Presents a procedure for calculating the compass direction and velocity of present plate motions at any geographical point of interest. Includes a table of the relative and geographic motion of the 11 largest plates and a flow chart for determining their present motion. Also offers suggestions for classroom instruction. (ML)

Describes the life and work of Charles Peirce, U.S. mathematician and philosopher. His accomplishments include contributions to logic, the foundations of mathematics and scientific method, and decision theory and probability theory. (MA)

Describes a learning activity when students construct a model of a buried valley by using computer assistance. Explanation of the problem includes mathematical models and illustrations. (MA)

Describes an interactive computer program which can be used by students to construct adaptive landscapes of two types as an illustration of the expected effects of selection. Simulates effects of selection on populations of this type and changes of gene frequency can be plotted on the same contour map. (Author/MA)

An elementary analysis of a common textbook airplane problem is given, and then, as an illustrative example, the possibilities of this mechanism for animal navigation are briefly considered. (Author/MA)

Presented is the design of an electrical analogue of the simple pendulum--a one-dimensional oscillator resonating within a frequency range which can be generated and observed with readily available instruments. One possible study sequence is outlined. (Author/MA)

Discusses a single pattern formation mechanism that could underlie the wide variety of animal coat markings found in nature. Presents the results of a mathematical model for how these patterns may be generated in the course of embryonic development. (CW)

By considering colors as sets of wavelengths and using Boolean Algebra of sets, the effects of combining colors can be represented in a formal mathematical system. (SD)

A simple teaching model, designed to show rapidly which are the principal factors in population growth and how they are related, is presented. The apparatus described allows students to play several different active roles. (MP)

Discusses a misconception about the cycloid that asserts the final point on the path of shortest time in the "Brachistochrone" problem is at the lowest point on the cycloid. Uses a BASIC program for Newton's method to determine the correct least-time cycloid. (MDH)

Presents a mathematical model that will help students explore concepts related to population growth such as doubling time, replacement level and zero population growth. (Auth/WB)

Presents the theory of primary and secondary rainbow formation utilizing simple optics and geometric concepts. Describes an appropriate, waterless classroom demonstration and includes the relevant mathematical formulas and models. (JJK)

Describes and illustrates the structure of different versions of Mobius bands called prismatic rings or twisted prisms. Different forms are mentioned, such as the one bent into circular shapes and the toroidal polyhedrons. (GA)

A model of Brownian motion is discussed which includes viscosity effects. The model lends itself to Monte Carlo simulation and thus is suitable for an elementary physics laboratory experiment. (BB)

The development of a mathematics model to simulate small animal populations is described. Assumptions of the population model and options in the program are discussed. (MK)