Discusses the theory behind the changes in the times of sunrise and sunset and the sun's apparent gradual week-to-week motion. (JRH)

Reports recent findings related to the particle Higgs boson and examines its possible contribution to the standard mode of elementary processes. Critically explores the strengths and uncertainties of the Higgs boson and proposed Higgs field. (ML)

Explains why the isolated sphere models are physically unsound. Describes an improved model for attempting a qualitative explanation of charge concentration. (YP)

Describes the use of analogies to explain scientific concepts. Presents the teaching-with-analogies model. (JRH)

Discusses how the discovery of chaos has created a new paradigm in scientific modeling and how findings are contributing to changes in thought about many different branches of science. Includes explanations and examples of how chaotic behavior can be understood. (ML)

Describes three models that provide a concrete experience of abstract concepts such as DNA replication, RNA synthesis, and protein synthesis. Explains their hands-on use and notes their advantages for teaching and learning. (JRH)

Examines the utility of the ancient Chinese concept of Tai-chi as a model for interpreting complex contemporary issues in science education. Describes the model and suggests how it can be useful in understanding scientific phenomena and in guiding instruction. (ML)

Presents the equations of motion governing the trajectory of a cricket ball subject to a linear drag force. Uses a perturbation expansion technique to solve the resulting trajectory equation for the range of a cricket ball struck into the outfield. (Author/ASK)

Presents an instructional strategy based on the thesis that science concept learning involves cognitive accommodation of an initially held framework. The three stages of the strategy--exposing alternative frameworks, creating conceptual conflict, and encouraging cognitive accommodation--are illustrated in two lessons on the particle model of…

An explanation of strong base effect demonstrates that deprotonation of a reactant shifts an equilibrium toward reactants in the same way that a deprotonation of a product shifts it towards products. (Author/SA)

Investigates the effect of modeling analogy on learning of the concepts of electricity in grade 6, 8, and 10. Describes 2 analogies (train analogy and thermal analogy) with diagrams and examples. Discusses the accessibility, transferability, and difficulty of each analogy. Reports treatment effect and some further implications. (YP)

"Mental modeling" refers to a student's ability to visualize or comprehend the information research process. This article reviews 50 years of changing conceptions of how we learn: behaviorist, cognitivist, and constructivist perspective; describes the application of three "mental models" to interactive technology; and discusses…

Reviews basic concepts of predator-prey interaction, encourages the presentation of the predator's role and describes a model of predator behavior to be used in secondary school or college classes. (LS)

Many science educators are concerned with students' ability to understand science as a process and with their conceptions of scientific knowledge. Preliminary work has shown that the use of a model organizer can result in student perceptions of improved understanding, but the reason for this effect is not known. This research was undertaken to…

Described is how crystal field theory and the angular overlap model can be applied to very simple molecules which can then be used to introduce such concepts as bonding orbitals, MO diagrams, and Walsh diagrams. The main-group compounds are used as examples and a switch to the transition metal complexes. (KR)