@inproceedings{PinnoKarstaedtMoellmannetal.2006, author = {Pinno, Frank and Karst{\"a}dt, Detlef and M{\"o}llmann, Klaus-Peter and Vollmer, Michael}, title = {Energy savings for an old factory building by optimisation of the heating system}, series = {In: InfraMation 2006 : proceedings / sponsored and published by the Inframation Training Center ... Vol. 7, 253-262}, booktitle = {In: InfraMation 2006 : proceedings / sponsored and published by the Inframation Training Center ... Vol. 7, 253-262}, pages = {253 -- 262}, year = {2006}, language = {en} } @article{VollmerMoellmann2013, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Is there a maximum size of water drops in nature}, series = {In: The Physics Teacher 51 (2013), 400 - 402}, journal = {In: The Physics Teacher 51 (2013), 400 - 402}, pages = {400 -- 402}, year = {2013}, language = {en} } @article{VollmerShaw2013, author = {Vollmer, Michael and Shaw, Joseph A.}, title = {Brilliant colours from a white snow cover}, series = {In: Physics Education 48 (2013) 3, 322-221}, journal = {In: Physics Education 48 (2013) 3, 322-221}, pages = {322 -- 331}, year = {2013}, language = {en} } @article{VollmerMoellmann2013, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Removing coins from a dice tower: no magic - just physics}, series = {In: The Physics Teacher 51 (2013) 4, pp 212-214}, journal = {In: The Physics Teacher 51 (2013) 4, pp 212-214}, pages = {212 -- 214}, year = {2013}, language = {en} } @article{VollmerMoellmann2012, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Hochgeschwindigkeitskameras im Physikunterricht}, series = {In: Der mathematische und naturwissenschaftliche Unterricht : MNU 65 (2012) 6, 349-355}, journal = {In: Der mathematische und naturwissenschaftliche Unterricht : MNU 65 (2012) 6, 349-355}, pages = {349 -- 355}, year = {2012}, language = {de} } @article{VollmerMoellmann2012, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Tropfen auf dem kalten Wein}, series = {In: Physik in unserer Zeit 43 (2012) 5, 252-253}, journal = {In: Physik in unserer Zeit 43 (2012) 5, 252-253}, doi = {10.1002/piuz.201290081}, pages = {252 -- 253}, year = {2012}, abstract = {Viele kennen die leidvolle Erfahrung: Beim Fr{\"u}hst{\"u}ckstisch gießt man einen Schuss Milch in den Kaffee, und prompt spritzt eine kleine Font{\"a}ne aus der Tasse, und ein Tropfen landet - hier gilt Murphys Gesetz fast immer - auf dem frisch angezogenen Hemd oder mit etwas Gl{\"u}ck nur auf der Tischdecke. Man kann dieses Ph{\"a}nomen unter kontrollierten Bedingungen mit Hochgeschwindigkeits-Kameras analysieren und interessante Physik hinter den Spritzern aufsp{\"u}ren.}, language = {de} } @article{VollmerMoellmann2012, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Raindrops keep falling on my head}, series = {In: Physik in unserer Zeit 43 (2012) 4, 200 - 201}, journal = {In: Physik in unserer Zeit 43 (2012) 4, 200 - 201}, doi = {10.1002/piuz.201290063}, pages = {200 -- 201}, year = {2012}, abstract = {Fallende Tropfen oszillieren zwischen zigarren- und pfannkuchen{\"a}hnlichen Formen. Das hat praktische Konsequenzen f{\"u}r moderne Methoden der Niederschlagsbestimmung, da Regenradarger{\"a}te als Eingangsparameter die statische Gleichgewichtsform der Tropfen zugrunde legen. Deshalb muss man auch deren dynamisches Verhalten kennen. Mit Hochgeschwindigkeitsvideos l{\"a}sst sich dieses sehr gut beobachten.}, language = {de} } @article{VollmerMoellmann2012, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Lorentz-Pendel in der Gl{\"u}hbirne}, series = {In: Physik in unserer Zeit 43 (2012) 2, 96-97}, journal = {In: Physik in unserer Zeit 43 (2012) 2, 96-97}, doi = {10.1002/piuz.201290031}, pages = {96 -- 97}, year = {2012}, abstract = {Die Lorentz-Kraft auf bewegte Ladungen im Magnetfeld l{\"a}sst sich auf unterschiedliche Weise demonstrieren. Ein beeindruckendes Beispiel ist die wechselstromdurchflossene Wendel einer Gl{\"u}hlampe, die in einem zeitlich konstanten Magnetfeld schwingt. Mit einer Hochgeschwindigkeitskamera kann man diese schnelle Bewegung zeitaufgel{\"o}st darstellen.}, language = {de} } @article{VollmerMoellmann2012, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Feynmans R{\"a}tsel der brechenden Spaghetti}, series = {In: Physik in unserer Zeit 43 (2012) 1, 46-47}, journal = {In: Physik in unserer Zeit 43 (2012) 1, 46-47}, doi = {10.1002/piuz.201290006}, pages = {46 -- 47}, year = {2012}, abstract = {Wenn man eine ungekochte Spaghetti-Nudel an beiden Enden fasst und zerbricht, entstehen immer drei Bruchst{\"u}cke oder mehr, nie jedoch nur zwei. Warum das so ist, fragte sich schon Richard Feynman. Mittlerweile ist die Frage gekl{\"a}rt, und Hochgeschwindigkeitsaufnahmen zeigen den Vorgang im Detail.