TY - JOUR A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - High Speed – Slow Motion: Technik digitaler Hochgeschwindigkeitskameras JF - In: Physik in unserer Zeit 42 (2011) 3, 144- 148 N2 - Moderne Hochgeschwindigkeitskameras arbeiten digital. Ihre CMOS- oder CCD-Sensoren ermöglichen hohe Bildwiederholraten. Bei professionelleren Systemen lässt sich dabei die Integrationszeit, also die Belichtungszeit der Einzelbilder, unabhängig von der Bildwiederholrate einstellen. Für die hohe Aufnahmegeschwindigkeit sorgt ein zweistufiger Prozess. Ein sehr schneller interner Speicher nimmt die Bilddaten zuerst auf, dann schreibt eine Ausleseelektronik diese in einen externen Speicher. Neben teuren Profisystemen wächst inzwischen das Segment an preiswerten Amateurkameras mit High-Speed-Option. Y1 - 2011 U6 - https://doi.org/10.1002/piuz.201101270 SP - 144 EP - 148 ER - TY - JOUR A1 - Vollmer, Michael A1 - Gedzelman, S. D. T1 - Blauer Mond: poetische Methapher oder beobachtbares Phänomen? JF - In: Naturwissenschaftliche Rundschau 62 (2009) 6, 285-291 Y1 - 2009 SP - 285 EP - 291 ER - TY - JOUR A1 - Vollmer, Michael T1 - Sonnen- und Mondfinsternisse: Beobachtungen, Messungen und quantitative Modelle JF - In: Praxis der Naturwissenschaften - Physik in der Schule 58 (2009) 2, 38-44 Y1 - 2009 SP - 38 EP - 44 ER - TY - JOUR A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - Thermographie : Grundlagen, Forschung und moderne Anwendungen in Industrie und Technik JF - In: Praxis der Naturwissenschaften - Physik in der Schule 57 (2008) 8, 5-14 Y1 - 2008 SP - 5 EP - 14 ER - TY - JOUR A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - Infrarotkameras: es gibt mehr zu sehen als unsere Augen wahrnehmen JF - In: Naturwissensschaftliche Rundschau 61 (2008) 11, 557—565 Y1 - 2008 SP - 557 EP - 565 ER - TY - JOUR A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter A1 - Arnold, Frank T1 - Ins eigene Segel blasen. Münchhausen-Effekt und Schubumkehr JF - In: Physik in unserer Zeit 39 (2008) 5, 241-245 N2 - Kann man sich mit seinem Segelboot fortbewegen, indem man ins eigene Segel bläst? Der Impulssatz erlaubt diesen an Münchhausen erinnernden Effekt. Das demonstriert ein vereinfachtes Gedankenexperiment, bei dem der Segler durch den Werfer eines Balls und das Segel durch eine starre Wand ersetzt wird. Allerdings ergibt die naive Theorie, die Luftmoleküle als ballähnliche Korpuskeln auffasst, einen zu hohen Impuls des reflektierten Luftstroms. Eine realistische Beschreibung liefert die moderne Strömungstheorie. Ihre Resultate sind experimentell erfolgreich umsetzbar. Technisch angewendet wird das Prinzip in der Schubumkehr von Flugzeugtriebwerken. Y1 - 2008 U6 - https://doi.org/10.1002/piuz.200801172 SP - 241 EP - 245 ER - TY - CHAP A1 - Chiaverina, Chris A1 - Vollmer, Michael T1 - Learning physics from the experiments T2 - In: Informal learning and public understanding of physics : third international GIREP seminar 2005 ; selected contributions ; [5 - 9 September 2005, Ljubljana, Slovenia] / ed.: Gorazd Planinšič ... Ljubljana : Faculty of Mathematics and Physics, 2006 Y1 - 2006 PB - Faculty of Mathematics and Physics CY - Ljubljana ER - TY - JOUR A1 - Vollmer, Michael T1 - Diffraction revisited : position of diffraction spots upon rotation of a transmission grating JF - In: Physics education 40 (2005), 562-565 Y1 - 2005 SP - 562 EP - 565 ER - TY - JOUR A1 - Vollmer, Michael T1 - Hot gases : transition from line spectra to thermal radiation JF - In: American journal of physics 73 (2005), 215-223 N2 - The question of how the line spectrum of atoms is transformed into the continuous spectrum of thermal radiation of a gas by repeated absorption and emission of photons is addressed. We consider a simple model of a hydrogen-like gas in thermal equilibrium where only the Lyman-α transition is allowed and calculate the spectra for increasing thickness of the gas. The transition from line spectra for optically thin samples to the spectra of thermal radiation for optically thick samples is demonstrated. We estimate the emissivities for hot gases and study the line width of spectral lines due to self-absorption processes. Y1 - 2005 SP - 215 EP - 223 ER - TY - JOUR A1 - Cowley, L. A1 - Laven, Ph. A1 - Vollmer, Michael T1 - Rings around sun and moon : coronae and diffraction JF - In: Physics Education 40 (2005) 1, 51-59 Y1 - 2005 SP - 51 EP - 59 ER - TY - JOUR A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter A1 - Karstädt, Detlef T1 - Microwave oven experiments with metals and light sources JF - In: Physics Education 39 (2004), 500-508 N2 - Don't put metal objects in the microwave' is common safety advice. But why? Here we describe demonstration experiments involving placing household metallic objects in a microwave oven. These allow a better understanding of the interaction of microwaves with materials. Light bulbs and discharge lamps can also be used in instructive demonstrations. Y1 - 2004 SP - 500 EP - 508 ER - TY - JOUR A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter A1 - Karstädt, Detlef T1 - More experiments with microwave ovens JF - In: Physics education 39 (2004) 4, 346 – 351 N2 - Microwave ovens can be used to perform exciting demonstrations that illustrate a variety of physics topics. Experiments discussed here show superheating, visualize the inhomogeneous heating that takes place in a microwave and also show how