本研究主要探討建構主義式的科學學習活動對於國小高年級學生認知結構的影響，並探討這樣的學習活動對於學習者在單元主要概念學習成效的影響。本研究之研究對象為兩班國小五年級學生，在分別實施三週的「電與磁」單元的建構主義式科學學習活動與一般教學活動後，研究者以錄音訪談方式收集資料，再以「概念流程圖析法」將訪談內容繪製成「概念流程圖」，並配合內容分析法分析學生在單元的核心概念之學習情形。研究結果發現：在經過建構主義式的科學學習活動之後，學習者在認知結構中「概念的數量」與「概念間的連結」均獲致較佳的科學學習成果；而且建構主義式的科學學習環境亦有效促進學習者「電與磁」單元的核心概念學習。而本研究也進一步建議教學者可以結合「衝突圖」策略和POE(Predict-Observe-Explain)教學策略作為建構取向教學活動設計的依據，以促進學習者的科學概念學習與意義建構。

This study was conducted to explore the effects of constructivist-oriented instruction on fifth graders' cognitive structures about basic electromagnetism. Furthermore, such effects on learners' acquisition in key ideas about basic electromagnetism were investigated. The subjects of this study were sixty-nine fifth graders in Taiwan, who were assigned to either a constructivist-oriented instruction group or a traditional teaching group. The research treatment was conducted for three weeks, and the interview data were gathered a week after the instruction about basic electromagnetism. The interview narratives were transcribed into the format of 'flow maps.' In addition, the key ideas about basic electromagnetism shown in the flow maps were also investigated through a series of content analyses. The results of this study revealed that the students in the constructivist-oriented instruction group, in general, attained better learning outcomes about basic electromagnetism after instruction, either in terms of the extent of concepts or the integration within their cognitive structures. Furthermore, the students in the constructivist-oriented instruction group likely learned more key ideas about basic electromagnetism. This study suggested that science teachers could combine the POE (Predict-Observe-Explain) strategy and the conflict map strategy to promote learners' conceptual learning and knowledge construction in science classrooms.

建構主義 ； 認知結構 ； 核心概念 ； 概念流程圖

Constructivist ； Cognitive Structure ； Key Ideas ； Flow Map