Presents a case study of how one 11th-grader learned the meaning of the velocity sign. Her learning was not just an acknowledgment of a rule but also a broad questioning and revision of her thinking about graphs and motion. (16 references) (Author/MKR)

This study was designed to determine students' abilities and difficulties in articulating the relationship between function and derivative. High-school students were presented 15 problems during two 75-minute interviews in which they were asked to construct functions experimentally in three different contexts: motion, fluids, and number-change. In…