Children's developing reasoning skills are better understood within the context of their social and cultural lives. As part of a research-museum partnership, this article reports a study exploring science-relevant conversations of 82 families, with children between 3 and 11 years, while visiting a children's museum exhibit about mammoth bones, and in a focused one-on-one exploration of a "mystery object." Parents' use of a variety of types of science talk predicted children's conceptual engagement in the exhibit, but interestingly, different types of parent talk predicted children's engagement depending on the order of the two activities. The findings illustrate the importance of studying children's thinking in real-world contexts and inform creation of effective real-world science experiences for children and families.