Donald Treacy

Minimally Invasive Tutoring of Complex Physics Problem Solving

Solving complex physics problems requires some kind of knowledge for selecting appropriate applications of physics principles. This knowledge is tacit, in that it is not explicitly taught in textbooks, existing tutoring systems or anywhere else. Experts seem to have acquired it via implicit learning and may not be aware of it. Andes is a coach for physics problem solving that has had good evaluations, but still does not teach complex problem solving as well as we would like. The conventional ITS approach to increasing its effectiveness requires teaching the tacit knowledge explicitly, and yet this would cause Andes to be more invasive. In particular, the textbooks and instructors would have to make space in an already packed curriculum for teaching the tacit knowledge. This paper discusses our attempts to teach the tacit knowledge without making Andes more invasive.

The effect of quenching on the defect structure of calcium fluoride doped with erbium

Audio frequency dielectric relaxation measurements over the temperature range 5.5–390 K and optical absorption studies at 8 K have been performed on various samples of rare‐earth doped calcium fluoride. Erbium was the principal dopant and the studies were carried out for a series of concentrations before and after vacuum anneal at 1125 K followed by a quick quench. Strong effects were observed on all spectra. A similar anneal followed by a slow cool returned the samples to their initial state. It is shown that RI and RII correlate with optical signals associated with the A and B sites of Tallant and Wright. The annealing results are consistent with the identification of these sites as monomer (single rare‐earth) sites of C4V and C3V symmetry, respectively. RIV, which has recently been shown to be associated with a dimer (two‐rare earths), correlates with optical signals associated with the C site of Tallant and Wright. This suggests that the dimer exhibits approximately trigonal symmetry. In addition, RII...

Implicit versus explicit learning of strategies in a non-procedural cognitive skill

University physics is typical of many cognitive skills in that there is no standard procedure for solving problems, and yet a few students still master the skill. This suggests that their learning of problem solving strategies is implicit, and that an effective tutoring system need not teach problem solving strategies as explicitly as model-tracing tutors do. In order to compare implicit vs. explicit learning of problem solving strategies, we developed two physics tutoring systems, Andes and Pyrenees. Pyrenees is a model-tracing tutor that teaches a problem solving strategy explicitly, whereas Andes uses a novel pedagogy, developed over many years of use in the field, that provides virtually no explicit strategic instruction. Preliminary results from an experiment comparing the two systems are reported.