In this paper I focus on the transition from everyday to scientific ways of reasoning, and on the intertwined roles of meaning-making dialogue and science content as they contribute to scientific literacy. I refer to views of science, and how scientific understanding is advanced dialogically, by Hurd (Science Education, 1998, 82, 402-416), Brown (The Journal of Learning Sciences, 1992, 2 (2), 141-178), Bruner (Acts of Meaning, Cambridge, MA: Harvard University Press, 1990), Roth (In J. Brophy (Ed.), Social Constructivist Teaching: Affordances and Constraints (Advances in Research on Teaching Series, Vol. 9), New York: Elsevier/JAI, 2003), and Wells (Dialogic Inquiry: Towards a Sociocultural Practice and Theory of Education, New York: Cambridge University Press, 1999). I argue that family collaborative dialogues in nonschool settings can be the foundations for scientific ways of thinking. I focus on the particular reflective family dialogues at the Monterey Bay Aquarium, when family members remembered and synthesized essential biological themes, centering on adaptation, from one visit to the next, in both Spanish and English. My approach is informed by sociocultural theory, with emphasis on the negotiations of meaning in the zone of proximal development (Vygotsky, 1978), as learners engage in joint productive activity (Tharp & Gallimore, Rousing Minds to Life: Teaching, Learning and Schooling in Social Context, New York: Cambridge University Press, 1988). Over the past decades, researchers have discovered that observing social activity, conversation, and meaning-making in informal settings (Crowley & Callanan, 1997; Guberman, 2002; Rogoff, 2001; Vasquez, Pease-Alvarez, & Shannon, Pushing Boundaries: Language and Culture in a Mexicano Community, New York: Cambridge University Press, 1994) has much to teach us regarding learning in general. To date there has been little research with Spanish-speaking families in informal learning settings and virtually none that integrates the home with both formal and informal learning.