Laboratoire de Didactique André Revuz, mathématiques et sciences expérimentales
Présentation
Le LDAR (EA 4434) est une unité de recherche en didactique des mathématiques, des sciences de la matière (physique, chimie) et des sciences de la nature (biologie, géologie, géographie) dont les travaux visent à éclairer ce qui, dans un savoir d’une discipline scientifique donnée (loi, concept, modèle, explication, etc.) est susceptible de générer des diffcultés d’apprentissage et d’enseignement.
Au-delà de cette visée compréhensive, les recherches conduites au sein du LDAR ont également pour objectif de proposer des palettes de possibilités d’actions, d’outils, de scénarios pour les enseignant.e.s de l’ensemble des trois segments éducatifs (premier et second degrés, enseignement supérieur), dans et hors l’École. Ils visent également à examiner l’influence des institutions au sein desquelles ces savoirs circulent et se transforment et la manière dont les enseignant.e.s manipulent, choisissent et font circuler ces savoirs en contexte d'apprentissage.
Le LDAR, un laboratoire régional
Le LDAR est une EA pluri-tutelle d'envergure régionale, conventionnée avec les universités d'Artois, de Cergy-Pontoise, de Paris Diderot (tutelle hébergeante), de Paris-Est Créteil et de Rouen Normandie ; il accueille près de 70 membres et entretient, par sa spécificité pluri-universitaire, des liens privilégiés avec les ESPE de Créteil, de Rouen Normandie, de Cergy-Pontoise, de Lille Nord de France et de Paris, et les UFR scientifiques de Paris Diderot et d’Artois.
Le LDAR et le master mention "didactique des sciences"
Au LDAR est adossée le master « didactique des sciences ». Ce master accueille chaque année près de 50 étudiant.e.s dont la plupart sont enseignant.e.s des trois segments éducatifs (primaire, secondaire, supérieur). Cette formation est alimentée par les résultats de la recherche dans les didactiques représentées ; elle contribue à la formation des futur.e.s chercheur.e.s en didactique et des formateurs et formatrices d’enseignant.e.s. Cela en fait un pôle d’attractivité aussi bien en France qu’à l’étranger, ainsi qu’un lieu d’échanges entre disciplines (didactique, histoire et philosophie des sciences, psychologie du développement, sociologie de l'éducation, etc.).
Equipes de recherche
Direction :
Cécile de Hosson, directrice, université Paris Diderot
Christophe Hache, directeur adjointe, université Paris Diderot
Isabelle Kermen, directrice adjointe, université d’Artois
Fabrice Vandebrouck : directeur adjoint, université Paris Diderot
Evelyne Scaron : gestionnaire
Site internet du LDAR : https://www.ldar.website/
[hal-00633466] Millimetron--a large Russian-European submillimeter space observatory
Date: 27 juin 2022 - 14:10
Desc: Millimetron is a Russian-led 12 m diameter submillimeter and far-infrared space observatory which is included in the Space Plan of the Russian Federation for launch around 2017. With its large collecting area and state-of-the-art receivers, it will enable unique science and allow at least one order of magnitude improvement with respect to the Herschel Space Observatory. Millimetron will be operated in two basic observing modes: as a single-dish observatory, and as an element of a ground-space very long baseline interferometry (VLBI) system. As single-dish, angular resolutions on the order of 3 to 12 arc sec will be achieved and spectral resolutions of up to a million employing heterodyne techniques. As VLBI antenna, the chosen elliptical orbit will provide extremely large VLBI baselines (beyond 300,000 km) resulting in micro-arc second angular resolution.
[hal-03481844] L’Astronomie pour l’éducation dans l’espace francophone
Date: 27 juin 2022 - 04:41
Desc: Le colloque Astronomie pour l’éducation dans l’espace francophone (AstroEdu-FR) s’est tenu du 7 au 9 janvier 2021, en hommage à Jean-Claude Pecker et sous le patronage de l’Académie des sciences de France. Son objectif était de proposer un état des lieux des pratiques et des objectifs qui se cachent derrière les termes « astronomie à l’école ». Cette première édition a réuni 258 participants, essentiellement des enseignants et des chercheurs, ainsi que des formateurs et médiateurs, tous francophones, venant de France métropolitaine, d’outre-mer et de 16 autres pays. Cet ouvrage, conçu à partir des différentes contributions au colloque, couvre plusieurs thèmes autour des pratiques enseignantes et de la formation : liens écoles-chercheurs ; pluridisciplinarité ; modéliser ; observer et expérimenter ; images ; maquettes ; logiciels et jeux sérieux ; livres, manuels et BD ; difficultés rencontrées ; égalité des chances.
