Description of the Study
This study was primarily carried out in grade 9 chemistry
classes (student age ~15 years), with six groups from grammar
schools, three groups from middle schools, and two groups
from comprehensive schools. Additionally, there were two
grade 10 classes, one from a grammar school and one from a
comprehensive school (student age ~16 years). The schools
were located in western or northern Germany and the class
size range was 22–32 students. None of the