The concept of pressure should be easy to understand; despite that, I’ve found frequent misunderstandings in students, teachers, and books. Is this quantity related to interaction or to the state of a system? Is it a vector, or scalar (or tensor) quantity? […]
The idea that light produces pressure evolved through a series of adoptions and rejections, from the hypothesis of Newton to the experiment of Lebedev, depending on the theory used to describe the nature of light. This article reviews the history of this development. […]
This is a detailed report of the study of the basic properties of light propagation with a middle-school class of 12 year pupils. It required about 20 hours of classroom time. The pupils performed experiments on the linear propagation of light and on the reflection on plane and concave mirrors using simple apparatus. […]
A law involving science curricula, proposed about one century ago, is analysed and its modern and still valid interpretation of science teaching and of the relationship between school education and the productive world is highlighted. […]
After describing the working principles of the crystal radio, the author puts them into practice designing, assembling and testing a simple radio system. Didactic suggestions are given. […]
The so called crystal radio is a simple receiver that can generate strong interest and emotions. Starting with the improvised ‘Blue Gillette blade’ detector used in the mythical ‘foxhole radios’ by the American soldiers during WWII, we explore some new and unusual detectors that can be assembled ‘in the kitchen’. […]
A detailed historical analysis of the development of Einstein’s Generai Relativity from 1907, year of his first paper on gravitation, to 1915, the conclusive year of his work, shows that the turning point of the development was the transformation of the classical gravitational theory into a Riemanian theory of space-time. […]