}, language = {de} } @article{VollmerMoellmann2011, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Der Ring-in-die-Kette Zaubertrick und ein historisches Vakuumexperiment in neuem Gewand: Erkenntnisgewinn durch Hochgeschwindigkeitsaufnahmen}, series = {In: Praxis der Naturwissenschaften - Physik in der Schule 60 (2011) 5, 30-35}, journal = {In: Praxis der Naturwissenschaften - Physik in der Schule 60 (2011) 5, 30-35}, pages = {30 -- 35}, year = {2011}, language = {de} } @article{Vollmer2000, author = {Vollmer, Michael}, title = {Wahlverhalten von Sch{\"u}lern der Sekundarstufe II im Fach Physik seit 1990 im bundesweiten Vergleich}, series = {Physik in der Schule 38 (2000) 5, 351-354}, journal = {Physik in der Schule 38 (2000) 5, 351-354}, pages = {351 -- 354}, year = {2000}, language = {de} } @article{VollmerMoellmann2013, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Das Splittern nach dem Schuss (Rasante Physik)}, series = {In: Physik in unserer Zeit 44 (2013) 5, 251-252}, journal = {In: Physik in unserer Zeit 44 (2013) 5, 251-252}, doi = {10.1002/piuz.201390089}, pages = {251 -- 252}, year = {2013}, abstract = {Rohe Eier sind, zwischen Daumen und Zeigefinger gehalten, sehr stabil. Das gilt auch f{\"u}r kugelf{\"o}rmige Christbaumkugeln. Mit solchen Feiertagsutensilien lassen sich interessante physikalische Experimente zur Inkompressibilit{\"a}t von Fl{\"u}ssigkeiten anstellen - und mit Hochgeschwindigkeitskameras studieren.}, language = {de} } @article{VollmerMoellmann2013, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Die M{\"u}nze im W{\"u}rfelturm (Rasante Physik)}, series = {In: Physik in unserer Zeit 44 (2013) 4, 200-201}, journal = {In: Physik in unserer Zeit 44 (2013) 4, 200-201}, doi = {10.1002/piuz.201390066}, pages = {200 -- 201}, year = {2013}, abstract = {Hinter manchem vermeintlichen Zaubertrick versteckt sich einfache Physik. Das entzieht den Tricks aber nicht ihre Faszination. Im Gegenteil. Ein gutes Beispiel ist das folgende R{\"a}tsel, das sowohl auf Kindergeburtstagen als auch auf Partys mit Erwachsenen erfolgreich eingesetzt werden kann. Hochgeschwindigkeits-Aufnahmen erm{\"o}glichen die physikalische Analyse.}, language = {de} } @article{VollmerMoellmann2013, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Zerst{\"a}uben großer Wassertropfen (Rasante Physik),}, series = {In: Physik in unserer Zeit 44 (2013) 3, 149-150}, journal = {In: Physik in unserer Zeit 44 (2013) 3, 149-150}, doi = {10.1002/piuz.201390049}, pages = {149 -- 150}, year = {2013}, abstract = {In der Natur kommen Wassertropfen in verschiedenen Gr{\"o}ßen vor. Kleine Tr{\"o}pfchen von etwa 10 μm sind {\"u}blich in Nebel und Wolken, w{\"a}hrend Regentropfen bis zu 5 mm Durchmesser erreichen k{\"o}nnen. Gr{\"o}ßere Tropfen k{\"o}nnen oszillieren, w{\"a}hrend kleinere im Allgemeinen kugelf{\"o}rmig sind. Offensichtlich k{\"o}nnen Wassertropfen nicht beliebig groß werden. Welche Faktoren beschr{\"a}nken die m{\"o}gliche Gr{\"o}ße?}, language = {de} } @article{VollmerMoellmann2013, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Schneller als der freie Fall (Rasante Physik)}, series = {In: Physik in unserer Zeit 44 (2013) 1, 46-47}, journal = {In: Physik in unserer Zeit 44 (2013) 1, 46-47}, doi = {10.1002/piuz.201390006}, pages = {46 -- 47}, year = {2013}, abstract = {L{\"a}sst man einen K{\"o}rper fallen, so beschleunigt dieser auf Meeresh{\"o}he in unseren Breiten bekanntermaßen mit etwa 9,8 m/s2. Ist es dennoch m{\"o}glich, dass unter diesen Bedingungen ein K{\"o}rper schneller fallen kann? Was auf den ersten Blick paradox erscheint, ist durchaus m{\"o}glich, wie sich mit Hochgeschwindigkeitsvideos eindrucksvoll belegen l{\"a}sst.}, language = {de} } @article{VollmerMoellmann2012, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Prost Neujahr: die Physik von Champagnerflaschen (Rasante Physik)}, series = {In: Physik in unserer Zeit 43 (2012) 6, 307-308}, journal = {In: Physik in unserer Zeit 43 (2012) 6, 307-308}, doi = {10.1002/piuz.201290100}, pages = {307 -- 308}, year = {2012}, abstract = {Sekt und Champagner geh{\"o}ren zur Silvesterfeier wie ein pr{\"a}chtiges Feuerwerk. Physiker verfallen hierbei leicht in Diskussionen {\"u}ber die Wurfparabeln der Sektkorken oder das akustische Ph{\"a}nomen des Knalls. Hochgeschwindigkeitskameras er{\"o}ffnen zus{\"a}tzlich die M{\"o}glichkeit, sehr schnell ablaufende Prozesse bei der Handhabung der edlen Tropfen sichtbar zu machen, zum Beispiel die adiabatische Expansion des Treibgases.