We present two studies of participatory sensing in the wild, in which groups of young people used sensors to collect environmental data along with contextual information such as photographs and written observations. These studies reveal how participants focused their attention on key events of interest, providing detailed information over a background of less carefully gathered automatic readings. Participants responded to events in their surroundings, sudden changes in sensor data, and recorded details relevant to the process of gathering the data itself. Based on these studies a framework is described, highlighting the negotiation of five activities in the experiences; planning, testing, navigation, capture and reflection. Author Keywords Participatory sensing, human-sensor dialogue. ACM Classification Keywords H5.m. Information interfaces and presentation (e.g., HCI): Miscellaneous. General Terms Design, Human Factors, Theory