Barbara Pecori

Harmonic and anharmonic oscillations investigated by using a microcomputer-based Atwood’s machine

We describe how the Atwood’s machine, interfaced to a personal computer through a rotary encoder, is suited for investigating harmonic and anharmonic oscillations, exploiting the buoyancy force acting on a body immersed in water. We report experimental studies of oscillators produced by driving forces of the type F=−kxn with n=1,2,3, and F=−k sgn(x). Finally we suggest how this apparatus can be used for showing to the students a macroscopic model of interatomic forces.

The Maxwell wheel investigated with MBL

The Maxwell wheel motion is experimentally investigated by interfacing the system to a PC with a force sensor and a position sensor. Mechanical energy transformations and the impluse-momentum theorem during the “collision” at the end of the string are studied.

A new microcomputer-based laboratory version of the Rüchardt experiment for measuring the ratio γ=Cp/Cv in air

We describe a new version of the Ruchardt experiment in which we record the time evolution of temperature, pressure, and volume oscillating around an equilibrium value. We use a portable microcomputer-based laboratory made of a graphic calculator, an interface, two commercial sensors (sonar and barometric sensor), and a homemade temperature sensor.

From Heuristics to Humble Theories in Physics Education: The Case of Modelling Personal Appropriation of Thermodynamics in Naturalistic Settings

The paper concerns the analysis of a successful classroom experience where secondary school students made evident progress in appropriating thermodynamics according to personal approaches. The main result of the analysis is the construction of a definition of appropriation which is operational in two senses: (i) it includes the indication of what observable features must be searched in students’ discourses for recognizing appropriation; (ii) it is effective for recognizing appropriation also in cases where it is not evident. The study is the first step of an iterative process aimed at developing a “humble theory” for explaining when, how and why appropriation is triggered and supported in real classrooms.

Physics of the seesaw

The idea behind this article was inspired by a previously publishedTPT note on harmonic and anharmonic oscillators, in which the oscillations of a bar on a cube were briefly discussed. We thought these oscillations deserved quantitative experimental investigation and that automated data acquisition could allow the data to be gathered.

Playing with a bulb lamp: RTL measurements and modelling

The electric, thermal and optical behaviour of an incandescent lamp was studied by a real time laboratory (RTL) apparatus, using two voltage probes and a light probe. The software STELLA was used to model the phenomena and to analyse the transient behaviour in absence of thermal equilibrium. We show how the Joule-heating effect explains the non-linear current/voltage relation and how the filament thermal capacity affects the phase lag of light peaks with respect to input power peaks.

The Challenge of Contemporary Society on Science Education: The Case of Global Warming

The big problems that contemporary society needs to address (e.g. climate change) challenge our traditional idea of education and require to revise the goals of science education research. Such problems are indeed so complex as to require a wide range of competencies to be engaged in producing and implementing solution strategies. Science education is forced to take into account the many dimensions that characterize contemporary science and to face the task of bringing together the potential of all the different perspectives [8]. An example of this kind of research, concerning environmental problems, will be briefly described and its first encouraging results illustrated.