Jürgen Teichmann

Studying Galileo at Secondary School: A Reconstruction of His ‘Jumping-Hill’ Experiment and the Process of Discovery

The manuscripts of Galileo, which were studied more intensively since 1973, offer some insights to his research process. This process differed strangely from the way we find in his publications. Specially we are allowed to guess that experiments played a much more important role for Galileo in spite there is only one manuscript sheet available, which undoubtedly contains measure values. The interpretation of this manuscript (folio 116 v) and the reconstruction of the instrument used (an inclined plane with a horizontal end), allow some very interesting questions (more than answers), which offer also pedagogical applications. The reconstructed experiments with Galileos normal inclined plane and with other instruments (pile driver, pendulums) allow further speculations which at least offer very useful “research games” for school classes. Such reconstructions have been made at the Deutsches Museum in Munich, also in contact with teachers and teacher students. The myth of Galileo as Columbus or Prometheus of a new science is at the same time fruitful and hindering for such reflections. This is also true for the so called critical work of historians, who from the 18th century till our presence tried to search for the roots of classical physics.

Lord Kelvin and the age-of-the-earth debate: a dramatization

This is a dramatization of a fictitious debate about the age of the earth that takes place in the Royal Institution, London, England, in the year 1872. The debate is among Sir William Thomson (later Kelvin), T.H. Huxley (Darwins ‘Bulldog’), Sir Charles Lyell, and Hermann von Helmholtz. In 1862 Thomson published his celebrated and widely studied ‘The Secular Cooling of the Earth’ that raised the post-Darwinian debate of the age of the earth above the level of popular controversy. He entered the debate with all the arrogance of a newly established ‘science of the century’, namely the recently drafted laws of thermodynamics. The debate is partly based on a lively exchange of comments and arguments that occurred between T.H. Huxley and William Thomson, starting in 1868, when Thomson addressed the Glasgow Geological Society. This long public discussion also involved the ideas and the work of geologist Charles Lyell and those of the celebrated German physicist Hermann von Helmholtz. The confrontation is between the unyielding physicists and the insecure biologists and geologists who required a much longer time for the age of the earth than the physicists were prepared to give them. However, the debate ends on a conciliatory note, suggesting that perhaps Sir Williams ‘storehouse of creation’ may contain a hereto undiscovered source of energy that is more bountiful than gravitational energy.

From William Hyde Wollaston to Alexander von Humboldt - Star Spectra and Celestial Landscape

Summary The discovery of dark lines in the spectrum of the sun as well as in some fixed stars since 1802 by William Hyde Wollaston, Joseph Fraunhofer and Johann Lamont is a relatively isolated phenomenon in the history of astronomy of the first half of the 19th century. Wollastons representation of the suns spectrum of 1802 can be seen as a simplification and reduction of the phenomenon by way of a seemingly clear connection with contemporary knowledge. Fraunhofers famous colour etching of the dark lines, of about 1817, can be regarded as a meticulous and painstaking representation of the known facts, taken to a high aesthetic level. Lamonts spectra of the fixed stars from 1836 are the first sketches of all of these phenomena. He emphasized the ‘oddness’, that is, the chaotic variety of identifiable lines. What was common to all of these representations was the general belief that something new and unimaginable could now be established as a scientific subject. The observations of these lines were coincidental with the thinking in other fields, as for example, in Alexander Humboldts understanding of nature, in Johann Wolfgang von Goethes theory of light and his interest in pictorial representations of nature, and in the new concept of landscape of the romantic painters.

Weltsystem und Weltbild — zur Kulturgeschichte von Astronomie / Physik

Spezialdisziplinen des Wissens im heutigen Sinne, wie Physik, Chemie, Biologie, Meteorologie, hat es lange nicht gegeben. Vor allem die Zeit der klassischen Antike sowie des christlichen Mittelalters bis weit in die Neuzeit hinein basierte auf einem ganz anderen System, das alle vorhandene Wissenseinteilung unter einem philosophisch-theologisch-ganzheitlichen Aspekt ordnete und weiterentwickelte. So unterschied etwa Aristoteles (Abb. 84) im 4. Jahrhundert v. Chr.: «... das es also drei betrachtende Wissenschaften gibt, Mathematik, Naturlehre und Gotteslehre.»110

Die Erde als Kugel — Rotation und Schwerkraft

Die alteste Vorstellung, die sich die Menschen von der Gestalt der Erde gemacht haben, ist die von der Erdscheibe. Sie wurde als in der Luft schwebend oder vom Ozean umspult angenommen. Freilich sprachen gegen diese Anschauung, wie sie beispielsweise von Homer vertreten wurde, eine Reihe von Beobachtungstatsachen, die auf die Dauer nicht verborgen bleiben konnten.

Sonne oder Erde — wo ist das Zentrum der Welt?

Die Erklarung von Bewegungen hangt vom Betrachtungsort ab, genauer: vom Koordinatensystem, das der Betrachter benutzt. Von einem fahrenden Schiff etwa beim Auslaufen aus dem Hafen sieht man ein zweites «zuruckgleiten», obwohl es — im Vergleich zum Land — ruht, wahrend ein Beobachter auf dem ruhenden Schiff naturlich das andere fahren sieht. Schon die Antike, auch ausereuropaische Kulturkreise, brachten dieses Beispiel, das zeigte, wie wesentlich man durch Ruhe und Bewegung getauscht werden kann. Die Scholastik schlos spater daraus, das rational nicht entschieden werden konne, ob sich der Fixsternhimmel oder statt dessen die Erde drehe.

Die wichtigsten Bewegungen am Himmel — mit dem bloßen Auge beobachtet

Das blose Auge war das erste astronomisch-optische Instrument des Menschen (Abb. 2). Es zeigte dem Menschen eine Vielfalt von Himmelserscheinungen, im wesentlichen Tausende von Sternen.3