本研究旨在比較資深與資淺國小教師在從事社會性科學議題的單元設計與教學前、後，其知識建構的異同及影響其知識建構的因素。研究為質性取向，利用繪製概念圖和訪談收集資料。四位教師教學年資的分布為四至十七年。分析結果顯示：教學設計前，教師對議題知識與論證知識的整合相當有限，其中資深教師以學生需求為主，資淺教師則以教學需求為考量。而教學設計與實踐促進教師內化和組織知識，四位教師不但將論證知識與議題知識統整在一起，而且也融合了教學知識，形成個人教導社會性科學議題的學科教學知識。教學後，資深教師比資淺教師多建構出有關教學困難、學生學習困難或評量方面的知識；與學生互動的課室經驗是影響教師知識建構的主要因素，它促進教師進行深層的反思並調整已建構的議題知識與教學知識，以應付實際教學的需要。

This study presents comparative case studies of novice and expert teachers’ knowledge construction for designing and implementing a SocioScientific Issue (SSI) unit in order to improve students’ argumentation skills. The study adopted a qualitative approach and data collection consisted of interviews and teachers’ concept maps about SSI instruction. The teaching experiences of four participants spanned 4 to 17 years. The results revealed the teachers’ limited integrated background knowledge of the issue and argumentation knowledge, before they designed the unit. The experienced teachers put emphasis on constructing knowledge for students’ needs, but the novice teachers tended to focus on teacher need to construct knowledge. The unit design and implementation supported teachers internalizing and integrating their background knowledge of the issue, of argumentation knowledge and instructional knowledge, and subsequently developing their pedagogical content knowledge for SSI instruction. The experienced teachers constructed knowledge about assessment, student difficulties and teaching difficulties, but the novice teachers did not. Classroom experience is the key factor that made the four teachers deeply reflect on their knowledge construction and then adjust their knowledge construction to meet the needs of their SSI instruction and of student learning.