Reflexió sobre art, composició i estructura Authors Claudi Mans i Teixidó Abstract The artistic technique of Ursus Wehrli is compared with the chemical analysis, and it is realized that the information supplied by the elemental analysis (empirical formula) is not sufficient to fully understand the properties of a substance: it is necessary to know how to visualize any object or substance at different levels of extension, from the naked eye to the level of atoms and molecules. The different degree of complexity between inert and biologic matter is also shown. Downloads Text complet (Català) Published 2013-07-10 Issue No. 13 (2012) Section Conceptes i models químics License The intellectual property of articles belongs to the respective authors.On submitting articles for publication to the journal Educació Química, authors accept the following terms:Authors assign to Societat Catalana de Química (a subsidiary of Institut d’Estudis Catalans) the rights of reproduction, communication to the public and distribution of the articles submitted for publication to Educació Química.Authors answer to Societat Catalana de Química for the authorship and originality of submitted articles.Authors are responsible for obtaining permission for the reproduction of all graphic material included in articles.Societat Catalana de Química declines all liability for the possible infringement of intellectual property rights by authors.The contents published in the journal, unless otherwise stated in the text or in the graphic material, are subject to a Creative Commons Attribution-NonCommercial-NoDerivs (by-nc-nd) 3.0 Spain licence, the complete text of which may be found at https://creativecommons.org/licenses/by-nc-nd/3.0/es/deed.en. Consequently, the general public is authorised to reproduce, distribute and communicate the work, provided that its authorship and the body publishing it are acknowledged, and that no commercial use and no derivative works are made of it.Educació Química is not responsible for the ideas and opinions expressed by the authors of the published articles.