Currents accounts of the development of scientific reasoning focus on individual children s ability to coordinate the collection and evaluation of evidence with the creation of theories to explain the evidence. This observatioal study of parent-child interaction in a children sscientific thinking in every day nonobligatory activity. When children enggaged en exhibit wiht parents their exploration of evidence wa observed to be longer broader and more focoused on relevant comparsions than children who engaged the exhibit without their parents.