Simple measurements of the decay time of cathodoluminescence are described. Cathodoluminescence is used in many devices, including computer monitors, oscilloscopes, radar displays and television tubes. The experimental setup is simple and easy to build. Two oscilloscopes, a function generator, and a fast photodiode are needed for the experiments.…

Investigates high school students' knowledge of natural phenomena related to the concept of light flux as it applies to the seasons and illumination after they studied optics. Discusses didactic, cognitive, and ontological perspectives in relation to specific changes in the science curriculum. Contains 71 references. (DDR)

Explores the potential of the RAY learning environment in improving learning about optics. Results indicate that this environment, which includes a flexible ray-tracing simulation, had a significant effect on the spontaneous and correct use of the model by students in solving problems and a limited effect on conceptual understanding, but promoted…

Explores high school students' and preservice teachers' knowledge of light, vision, and related topics before and after commonly practiced instruction. Suggests a hierarchical structure to represent the collective conceptual knowledge of students and teachers in terms of facets and schemes of knowledge. Makes suggestions for designing instruction…