}, language = {de} } @article{GedzelmanVollmer2011, author = {Gedzelman, Stanley David and Vollmer, Michael}, title = {Crepuscular rays: laboratory experiments and simulations}, series = {In: Applied Optics Vol. 50 (2011) 28, pp. F142-F151}, journal = {In: Applied Optics Vol. 50 (2011) 28, pp. F142-F151}, doi = {http://dx.doi.org/10.1364/AO.50.00F142}, year = {2011}, abstract = {Model simulations of laboratory-generated and natural crepuscular rays are presented. Rays are created in the laboratory with parallel light beams that pass through artificial fogs and milk-water solutions. Light scattered by 90° in a dilute mixture of whole milk first increases in intensity with distance from the source to a maximum as a result of multiple scattering by mainly small angles before decreasing exponentially due to extinction as distance continues to increase. Crepuscular rays are simulated for three cloud configurations. In case 1, the Sun at the zenith is blocked by a cloud with an overhanging anvil. The rays appear white against blue sky and are brightest when atmospheric turbidity, β≈11 . Shading by the anvil separates maximum brightness from apparent cloud edge. In case 2, a ray passes through a rectangular gap in a cloud layer. The ray is faint blue in a molecular atmosphere but turns pale yellow as β and solar zenith angle, ϕsun , increase. At ϕsun=60° it appears most striking when the cloud is optically thick, β≈5 , and the beam width Δx≈1000 m . In these cases, increasing aerosol radius, raer , to about 1000 nm brightens, narrows, and shortens rays. In case 3, the twilight Sun is shaded by a towering cloud or mountain. The shaded rays are deeper blue than the sunlit sky because the light originates higher in the atmosphere, where short waves have suffered less depletion from scattering. The long optical path taken by sunlight at twilight makes color and lighting contrasts of the rays greatest when the air is quite clean, i.e., for β-1≪1 . In all cases, the brightest rays occur when sunlight passes through an optical thickness of atmosphere, τ≈O(1) . © 2011 Optical Society of America}, language = {en} } @article{VollmerMoellmann2011, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Rainbows, water droplets, and seeing—slow motion analysis of experiments in atmospheric optics}, series = {In: Applied optics Vol. 50 (2011) 28, pp. F21-F28}, journal = {In: Applied optics Vol. 50 (2011) 28, pp. F21-F28}, doi = {http://dx.doi.org/10.1364/AO.50.000F21}, pages = {F21 -- F28}, year = {2011}, abstract = {Many physics processes underlying phenomena in atmospheric optics happen on a rather short time scale such that neither the human eye nor video cameras are able to analyze the details. We report applications of high-speed imaging of laboratory experiments in atmospheric optics with subsequent slow motion analysis. The potential to study respective transient effects is investigated in general and for a few phenomena in detail, in particular for rainbow scattering due to single oscillating droplets during free fall, and for light propagation effects through atmospheric paths with turbulences, leading, e.g., to scintillation of stars or shimmering of mirage images. © 2011 Optical Society of America}, language = {en} } @article{VollmerMoellmann2012, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Vapour pressure and adiabatic cooling from champagne: slow motion visualization of gas thermodynamics}, series = {In: Physics Education 47 (2012) 5, 608-615}, journal = {In: Physics Education 47 (2012) 5, 608-615}, pages = {608 -- 615}, year = {2012}, language = {en} } @article{VollmerMoellmann2012, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Low cost hands-on experiments for Physics teaching}, series = {In: Latin-American Journal of Physics Education 6 (2012) Suppl. I, pp. 3-9}, journal = {In: Latin-American Journal of Physics Education 6 (2012) Suppl. I, pp. 3-9}, issn = {1870-9095}, pages = {3 -- 9}, year = {2012}, language = {en} } @article{VollmerMoellmann2012, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Oscillating droplets and incompressible liquids: slow motion visualization of experiments with fluids}, series = {In: Physics Education 47 (2012), 664-679}, journal = {In: Physics Education 47 (2012), 664-679}, pages = {664 -- 679}, year = {2012}, language = {en} } @article{VollmerMoellmann2011, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Ring falling into a chain: no magic - just physics}, series = {In: The Physics Teacher 49 (2011), 335-337}, journal = {In: The Physics Teacher 49 (2011), 335-337}, pages = {335 -- 337}, year = {2011}, language = {en} } @article{FrankeWiekhorstNordmeierVollmeretal.2011, author = {Franke-Wiekhorst, A. and Nordmeier, V. and Vollmer, Michael and Welzel-Breuer, M. and Wodzinski, R.