Added Value in Education (AVE)
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Administration
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11/06/2013
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Authors: Elena Sassi (IT), Gorazd Planinšič (SI), Laurence Viennot (FR), Christian Ucke (DE)
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Colour phenomena & partial absorption
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Administration
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11/07/2013
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This experiment is designed in order to make students consider not only the spectral composition of light but also its intensity, and to consider the absorption of light by a pigment as partial, instead of as total or zero. These conceptual steps, indeed, are essential to reconcile classical school knowledge about colour and observation of daily life phenomena.
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Colour phenomena & selective absorption
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Administration
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11/07/2013
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This paper was written by Laurence Viennot.
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Floating between two liquids
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Administration
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11/07/2013
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The hydrostatic equilibrium of a solid floating “between two liquids” is analysed, first as a classical exercise, then as a simple experiment with a particular staging. It is suggested to use this situation to address some students’ difficulties about: pressure in statics of fluids, role of atmospheric pressure, Archimedes’ up-thrust, and thinking this setting as a system. It is shown that a possible way to help students overcome some of these difficulties, especially the last one, is to use graphical representations.
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Fluids: the love meter
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Administration
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11/07/2013
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The paper - describes the well-known toy love meter - explains the thermodynamical background (vapour pressure, temperature dependance) - suggests how to build a love meter.
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Fluids: poster
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Administration
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11/07/2013
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This example shows Archimedes' upthrust and downthrust.
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Fluids: various experiments with fluids statics
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Administration
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11/07/2013
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The document describes various experiments involving fluid statics, especially Archimedes' up- and downthrust.
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Jets & inverted jets: a matter of differences
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Administration
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11/07/2013
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The paper expands the classical water jets case to several variants in order to stress the importance of differences caused by the media inside and outside of the container. Descriptions of the cases employs p(h) graphs that prove to serve as a powerful tool for making predictions and fostering formal thinking.
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Shadows: stories of light
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Administration
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11/07/2013
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The paper opens the stage by addressing some typical students’ difficulties when trying to explain shadows produced by the Sun. The story continues with caveats on terminology and on interpretations of shadow-images, following by the short theoretical analysis of shadow produced by an extended light source. In the next part three staging variants are described: shadows produced by a point light source, shadows produced after refraction of light beam on a spherical surface and shadows produced by different coloured lights. Throughout the paper several simple experiments, ranging from demonstration to laboratory experiments are suggested and their education roles discussed. In the Appendix a spectral properties of some typical school equipment for producing coloured light is shortly presented.
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Siphon: staging the siphon
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Administration
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11/07/2013
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After a reminder of the static interpretation of a siphon, this paper analyses the risks of some misunderstandings often present in common explanations of the dynamic situation. A particular staging of this experiment is then suggested, in order to emphasize that a systemic approach is needed to understand siphon at work. A short video complements the document.
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Siphon: video
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Administration
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11/07/2013
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After a reminder of the static interpretation of a siphon, this paper analyses the risks of some misunderstandings often present in common explanations of the dynamic situation. A particular staging of this experiment is then suggested, in order to emphasize that a systemic approach is needed to understand siphon at work. A short video complements the document.
Video: siphon versus pulley
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Siphon
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Administration
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11/07/2013
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The paper: - presents the hydrostatic and dynamic theory of the Siphon - stresses the role of cohesive forces in the liquid - explains why a siphon works whatever the external pressure is
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Water Jets: bottle with holes
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Administration
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17/07/2013
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In some textbooks, a simple experiment is often presented about a jet of fluid streaming out of holes made in a vessel full of water. In this paper, we have chosen to discuss this topic partly because of erroneous assumptions that are prevalent is such treatments. Textbooks commonly ignore that the range of a water jet depends not only on the exit velocity but also on the time of flight until the jet reaches a horizontal surface. In addition, the connections made between this experiment and the dependence of hydrostatic pressure on depth often lead to erroneous explanations in both words and drawings. These errors seem to recur over extensive periods of time possibly through copying from one textbook to another. Our presentation here is restricted to the case of non-viscous incompressible fluids, jet streams from a container with a stationary free surface and geometrically perfect exit holes.
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Weather glass
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Administration
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11/07/2013
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The weather glass provides a context for didactically valuable experimentation and discussion. There are many reasons for this. It provides a rich context for elaboration of the ideal gas law, in a way that makes the formulae and diagrams more meaningful for basic physics courses. It has survived more than a millennium and it is still commercially available. It was used by the Arab people well before they came to Spain in the 8th century. Hence, it allows for historical links across many centuries. It can trigger interest and motivation in teachers and students because of the widespread attention to weather forecasting and climate change. It is an emblematic experiment of the low-cost laboratory approach, which can be constructed readily with everyday, easily obtained materials. It is appropriate for classroom exercise and homework, a collaborative student activity or a project in a teacher preparation program.
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Which side to put the survival blanket?
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Administration
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28/07/2014
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Although a survival blanket is a well-known object, it is not obvious which side, silver or gold, should be put outside in order better to protect against cold. This paper sums up the reasons why this problem may be instructive, beyond its practical implications: Common ideas and instructions for use share a restricted analysis, limited to the high reflective power of the silver side. An analysis and a solution of this problem are proposed, and some activities with students are suggested.
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