本研究以知識創新的教學理念為基礎，設計國小自然課程中有關「節能減碳」知識的學習活動，並經由知識論壇平臺的輔助以促進學生以翻新想法為核心的合作學習。本研究採個案研究，以臺灣國小五年級學生為研究對象。以知識創新的教學理念進行一學年有關節能減碳教育的教學，學生利用知識論壇平臺進行互動、合作與討論。結果發現，知識創新教學有助於促進學生間以「想法」為單位的合作學習，例如學生在知識論壇上的「修改他人想法的貼文」在學習第一至三階段中不斷成長，「共有作者貼文」的比例在學習階段一至四中不斷成長。透過知識論壇的合作互動，學生能夠產生許多關於節能減碳的個人想法，同時分享並不斷改進想法，使想法更具完整性與解釋力。另外，與國中教材的重要概念相比，結果亦顯示在知識創新的教學下學生能提出更豐富、多元的節能減碳的想法。證實知識創新環境中的學習有助於培養學生集體知識共構的習慣，以及豐富學生的合作學習經驗。本研究建議：鼓勵以想法為中心的合作學習與互動，以幫助學生發展知識創新的關鍵能力。 This study aimed to help students collectively construct knowledge regarding energy saving, using an innovative pedagogical approach called knowledge building. Participants in this case study were 5th-grade students in Taiwan. They worked in Knowledge Forum-a knowledge building environment-for a complete school year. The analysis indicated that knowledge building did make students become more collaborative; as a result, they were able to engage deeply in the process of ideas generation, idea interaction, and idea improvement, rather than to engage in superficial social talk. In addition, it was found that students were able to discuss and form rich concepts of energy saving; they were not only able to share ideas, but to deepen their ideas relevant to energy-saving; it was found that there were significantly more concepts co-constructed in class than concepts covered in some official curriculum materials. In sum, knowledge building seemed to be useful for students to create collaborative knowledge in science learning. Some implications regarding teaching and collaborative learning were discussed.