In recent decades, the literature paid attention to students' conceptions of the nature of disciplines. This study aimed to investigate how students' cohesive and fragment conceptions of physics changed with a major change in senior high school physics syllabus. We obtained measures of conceptions of physics by utilizing a 20-item questionnaire and triangulated by open-ended responses. The sample was 1979 first year university students from three different years surveyed in their first laboratory session. The first cohort of 780 first year university students had experienced the "old" syllabus in high school and the next two cohorts of 511 and 688 first year university students had experienced a "rejuvenated" high school syllabus. By establishing the reliability and validity we found that there exists a substantial shift in student conceptions of the cohesiveness of physics coinciding with the school syllabus change. This shift was mirrored in qualitative data. Furthermore, students with more previous engagement in physics learning, on the average, demonstrated less fragmented and more cohesive conceptions with the rejuvenated syllabus than with the old syllabus. (Contains 5 tables and 3 figures.)