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Anno XXXIII - n.4 - ottobre/dicembre 2000 La legge di conservazione dell’energia: applicazione al rotolamento con e senza strisciamento
The motion of common rolling bodies is a source of helpful hints towards understanding the properties of rigid bodies in general. In introductory courses dissipative phenomena are usually ignored, both at the highschool and at the university level. In this paper we analyse the role of friction on rolling and we show that the interplay between mechanics and thermodynamics facilitates understanding the behaviour of such systems. […]
Anno XXXIII - n.4 - ottobre/dicembre 2000 La nascita e la prima affermazione della teoria di campo
The developments that, starting from the experiments of Oersted, produced the first enunciation of field theory are examined. Some details of the works of Faraday and his use of analogies are discussed, followed by Maxwell’s interpretations and mathematical models giving rise, […]
Anno XXXIII - n.4 - ottobre/dicembre 2000 Cogli l’attimo fuggente nell’induzione magnetica
Transient phenomena in electromagnetic induction are usualy very ‘fleeting’. An on-line data acquisition system, with the opportunity of triggering the start of measurement, allows the visualization of a wide range of phenomena, a check of theoretical predictions on them and the storage of data for further processing. […]
Anno XXXIII - n.3 - luglio/settembre 2000 Il problema della radiazione di corpo nero e la nascita del concetto di quanto
A historical account of the experimental and theoretical developments connected to Planck’s blackbody radiation law. In that law Planck for the first time invoked the ‘quantum of action’ concept and a related universal constant ‘h’. Einstein’s subsequent analysis of the structure of radiation led to the light-quantum hypotesis. […]
Anno XXXIII - n.3 - luglio/settembre 2000 Vedi alla voce quanto
A hundred years ago Max Planck introduced the quantum of action concept; the anniversary is celebrated in many ways all over the world. In the present paper we want to stress that the Planck constant h ‘initially introduced to account for some facts in a field of research which seemed a marginal one’ […]
Anno XXXIII - n.3 - luglio/settembre 2000 Jordan, Pauli, politica, Brecht e una costante gravitazionale variabile
Pascual Jordan was one of the great theoretical physicists of the century. But his attempt to modify general relativity with a variable gravitational constant did nothing to enhance his reputation. Nor did his conspicuous membership in the Nazi Party. […]
Anno XXXIII - n.3 - luglio/settembre 2000 Sviluppo del concetto di modello in alunni di 15-16 anni
In the eighties the author developed an introductory science course for 15 year old students at the beginning of secondary school in Holland. The aim of the course was to show how scientific knowledge, leading to laws and theorization through models, […]
Anno XXXIII - n.2 - aprile/giugno 2000 Determinismo e realismo nella fisica del XX secolo
Quantum mechanics and other 20th century developments of physics hugely changed certain basic ideas of classical physics such as determinism, realism and locality. The paper examines the evolution of these ideas through the discussion of both ideal and actually performed experiments. […]
Anno XXXIII - n.2 - aprile/giugno 2000 Meraviglie del cavolo! (ovvero della dimensione frattale del cavolfiore)
The paper deals with the wonderful fractal structure of a kind of cauliflower (Brassica Oleracea Botrytis Cimosa). The fractal dimension of the vegetable is empirically detected by measurement and a simple mathematical model of the fractal cauliflower is then built which agrees with the experimental data. […]