From November 5, 2019 to May 3, 2020, the Palais de la découverte in Paris is offering an experimental stroll, which showcases the scientific approach, The Magnetic Exhibition. Through five islands, the exhibition answers many questions about magnetism in an interactive way: where to find it? How can it be explained? What is it used for? What are the roles in a computer? What kind of research?
An exposure that begins with an application known to all, from a very young age. : the magnet stuck to the fridge! She then presents the various manifestations of magnetism and goes back over the origins of a fascinating phenomenon. Daily applications, fundamental role in a computer... from one discovery to another, the public is guided to the interior of a research laboratory, whose activity is devoted to the creation of nanomaterials with new magnetic properties. Through five islets, the exhibition interactively answers a large number of questions about magnetism: where to find it? How can it be explained? What is it used for? What are its roles in a computer? What kind of research?
"Motors, wind turbines, induction plates, subway tickets or bank cards... While magnetism surrounds us, this physical phenomenon is poorly understood. Through experience, manipulation and observation, the Magnetism exhibition invites the public to discover the principles and effects of magnetism, which is at the origin of many applications in our daily lives. It places the season of the Palais de la découverte, with the exhibition On Love, under the sign of attraction.
Bruno Maquart, President of Universcience "
Tour of the exhibition
This exhibition proposes about sixty experiments presented on 36 tables divided into five thematic islands. They punctuate the visitor's journey, questioning their knowledge of magnetism and inviting them to discover its properties and usefulness through various manipulations.
The tour is punctuated by "magnetic moments": flash mediations on various themes, animated by different scientific mediators (specialised in physics, computer and digital sciences, earth sciences, astronomy and astrophysics, life sciences).
Island 1: Magnetism, where to find it?
The first part of the exhibition familiarizes the public with magnetism and its elementary properties, identifies the various possible origins (magnets, currents, Earth) and allows the visualization of the magnetic field produced by each of them.
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At the beginning of his visit, the visitor is invited to observe more or less strong attraction phenomena between two magnets, then to test the intensity of the repulsion forces between them. He discovers certain fundamental properties of magnets, the systematic existence of a North and a South Pole, and the principle of the compass. He visualizes the magnetic field produced by a magnet, first in 2D, then in space, thanks to iron powder and ferrofluids. He can then test the reaction of various materials in the presence of a strong magnet and discovers the magnetic field produced by an electric current, particularly through one of its applications, the magnetic sorting of waste. Here he can have fun making a ferrofluid "dance" to the sound of his voice: by singing into a microphone, the ferrofluid deforms into rhythm!
This island continues with the exploration of the Earth's magnetism.
Island 2: Magnetism, how to explain it?
This section reveals to the public the origin of the magnetic properties of materials. It offers a journey to the infinitely small, where the phenomena responsible for the behaviour of magnetic materials can be observed and illustrated with macroscopic scale models.
One experiment shows the appearance of paramagnetic behaviour above a certain temperature, specific to each ferromagnetic material. Finally, the visit of this space ends with an experimental illustration of a behaviour of extremely low intensity, but common to all materials: diamagnetism, which can be at the origin of a levitation phenomenon.
Island 3: Magnetism, what for?
This island invites the public to visit various applications of magnetism, which are omnipresent in our daily lives, and explains its principles of operation. The visitor discovers here the appearance of a force, known as the "Laplace force", which is exerted on an electric circuit through which a current flows and which is placed in a magnetic field. He understands its usefulness in the operation of loudspeakers, electric motors and fans, for example.
Further on, he observes the phenomenon of induction and realizes that it can be used to produce electricity, such as in bicycle lighting, alternators and wind turbines.
Two experiments then materialize the existence of eddy currents, these electric currents generated in conductive materials placed in the magnetic field of a moving magnet, and used in the speed bumps of trucks or apartment bicycles.
A surprising experiment also presents the principle of magnetic levitation thanks to electromagnetism, which is the basis of the operation of some ultra-fast trains.
Finally, the following tables highlight the basics of induction heating, electrical transformers, Witricity (like Wireless Electricity) - used in wireless chargers for mobile phones - through the RFID (for Radio Frequency Identification) system of locks or the Navigo card.
Island 4: Magnetism, what roles in a computer?
This island is fully dedicated to the computer. The objective is to show how magnetism is omnipresent in its operation, whether in its components or in the recording of data.
After becoming familiar with binary coding, the visitor observes the principle of writing and reading a byte, the information unit, on a magnetic medium. The walk then leads them to discover how the objects resulting from the manipulation of magnets on the scale of the infinitely small are omnipresent in their daily lives, whether in bank cards, subway tickets, or in an object so familiar and yet of such elaborate structure, the fridge magnet.
The visit continues with the discovery and explanation of giant magnetoresistance, which earned the French physicist Albert Fert the Nobel Prize in Physics in 2007. The most recent research, aimed at ultra-fast and miniaturised storage of information and at reducing energy consumption, is discussed through two examples: writing by ultra-short laser pulses and four-state coding.
Islet 5: Magnetism, what research?
At the end of his journey, the public discovers the working instruments of the Jean-Lamour Institute and their use to manufacture materials with new magnetic properties. They are invited to observe a 3D model of the DAUM deposition platform, and analyse under ultra-high vacuum nanomaterials, an internationally renowned facility.
The visitor explores the principle of crystal growth under ultra-high vacuum to create single crystals of new materials, and then experiments with lithographic fabrication of nanometric objects.
He ends his visit with two examples of more applied research: he discovers the performance of new innovative magnetic sensors with giant magnetoresistance, and ongoing research aimed at enhancing the performance of magnetography, a secure printing technique very useful for legal or banking services.
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At the end of the exhibition, the public discovers a veritable chamber for spectroscopic analyses of ultra-vacuum deposition spectroscopy that has been used in research for more than twenty years.
Around the exhibition see all the program
Exhibition at the Palais de la découverte, avenue Franklin-Roosevelt - 75008 Paris
An original exhibition designed by the Jean-Lamour Institute, a joint CNRS - University of Lorraine research unit.
Produced by : Institut Jean-Lamour - CNRS (National Centre for Scientific Research) - University of Lorraine - SFP (French Physical Society).
With the support of : - L'Europe s commitment - Investing in the future - Région Grand-Est- LUE (Lorraine university of excellence).
