‘Natural reality, with its properties, its laws and its components is a datum that man has the ability to interrogate. The aim of the exhibition is to guide us through the journey that has led man to the present comprehension of the structure of the matter. Starting from the initial wonder in front of the observed reality, a work and a method make it possible to recognise ever new aspects of reality, through the formulation of models and their verification by means of experiments. The journey inside matter that is proposed to us, starts from particular objects, visible to the naked eye, which impress us with their beauty and regularity: crystals. It then develops through successive passages (from crystal to atom, from atom to nucleus with electrons, from nucleus to nucleons, from nucleons to quark), which lead us to explore ever tinier objects, more and more difficult to analyse. The structure of crystals indicates that they can be thought of as being constituted of smaller components, regularly spaced. These components are the atoms, whose existence is proved by a great deal of experimental evidence. The observation of many properties of the atoms indicates that they are made of a nucleus and of electrons. Whereas the electrons still appear today to be truly elementary, phenomena like radioactivity show that the nucleus is made up of parts (nucleons, that is protons and neutrons). Experiments of collisions of nucleons (brought to very high energies thanks to the use of particle accelerators) reveal that they have an internal structure: the components of the nucleus have been named quarks. The exhibition is structured in many panels with photographs, drawings and explanatory texts. Not only will some specimens of crystals be displayed, but also models of accelerators and nuclear power stations; it will also be possible to use equipment for physics experiments.’