arXiv subjects

Martín Monteiro

Publications and source records attributed to Martín Monteiro.

At least 19 recordsLinked to original sources

arXiv2026

Uniform and Accelerated Circular Motion with a Smartphone: A No-Code, AI-Generated Browser Laboratory

Smartphones have become a standard measurement instrument in the physics laboratory. Their built-in accelerometers, gyroscopes, magnetometers, and cameras have been used to investigate a wide range of phenomena in mechanics, and rotational motion in particular has proven especially well-suited to smartphone-based experiments. A recurring limitation, however, is that most experiments rely on precompiled sensor apps whose interfaces cannot be tailored to a specific activity, and until recently creating customized smartphone laboratories required programming knowledge beyond what most physics teachers possess. This paper makes two connected contributions. First, we present a validated smartphone experiment for uniform circular motion (UCM) and uniformly accelerated circular motion (UACM), in which the angular velocity and the angular acceleration are obtained from two independent smartphone channels and checked against independent video analysis with Tracker.10,14 Second, we show that generative AI can serve as a no-code development tool for the physics laboratory: the browser-based application used here was produced entirely through natural-language prompting, with no manual coding, extending to rotational motion the approach we recently introduced for acoustic experiments. The emphasis is therefore not only on what is measured, but also on how the measuring instrument itself was built.

physics.ed-ph↗

arXiv2025

Enhancing Kinematics Understanding Through a Real-Time Graph-Based Motion Video Game

Kinematics is a core topic in early physics courses, yet students often struggle to interpret motion and its graphical representations. To tackle these difficulties, we developed MissionMotion, a physical-computational videogame where students reproduce target motion graphs using real-time data from their own movements or from sensors connected through micro:bit or Arduino. The system displays both the target and the user-generated graph, providing immediate visual feedback and a score based on similarity. We piloted the environment with ninth-grade students in different school contexts and evaluated their experience using the MEEGA+ instrument. The results show strong engagement, positive perceptions of usability, and evidence that the game promotes reflection on motion graphs in ways that rarely emerge in traditional lessons. MissionMotion runs on any web-enabled device and all materials are openly available, offering teachers an accessible tool to integrate experimentation, computational thinking, and playful learning into physics classrooms.

physics.ed-ph↗

arXiv2025

Enhancing Kinematics Understanding through a Video Game Based on Real-Time Motion Graphs

Interpreting kinematic graphs remains a significant challenge in physics education. The MissionMotion Project addresses this issue by providing a gamified physical-computational environment combining low-cost sensors, physical activity, computational thinking, and real-time visualization of motion graphs. This paper presents the design, development, and implementation of the project, with a particular focus on the pilot phase conducted with high school students in Uruguay. During this phase, we primarily used the MEEGA+ questionnaire to evaluate the gaming experience, usability, and motivation of the participants. Our analysis of the results shows high levels of satisfaction, perceived learning, and engagement, supporting the proposal's viability. Finally, we plan to conduct a large-scale conceptual evaluation to analyze how the proposal impacts understanding of kinematic graphs using standardized assessment tools.

physics.ed-ph↗

arXiv2025

Light intensity does not always decay with the inverse of the square of the distance: an open-inquiry laboratory

The square inverse law with distance plays an important role in many fields of physics covering electromagnetism, optics or acoustics. However, as every law in physics has its range of validity. We propose an open-inquiry laboratory where we challenge these concepts by proposing experiments where the intensity of light decays linearly or even remains constant over a range of distances. Using the light sensors built into smartphones, it is possible to measure light curves for different sources: point, linear, planar and even LED ring lights. The analysis of these curves allows us to discuss the limits of the physical theories. This low-cost laboratory, initially proposed in the context of the COVID19 pandemic, has the virtue of challenging intuition and encouraging the critical spirit of the students.

physics.ed-ph↗

arXiv2025

Revisiting the displacement current: Two key examples showing when and why it can be neglected

This work explores the role of the displacement current in systems beyond capacitors, focusing on coaxial cables and resistors with alternating currents. Although its contribution, compared to that of the conduction current, is negligible at low frequencies, the displacement current becomes essential for accurately describing electromagnetic fields in dynamic regimes. Introductory physics textbooks typically restrict the discussion of displacement currents to capacitor charging, which can limit the students' understanding of its broader relevance and the interdependence of Maxwell's equations. By analyzing two specific cases, we clarify the conditions under which the displacement current can be neglected, when simplified laws like Biot-Savart are valid, and where coupled electromagnetic equations are essential. This approach highlights the boundaries of common models and promotes a deeper understanding of dynamic field interactions.

