The ability to solve physics problems in symbolic and numeric representations

The aim of this study is to analyze the ability of students to solve the problems of linear motion kinematics expressed in symbolic and numeric representation. Research was survey with cross-sectional design. Research subjects included 26 first year undergraduate students in physics at one of the State Universities in Malang which was consisted of 10 men and 16 women. The research instrument was open-ended test of linear motion kinematics problems expressed in symbolic and numeric representations with a reability of 0,807 The research data were analyzed using descriptive and non-parametric inferential statistics. The results showed that the ability of students to solve linear motion kinematics problems in both symbolic and numeric representation was medium. Students had difficulty solving physical problems in both symbolic and numeric representations. It was also found that the problems of linear motion kinematics in symbolic representations were more difficult for students to solve than numeric representations. The study suggested further research to explore the causes of student difficulties more authentically, e.g. by interviewing or thinking aloud.

Green function for the Grad-Shafranov operator

The Grad-Shafranov equation, often written in cylindrical coordinates, is an elliptic partial differential equation in two dimensions. It describes magnetohydrodynamic equilibria in axisymmetric toroidal plasmas, such as tokamaks, and yields the poloidal magnetic flux function, which is related to the azimuthal component of the vector potential for the magnetic field produced by a circular (toroidal) current density. The Green function for the differential operator can be obtained from the vector potential for the magnetic field of a circular current loop, which is a typical problem in magnetostatics. The purpose of the paper is to collect results scattered in electrodynamics and plasma physics textbooks for the benefit of students in the field, as well as attracting the attention of a wider audience, in the context of electrodynamics and partial differential equations.

The quantum beam splitter revisited without a vacuum state

In this article we explain in a new light two fundamental concepts ofquantum optics, the quantum beam splitter and the quantum interferometer, in termsof two state quantum wave functions. This method is consistent with the concept ofentanglement, and hence the algebra needed to describe them is reduced to additionsand products of the components of the quantum states. Furthermore, under thepremises of this method it is possible to study quantum states of greater complexity,like those arising from the addition and products of single photon states.

The misconception in graphene’s dispersion energy simulations

This study aims to find equations and simulations that satisfy the characteristics of graphene’s energy dispersion and identify misconceptions that may occur. Here we give students nine articles about graphene’s dispersion energy. They were asked to identify the equations, parameters, and software used in each of the articles. The assignment was then to make the distribution of the data in a spreadsheet. The parameters used were the lattice constant of 2.46 Å, the range of the k wave function for the x and y axes of -2πa to 2πa, and the interval for each range of 0.1. Each equation is divided into two parts, E(+) and E(-). The analysis was carried out by making a slice in the middle of the x and y axes, as well as the main and off-diagonals. Graphene has Dirac points where the band gap is zero. This means that there is no distance or very small distance between the valence and conduction bands. From this activity, it can be concluded that Rozhkov (2016) has the equations and simulations that best satisfy graphene’s dispersion energy. Misconceptions occur in almost all existing equations and simulations.

Strategies of Physics Learning Based on Traditional Games in Senior High Schools during the Covid-19 Pandemic

Physics learning during the Covid-19 pandemic must still be done so that students can still get physics intake. This phenomenological research aims to explore physics teacher strategies in conducting traditional game-based learning in senior high schools during the Covid-19 pandemic. The research data was collected through in-depth interviews with 10 physics teachers from five senior high schools in Yogyakarta. The ten participants were taken using the purposive sampling technique. The data analysis used analytic reduction which started with identifying important statements from the interview results, determining the core theme, and interpreting the physics learning strategy essence. The research results found that traditional game-based physics learning was carried out using contextual, inquiry, project, and problem-based learning models. The physics material is integrated into traditional games which include tulup, benthik, bekelan, sulamanda, egrang, sekongan, jeblugan, and gobak sodor. Physics learning evaluation is carried out by assessing assignments, performance, presentations, tests, and the results of making students' traditional games. Traditional game-based physics learning is done through distance learning applications such as Zoom, Google Meet, Google Classroom, Google Mail, and WhatsApp. Supporting factors for learning physics based on traditional games include efficient learning, learning can be done anywhere, and students can explore their abilities widely. Inhibiting factors for learning physics based on traditional games include unstable internet networks, students’ different abilities, and never done distance learning. The physics teacher’s competence, the student’s abilities, and the facilities availability are the main factors in determining the learning physics success based on traditional games during the Covid-19 pandemic.

