The aim of the study is to explore and analyze conceptions of students at different grades on dissolution concept by means of phenomenographic approach. To collect data, individual and group interviews methods were used. The interviews were conducted with 20 students who were selected randomly from each of grade. At the end of data analysis, 8 categories were identified. These are: (I) distribution of particles (2) space amongst solvent particles (3) interaction between solute and solvent (4) disappearing of solute (5) density of solute (6) properties of solvent (8) pressure differences of matter. It is found out that types of students' responses rely on the selected or given tasks. Moreover, it is concluded that there is a poor progress in terms of conceptual understanding in spite of instructional exposure. Taking into consideration the results, it is suggested that to overcome or diminish misconceptions appropriate strategies should be improved.