The aim of this study is to investigate students' understanding of solubility, dissolution and effect of substance type on solubility. The sample is composed of 77 first year prospective science and technology student teachers in Fatih Faculty of Education at KTU, in 2008-2009 academic year. Data were collected by a worksheet prepared according to POE technique applied in the lab and interviews were done with six students selected from the groups. Some misconceptions are found and given at the end of the study and as a result some suggestions were made about using POE activities. (C) 2010 Elsevier Ltd. All rights reserved.