P. Simeão Carvalho

Teaching physics with Angry Birds: exploring the kinematics and dynamics of the game

In this paper, we present classroom strategies for teaching kinematics at middle and high school levels, using Rovio’s famous game Angry Birds and the video analyser software Tracker. We show how to take advantage of this entertaining video game, by recording appropriate motions of birds that students can explore by manipulating data, characterizing the red bird’s motion and fitting results to physical models. A dynamic approach is also addressed to link gravitational force to projectile trajectories.

A Simple Experiment to Explore Standing Waves in a Flexible Corrugated Sound Tube

Sound tubes, pipes, and singing rods are used as musical instruments and as toys to perform amusing experiments. In particular, corrugated tubes present unique characteristics with respect to the sounds they can produce; that is why they have been studied so intensively, both at theoretical and experimental levels.1–4 Experimental studies usually involve expensive and sophisticated equipment that is out of reach of school laboratory facilities.3–6 In this paper we show how to investigate quantitatively the sounds produced by a flexible sound tube corrugated on the inside by using educational equipment readily available in school laboratories, such as the oscilloscope, the microphone, the anemometer, and the air pump. We show that it is possible for students to study the discontinuous spectrum of sounds produced by a flexible corrugated tube and go even further, computing the speed of sound in air with a simple experimental procedure.

How to build a low cost spectrometer with Tracker for teaching light spectra

Optics is probably one on the most exciting topics in physics. However, it also contains some of the less understood phenomena by students—the light spectra obtained from the diffraction of light. The experimental study of light spectra for studying radiating bodies, usually requests sophisticated and expensive equipment that is not normaly affordable for schools, and only a few teachers know how to measure the wavelength of light in a spectrum. In this work we present a simple and inexpensive setup, with enough accuracy for measuring light spectra to be used both in physics and chemistry classes. We show how freeware software Tracker, commonly used for teaching mechanics, can serve to measure wavelengths with about 2 nm of resolution. Several approaches to the calibration of different setups are also provided, depending on the degree of accuracy demanded.

Teaching Optical Phenomena with Tracker.

Since the invention and dissemination of domestic laser pointers, observing optical phenomena is a relatively easy task. Any student can buy a laser and experience at home, in a qualitative way, the reflection, refraction and even diffraction phenomena of light. However, quantitative experiments need instruments of high precision that have a relatively complex setup. Fortunately, nowadays it is possible to analyse optical phenomena in a simple and quantitative way using the freeware video analysis software ?Tracker?. In this paper, we show the advantages of video-based experimental activities for teaching concepts in optics. We intend to show: (a) how easy the study of such phenomena can be, even at home, because only simple materials are needed, and Tracker provides the necessary measuring instruments; and (b) how we can use Tracker to improve students? understanding of some optical concepts. We give examples using video modelling to study the laws of reflection, Snell?s laws, focal distances in lenses and mirrors, and diffraction phenomena, which we hope will motivate teachers to implement it in their own classes and schools.

Dielectric and Magnetic Properties of ReMnO3 (Re = Eu, Gd) Ceramics

EuMnO 3 and GdMnO 3 ceramics have been synthesised by urea sol-gel combustion method. The dielectric and magnetic properties of high quality ceramics of both compounds were performed in the 5 K–300 K temperature range. The magnetic phase transitions in both compounds are marked by anomalies in the temperature behaviour of both dielectric constant and induced magnetization. The experimental results are discussed and compared with those ones obtained in single crystals.

How to Use a Candle to Study Sound Waves.

It is well known that sound waves in air are longitudinal waves. Although teachers use analogies such as compressing horizontal springs to demonstrate what longitudinal waves look like, students still present some difficulty in understanding that (1) sound waves correspond to oscillations of air particles, and (2) there is no “air flow” (transport of particles) in sound waves.1,2 These difficulties arise from the impossibility to actually “see” air particles moving, and from the common sense idea that free particles always have translational motion.

Raman scattering in liquid crystalline compounds displaying ferro-ferri- and antiferroelectric phase transitions

Abstract Integrated Raman intensity of the stretching mode of the benzene rings has been studied as a function of temperature in order to determine the peculiarities of the phase sequence in new chiral liquid crystals.

Dynamics of a Sliding Ladder Leaning against a Wall.

This study is about the dynamics of a sliding ladder leaning against a vertical wall. The results are understood by considering the motion divided in two parts: (i) for with one degree of freedom, and (ii) for with two degrees of freedom, where the separation is determined by the instance when the ladder loses its contact with the wall. The observed experimental details are explained by appealing a simple model based on elementary notions of mechanics. We emphasize some features, such as a maximum of the x component of the velocity and of the acceleration of the centre of mass in the first part, and a minimum of the normal reaction force on the floor in the second.

Measuring and teaching light spectrum using Tracker as a spectrometer

In this work we present a simple and low cost setup that allows obtaining the light spectra and measuring the wavelength of its features. It is based on a cheap transmission diffraction grating, an ordinary digital camera and using Tracker software to increase measuring accuracy. This equipment can easily be found in most schools. The experimental setup is easy to implement (the typical setup for a pocket spectroscope) replacing the eye with the camera. The calibration is done using a light source with a well-known spectrum. The acquired images are analyzed with Tracker (freeware software frequently used for motion studies). With this system, we have analyzed several light sources. As an example, the analysis of the spectra obtained with compact fluorescent lamp allowed to recognize the spectrum of mercury in the lamp, as expected. This spectral analysis is therefore useful in schools, among other topics, to enable the recognition of chemical elements through spectroscopy, and to alert students to the different spectra of illuminating light sources used in houses and public places.

Storing the Electric Energy Produced by an AC Generator

Producing energy from renewable energy sources is nowadays a priority in our society. In many cases this energy comes as electric energy, and when we think about electric energy generators, one major issue is how we can store that energy. In this paper we discuss how this can be done and give some ideas for applications that can serve as a motivation for projects with students.