In this study, we identify the pedagogical practices the science teachers use for successfully conducting their argumentation-based science lessons and examine the process of managing informal formative assessments. For this qualitative study, we collected data via video and audio devices from classroom implementations after conducting two professional development courses on assessment practices in inquiry settings and argumentation in science classrooms. We analysed the data from the conversation analysis (CA) perspective to conduct a data-driven study. Our results show that there are multiple pedagogical practices that teachers use to achieve lesson purposes and shape lessons. These are primarily the revealing of different claims and warrants or counterarguments about the same phenomenon or situation, prompting the class to discuss different arguments, including more than one student in interaction. Regarding the nature of answers produced by students, the teachers also make implicit or explicit positive and negative assessments, avoid explicit assessments, and give content feedback as pedagogical practices and use them for managing the informal formative assessment process. The results show that the teachers perform some pedagogical practices via the information gained by the informal formative assessment process. These pedagogical practices provide them with new road maps to achieve the lesson goal by increasing classroom interactions.