When sound waves are taught at the secondary level, the speed of propagation of sound is one of the most important characteristics to be analyzed. However, it is very common in textbooks that the value of sound speed in air is considered constant regardless of the experimental conditions. The great question is that since sound is a mechanical wave, its speed is influenced by the medium of propagation and also by the temperature. In most cases, the techniques reported for that goal usually make use of expensive equipment and techniques that may not be affordable and/or easy to implement in schools, which is an experimental limitation for the teachers to show this influence on their students. In this work, we present a low-cost experimental apparatus, controlled by the open source electronic platform Arduino®, with which it is possible to determine the speed of propagation of sound as a function of the temperature for a short measuring region, thus enabling the students to verify experimentally this important feature of sound waves.

The result of additive colors is always fascinating to young students. When we teach this topic to 14- to 16-year-old students, they do not usually notice we use maximum light quantities of red (R), green (G), and blue (B) to obtain yellow, magenta, and cyan colors in order to build the well-known additive color diagram of Fig. 1. But how about using different light intensities for R, G, and B? What colors do we get? This problem of color mixing has been intensively discussed for decades by several authors, as pointed out by Ruiz's “Color Addition and Subtraction Apps” work and the references included therein. An early LED demonstrator for additive color mixing dates back to 1985, and apps to illustrate color mixing are available online. In this work, we describe an experimental setup making use of a microcontroller device: the Arduino Uno. This setup is designed as a game in order to improve students' understanding of color mixing.

We derive the steady-state solution of the Fokker-Planck equation that describes the dynamics of the nondegenerate optical parametric oscillator in the truncated Wigner representation of the density operator. We assume that the pump mode is strongly damped, which permits its adiabatic elimination. When the elimination is correctly executed, the resulting stochastic equations contain multiplicative noise terms and do not admit a potential solution. However, we develop a heuristic scheme leading to a satisfactory steady-state solution. This provides a clear view of the intracavity two-mode entangled state valid in all operating regimes of the optical parametric oscillator. A non-Gaussian distribution is obtained for the above threshold solution.

The phenomenon of adding colours is a relevant topic and integrates school programmes in different countries. In most cases, it is presented by teachers through static images, drawn on the board or schematised in school textbooks. This approach stems, in many cases, from the lack of adequate resources that allow a discussion without inducing misunderstandings, which unfortunately does not meet the necessary demands for learning. From the perspective of a necessary methodological change, a path is presented: the use of active methodologies enrolling students in their learning process based on the joint discussion of science and technology. Based on these principles, we present in this work a proposal for an experimental setup that can be used in classes where the discussion of adding colours occurs, allowing students to carry out a real-time comparison between the colour perceived in an RGB light-emitting diode display, and the colour produced in a computer screen. In addition to the phenomenological aspects, the setup will allow students to perceive the differences in shades and, consequently, how technology in the perception of colour.

Renewable energy is a trending topic due to its importance in today’s society especially because of global warming. Because of its importance, this topic should be discussed at schools in an inclusive education environment. Experimental work is a very good activity to provide students effective conceptual discussions, but it is necessary to improve the teaching–learning process for an inclusive education paradigm. In this paper we propose a low-cost experimental activity using Arduino that allows regular students and blind students to explore together and understand features and properties about solar energy and a photovoltaic panel, such as how the electric power generated by the photocell depends on the angle of incidence of solar light and the load resistance of the circuit.

This work presents a pedagogical proposal that employs the Circuit Construction Kit: DC computer simulation from the PhET platform to address Millman’s theorem and facilitate the understanding of the principles involved in the electrical equilibrium of biological cells. The study models the cell membrane potential as a simplified electrical circuit, considering ion channels (Na⁺, K⁺, and Cl⁻) as resistors and concentration gradients as voltage sources. Through simulation, the effects of varying ionic conductances on the resting potential are analysed, highlighting how the inactivation of the Cl⁻ channel or changes in the conductances of Na⁺ and K⁺, aimed at restoring equilibrium, affect cellular homeostasis and excitability. We argue that the proposed approach promotes intuitive learning by reducing reliance on mathematical formalism and encouraging the application of physical concepts to real physiological contexts. The simulation has proven to be an effective teaching tool in health-related courses, fostering virtual experimentation and the qualitative interpretation of complex phenomena.