}, title = {Fobinet: an internet supported platform for nationwide coordination, promotion and funding of physics teacher training activities in Germany}, series = {In: Physics Education 46 (2011), 240-243}, journal = {In: Physics Education 46 (2011), 240-243}, pages = {240 -- 243}, year = {2011}, language = {en} } @article{Vollmer2013, author = {Vollmer, Michael}, title = {Infrared}, series = {In: European journal of physics 34 (2013) 6, S49}, journal = {In: European journal of physics 34 (2013) 6, S49}, doi = {doi:10.1088/0143-0807/34/6/S49}, pages = {S49}, year = {2013}, language = {en} } @article{EtkinaPlaninšičVollmer2013, author = {Etkina, Eugenia and Planinšič, Gorazd and Vollmer, Michael}, title = {Light cone: Engaging students of all levels in processes that physicists use in research}, series = {In: American journal of physics 81 (2013) 11, 815-822}, journal = {In: American journal of physics 81 (2013) 11, 815-822}, doi = {10.1119/1.4822176}, pages = {815 -- 822}, year = {2013}, abstract = {A cone of light appears in a tank of water when a laser pointer shines through the water onto a white piece of paper upon which the tank is sitting. We describe how students can understand the origins of this cone by constructing multiple explanations, then proposing and designing experiments to test their explanations. This process is the foundation of the Investigative Science Learning Environment (ISLE) framework, designed to engage students in the reasoning activities similar to those that physicists use to construct and apply new knowledge. We describe typical student ideas and provide a list of equipment and suggestions for facilitating student exploration relating to optics. We also explain the formal physics behind the phenomena that are involved in the experiment. Finally, we suggest how the ISLE framework can be used to help instructors find problems and experiments that engage students in devising and testing multiple explanations.}, language = {en} } @article{VollmerMoellmann2013, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {James Bond und die zerplatzenden Christbaumkugeln}, series = {Physik in unserer Zeit 44 (2013) 6, 304-306}, journal = {Physik in unserer Zeit 44 (2013) 6, 304-306}, doi = {10.1002/piuz.201390109}, pages = {304 -- 306}, year = {2013}, abstract = {Rohe Eier oder wassergef{\"u}llte Christbaumkugeln platzen beim Eindringen des Projektils einer Luftpistole. Dieser Vorgang l{\"a}sst sich einfach durch die sehr geringe Kompressibilit{\"a}t des Wassers und eine damit verbundene starke Druckerh{\"o}hung erkl{\"a}ren (Physik in unserer Zeit 2013, 44(5), 251). Eine genaue Analyse aller Vorg{\"a}nge sollte aber auch Fragen beantworten wie: Spielen vorhandene Luftblasen in der Fl{\"u}ssigkeit eine Rolle? Wie lange dauert es bis zum Aufplatzen, und muss die wassergef{\"u}llte Kugel eigentlich fest verschlossen sein?}, language = {de} } @article{VollmerMoellmannSchlichting2014, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter and Schlichting, Hans Joachim}, title = {Double pane windows—elastic deformations, gas thermodynamics, thermal and optical phenomena}, series = {In: European Journal of Physics 35 (2014) 4, 045023}, journal = {In: European Journal of Physics 35 (2014) 4, 045023}, doi = {10.1088/0143-0807/35/4/045023}, year = {2014}, abstract = {Double pane windows are common objects which can enrich physics teaching at undergraduate level at least in five different fields. First, having sealed inner spaces filled with gas, one can discuss gas law problems upon changes of pressure and/or temperature. Second, when discussing temperature differences between inside and outside, one needs to take into account the associated heat transfer mechanisms which define the pane temperatures, enclosing the gas. Third, using elastic properties of the glass, one may treat deformations of the window panes upon those changes or additional manually applied external pressure. Fourth, the reflective properties of glass combined with the pane deformations result in concave or convex mirrors, which when illuminated by the Sun, may lead to focal points on projection areas such as facing houses. Fifth, such areas receive an increased irradiance which leads to associated thermal effects. Starting from the most obvious daily life phenomenon, the fascinating caustics of reflected sunlight on streets or walls, all of these double pane window phenomena are investigated experimentally as well as theoretically.