This study explored how first year undergraduate nursing students learn in clinical placements as part of a program informed by Wenger's (1998) social theory of learning. Forty-nine written student narrative accounts of a learning experience were analysed and three triggers for learning were identified. The first trigger is that participation (or observation) of a task or procedure leads students into a complex, dramatic reading of nursing work. The second is that when students are personally (emotionally) confronted by the work, it presents a high challenge situation, recognized by students as a significant learning opportunity. The third trigger is encounters with different nurses assist students to construct an image of what they want to be as a nurse. These three triggers appear to align with Wenger's Communities of Practice constructs for identity, engagement, imagination, and alignment, and provides preliminary evidence supportive of the social theory of learning for nursing students on clinical placement.