Parent-child "everyday" conversations have been suggested as a source of children's early science learning. If such conversations are important, then it would be pertinent to know whether children from different family backgrounds have different experiences talking about science in informal settings. We focus on the relation between parents' schooling and both their explanatory talk in science-related activities and the styles of interaction they use with their children. Families from different schooling backgrounds within one under-represented group in science education--Mexican-descent families--were included in this study. Forty families were observed in two science-related activities. In the sink-or-float task, families were asked to predict which of a variety of objects would sink and which would float, and then to test their predictions in a tub of water. The second activity was an open-ended visit to a local children's museum. Results showed similar patterns in scientific talk on the sink-or-float task across the two groups. However, the interaction style varied with schooling across the two activities; parents with higher schooling were more directive than parents with basic schooling. Interaction style was also found to vary with task structure, with more open-ended tasks affording more collaborative interactions. Such research into parent-child conversations in science-related activities can help begin to guide us in bridging children's learning environments--home, school, and museum--and potentially fostering children's science learning, particularly in those groups under-represented in the sciences. (Contains 2 tables, 1 figure and 4 notes.)