}, language = {en} } @article{VollmerMoellmann2014, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Schnelles Verblassen leuchtender Spuren}, series = {In: Physik in unserer Zeit 45 (2014) 5, 252-253}, journal = {In: Physik in unserer Zeit 45 (2014) 5, 252-253}, doi = {10.1002/piuz.201490088}, pages = {252 -- 253}, year = {2014}, abstract = {Wohl jeder, der schon einmal mit Physik zu tun hatte, kennt die meist gr{\"u}nlichen Leuchtspuren von Oszillographen. Sie erm{\"o}glichen es, zeitabh{\"a}ngige Signale zu visualisieren und quantitativ auszumessen, insbesondere auch dann, wenn die Ph{\"a}nomene sehr schnell ablaufen. Die Reaktionsdynamik der leuchtenden Phosphore auf den Bildschirmen wird mit Hochgeschwindigkeits-Videos deutlich sichtbar.}, language = {de} } @article{VollmerMoellmann2014, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Wenn es knallt und kracht}, series = {In: Physik in unserer Zeit 45 (2014) 3, 148-149}, journal = {In: Physik in unserer Zeit 45 (2014) 3, 148-149}, doi = {10.1002/piuz.201490046}, pages = {148 -- 149}, year = {2014}, abstract = {An die Knallgasprobe erinnert sich wohl noch jeder aus dem Chemieunterricht. Die Zeitskala, auf der Wasserstoff und Sauerstoff reagieren h{\"a}ngt davon ab, ob die beiden Reaktionsgase zu Beginn getrennt oder gemischt vorliegen. Dies zeigt sich deutlich in Hochgeschwindigkeits-Aufnahmen von Experimenten, bei denen Luftballons entweder mit reinem Wasserstoff oder aber mit Knallgas gef{\"u}llt werden.}, language = {de} } @article{VollmerMoellmann2014, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Achtung Solarofen : Kaustiken von Hochhausverglasungen}, series = {In: Physik in unserer Zeit 45 (2014) 3, 134-139}, journal = {In: Physik in unserer Zeit 45 (2014) 3, 134-139}, doi = {10.1002/piuz.201401360}, pages = {134 -- 139}, year = {2014}, abstract = {Konkav gew{\"o}lbte Glasfassaden von Großbauten k{\"o}nnen bei ung{\"u}nstiger Orientierung zur Sonne zum Brennspiegel werden. Unfreiwillig ber{\"u}hmt gewordene Beispiele sind das Vdara-Hotel in Las Vegas und das "Walkie-Talkie"-Hochhaus in London. Dieser Effekt tritt auch nur an bestimmten Tagen bei passendem Sonnenstand auf. Da die Fassaden keine perfekten Parabolspiegel sind, produzieren sie keinen scharfen Brennpunkt, sondern aufgeweitete Brennflecke, sogenannte Kaustiken. Trotzdem k{\"o}nnen dort hohe Bestrahlungsst{\"a}rken auftreten. Simulationen und Experimente mit Modellen best{\"a}tigen dies.}, language = {de} } @article{VollmerMoellmann2014, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Das farbenpr{\"a}chtige Glitzern frischen Schnees}, series = {In: Physik in unserer Zeit 45 (2014) 2, 97-98}, journal = {In: Physik in unserer Zeit 45 (2014) 2, 97-98}, doi = {10.1002/piuz.201490031}, pages = {97 -- 98}, year = {2014}, abstract = {Regenb{\"o}gen, Halos, Koronen, Himmelsfarben - es gibt eine Vielzahl farbenpr{\"a}chtiger Ph{\"a}nomene in der Natur, verursacht durch Reflexion, Brechung oder allgemein gesprochen durch Streuung des Lichts an Wassertropfen, Eiskristallen oder Aerosolen. Das farbige Glitzern einer Schneeschicht scheint zun{\"a}chst anderer Natur zu sein, l{\"a}sst sich aber auf analoge Weise erkl{\"a}ren.}, language = {de} } @article{VollmerMoellmann2014, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Physikalische Zauberei : die Kette im Ring}, series = {In: Physik in unserer Zeit 45 (2014) 1, 44-45}, journal = {In: Physik in unserer Zeit 45 (2014) 1, 44-45}, doi = {10.1002/piuz.201490004}, pages = {44 -- 45}, year = {2014}, abstract = {Ein einfacher physikalischer Zaubertrick besteht darin, eine Kette {\"u}ber den Handr{\"u}cken zu legen und danach von unten einen Ring {\"u}ber die Kette zu schieben. Der Ring kann entweder von der zweiten Hand oder der die Kette haltenden Hand gehalten werden. Er wird sodann losgelassen und soll (mit einem Knoten) in der Kette h{\"a}ngen bleiben.}, language = {de} } @article{NugentShawVollmer2015, author = {Nugent, Paul W. and Shaw, Joseph A. and Vollmer, Michael}, title = {Colors of thermal pools at Yellowstone National Park}, series = {Applied Optics Vol. 54 (2015 ) 4, pp. B128-B139}, journal = {Applied Optics Vol. 54 (2015 ) 4, pp. B128-B139}, doi = {10.1364/AO.54.00B128}, pages = {B128 -- B139}, year = {2015}, abstract = {Abstract The brilliant visible colors of various hot springs and pools in Yellowstone National Park are explained with a combination of scattering from the water and from microbial mats that coat the bottoms of these thermal features. A simple 1D radiative transfer model was used to simulate the colors recorded in visible photographs and the spectrum of light making up these colors. The model includes attenuation in water by absorption and molecular scattering as well as reflection characteristics of the microbial mats and surface reflection of the water. Pool geometries are simulated as simple rough cones scaled to have depths and widths that match published data. Thermal images are also used to record the spatial distribution of water skin temperature. The measurements and simulations confirm that colors observed from shallow-water features arise primarily from the spectral properties of the microbial mat, which is related to the water temperature, while colors observed from deeper water arise primarily from the wavelength-dependent absorption and scattering in the water.