Troxel (1968) compared “traditional” chemistry instruction with both CHEM Studyand the Chemical Bond Approach (CBA). In theory, CHEM Study and CBA stress
inquiry and are laboratory centered, which theoretically should promote better understandings
NOS. However, when teacher background in terms of teaching within
the discipline, experience in teaching the course, general philosophy, and student
background relative to school size were held constant, no significant differences
were found in students’ conceptions of NOS