Identifying student difficulties with basic scientific reasoning skills: An example from control of variables

Current national and local standards for the science learning of K-12 students emphasize both basic concepts (such as density) and fundamental reasoning skills (such as proportional reasoning, the interpretation of graphs, and the use of control of variables).~~At Western Washington University (WWU) and the University of Washington (UW), an effort is underway to examine the ability of university students to apply these same concepts and skills.~Populations include students in liberal arts physics courses, introductory calculus-based physics courses, and special courses for the preparation of teachers. ~One focus of the research has been on the idea of control of variables. This topic~is studied by students at all levels, from the primary grades, in which the notion of a ``fair test,'' is sometimes used, to university courses.~ This talk will discuss research tasks in which students are expected to infer from experimental data whether a particular variable influences ($i.e.,$ affects) or by itself determines ($i.e.,$ predicts) a given result.~ Student responses will be presented to identify specific difficulties.