The way teachers support students' Knowledge Building discourse may influence their subsequent discourse moves and emotions. However, in previous research on Knowledge Building, teacher scaffolding was rarely scrutinized, especially in offline Knowledge Building discourse; neither was how the support is associated with students' discourse moves or emotions. This study addressed these issues by examining how two teachers scaffolded the offline Knowledge Building discourse of a class of students from grade 2 to grade 3 and the associations between teacher scaffolding and students' discourse moves and emotions. Through discourse analysis, we identified a few patterns of teaching scaffolding for Knowledge Building, including giving instructions, asking for elaboration, revoicing, asking for explanations, inviting different ideas, and inviting new directions. Using correlation analyses, we found positive correlations between teacher asking for explanations and students providing partial or elaborated explanations. Teacher inviting new directions was positively correlated with students' questions. There was a negative correlation between teacher asking for elaboration and student curiosity. This study has implications for how teacher support can be designed to foster desired student discourse moves and emotions.