F. HERRMANN, M. POHLIG
KITopen (21.04.2023)
F. HERRMANN, M. POHLIG
KITopen (14.04.2023)
F. HERRMANN, M. POHLIG
MNU 06, S. 478-483 (2021)
F. HERRMANN, M. POHLIG
Proceedings - Conference: 16th Marcel Grossmann meeting (2021)
F. HERRMANN, M. POHLIG
Proceedings - Conference: 16th Marcel Grossmann meeting (2021)
F. HERRMANN, M. POHLIG
MDPI in 1st Electronic Conference on Universe
Phys. Sci. Forum 2021-02-22 | journal-article
DOI: 10.3390/ecu2021-09282
Part of ISSN: 2673-9984
F. HERRMANN, M. POHLIG
MNU 06, S. 487-491 (2020)
F. HERRMANN, M. POHLIG
Proceedings of the GIREP MPTL conference 2014, Palermo,
Chapter 3, Physics teaching and learning at secondary level, p. 269
H. HAUPTMANN, F. HERRMANN, M. POHLIG, P. SCHMÄLZLE, K. SCHNEIDER, H.M. STRAUCH, H. SCHWARZE
Aus dem Vorwort des Themenhefts: Wir sind daran gewöhnt, in Physik und Technik mit Strömen zu operieren: elektrische Ströme, Energie- ströme, Massenströme, Stoffströme, Datenströme. Es ist für uns so normal, dass wir uns die Frage nach der Berechtigung dieses Vorgehens gar nicht mehr stellen. Dabei sind Ströme physikalischer Größen keine Selbstverständlichkeit. Man hat sie nicht in der Natur vorgefunden, sondern sie sind Konstruktionen der Naturwissenschaft. Und sie sind eine recht moderne Vorstellung. Zu Newtons Zeit gab es noch keine elektrische La- dung und keine Energie, und natürlich auch nicht die entsprechenden Ströme….
M. POHLIG, J. ROSENBERG
Lat. Am. J. Phys. Educ Vol 6, Suppl I (August 2012)
F. HERRMANN, M. POHLIG, N.A. ÁVILA
P. BRONNER, H. HAUPTMANN, F. HERRMANN, M. POHLIG, M. SEITZ, M. STEINBRENNER, P. ZACHMANN
Aus dem Vorwort des Themenhefts: Die Entwicklungen in der Physik- und der Chemiedidaktik verfolgen bisweilen divergierende Pfade: Während aktuelle Lehrwerke für den Physikunterricht nahezu vollständig auf den Begriff Arbeit verzichten und stattdessen konsequent Energie verwenden, findet diese Entwicklung in chemiedidaktischen Beiträgen und Lehrwerken kein nennenswertes Echo. Neben der Energie wird verbreitet auch mit mechanischer und elektrischer Arbeit, mit Wärme sowie Enthalpie, freier Energie und freier Enthalpie argumentiert. Es haben sich in der Physik und Chemie Gewohnheiten etabliert, die eine fächerübergreifende Betrachtungsweise behindern. …
M. POHLIG, H.M. STRAUCH
F. HERRMANN, M. POHLIG
American Journal of Physics 90, 410 (2022);
We learn and teach classical mechanics essentially as it was developed by Newton. The theory is more than 300 years old, but still useful for many purposes. However, even in contexts where it produces correct results, it has a flaw: it uses actions at a distance. In addition, it is not able to describe the transport and storage of energy in the gravitational field locally.
The general theory of relativity not only eliminated the actions at a distance of Newtonian mechanics, but also predicted phenomena which the Newtonian theory of gravitation could not explain. However, for solving many problems and for an introduction of gravitation in a standard lecture, general relativity is too complicated, mainly because of the tensor calculus.
To bridge the gap between these two theories we propose to use Heaviside’s theory of gravitoelectromagnetism. This theory has the same structure as Maxwell’s electromagnetism. It has the advantage that it does not describe forces as actions at a distance and that it allows to establish a local energy balance.
We discuss the limits of applicability of Heaviside’s theory. It turns out that besides the well-known condition low field/slow motion, another condition must be satisfied. The theory is only applicable to quasi-stationary processes. In particular, it cannot describe gravitational waves. Nevertheless, it is useful for teaching, because some major shortcomings of the Newtonian theory are avoided.
Mass is usually introduced as a measure of the inertia of a body. But what do we mean by inertia anyway? We introduce a measure of inertia. It turns out that for high, relativistic velocities neither the rest mass nor the relativistic mass fulfills the requirements for a meaningfully defined measure of inertia. But how are we going to talk about inertia in the physics lesson? How can we use students' everyday language and still arrive at a clear conceptualization? We will try to give an answer to these questions.
Gravitation is still taught largely in a way that suggests the existence of action-at-a-distance. A theory without such shortcomings, gravitoelectromagnetism, was proposed by Heaviside in 1893, but it did not become well-established because many effects it describes are very small and the later emergence of general relativity seemed to make a theory of gravitoelectromagnetism superfluous. We argue that gravitoelectromagnetism still retains relevance in the physics curriculum because it by no means describes only tiny effects and does not demand the mathematical level of general relativity.
