From Journal of Research in Science Teaching:

This article presents results from a survey intended to measure adolescents’ continuing motivation for science, such as their involvement in extracurricular science-related activities. The researchers investigated the relationship between school type, grade, and gender and participants continuing motivation for science learning. Almost 3,000 5th-8th grade students from various schools in Israel participated. Results indicate that females had lower continuing motivation for science than boys and the continuing motivation for individuals in traditional schools decreased between 5th and 8th grade, but that those in democratic schools had a constant level of continuing motivation.