to use a mobile phone to detect radiation leaking from the oven. Finally eggs can give some spectacular (though messy) explosions. In all cases please note the safety advice given. Y1 - 2004 SP - 346 EP - 351 ER - TY - JOUR A1 - Parker, Kerry A1 - Vollmer, Michael T1 - Bad food and good physics : the development of domestic microwave cookery JF - In: Physics Education 39 (2004) 1, 82-90 N2 - This article forms the second of two papers on the subject of microwave cookers. In the first paper Michael Vollmer describes the physics behind the production of microwaves in the magnetron of the oven, the waveguide and the interaction between the microwaves and the food. This article looks at the physics of cooking, and how the appliance and the food industries have developed products which are now part of many of our students' lifestyles. We include many interesting demonstrations that illustrate this history and which could be used to teach many principles of physics. Y1 - 2004 SP - 82 EP - 90 ER - TY - JOUR A1 - Vollmer, Michael T1 - Physics of the microwave oven JF - In: Physics education 39 (2004) 1, 74-81 N2 - This is the first of two articles about the physics of microwave ovens. This article deals with the generation of microwaves in the oven and includes the operation of the magnetrons, waveguides and standing waves in resonant cavities. It then considers the absorption of microwaves by foods, discussing the dielectric relaxation of water, penetration depths of electromagnetic waves in matter and, in considering the possible chemical changes during the microwave heating, multi-photon ionization or dissociation. Y1 - 2004 SP - 74 EP - 81 ER - TY - JOUR A1 - Vollmer, Michael T1 - Physics teacher training and research in physics education: results of an inquiry by the European Physical Society JF - In: European journal of physics 24 (2003), 131-147 N2 - An inquiry among national experts on physics education research and teaching has been carried out using a questionnaire that deals with the organization of physics teacher training and the main tasks and research activities of professionals in physics education. The goal was to collect data on a European scale on physics teacher training at universities by professionals as well as on research activities by professionals in the field of physics education. Results are presented based on answers from 22 European countries. Y1 - 2003 SP - 131 EP - 147 ER - TY - JOUR A1 - Vollmer, Michael T1 - Estimating the thickness of the atmosphere by rayleigh scattering JF - In: American journal of physics 71 (2003) 10, 979-983 Y1 - 2003 SP - 979 EP - 983 ER - TY - JOUR A1 - Gedzelman, S. D. A1 - Vollmer, Michael T1 - Twice in a blue moon JF - In: Weatherwise 62 (2009) 5, 28-35 Y1 - 2009 SN - 0043-1672 SP - 28 EP - 35 ER - TY - JOUR A1 - Vollmer, Michael T1 - Newton´s law of cooling revisited JF - In: European Journal of Physics 30 (2009), 1063-1084 Y1 - 2009 SN - 0143-0807 SP - 1063 EP - 1084 ER - TY - JOUR A1 - Gedzelman, S. D. A1 - Vollmer, Michael T1 - Progress in atmospheric optics and light and color in nature JF - In: Bulletin of the American Meteorological Society : BAMS 90 (2009), 689-693 Y1 - 2009 SN - 0003-0007 SP - 689 ER - TY - JOUR A1 - Vollmer, Michael T1 - Mirrors in the Air: Mirages in Nature and in the Laboratory JF - In: Physics Education 44 (2009) 2, 165-174 Y1 - 2009 SN - 0031-9120 SP - 165 EP - 174 ER - TY - JOUR A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - Michelson Interferometer for your kitchen table JF - In: The Physics Teacher 46 (2008), 114-117 Y1 - 2008 SN - 0031-921x SP - 114 EP - 117 ER - TY - JOUR A1 - Planinsic, G. A1 - Vollmer, Michael T1 - The surface to volume ratio in thermal physics: from cheese cube physics to animal metabolism JF - In: European Journal of Physics 29 (2008), 369-384 Y1 - 2008 SN - 0143-0807 SP - 369 EP - 384 ER - TY - JOUR A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter A1 - Arnold, F. T1 - Locomotion by blowing into the sail of a sailboat? From a basic physics question to thrust reversal of jet airplanes JF - In: Physics Education 42 (2007), 369-377 Y1 - 2007 SN - 0031-9120 SP - 369 EP - 377 ER - TY - JOUR A1 - Vollmer, Michael A1 - Möllmann, Klaus-Peter T1 - Infrared thermal imaging as a tool in university physics education JF - In: European Journal of Physics 28 (2007), S37-S50 Y1 - 2007 UR - http://iopscience.iop.org/0143-0807/28/3/S04/pdf/0143-0807_28_3_S04.pdf SP - 37 EP - 50 ER - TY - JOUR A1 - Möllmann, Klaus-Peter A1 - Vollmer, Michael T1 - Measurements and predictions of the illuminance during a solar eclipse JF - In: European journal of physics 27 (2006), 1299-1314 N2 - Measurements of illuminance during a solar eclipse are presented. The data are compared to theoretical predictions, based on a geometrical model for obscuration. The model assumes a straight and uniform motion of the sun and moon as well as a spherical shape of both, i.e. it neglects any effects of limb darkening. Furthermore, the sun's disk is assumed to have homogeneous luminosity, i.e. any luminosity variations due to sun spots are neglected. Input parameters are the duration of the eclipse, the duration of totality, the impact parameter, i.e. the distance between the two trajectories of sun and moon, and the sizes of sun and moon. The model applies to all types of eclipses, partial, annular and total. Y1 - 2006 SP - 1299 EP - 1314 ER -