Researchers and practitioners alike express concerns about the conceptual difficulties associated with the concepts of momentum and kinetic energy currently taught in school physics. This article presents an in-depth analysis of the treatment given to them in 44 published textbooks written for UK secondary school certificate courses. This is set…

Pulsed ultrasound was used to study tongue movements in the speech of children from 3 to 11 years of age. Speech data attained were characteristic of systems that can be described by second-order differential equations. Relationships observed in these systems may indicate that speech control involves tonic and phasic muscle inputs. (Author/RH)

This study compared the batting swing of two skilled congenitally blind beep baseball players to a perfect kinetic-link model for the batting skill. It found that the subjects used a modified batting technique and that there was an inverse relationship between the subjects' performances and the kinetic-link model. (Author)

Examines whether kindergarteners, second-graders, fourth-graders, and adults can extract relative weight information from observing collisions and lifting events, and if they can judge whether or not collisions are momentum-conserving. Subjects saw either videotapes of events or sequences of static images; younger children appeared to be…

Reviews research on student learning about collisions in physics instruction. Focus is placed on the main differences between the spontaneous perspective in describing/interpreting collisions and the disciplinary perspective based upon the energy and linear momentum conservation laws. (PR)

Almost all experimental investigations on concepts of time (T), distance (D) and velocity (V) since 1946 have been based on the Piagetian theory. However, there are several controversial points in Piaget's investigations. In the experiment described in this paper, developmental changes of concepts concerning relation of T, D, and V were examined…