This dissertation examines students' social-emotional experience with knowledge building pedagogy from the lenses of grit and growth mindset. The goal of this dissertation is to understand how interest, perseverance of effort and growth mindset oriented feedback engage students social emotionally in knowledge building to sustain and deepen their inquiry and discourse. This dissertation includes two qualitative studies across two separate school years. Study 1 examines how fifth-grade students perceived and coped with the new changes and challenges brought to them by knowledge building pedagogy. The goal of Study 1 is to understand students' social-emotional engagement in knowledge building at individual level. The data source is nine students' interview transcripts. The findings show that students made cognitive and social emotional efforts to address a range of knowledge building inquiry challenges. Study 2 examines both individual students' social emotional experience with knowledge building pedagogy and how growth-mindset oriented feedback supported students' interest and perseverance of effort in pursuing and deepening their science inquiry. The goal of Study 2 is to understand students' social-emotional engagement in knowledge building at both individual and community levels. The data source includes eight students' interview transcripts, and video-recordings and transcripts of nine classroom meetings. Deductive and inductive approaches to data analysis were applied to analyze the class recording data. The findings suggest that student's interest and persistent effort, as well as teacher's growth mindset oriented feedback in the knowledge building community, engage students social emotionally to face and overcome inquiry challenges to achieve community knowledge advancement. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]