}, language = {en} } @article{GrossmannMoellmannVollmer2015, author = {Großmann, Michael and M{\"o}llmann, Klaus-Peter and Vollmer, Michael}, title = {Artificially generated halos: rotating sample crystals around various axes}, series = {Appield Optics 54 (2015) 4, B97-B106}, journal = {Appield Optics 54 (2015) 4, B97-B106}, doi = {10.1364/AO.54.000B97}, pages = {B97 -- B106}, year = {2015}, abstract = {Abstract So far experiments with artificial halos from single transparent crystals have suffered from the lack of apparatus that allows simultaneous rotation around two and three axes. A new setup is presented which overcomes these restrictions by combining electrical as well as pneumatic concepts. This enables reproducible experiments of the most common halos observed in nature and for the first time artificial ring halos from single hexagons rotating around three axes simultaneously. In addition, an old qualitative halo demonstration based on perceived colors of rotating colored areas whose contours represent scattering plots has been reinvestigated and the usually nonsaturated color of artificial parhelia was visualized using a crossed prism method. These new experiments are discussed in the context of all known artificial halo experiments. © 2014 Optical Society of America}, language = {en} } @misc{Vollmer2010, author = {Vollmer, Michael}, title = {High speed - slow motion I: new insights for hands on experiments in mechanics}, year = {2010}, language = {en} } @misc{Vollmer2010, author = {Vollmer, Michael}, title = {High speed - slow motion II : more experiments using gases, fluids, heat and electromagnetism}, year = {2010}, language = {en} } @misc{VollmerMoellmann2011, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {High speed - slow motion: fascinating phenomena observed in hands-on experiments}, year = {2011}, language = {en} } @misc{Vollmer2011, author = {Vollmer, Michael}, title = {Low cost hands-on experiments for physics teaching}, year = {2011}, language = {en} } @article{ShawNugentVollmer2015, author = {Shaw, Joseph A. and Nugent, Paul W. and Vollmer, Michael}, title = {Infrared Moon imaging for remote sensing of atmospheric smoke layers}, series = {Applied Optics 54 (2015) 4, B64-B75}, journal = {Applied Optics 54 (2015) 4, B64-B75}, doi = {10.1364/AO.54.000B64}, pages = {B64 -- B75}, year = {2015}, abstract = {Abstract Simultaneous visible and long-wave infrared (IR) images of the Moon were used with a simple energy-balance model to study the spatial pattern of lunar surface temperatures. The thermal images were obtained with a radiometrically calibrated, compact, low-cost, commercial IR camera mounted on a small telescope. Differences between the predicted and measured maximum Moon temperatures were used to determine the infrared optical depth (OD), which represents the path-integrated extinction of an elevated layer of wildfire smoke in the atmosphere. The OD values retrieved from the IR Moon images were combined with simultaneous OD measurements from a ground-based, zenith-pointing lidar operating at a wavelength of 532 nm to determine an IR-to-visible OD ratio of 0.50±0.18 for moderately aged wildfire smoke aerosol. © 2014 Optical Society of America}, language = {en} } @article{VollmerShawNugent2015, author = {Vollmer, Michael and Shaw, Joseph A. and Nugent, Paul W.}, title = {Visible and invisible mirages: comparing inferior mirages in the visible and thermal infrared}, series = {Applied Optics 54 (2015) 4, B76-B84}, journal = {Applied Optics 54 (2015) 4, B76-B84}, doi = {10.1364/AO.54.000B76}, pages = {B76 -- B84}, year = {2015}, abstract = {Abstract Visible (VIS)-light and thermal infrared (IR) inferior mirages in the 8-14 μm waveband have been observed simultaneously for the takeoff and landing of various airplanes at distances of several kilometers. Similarities as well as differences between the VIS and IR mirages are discussed. © 2014 Optical Society of America}, language = {en} } @article{VollmerMoellmannShaw2015, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter and Shaw, Joseph A.