Explanation as a genre may support children’s reasoning and understanding particularly effectively. In this study, 20 fourth graders were given the task of explaining the effects of a pollutant on an ecosystem to third graders. Before writing, they completed a commercially developed science unit, instruction in reading and writing an explanation, and text reading. An analysis of their writings revealed that all children used rhetorical devices to connect with third-grade readers. Sixteen children synthesized text content with personal experiences to compose subexplanations that reported information, gave examples, and presented scenarios and that were logically ordered to enhance reader understanding. Nine of these children explicitly used the scientific model to explain phenomena. Outcomes suggested that writing explanations supported children’s reasoning about and understanding of an important scientific model.

To change the mind of a reader, authors compose written persuasion according to a set of rhetorical features. This article describes the features of persuasive texts and reviews research results to explore whether adults indeed change their minds after reading persuasion. Toulmin's (1958) model of argument and Aristotle's model of persuasive content characterize the structure and content of well-written persuasion. Research in social psychology and text comprehension shows that adults typically build a case for their own prereading belief rather than process a persuasive text mindfully, weigh evidence, and change their beliefs. An important contract between author and reader is typically broken. Research on designing text to disabuse students of scientific misconceptions points to text features that authors could use to encourage readers to read persuasion mindfully.