BETWEEN FACTS AND MODELS: EXPERIMENTAL PHYSICS DEMONSTRATIONS AS A TEACHING RESOURCE AT THE UNIVERSITY OF VALENCIA
Experimental physics demonstrations (often shortened demos) are a very important resource for physics teaching with a large tradition in many countries. Physics demos are simple experimental devices which allow the observation of physical phenomena “in situ” in connection with theory or problem solving explanations, helping to interlock the facts distilled from an accurate observation of real physical phenomena with the abstract physics models developed to explain them, hence, improving conceptual understanding and helping to internalize that complex reality-theory correspondence which is essential to the scientific method. In fact, the physics “Tuning Project” commission which established the common learning outcomes and competences in all physics degrees in Europe, highlighted “lectures embedding practical demonstrations” as an educational activity that is appropriate for the development of the teaching/learning process .
Despite the importance of this physics specific teaching resource, physics demos are not currently a teaching/lecturing practice in Spain. They are not so at junior or high school, where students don’t even visit the laboratory in many cases. And not even at university, where laboratory sessions seem to fulfil a specific experimental training and not to focus on basic conceptual understanding. More than a century ago physics demonstrations devices and instrumentation were the core of physics teaching in secondary and university education, but this practice was abandoned in Spain for different reasons. The fact is that for a long time there have not been demo collections, specific budget, technical support or teaching tradition in this sense.
A working group in the Physics Faculty at the University of Valencia is developing a collection of physics demos for classroom lectures, available for professors who teach physics subjects in all the sciences and engineering degrees. This project  has been possible thanks to some funding by the Physics Faculty and the University Innovation Unit, but mainly to the cooperation among professors in the working team, which has overcome the lack of human resources and technical support. This physics collection currently contains more than eighty demos of different general physics topics and involves different 15 university degrees, 20 different physics subjects and around 2000 students. As far as we know, this is the only project of physics demos development and general practice in Spain.
In this contribution we describe the Physics Demo Project of the University of Valencia: the collection of physics demonstrations, the demo loan system on which it is based, its academic uses, the expected outcomes and the challenges and problems we face when teaching university introductory physics with the help of these experimental resources.
 Tuning Physics Project, summary of outcomes; http://www.unideusto.org/tuningeu/subject-areas/physics/summary-of-outcomes.html
 Project web page: http://www.uv.es/gradofis/w3demos