Each year about 10.000 high school students in 40 countries come for one day or two of activities at one of the 200 nearby universities or research centers around the world in order to unveil the mysteries of Particle Physics. Lectures from active scientists give insight in topics and methods of basic research at the fundaments of matter and forces, enabling the students to perform themselves measurements on real data from particle physics experiments. At the end of each day, similarity to what happens frequently in a real international research collaboration, the participants join a world-wide video conference for discussion and combination of their results.
At the São Paulo Research and Analysis Center (SPRACE) the International MasterClass event has been organized since 2008, always with increasing number of schools and participants. In 2014, SPRACE hosted more than 20 high schools from São Paulo and vicinities, bringing around 250 students and teachers for taking part in the three days of the event. In 2014 a new format was tested, where more experienced high school teachers had the task to prepare the students in their own premises, bringing them to the one-day MasterClass event ready to perform the experimental analysis, whose results were later discussed in video conference. In two other days, the traditional format develop by SPRACE over the years was adopted: participants learn about Particle Physics in the first morning, through lectures conducted by experienced scientists. Then, during the afternoon, the teachers were enrolled in the experimental exercises, while the students were divided in several groups for participating in a variety of Physics demonstration, educational games, experiments, etc. This same group returned the following day, when the students performed the exercises and videoconference, while the teachers, already prepared in the eve, helped them as tutors. The videoconference is usually coordinated by two moderators at CERN and counts with the simultaneous participation of students in five research centers, in different countries around the world.