Families play an important role in informal science learning, but they may need supports for engaging in science that is exploratory, inquiry based, and builds on family practices. We designed resources that frame scientific sensemaking as an active and playful process of exploration in which family members are coparticipants. This approach contrasts with more traditional school-like canonical patterns of engagement in family science conversations where adults state facts and provide explanations to children. The "Anytime, Anywhere" resources were designed to locate phenomena of interest in outdoor settings and cue families about how they might engage playfully in exploration by using sensemaking activities and conversation starters. We analyzed families' video-recorded activities and interviews as they field-tested the resources at a coastal beach. The analysis shows families engaged in three features of scientific sensemaking, both in response to our designed activities and spontaneously. They elicited ideas and mechanistic processes, made hypotheses, and experimented to test ideas. We propose emerging design recommendations for "Anytime, Anywhere" family scientific sensemaking activities, which can inform learning design in a variety of settings.