Search Results (4 total)

Coordination class theory is used to explain college students’ judgments about animated depictions of moving objects. diSessa’s coordination class theory models a “concept” as a complex knowledge system that can reliably determine a particular type of information in widely varying situations. In the experiment described here, fifty individually interviewed college students judged the realism of two sets of computer animations depicting balls rolling on a pair of tracks. The judgments of students from an introductory physics class were strongly affected by the number of balls depicted (one or two), but the judgments of students from an educational psychology class were not. Coordination analysis of interview transcripts supports the interpretation that physics students’ developing physics knowledge led them to consistently miss or ignore some observations that the other students consistently paid attention to. The analysis highlights the context sensitivity and potential fragility of coordination systems, and leads to the conclusion that students’ developing knowledge systems might not necessarily result in consistently improving performance.

The effect of center-of-mass correlations and a restriction of the set of intermediate nuclear states have been studied for pion scattering from the mass three system. Results indicate that, for the present, these effects can be ignored.

NUCLEAR REACTIONS ³He(π^±, π^±)³He, ³He(π^-, π⁰)³He, center-of-mass effects, nuclear correlations, intermediate states, nuclear structure information.

Charge exchange angular distributions for the reaction ³He(π^-, π⁰)³H are calculated using realistic nuclear form factors obtained from electron scattering experiments in the Glauber multiple scattering formalism. It is found that the charge exchange scattering is not very sensitive to the magnetic form factors at low q and, in particular, is not sensitive to changes in the mean square magnetic radius at the ±5% level. Calculations are also compared with the most recent experimental results.

NUCLEAR REACTIONS ³He(π^-, π⁰)³H, nuclear structure form factors, Glauber multiple scattering theory.