In this qualitative case study, we purposively selected a passive student in elementary science class from a small group and examined what factors contributed to her socially and momentarily construction of epistemic emotions. We used various data such as emotion diaries, transcripts of the video recordings, postlesson interviews, and field notes to document her involvement in the six lessons of the scientific modeling of the human respiratory system. Our analysis revealed that she constructed the epistemic emotions of "frustration," "anxiety," and "joy." Her nonparticipation and constructed epistemic "frustration" in Lesson 1 were because of her unfamiliarity with the task and her perception that her ideas will be rejected by others. Due to her lack of previous knowledge, that desire to engage in the small group argumentative discussions was affected by her perception that her ideas would be rejected. With slightly increased familiarity and a sense of acceptance in Lessons 2 and 3, she displayed passive participation and constructed epistemic "anxiety" because she was not certain whether her opinions were scientifically correct or not. With the uncertainty of her ideas, she was not able to develop a personal motivational drive to engage in effortful participation. Finally, she exhibited active participation and constructed epistemic "joy" in Lessons 5 and 6 when she became familiar with scientific argumentation and scientific modeling, in addition to her developed sense of full acceptance. These results indicated the intertwined relations of affective, cognitive, and social aspects of learning on student's participation and construction of epistemic emotions.