The purpose of this study was to develop the FPHER (problem finding, prediction & discussion, hands-on & experiment, explanation & arrangement, enrichment) instructional model emphasizing the social interactions, and as applied, characteristics of verbal interactions were examined overall and with each step. For this study, this model was applied to the students in 10th grade chemistry classes in a science high school, and their group verbal interactions were recorded and analyzed. The results of this study show that most verbal interactions were classified as on-task interactions in the FPHER instructional model, where suggestions were predominant to the acceptance of opinions. There were a few interactions in the F step, and there were many suggestions relating to the solutions and lacking in confidence in the P step. There were many suggestions relating to the process and orders in the H step. Also, there were many questions, some explanation and dissatisfaction, as well as a lack of confidence in the E step. There were many high-level interactions in the R step, and mainly interactions with worksheets showing high-level problem-solving abilities. More in-depth research is needed to develop the teaching strategies that can activate student-to-student interaction and student-teacher interaction with regard to instructions, enhancing thought as counter-argument, justification or sophistication, based on the instructional model in this study.