physics.ed-ph↗

arXiv2025

Displacement current: examples that go beyond the beaten path

The Ampere-Maxwell's law and the displacement current constitute one of the most difficult aspects of electromagnetic theory for students in introductory electromagnetics courses. Here we present a set of examples that go beyond the classical ones usually discussed in introductory textbooks. In-depth analysis of these examples allows students to develop a deeper understanding of electromagnetic theory even in students who have not acquired the full mathematical toolkit of the more advanced courses.

physics.ed-ph↗

arXiv2024

Utilizing smartphone sensors for accurate solar irradiance measurement and educational purposes

The global transition towards cleaner and more sustainable energy production is a major challenge. We present an innovative solution by utilizing smartphone light sensors to measure direct normal solar irradiance, the primary component of ground-level solar radiation. We provide comprehensive guidelines for calibrating the sensor using two methods: a professional reference measurement and clear-sky satellite estimates. The latter method is particularly advantageous in resource-constrained environments. Once calibrated, the smartphone becomes a valuable tool for measuring the solar resource. We propose an instructional laboratory focusing on the physics of solar radiation and its interaction with the Earth's atmosphere, exploring solar variations across locations, cloud conditions, and time scales. By integrating irradiance values measured throughout a day the daily irradiation can be estimated. This approach enhances students' understanding of solar radiation attenuation and its relationship with atmospheric interactions. This method offers a practical and educational solution for promoting renewable energy knowledge and addressing the challenges of the energy transition.

physics.ed-ph↗

arXiv2023

The Circular Atwood Machine

The Atwood Machine, a classic apparatus in physics education, has historically been pivotal in demonstrating Newtonian mechanics, specifically Newton's Second Law. This study introduces an innovative adaptation, the circular Atwood machine, aimed at exploring circular motion and angular dynamics and integrating emerging technologies, specifically smartphone sensors. Through a rotating disc subjected to controlled external torque, the experiment delves into the relationship between the torque applied and the resulting angular momentum. The study not only presents the theoretical framework but also outlines a practical setup using readily available materials, emphasizing the potential for contemporary technology to enhance the comprehension and teaching of fundamental physical concepts.

physics.ed-ph↗

arXiv2023

RLC series circuit made simple and portable with smartphones

This article presents a novel method for studying RLC series circuits using two smartphones, one used as a signal generator and the other as an oscilloscope. We measure the voltage at the external resistor as a function of frequency when subjected to a sinusoidal electromotive force. The experimental results demonstrate a remarkable agreement with the theoretical curve for the voltage at the resistor and the resonance frequency, validating the accuracy of the smartphone-based setup. The experiment fills the gap in educational materials related to electrical circuits and provides a portable alternative to traditional, expensive laboratory equipment.

physics.ed-ph↗

arXiv2023

Experimenting with RC and RL series circuits using smartphones as signal generators and oscilloscopes

Simple, portable and low-cost experiments as RC and RL series circuits are proposed to experiment with DC circuits. Very common elements are used: a few electronics components (resistors, capacitors, coils and connecting wires) and two smartphones. We consider the charging and discharging of a capacitor in the RC circuit and also that of coil in the RL circuit. Using a smartphone as an oscilloscope we observe voltages variations which are the transient response to a square signal generated in the second smartphone. These voltage variations are directly related to the electrostatic or magnetic energy stored in the circuits. The experimental data have been collected with the smartphone used as an oscilloscope and corroborated with theoretical predictions based on Kirchhoff's laws. The comparison showed differences of the order of the 1\% or less between the calculated capacitance or inductance compared to the manufacturer values. This approach which avoids the use of expensive signal generators, oscilloscopes, or any specialized hardware can be performed in less-favored contexts and even as a home assignment.

physics.ed-ph↗

arXiv2023

Seeing the invisible: convection cells revealed with thermal imaging

Fluid instabilities are ubiquitous phenomena of great theoretical and applied importance. In particular, an intriguing example is the thermocapillary or Bénard-Marangoni instability which occurs when a thin horizontal fluid layer, whose top surface is free, is heated from below. In this phenomenon, after passing a certain temperature difference threshold, the fluid develops a regular pattern, usually hexagonal, of convection cells known as Bénard convection. In general this pattern is not visible to the naked eye unless specific tracers are incorporated into the fluid. The use of thermal imaging is a simple alternative not only for directly observing these phenomenon but also for obtaining valuable quantitative information, such as the relationship between the critical wavelength and the thickness of the fluid layer. Here, we propose an experiment specially suited for laboratory courses in fluid mechanics or nonlinear physics that involves the use of thermal cameras, or appropriate smartphone accessories, to study Bénard convection.

physics.flu-dyn↗

arXiv2021

What are the attitudes and beliefs about Science of the Physics teachers and future Physics teachers in Uruguay?