[hal-02882981] Learning scenarios for a 3D virtual environment: The case of special relativity.
Date: 26 juin 2022 - 13:16
Desc: Special Relativity, as introduced by Einstein, is regarded as one of the most important revolutions in the history of physics. Nevertheless, the observation of direct outcomes of this theory on mundane objects is impossible because they can only be witnessed when travelling at relative speeds approaching the speed of light c. These effects are so counterintuitive and contradicting with our daily understanding of space and time that physics students find it hard to learn special relativity beyond mathematical equations and to understand the deep implications of the theory. Although we cannot travel at the speed of light, Virtual Reality (VR) makes it possible to experiment the effects of relativity in a 3D immersive environment (a CAVE: Cave Automatic Virtual Environment). The use of the immersive environment is underpinned by the development of dedicated learning scenarios created through a dialectic between VR-related computational constraints and cognitive constraints that include students’ difficulties.
[hal-01663435] Designing learning scenarios for a 3D virtual environment: The case of special relativity
Date: 26 juin 2022 - 13:08
Desc: Special Relativity, as introduced by Einstein, is regarded as one of the most important revolutions in the history of physics. Nevertheless, the observation of direct outcomes of this theory on mundane objects is impossible because they can only be witnessed when travelling at relative speeds approaching the light velocity c. These effects are so counterintuitive and contradicting with our daily understanding of space and time that physics students find it hard to learn special relativity beyond mathematical equations and to understand the deep implications of the theory. Although we cannot travel at the speed of light, Virtual Reality (VR) makes it possible to experiment the effects of relativity in a 3D immersive environment (a CAVE: Cave Automatic Virtual Environment). The use of the immersive environment is underpinned by the development of dedicated learning scenarios created through a dialectic between VR-related computational constraints and cognitive constraints that include students' difficulties. Investigating student's understanding of relativistic situations (that involve relative speeds close to c) led to the typifying of a cognitive profile that governed the situations to be implemented into the CAVE and the associated learning scenarios.
[in2p3-01058892] Planck 2013 results. XXXI. Consistency of the Planck data
Date: 26 juin 2022 - 13:01
Desc: The Planck design and scanning strategy provide many levels of redundancy that can be exploited to provide tests of internal consistency. One of the most important is the comparison of the 70 GHz (amplifier) and 100 GHz (bolometer) channels. Based on different instrument technologies, with feeds located differently in the focal plane, analysed independently by different teams using different software, and near the minimum of diffuse foreground emission, these channels are in effect two different experiments. The 143 GHz channel has the lowest noise level on Planck, and is near the minimum of unresolved foreground emission. In this paper, we analyse the level of consistency achieved in the 2013 Planck data. We concentrate on comparisons between the 70, 100, and 143 GHz channel maps and power spectra, particularly over the angular scales of the first and second acoustic peaks, on maps masked for diffuse Galactic emission and for strong unresolved sources. Difference maps covering angular scales from 8° to 15′ are consistent with noise, and show no evidence of cosmic microwave background structure. Including small but important corrections for unresolved-source residuals, we demonstrate agreement (measured by deviation of the ratio from unity) between 70 and 100 GHz power spectra averaged over 70 ≤ ℓ ≤ 390 at the 0.8% level, and agreement between 143 and 100 GHz power spectra of 0.4% over the same ℓ range. These values are within and consistent with the overall uncertainties in calibration given in the Planck 2013 results. We also present results based on the 2013 likelihood analysis showing consistency at the 0.35% between the 100, 143, and 217 GHz power spectra. We analyse calibration procedures and beams to determine what fraction of these differences can be accounted for by known approximations or systematicerrors that could be controlled even better in the future, reducing uncertainties still further. Several possible small improvements are described. Subsequent analysis of the beams quantifies the importance of asymmetry in the near sidelobes, which was not fully accounted for initially, affecting the 70/100 ratio. Correcting for this, the 70, 100, and 143 GHz power spectra agree to 0.4% over the first two acoustic peaks. The likelihood analysis that produced the 2013 cosmological parameters incorporated uncertainties larger than this. We show explicitly that correction of the missing near sidelobe power in the HFI channels would result in shifts in the posterior distributions of parameters of less than 0.3σ except for As, the amplitude of the primordial curvature perturbations at 0.05 Mpc-1, which changes by about 1σ. We extend these comparisons to include the sky maps from the complete nine-year mission of the Wilkinson Microwave Anisotropy Probe (WMAP), and find a roughly 2% difference between the Planck and WMAP power spectra in the region of the first acoustic peak.
