A primary electron beam of a transmission electron microscope is scattered into secondary beams by the planes of atoms of a single crystal. These secondary beams are focused to form a diffraction pattern on the final screen. This experiment is similar to the Thompson one which, independently by Davisson and Germer, demonstrated the de Broglie…

The derivation and description of the modes in optical waveguides and fibres are reviewed. The version frequently found in undergraduate textbooks is shown to be incorrect and misleading due to the assumption of an axial ray of light corresponding to the lowest order mode. It is pointed out that even the lowest order must still be represented in…

Based on relativistic velocity addition and the conservation of momentum and energy, I present simple derivations of the expressions for the relativistic momentum and kinetic energy of a particle, and for the formula E = mc[superscript 2]. (Contains 5 footnotes and 2 figures.)

The explosion of knowledge in all of the biological sciences, and specifically in physiology, has created a growing problem for educators. There is more to know than students can possibly learn. Thus, difficult choices have to be made about what we expect students to master. One approach to making the needed decisions is to consider those "core…

Nineteen pre-service and in-service teachers taking a chemistry teaching methods course at a university in Hong Kong were asked to take a diagnostic assessment. It consisted of seven multiple-choice questions about the chemistry of the lead-acid battery. Analysis of the teachers' responses to the questions indicated that they had difficulty in…

Teaching about the nature of science is seen as a priority within science education, and has also been highlighted as a suitable context for challenging the most able ("gifted") learners at secondary school level. This article discusses a practical session designed to introduce the idea of physical (natural) laws. The session asks…

The need for a revised curriculum within the life sciences has been well-established. One strategy to improve student preparation in the life sciences is to redesign introductory courses like biology, chemistry, and physics so that they better reflect their disciplinary interdependence. We describe a medically relevant, context-based approach to…

This paper discusses the results of a study of the requirements for developing a remote radio frequency (RF) laboratory for electrical engineering students. It investigates students' preferred usage of the technical content of a state-of-the-art RF laboratory. The results of this study are compared to previous findings, which dealt with other user…

This longitudinal study reports the results of a replication of "Tutorials in Introductory Physics" in high schools of a Latin-American country. The main objective of this study was to examine the suitability of "Tutorials" for local science education reform. Conceptual learning of simple resistive electric circuits was…

This study uses history of science in teaching natural sciences from the early grades. The theoretical framework used is Cultural Historical Activity Theory (CHAT), which is a theory with expanding applications in different fields of science. The didactical scenario, in which history of science is used in a CHAT context, refers to Newton's…

The purpose of this study was to determine the effects of a socioscientific issues-based instructional model on secondary agricultural education students' content knowledge, scientific reasoning ability, argumentation skills, and views of the nature of science. This study utilized a pre-experimental, single group pretest-posttest design to assess…

Student knowledge of the Nature of Science (NOS) is critical to their understanding of science. NOS encapsulates the tenets of how science is regarded and the heuristics by which science is judged to be valid and appropriate. The importance of NOS to science education has lead to curricular and policy development that mandate the construct be…

The topic of coupled oscillations is rich in physical content which is both interesting and complex. The study of the time evolution of coupled oscillator systems involves a mathematical formalization beyond the level of the upper secondary school student's competence. Here, we present an original approach, suitable even for secondary students, to…

The microbial growth curve is widely studied within microbiology classes and bacteria are usually the microbial model used. Here, we describe a novel laboratory protocol involving flow cytometry to assess the growth dynamics of the unicellular microalgae "Isochrysis galbana." The algal model represents an appropriate alternative to…

This paper describes a method and setup to quickly and easily measure a model rocket engine's thrust curve using a computer data logger and force probe. Horst describes using Vernier's LabPro and force probe to measure the rocket engine's thrust curve; however, the method of attaching the rocket to the force probe is not discussed. We show how a…