Why Do We Believe that an Atom is Colourless? Reflections about the Teaching of the Particle Model

Research on students‘ ideas about the particle model of matter shows thatstudents attribute to atoms or molecules all the properties shown by bulkmatter. These results indicate a failure in didactic communication of therules of the particle model. An analysis of some contemporary textbooks showsthat this is indeed the case. After reflection on the rules of the modelinggame, suggestions are made for didactic practice. In particular, the focus ison problems connected with the visual communication through representationsresulting from modern technology (i.e. Scanning Tunneling Microscopy).