This study is empirical research about alternative ideas on the concept of force for five different age groups, primary school students (11), middle school students (15), high school students (17), students of the Department of Primary Education (21), and active teachers in primary education (27-50). We used the same questionnaire for all groups,…

In 1879, in the midst of the debate between English and continental scientists about the nature of cathode rays, William Crookes conducted an experiment in which a small mill or "paddle wheel" was pushed along tracks inside a cathode ray tube (CRT) (similar to that shown in Fig. 1) when connected to a high-voltage induction coil. Crookes…

A partially unusual behaviour was found among 14 sophomore students of civil engineering who took a pre test for a free fall laboratory session, in the context of a general mechanics course. An analysis contemplating mathematics models and physics models consistency was made. In all cases, the students presented evidence favoring a correct free…

Students' understanding of the concept of relative speed is described. A variety of ways of understanding relative speed and of viewing a problem that dealt with this concept were uncovered. The results are used to suggest ways for teachers to proceed in assisting students to enhance their understanding of relative speed. (PR)

Explains reasons why students have misconceptions concerning pendulum swings. Presents a series of 10 pendulum task cards to provide middle-school students with a solid mental scaffolding upon which to build their knowledge of kinetic energy and pendulums. (PR)