Falsos Positivos de la ciencia.

Un falso positivo en la ciencia, es un descubrimiento anunciado y luego rebatido; la historia de los falsos positivos ilustra el proceso científico y la cultura en la cuál éste está inmerso. En el anuncio de un descubrimiento falso juegan tanto las fluctuaciones estadísticas como los errores sistemáticos de los experimentos, la ambición de los científicos, y las expectativas y esperanzas de las comunidades investigadoras. También las prácticas y los estándares de revisión; en el camino a la construcción de un consenso científico hay obstáculos tanto de carácter social como metodológico. En el caso particular de las matemáticas tenemos el caso de la prueba fallida, en donde un error lógico o conceptual lleva al anuncio de un resultado correcto al que se llega por un argumento erróneo. En este trabajo se discute la historia de las demostraciones fallidas en matemáticas tal como es el caso de Vladimir Voevodsky, la controversia sobre el efecto Mpemba, el fiasco del exceso de difotones a 750 GeV en el Gran Colisionador de Hadrones, y el caso de deshonestidad científica de Jan Hendrik Schön.

Didactical situations to treat Lorentz and Galileo transformations in theoretical physics

Notions of Electromagnetism and Special Theory of Relativity (STR) require important mathematical knowledge applied to theoretical physics. Recognizing pedagogical difficulties in the teaching of theoretical physics, the Theory of Didactical Situations (TDS), which consists of a set of practices that aim to contribute to the improvement of mathematics teaching. In this context, the present work is motivated to present a set of practices based on TDS with a focus on teaching Electromagnetism and STR, where problems that require an understanding of the transformations of Galileo and Lorentz. Specifically, the didactic situation is constructed by means of four problem proposals, while in the adidatic situation, the student is invited to understand the roles of these transformations in the study of these problems. Ultimately, the relevance of the educator in the institutionalization situation is reinforced, a moment when it must be clarified how all mathematical relations are strongly related to physical principles.

Método conservativo de diferencias finitas de alto orden para una clase de sistemas de Schrödinger no lineales

Se presenta un método en tiempo para aproximar la solución de una clase de sistemas de ecuaciones no lineales de Schrödinger, el cual conserva la potencia de cada componente y el Hamiltoniano del sistema de manera exacta. Para la discretización espacial se consideran fórmulas explı́citas y compactas de diferencias finitas, ambas de cuarto y sexto orden, sin embargo fórmulas de mayor orden también podrı́an ser utilizadas. La técnica para avanzar en tiempo se basa en unamodificación del esquema conservativo de Crank-Nicolson, la cual se aplica de manera secuencial a cada una de las componentes del campo vectorial. La conservación de los invariantes discretos y el orden de convergencia del método se validan por medio de una serie de experimentos numéricosutilizando diferentes potenciales no lineales.

Heating up a lantern with a tealight candle

This paper provided physics principles and a method to heating up a lantern with a tealight candle, so it reaches 2.5 m within the shortest time. The experiments aimed to determine optimal parameters in filling paper lanterns with hot air and the ideal shape of lanterns that would travel most quickly in a vertical direction. Hot air from burning a 28-wick candle was directed through a heat transfer system to fill the lanterns. The small ellipsoid lantern required the shortest time. This problem is suitable as a platform for STEM education approach on topics of convection, buoyancy and drag force.

La conceptualización errada del campo eléctrico con cálculo integral en clases virtuales en estudiantes de física aplicada

En este trabajo se replicó un método basado en el teorema de Vergnaud sobre la conceptualización del campo eléctrico con cálculo integral realizado en una universidad privada de la ciudad de Guayaquil. El objetivo de este estudio es relacionar y conectar la interacción que existe entre el dominio conceptual – epistemológico (Saber comprender) con el hacer del dominio metodológico (Saber hacer) con el propósito de ampliar y profundizar el concepto mediante la experimentación a través de un material instruccional en las clases virtuales (Teoría de Gagné). Nuestro trabajo se fundamenta en la investigación acción con un enfoque explicativo, ya que desde la óptica de la práctica pedagógica pretendemos dar respuesta a los problemas de conceptualización sobre las variables que participan en el campo eléctrico. El diseño del estudio es experimental se trabajó con grupos intactos, uno de control (Gc) y otro experimental (Ge). Los resultados indican que el grupo experimental desarrolló una mejor conceptualización en los contenidos de campo eléctrico con cálculo integral a diferencia del grupo de control que recibió una instrucción tradicional.