HOW NOVICE PHYSICS STUDENTS DEAL WITH EXPLANATIONS

An extensive study was conducted of students' explanations written in response to 'what if...?' questions in elementary mechanics. The study showed that the structure of students' explanations yields roughly th e same ranking of students as do problem-solving tests, but in additio n provides a wealth of insights into (1) context dependence and catego rization in students' use of concepts, (2) the effect of misconception s on context dependence, and (3) the types of explanations that studen ts tend to produce. A follow-up study, in which students were presente d with pairs of pre-written explanations to 'what if...?' questions an d asked to indicate a preference, showed that students do not necessar ily prefer the types of explanations they write, and have greater diff iculty assessing the correctness of explanations that are counter to p reference type. Evidence is presented that, for many students, the lin ks between physics thinking and real-world thinking are all too tenuou s.