In this study, it was aimed to determine the students' conceptual understanding and misconceptions about the concepts in the 8th grade Matter and Properties unit. Students (n = 180) of two middle schools in Istanbul Province participated in the study. The qualitative research method was used to determine students' conceptual understanding. A paper-and-pencil questionnaire consisting of six questions was applied as a data collection tool. Student responses to the questionnaires were subcategories by content analysis, and the percentages of the responses were determined. As a result of the findings obtained from the study, it was seen that 8th-grade students had some conceptual deficiencies and misconceptions about pressure and buoyancy.