todos los alumnos llevan consigo casi de manera permanente, pueden convertirse en herramientas muy útiles tanto para realizar algunos experimentos sencillos de física como para motivar el trabajo personal de los alumnos y hacerles más interesante y atractivo el aprendizaje de la física

Física en el Bolsillo

Innovación EducativaLos sensores de los smartphones permiten la utilización de estos en el aprendizaje práctico de la física tanto en el laboratorio como fuera de el. Se presentan algunos ejemplos de experiencias realizadas con estos dispositivosFísica AplicadaDepartamento de Física de la Materia CondensadaPonencia invitada en las XI Jornadas de Enseñanza de la Física, que tuvieron lugar en la Universidad de Burgos en septiembre de 2016

Measuring the coefficient of restitution and more: a simple experiment to promote students’ critical thinking and autonomous work

Innovación EducativaAbstract A simple experiment on the determination of the coefficient of restitution of different materials is taken as the basis of an extendable work that can be done by the students in an autonomous way. On the whole, the work described in this paper would involve concepts of kinematics, materials science, air drag and buoyancy, and would help students to think of physics as a whole subject instead of a set of, more or less, isolated parts. The experiment can be done either in teaching laboratories or as an autonomous work by students at home. Students’ smartphones and cheap balls of different materials are the only experimental materials required to do the experiment. The proposed work also permits the students to analyse the limitations of a physical model used in the experiment by analysing the approximations considered in it, and then enhancing their critical thinking

Bosonization on a lattice: The emergence of the higher harmonics

6 págs.; 2 figs.A general and transparent procedure to bosonize fermions placed on a lattice is presented. Harmonics higher than kF in the one-particle Green function are shown to appear due to the compact character of real electron bands. Quantitative estimations of the role of higher harmonics are made possible by this bosonization technique. © 1995 The American Physical Society.J.F. was supported by DEYCIT Project No. PB93-1248.Peer Reviewe

GIREP

Transparencias de la charla que se impartirá en el congreso GIREP que se celebrará en julio de 2017 en Dubli

Isolated HBsAg positivity in a Mexican patient with newly diagnosed lupus nephritis

Abstract Introduction: Hepatitis B surface antigen (HBsAg) is usually regarded as a marker of hepatitis B virus (HBV) infection. The concurrence of lupus nephritis (LN) and HBsAg-positivity is a challenge for the clinician, since immunosuppressant use may be associated with an increase in viral replication and an exacerbation of liver disease. Case presentation: Here, we describe the case of a 30-year-old Mexican woman with newly diagnosed focal proliferative LN who also tested repeatedly positive for HBsAg by chemiluminescent microparticle immunoassay (CMIA). She had no clinical features of hepatitis and her liver function tests were within normal limits. Her abdominal ultrasound was also normal. While waiting for further results, she was started on lamivudine (100 mg daily). However, total HBV core antibody test was negative. Owing to the infrequency of this serological pattern, an in vitro polymerase chain reaction (PCR) assay was performed and HBV was not detected. Overall, we interpreted these results as a false-positive screening. Methylprednisolone pulse therapy was subsequently given (1 g daily for three doses) without hepatic repercussion, neither clinically nor biochemically. Conclusions: Isolated HBsAg positivity may result from multiple causes, one of which is crossreactivity. To the best of our knowledge, this is the first report of a false-positive reading using CMIA technique in an active lupus patient. It is reasonable to stress that lupus patients with a positive screening for HBV should undergo a confirmatory assay (such as genomic detection), since this diagnosis may have important therapeutic implications. � 2016 Egyptian Society of Rheumatic Diseases. Publishing services provided by Elsevier. B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/

Experimentando y Aprendiendo Física con Smartphones

For a better understanding and learning physics students need practical experimentation as much as teachers' theoretical explanations. Sometimes experimental equipment costs or time availability limit the students work in the laboratory. Current smartphones are powerful calculation devices with built-in sensors which can be used as measurement tools in many simple physics experiments by replacing more expensive laboratory equipment and also allow the students to do experiments by themselves along everyday activities increasing students' autonomous work and engagement. In this work we describe briefly some experiments performed with smartphones and discuss their results and learning interest