#2022 Published under an exclusive license by American Association of Physics Teachers
Im Zusammenhang mit der Relativitätstheorie begegnen uns in Schulbüchern zwei Situationen, in denen zwei Beobachter unterschiedlich schnell altern. Es scheint sich um zwei voneinander unabhängige Effekte zu handeln. Oft wird der eine als speziell-, der andere als allgemein-relativistisch bezeichnet. Tatsächlich handelt es sich beide Male um ein und denselben Effekt, beschrieben in zwei verschiedenen Bezugssystemen.
Abstract: “What is heat?” was the title of a 1954 article by Freeman J. Dyson, published in Scientific American. Apparently, it was appropriate to ask this question at that time. The answer is given in the very first sentence of the article: heat is disordered energy. We will ask the same question again, but with a different expectation for its answer. Let us imagine that all the thermodynamic knowledge is already available: both the theory of phenomenological thermodynamics and that of statistical thermodynamics, including quantum statistics, but that the term “heat” has not yet been attributed to any of the variables of the theory. With the question “What is heat?” we now mean: which of the physical quantities deserves this name? There are several candidates: the quantities Q, H, Etherm and S. We can then formulate a desideratum, or a profile: What properties should such a measure of the quantity or amount of heat ideally have? Then, we evaluate all the candidates for their suitability. It turns out that the winner is the quantity S, which we know by the name of entropy. In the second part of the paper, we examine why entropy has not succeeded in establishing itself as a measure for the amount of heat, and we show that there is a real chance today to make up for what was missed.
We discuss a paradox from the field of relativistic thermodynamics: two heat reservoirs of the same proper temperature move against each other. One is at rest in the inertial reference frame SA, the other in SB. For an observer, no matter in which of the two reference frames he is at rest, the temperatures of the two reservoirs are different. One might, therefore, conclude that a thermal engine can be operated between the reservoirs. However, the observers in SA and SB do not agree upon the direction of the entropy flow: from SA to SB, or from SB to SA. The resolution of the paradox is obtained by taking into account that the 'drive' of an entropy current is not simply a temperature difference, but the difference of a quantity that depends on both temperature and velocity.
The Karlsruhe Physics Course (KPC) is a novel approach to the teaching of physics at the secondary school. The KPC text books have since been used in a certain, slightly increasing number of German schools. Simultaneously, ideas of the KPC have found their way into the mainstream textbooks. The basic ideas of the course had been published in the European Journal of Physics, the American Journal of Physics and other scientific reviews. Several selected chapters had been presented on previous GIREP-Meetings.
Only recently, the German Physical Society (DPG) got aware of the course. In their opinion the KPC represents a danger to the teaching of physics at school and University.
Therefore, the DPG nominated an „expert group“ with the assignment of finding scientific errors in the KPK. The group believed to have found such errors. Thereupon the DPG has initiated a campaign with the objective of eliminating not only the KPC textbooks from the market but to eradicate any other manifestation of ideas that might have originated in the KPC work.
DPG did so not only in Germany but worldwide. So, among other things, DPG alerted the European Physical Society and the Chinese Physical Society.
As a result of these measures, a discussion of unusual fierceness arose, first in Germany, but then spreading to other countries. Thereby the physics community got more and more polarized.
A chronicle of an eventful year and a brief evaluation will be given from the perspective of the author.
Aus dem Prolog: ,“Das Konzept der Entropie ist ohne Zweifel eines der okkultesten Konzepte der Physik" Heuser spricht mit diesem Satz, der in seinem Duktus jeden Widerspruch undenkbar erscheinen lässt, einer großen Menge von Physiklehrerinnen und Physiklehrern aus dem Herzen und treibt, einen amerikanischen Cartoonisten zitierend die Polemik auf die Spitze:“lf you can live with entropy, you can live with anything“. Dagegen steht H.L. Collendars (1863- 1930) Überzeugung, Entropie könne auf eine Weise verständlich gemacht werden, “which any schoolboy could understond“. …
Es wird gezeigt, wie ein Physikunterricht, der in der Wärmelehre die Entropie neben der Temperatur als zentrale Begriffe vermittelt und, unterstützt durch ein Modellbildung wie POWERSIM™, physikalische Sachverhalte vermitteln kann, deren unterrichtliche Behandlung ohne ein computerunterstütztes Modellbildungssystem zu schwierig sind, obwohl sie der täglichen Erfahrung einer Schülerin /eines Schülers sehr nahe kommen. Die vorgestellte Aufsatz geht von den elementaren Modellen des Heizens und Abkühlens von Körpern aus, macht Fließgleichgewichte verständlich und zeigt schließlich ein einfaches Modell für eine globale Erwärmung der Erde. (Anmerkung: Die Modelle lassen sich einfach auch in andere Softwaremodelle (z.B. Coach 7 etc.) übertragen.)
Legt man sich nicht auf den traditionellen Weg fest, so kann man mit einfachen Mitteln schnell zu den wichtigen Ergebnissen der speziellen Relativitätstheorie gelangen. Man verwendet Kenntnisse, die man bereits auf anderen Gebieten der Physik gewonnen hat. Der Aufsatz zeigt diesen Weg auf und begründet ihn.
©2023 MPohlig