"Future Guide" als didaktisches Prinzip - Zur Integration handlungsorientierter und multimedialer Lernumgebungen

Mit zunehmender Vernetzung der deutschen Schulen treten die noch bestehenden Defizite hinsichtlich pädagogisch gehaltvoller Konzepten für den Einsatz des Internet im schulischen Unterricht immer offener und deutlicher zu Tage. Unzählige Lehrkräfte aller Schularten suchen händeringend nach didaktisch sinnvollen Nutzungsmöglichkeiten des Internet in ihrem alltäglichen Unterricht. Der Beitrag will mit «Future Guide» ein didaktisches und methodisches Konzept für die Integration Neuer Medien und handlungsorientierter Unterrichtsformen skizzieren, das pädagogisch sinnvolle Einsatzmöglichkeiten des Internet und netznaher Arbeitsformen in nahezu allen Unterrichtsfächern eröffnet. Der Beitrag will mit «Future Guide» ein didaktisches und methodisches Konzept für die Integration Neuer Medien und handlungsorientierter Unterrichtsformen skizzieren, das pädagogisch sinnvolle Einsatzmöglichkeiten des Internet und netznaher Arbeitsformen in nahezu allen Unterrichtsfächern eröffnet

Local manifestations of cometary activity

Comets are made of volatile and refractory material and naturally experience various degrees of sublimation as they orbit around the Sun. This gas release, accompanied by dust, represents what is traditionally described as activity. Although the basic principles are well established, most details remain elusive, especially regarding the mechanisms by which dust is detached from the surface and subsequently accelerated by the gas flows surrounding the nucleus. During its 2 years rendez-vous with comet 67P/Churyumov-Gerasimenko, ESA's Rosetta has observed cometary activity with unprecedented details, in both the inbound and outbound legs of the comet's orbit. This trove of data provides a solid ground on which new models of activity can be built. In this chapter, we review how activity manifests at close distance from the surface, establish a nomenclature for the different types of observed features, discuss how activity is at the same time transforming and being shaped by the topography, and finally address several potential mechanisms.Comment: This paper is a review chapter in the upcoming book "Comets: Post 67P Perspectives" edited by ISSI and Space Science Reviews. Accepted on 08 April 201

Gas flow in near surface comet like porous structures: Application to 67P/Churyumov-Gerasimenko

We performed an investigation of a comet like porous surface to study how sub-surface sublimation with subsequent flow through the porous medium can lead to higher gas temperatures at the surface. A higher gas temperature of the emitted gas at the surface layer, compared to the sublimation temperature, will lead to higher gas speeds as the gas expands into the vacuum thus altering the flow properties on larger scales (kilometres away from the surface). Unlike previous models that have used modelled artificial structures, we used Earth rock samples with a porosity in the range 24 – 92 % obtained from X-ray micro computed tomography (micro-CT) scans with resolution of some μm. Micro-CT scanning technology provides 3D images of the pore samples. The direct simulation Monte Carlo (DSMC) method for the rarefied gas dynamics is directly applied on the digital rock samples in an unstructured mesh to determine the gas densities, temperatures and speeds within the porous medium and a few centimetres above the surface. The thicknesses of the rock samples were comparable to the diurnal thermal skin depth (5cm). H2O was assumed to be the outgassing species. We correlated the coma temperatures and other properties of the flow with the rock porosities. The results are discussed as an input to analysis of data from the Microwave Instrument on Rosetta Orbiter (MIRO) on the 67P/Churyumov-Gerasimenko

Innovation and Internet. "Schools on the net" as pedagogical concept

Allenthalben werden mit "Schulen ans Netz" große Erwartungen verbunden. Aber im Alltag gibt es noch erhebliche Schwierigkeiten. Aus der Praxis eines Beauftragten für die EDV-Fortbildung werden hier viele Anregungen und Hinweise zum Downloaden vermittelt. (DIPF/Orig.)Everywhere great expectations are linked with "schools on the net". But the daily routine shows that there are still considerable difficulties. A specialist on further training in this sector will provide advice and useful information for "downloading". (DIPF/Orig.

