The sample consisted of 40 senior university students from different branches of engineering who were about to begin an elective subject on acoustics, taught yearly from 2008 to 2010 (three semesters). The curricula for both their secondary education and the first-year subject of engineering physics included simple harmonic motion and waves in general. Furthermore, depending on their chosen branch, some, such as those studying telecommunications, had received broader instruction on those aspects of sound most closely related to their specific branch. In other branches, such as computing or chemistry, sound is not addressed by the rest of the curriculum.