Since 2009 Vetenskap & Allmänhet (Public & Science, VA) coordinates an annual mass experiment as part of ForskarFredag — the Swedish events on the European Researchers' Night. Through the experiments, thousands of Swedish students from preschool to upper secondary school have contributed to the development of scientific knowledge on, for example, the acoustic environment in classrooms, children's and adolescents' perception of hazardous environments and the development of autumn leaves in deciduous trees. The aim is to stimulate scientific literacy and an interest in science while generating