Every year thousands of students from all around the world and their teachers take part in an outreach event developed by the International Particle Physics Outreach Group (IPPOG): The International Particle Physics Masterclasses – hands on particle physics. During this event, they engage with scientists, learn about particle physics and simulate the work of a high-energy physics scientist. In the city of São Paulo, Brazil, the SPRACE (São Paulo Research and Analysis Center) team locally organizes this event every year since 2008. We studied how attending this event and a workshop on particle physics, also promoted by the SPRACE team, can help physics teachers to address particle physics in high school. To collect data, we used a questionnaire answered by the teachers at the end of the International Physics Masterclasses in March 2016. The conclusion was that attending these events, teachers are increasing their scientific knowledge, getting more confident and getting to know new materials and new ways to address particle physics in high school.