EGITIM VE BILIM-EDUCATION AND SCIENCE, vol.42, no.192, pp.139-172, 2017 (SSCI)
Slope is a fundamental concept for numerous higher mathematical concepts, especially for derivative. Moreover, this concept is a cornerstone in many different areas such as art, architecture, engineering, and physics. Prior to learning the concept of slope formally, students have informal knowledge because of its use in daily life. However, students learn the concept formally in eighth grade for the first time. The purpose of this study was to investigate eighth grade students' construction processes of the concept of slope. This study is a part of a dissertation research, which focused on designing a teaching process of slope and investigating students' mathematizing and construction process of the concept. The participants of this study were five eighth grade students. These students were chosen based on the results of an open-ended test related to the concepts prerequisite for the concept of slope. The study was designed as a qualitative study. Data of this study were collected by 15 clinical interviews and participants were interviewed three times. Data were analyzed by thematic analysis method and participants' stages of comprehension the concept of slope were interpreted in the context of APOS theory.