}, title = {The optics and physics of near infrared imaging}, series = {Proceedings of SPIE 9793, Education and Training in Optics and Photonics: ETOP 2015, 97930Z (October 8, 2015)}, journal = {Proceedings of SPIE 9793, Education and Training in Optics and Photonics: ETOP 2015, 97930Z (October 8, 2015)}, doi = {10.1117/12.2223094}, year = {2015}, abstract = {abstract A large part of photonics research and development, as well as commercial applications such as optical data transmission or infrared thermal imaging, occurs in the infrared spectral range between 0.8 μm and 15 μm. However, relatively little material is so far available for experimentally teaching the physics and optics of this spectral range. We report a respective new approach in the near infrared (NIR) range between 0.8 μm and 1.7 μm that allows visualization of a number of fascinating physics phenomena. First, we use the near-infrared sensitivity of silicon-based detectors in rather inexpensive video cameras and digital single-lens reflex cameras by removing the infrared-blocking filter and replacing it with a visible-radiation blocking filter. Second, we utilize modern NIR cameras based on InGaAs detectors. With both camera types we illustrate and explain a number of physics concepts that are especially suitable for curricula in optics and photonics. Examples include the strangely bright appearance of vegetation, contrast enhancement between clouds and sky, the initially surprising differences of optical material properties between the VIS and NIR range, the possibilities of visualizing buried hidden structures and texts, and recent medical applications to locate blood vessels below the skin. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.}, language = {en} } @article{ShawNugentVollmer2015, author = {Shaw, Joseph A. and Nugent, Paul and Vollmer, Michael}, title = {Colors of the Yellowstone thermal pools for teaching optics}, series = {Proceedings of SPIE 9793, Education and Training in Optics and Photonics: ETOP 2015, 97931S (October 8, 2015)}, journal = {Proceedings of SPIE 9793, Education and Training in Optics and Photonics: ETOP 2015, 97931S (October 8, 2015)}, doi = {10.1117/12.2223177}, year = {2015}, abstract = {abstract Nature provides many beautiful optical phenomena that can be used to teach optical principles. Here we describe an interdisciplinary education project based on a simple computer model of the colors observed in the famous thermal pools of Yellowstone National Park in the northwestern United States. The primary wavelength-dependent parameters that determine the widely varying pool colors are the reflectance of the rocks or the microbial mats growing on the rocks beneath the water (the microbial mat color depends on water temperature) and optical absorption and scattering in the water. This paper introduces a teaching module based on a one-dimensional computer model that starts with measured reflectance spectra of the microbial mats and modifies the spectra with depth-dependent absorption and scattering in the water. This module is designed to be incorporated into a graduate course on remote sensing systems, in a section covering the propagation of light through air and water, although it could be adapted to a general university optics course. The module presents the basic 1-D radiative transfer equation relevant to this problem, and allows them to build their own simple model. Students can then simulate the colors that would be observed for different variations of the microbial mat reflectance spectrum, skylight spectrum, and water depth. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.}, language = {en} } @article{VollmerMoellmann2015, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Bouncing Poppers}, series = {The Physics Teacher 53 (2015) 8, 489.493}, journal = {The Physics Teacher 53 (2015) 8, 489.493}, doi = {10.1119/1.4933153}, year = {2015}, abstract = {Abstract Toys are known to attract interest in physics and they are therefore often used in physics teaching of various topics. The present paper deals with a simple toy, the so-called "hopper popper," which, similar to superballs, can be used when teaching mechanics. We suggest some experiments and describe the basic physics of this toy, also providing background information for teachers.}, language = {en} } @article{VollmerMoellmann2015, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {The tablecloth pull revisited}, series = {Physics Education 50 (2015) 3}, journal = {Physics Education 50 (2015) 3}, pages = {324 -- 328}, year = {2015}, abstract = {Abstract A very old and well-known magical trick is the so-called tablecloth pull. A table is covered with a tablecloth, on top of which are certain objects. The task is to remove the tablecloth while the objects—which must not be touched—stay on top of the table. This article describes the physics behind the experiment, and presents examples recorded with high-speed cameras.