The purposes of this study were to examine students' involvement with scientific argumentation and to find out how their participation changed as they spent more time in arguing. Case study design with qualitative methods was guided to the research. The participants of the study were 13 senior pre-service physics teachers, four of whom were females. Argumentation sequences lasted six weeks and included two subjects, i.e. kinematics, and heat and temperature. The duration of each sequence was approximately 50 minutes. Data were collected via students' worksheets and video recordings made during the argumentations. The following conclusions can be drawn from the study: First, although students get used to argue, the quantity of their argumentations does not increase when the subject that they discussed about is changed. Second, argumentation quantity in terms of the number of claims and supports improves during argumentation process when the subject does not change. Third, argumentation quantity in terms of the number of counterclaims, change of claims, and warrants does not depend on the number of argumentation sequences and the subject, content as well as context of argumentation. Finally, the number of rebuttals is affected from the subject.