Argumentation plays a central role in the development and justification of scientific knowledge. Learners could attain a more scientifically acceptable conceptual understanding by attending argumentation-based discussions. During argumentation-based discussions, students need to activate some metacognitive processes related to concept learning, such as being aware of their and others' existing concepts, monitoring the consistency between their own claims and counterclaims, and evaluating the validity of the evidence they applied to justify their claims. In this article, some prompts were inserted that aim to activate preservice science teachers' (PSTs') metaconceptual processes explicitly and systematically into the stages of Predict-Observe-Explain activities, one of the ways to engage students in argumentation. This activity aimed to facilitate PSTs in constructing more scientifically acceptable concepts about simple electrical circuits by ensuring the activation of various metaconceptual processes as they justify or reason the validity of different claims.