Critical approaches to internet resources. Recommendations for media supported searches in the classroom

Informationen aus dem Internet bedürfen - vielleicht noch mehr als das gedruckte Wort - einer kritischen Prüfung auf ihre Zuverlässigkeit. Anhand eines Leitfadens können Schülerinnen und Schüler (aber auch Lehrerinnen und Lehrer) zum kritischen Umgang mit einem verführerischen Medium angeleitet werden. (DIPF/Orig.)Information extracted from the internet require - perhaps even more than the printed word - a critical study of their reliability. A guideline enables students but also teachers to critically deal with a tempting medium. (DIPF/Orig.

Progress in the development of a S RETGEM-based detector for an early forest fire warning system

In this paper we present a prototype of a Strip Resistive Thick GEM photosensitive gaseous detector filled with Ne and ethylferrocene vapours at a total pressure of 1 atm for an early forest fire detection system. Tests show that it is one hundred times more sensitive than the best commercial ultraviolet flame detectors and therefore, it is able to reliably detect a flame of 1.5x1.5x1.5 m3 at a distance of about 1km. An additional and unique feature of this detector is its imaging capability, which in combination with other techniques, may significantly reduce false fire alarms when operating in an automatic mode. Preliminary results conducted with air filled photosensitive gaseous detectors are also presented. The approach main advantages include both the simplicity of manufacturing and affordability of construction materials such as plastics and glues specifically reducing detector production cost. The sensitivity of these air filled detectors at certain conditions may be as high as those filled with Ne and EF. Long term test results of such sealed detectors indicate a significant progress in this direction. We believe that our detectors utilized in addition to other flame and smoke sensors will exceptionally increase the sensitivity of forest fire detection systems. Our future efforts will be focused on attempts to commercialize such detectors utilizing our aforementioned findings.Comment: Presented at the International Conference on Micropattern gaseous detectors, Crete, Greece, June 200

Earth-like Habitats in Planetary Systems

Understanding the concept of habitability is related to an evolutionary knowledge of the particular planet-in-question. Additional indications so-called "systemic aspects" of the planetary system as a whole governs a particular planet's claim on habitability. Here we focus on such systemic aspects and discuss their relevance to the formation of an 'Earth-like' habitable planet. We summarize our results obtained by lunar sample work and numerical models within the framework of the Research Alliance "Planetary Evolution and Life". We consider various scenarios which simulate the dynamical evolution of the Solar System and discuss the likelihood of forming an Earth-like world orbiting another star. Our model approach is constrained by observations of the modern Solar System and the knowledge of its history. Results suggest that the long-term presence of terrestrial planets is jeopardized due to gravitational interactions if giant planets are present. But habitability of inner rocky planets may be supported in those planetary systems hosting giant planets. Gravitational interactions within a complex multiple-body structure including giant planets may supply terrestrial planets with materials which formed in the colder region of the proto-planetary disk. During these processes, water, the prime requisite for habitability, is delivered to the inner system. This may occur either during the main accretion phase of terrestrial planets or via impacts during a post-accretion bombardment. Results for both processes are summarized and discussed with reference to the lunar crater record. Starting from a scenario involving migration of the giant planets this contribution discusses the delivery of water to Earth, the modification of atmospheres by impacts in a planetary system context and the likelihood of the existence of extrasolar Earth-like habitable worlds.Comment: 36 Pages, 6 figures, 2014, Special Issue in Planetary and Space Science on the Helmholtz Research Alliance on Planetary Evolution and Lif

Cometary Nuclei – from Giotto to Rosetta

We will briefly recapitulate the beginning of modern cometary physic. Then we will assess the results of the cometary flyby missions previous to ESA’s Rosetta rendezvous with comet 67P/Churyumov-Gerasimenko. Emphasis is given to the physical properties of cometary nuclei. We will relate the results of the Rosetta mission to those of the flybys. A major conclusion is that the visited cometary nuclei seem to be alike but represent different stages of evolution. Coma composition and appearance are not only controlled by the composition of the nucleus but also strongly influenced by the shape and rotation axis orientation of the nucleus and resulting seasons that generate varying surface coverage by back fall material. Rosetta showed that the coma composition is not only varying spatially but also strongly with time during the perihelion passage. Hence past interpretations of cometary coma observations have to be re-considered. Finally, we will try to assess the impact of the cornerstone mission leading to a critical evaluation of the mission results. Lessons learned from Rosetta are discussed; major progress and open points in cometary research are reviewed