}, language = {en} } @article{VollmerMoellmann2015, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Flickering lamps}, series = {European Journal of Physics 36 (2015) 3}, journal = {European Journal of Physics 36 (2015) 3}, doi = {10.1088/0143-0807/36/3/035027}, pages = {035027}, year = {2015}, abstract = {Abstract Many processes in electromagnetism vary with time. Some of them are well known, in particular those related to line frequencies of 50 Hz or 60 Hz such as fluctuating light output of discharge and incandescent lamps. The flickers of discharge and incandescent lamps have quite different physical principles involved, which are investigated experimentally using high-speed cameras and theoretically using simplified models. The topic is related to other phenomena such as the transient behaviour of phosphor layers covering the screen of oscilloscopes and the time-varying Lorentz force acting on the filament of light bulbs. All studies are well suited for teaching selected aspects of electromagnetism and light at undergraduate level at university.}, language = {en} } @article{VollmerMoellmann2015, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Light-emitting pickles}, series = {Physics Education 50 (2015) 1}, journal = {Physics Education 50 (2015) 1}, pages = {94 -- 104}, year = {2015}, abstract = {Abstract We present experiments giving new insights into the classical light-emitting pickle experiment. In particular, measurements of the spectra and temperatures, as well as high-speed recordings, reveal that light emission is connected to the polarity of the electrodes and the presence of hydrogen.}, language = {en} } @article{VollmerMoellmann2015, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Krach-bumm-peng - B{\"o}ller und Tischfeuerwerke}, series = {Physik in unserer Zeit 46 (2015) 6, 305-306}, journal = {Physik in unserer Zeit 46 (2015) 6, 305-306}, doi = {10.1002/piuz.201590105}, pages = {305 -- 306}, year = {2015}, abstract = {Abstract Zu Silvester wird es wieder krachen und knallen, draußen oder drinnen. Hochgeschwindigkeits-Videos von Chinakrachern offenbaren deren dynamische Explosionsphase. Auch die weniger spektakul{\"a}ren Tischfeuerwerke zeigen noch so manches interessante Detail.}, language = {de} } @article{VollmerMoellmann2015, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Flimmernde Luft und funkelnde Sterne}, series = {Physik in unserer Zeit 46 (2015) 5, 254-255}, journal = {Physik in unserer Zeit 46 (2015) 5, 254-255}, doi = {10.1002/piuz.201590087}, pages = {254 -- 255}, year = {2015}, abstract = {Abstract Das Flimmern der Sterne, von manchen als romantisch empfunden, ist f{\"u}r Astronomen ein {\"A}rgernis. Selbst bei klarer Luft scheinen die Sterne herumzuh{\"u}pfen und in st{\"a}ndiger Bewegung zu sein. Das Maß des Seeings, wie die Wissenschaftler sagen, beschr{\"a}nkt das r{\"a}umliche Aufl{\"o}sungsverm{\"o}gen von Teleskopen. Mit einer einfachen Versuchsanordnung und einer Hochgeschwindigkeits-Kamera l{\"a}sst sich dieses Ph{\"a}nomen im Labor nachstellen und analysieren.}, language = {de} } @article{VollmerMoellmann2015, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Der Trick mit der Tischdecke}, series = {Physik in unserer Zeit 46 (2015) 4, 199-201}, journal = {Physik in unserer Zeit 46 (2015) 4, 199-201}, doi = {10.1002/piuz.201590067}, pages = {199 -- 201}, year = {2015}, abstract = {Abstract Eine Tischdecke unter einem Service feinsten Porzellans wegzuziehen ohne dass etwas vom Tisch f{\"a}llt und zerbricht ist sicher eine Herausforderung. Aber viele Vorf{\"u}hrungen, auch in Experimentalphysik-Vorlesungen beweisen: es funktioniert. Hochgeschwindigkeits-Videos k{\"o}nnen diesen heiklen Experimenten physikalische Details entlocken.}, language = {de} } @article{VollmerMoellmann2015, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter}, title = {Springende H{\"u}pfgummis}, series = {Physik in unserer Zeit 46 (2015) 3, 149-150}, journal = {Physik in unserer Zeit 46 (2015) 3, 149-150}, doi = {10.1002/piuz.201590049}, pages = {149 -- 150}, year = {2015}, abstract = {Abstract H{\"u}pfgummis sind einfache, preiswerte Spielzeuge, die in Spielwarenl{\"a}den oder Science Centern erh{\"a}ltlich sind. Sie erm{\"o}glichen interessante Einblicke in physikalische Ph{\"a}nomene der Mechanik - insbesondere mit Hochgeschwindigkeits-Videos.}, language = {de} }