Drawing on episodes of interaction between a teacher and two students engaged in a science experiment and the students' subsequent written reports, this article investigates intertextual links between the spoken and written texts. First, the oral participation modes of the students are examined, focusing on key features of the discursive process. Second, their individual reports are analyzed with respect to ideational content and linguistic realization. Results of the analyses reveal that the more articulate of the students entered fully into the interpretation of what they had observed, while the other seemed more concerned with replicating the experimental phenomenon than with engaging in its explanation. This differential oral involvement was reflected in their written reports: Unlike the latter, the former student incorporated all the main themes from the oral interaction and handled the explanatory challenge by the use of interpersonal dialogic strategies. In conclusion, the educational implications of these findings are discussed.