Abstract

The objective of this study was to explore seventh-grade students’ previous conceptions about properties of matter. The participants were forty-eight mixed-ability students (twenty-four boys and twenty-four girls) from eight educational opportunity expansion schools located in the Nakhon Pathom province in central Thailand. The interview-about-instance (IAI) technique was used to collect data, and all interviews were audio recorded. The interviews were transcribed verbatim, and their transcripts were qualitatively analyzed by coding and categorizing. The students’ conceptions were categorized into three categories: scientific conceptions (SC), partial scientific conceptions (PC), and alternative conceptions (AC). The frequency of conception in each category was counted and calculated for percentage. The analysis revealed that the participating students held a variety of previous conceptions about properties of matter, ranging from SC, PC, to AC. The two dominant ACs held by the students were classification of matter and changes in the state of matter. Science teachers need to take these ACs into consideration when designing future lessons. The implications regarding teaching and learning about properties of matter are also discussed.