The National Science Education Standards (NSES) emphasize the use of models in science instruction by making it one of the five unifying concepts of science, applicable to all grade levels. The NSES recommend that models be a focus of instruction--helping students understand the use of evidence in science, make and test predictions, use logic, and…

Some single species and two species interactions in population models are presented to show how credible examples can be used to teach an underlying, common mathematical structure within apparently different concepts. The models examined consist of differential equations, and focus on real-world issues. (MP)

Various simple ex post wealth neutrality measures capture different aspects of the concept; the use of one measure alone or several measures independently can lead to interpretation problems. The Adjusted Relationship Measure is introduced to pay attention to actual revenue differences associated with wealth differences. (Author/BW)

Money models that can be used in a group-instruction mode and a shorthand notation that allows students to demonstrate their ability to count out change by a written procedure are described and discussed. (MK)

Presents four activities that use graphing calculators, spreadsheets, and graphing software to model population growth. (MKR)

By developing a sequence of mathematical models of harmonic motion, shows that mathematical models are not right or wrong, but instead are better or poorer representations of the problem situation. (MKR)

Presents an activity that utilizes the mathematical models of forest fires and oil spills that were generated (in the first part of this activity, published in the November 1998 issue) by students using probability and cellular automata. (ASK)

Provides a brief synopsis of the development of the National Fire Danger Rating System along with an explanation of how it works and possible ways to use it in a modeling or problem-solving unit in a secondary mathematics classroom. (ASK)

Presents an activity on linear functions that is designed to help students become familiar with the graphs, equations, and tables of these functions while focusing on issues related to cost, revenue, and profit. (ASK)

Activities in which students make and prove conjectures and devise their own geometric axiom systems are discussed. (SD)

An activity sequence is described. Several aspects of a population problem are developed using isoperimetric graph paper and symmetry principles to derive general rules. (SD)

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)