In 2005 the European particle physics masterclasses attracted 3000 students from 18 European countries to visit one of 58 universities and education centres. The participants worked with data from real high energy particle collisions, learned about particle physics, and experienced research and education environments at European universities. In an evaluation of the masterclasses 70% of the participants reported that they learned ‘much’ or ‘very much’ about the organization of scientific research and more than 80% of the participants, in some countries more than 95%, highly appreciated the masterclass programme in general. The appreciation of the masterclasses was independent of gender, pre-knowledge of particle physics and computer knowledge. An event like the masterclasses, where the students are engaged in an experimental research process, has the potential to add valuable experiences to physics education in school environments.