We investigated the epistemological conceptions of the uruguayan Physics teachers and future Physics teachers through the application of the CLASS test (Colorado Learning Attitudes about Science Survey), one of the most accepted instruments in the research community in Physics education. The results obtained allow us to compare the attitudes and beliefs about science of both groups and quantitatively evaluate the agreement or not with the conceptions of experts in the field. First, we present a general screenshot of the responses and then we identify categories in which there are significant similarities or differences between the two groups studied and in turn with the reference of the experts. The categories that show significant positive or negative variations between the opinions of future teachers and teachers indicate the areas where training is favorable or unfavorable. On the other hand, the areas where the differences with the opinions of the experts are globally notorious suggest that they should be strengthened. To get a more global perspective, we also compare our results with those published in the literature. Finally, we raise several questions that we think may favor further inquiries.

physics.ed-ph↗

arXiv2021

Simple physics behind the flight of a drone

The flight of a quadcopter drone, readily available as a toy, is analyzed using simple physics concepts. A smartphone with built-in accelerometer and gyroscope was attached to the drone to register the accelerations and angular velocities along the three spatial axis while the drone is taking off, landing or rotating. The vertical speed, the height and one of the angular coordinates are obtained through numerical integration of the acceleration values and compared with information provided by the manufacturer. The analysis of these quantities provides an opportunity to gain insight into important physics concepts involving Newton laws and conservation principles in a stimulating environment.

physics.ed-ph↗

arXiv2020

When the quarter jumps into a cup (and when it does not)

While Bernoulli's equation is one of the most frequently mentioned topics in Physics literature and other means of dissemination, it is also one of the least understood. Oddly enough, in the wonderful book "Turning the world inside out" [1], Robert Ehrlich proposes a demonstration that consists of blowing a quarter dollar coin into a cup, incorrectly explained using Bernoulli's equation. In the present work, we have adapted the demonstration to show situations in which the coin jumps into the cup and others in which it does not, proving that the explanation based on Bernoulli's is flawed. Our demonstration is useful to tackle the common misconception, stemming from the incorrect use of Bernoulli's equation, that higher velocity invariably means lower pressure.

physics.pop-ph↗

arXiv2019

Free surface of a liquid in a rotating frame with time-depend velocity

The shape of liquid surface in a rotating frame depends on the angular velocity. In this experiment, a fluid in a rectangular container with a small width is placed on a rotating table. A smartphone fixed to the rotating frame simultaneously records the fluid surface with the camera and also, thanks to the built-in gyroscope, the angular velocity. When the table starts rotating the surface evolves and develops a parabolic shape. Using video analysis we obtain the surface's shape: concavity of the parabole and height of the vertex. Experimental results are compared with theoretical predictions. This problem contributes to improve the understanding of relevant concepts in fluid dynamics.

physics.ed-ph↗

arXiv2018

A bottle of tea as a universal Helmholtz resonator

Resonance is an ubiquitous phenomenon present in many systems. In particular, air resonance in cavities was studied by Hermann von Helmholtz in the 1850s. Originally used as acoustic filters, Helmholtz resonators are rigid-wall cavities which reverberate at given fixed frequencies. An adjustable type of resonator is the so-called universal Helmholtz resonator, a device consisting of two sliding cylinders capable of producing sounds over a continuous range of frequencies. Here we propose a simple experiment using a smartphone and normal bottle of tea, with a nearly uniform cylindrical section, which, filled with water at different levels, mimics a universal Helmholtz resonator. Blowing over the bottle, different sounds are produced. Taking advantage of the great processing capacity of smartphones, sound spectra together with frequencies of resonance are obtained in real time.

physics.ed-ph↗

arXiv2016

The polarization of light and the Malus' law using smartphones

Originally an empirical law, nowadays Malus' law is seen as a key experiment to demonstrate the transverse nature of electromagnetic waves, as well as the intrinsic connection between optics and electromagnetism. In this work, a simple and inexpensive setup is proposed to quantitatively verify the nature of polarized light. A flat computer screen serves as a source of linear polarized light and a smartphone (possessing ambient light and orientation sensors) is used, thanks to its built-in sensors, to experiment with polarized light and verify the Malus' law.

physics.ed-ph↗

arXiv2015

Exploring the atmosphere using smartphones

The characteristics of the inner layer of the atmosphere, the troposphere, are determinant for the earth's life. In this experience we explore the first hundreds of meters using a smartphone mounted on a quadcopter. Both the altitude and the pressure are obtained using the smartphone's sensors. We complement these measures with data collected from the flight information system of an aircraft. The experimental results are compared with the International Standard Atmosphere and other simple approximations: isothermal and constant density atmospheres.

physics.ed-ph↗