Beginning teachers in Northern Ireland and the United States conducted structured inquiry pro-jects in which they investigated elementary children’s understanding of history and social studies. Interviews with the teachers and analysis of their written assignments indicate that these investi-gations challenged their beliefs about children’s prior knowledge and their own instructional tech-niques. Teachers initially believed that inadequate cognitive development and lack of background knowledge limited children’s ability to understand history and social studies; however, after taking part in these projects, they developed a new appreciation for children’s prior ideas and a clearer com-mitment to their own role in building on that knowledge. ...