In 1913 the German physicist Johannes Stark and the Italian physicist Antonino Lo Surdo (1880-1949) discovered virtually simultaneously and independently that hydrogen spectral lines are split into components by an external electric field. Both of their discoveries ensued from studies on the same phenomenon, the Doppler effect in canal rays, but they arose in different theoretical contexts. Stark had been working within the context of the emerging quantum theory, following a research program aimed at studying the effect of an electric field on spectral lines. Lo Surdo had been working within the context of the classical theory, and his was an accidental discovery. Both discoveries, however, played important roles in the history of physics: Stark's discovery contributed to the establishment of both the old and the new quantum theories; Lo Surdo's discovery led Antonio Garbasso (1871Garbasso ( -1933 to introduce research on the quantum theory into Italian physics. Ironically, soon after their discoveries, both Stark and Lo Surdo rejected developments in modern physics and allied themselves with the political and racial programs of Hitler and Mussolini.
The so-called Rutherford's experiment, as it is outlined in many physics textbooks, is a case in point of the flaws around the history at the educational level of one of the decisive event of modern physics: the discovery that the atom has a nucleus. This paper shows that this alleged experiment is a very approximate and very partial synthesis of a series of different particle scattering experiments, starting with that carried out by Rutherford in 1906 and ending with Geiger and Marsden's 1913 experiments.
Questa è la versione dell'autore dell'opera:[Leone M. History of physics as a tool to detect the conceptual difficulties experienced by students: the case of simple electric circuits in primary education.
As is well known, the positron was discovered in August 1932 by Carl Anderson while studying cloud chamber tracks left by cosmic rays. Far less known is the fact that a few months before Anderson's discovery, in April 1932, Frédéric Joliot and Irène Curie had missed an opportunity to discover the positron during a nuclear physics experiment. One year later, in April 1933, the French researchers eventually succeeded in discovering the mechanism of positron-electron pair production. The complex relationship between Anderson's discovery of the positron, Joliot and Curie's missed discovery, and their following work on the pair production is discussed here in detail.
A few months before its "official" discovery in September 1932 by Anderson at Cal Tech in Pasadena, the positron was almost simultaneously observed by no less than two additional research teams: one at Cavendish Laboratory in Cambridge, England, and one at Institut du Radium in Paris, France. In this paper, we examine this curious case of multiple independent observations by studying the primary literature. This study identifies the motivations that led these researchers to independently design the experiments suitable for the detection of this novel particle and shows that none of these teams were looking for a positive electron.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.