Rates of Change:
Modelling Population and Resources
Eva Paus, Economics Department
Harriet Pollatsek, Department of Mathematics, Statistics and Computation
Mount Holyoke College
This is the subject of the present monograph. A crucial element in the
teaching of this unit is the program STELLA by High Performance Systems.
By the use of clever visual icons, STELLA permits the student to model
dynamical systems of considerable complexity without the explicit use of
calculus. The central visual metaphor is "plumbing." Quantities that
grow or shrink appear as the contents of "bathtubs." "Pipes" feed into
and out of the tubs, each with a "valve" which determines the rate of
increase or decrease. These rates may, in turn, depend on other
quantities in the system in a variety of ways.
This text allows student to approach problems normally reserved for
those with a calculus background. Lots of discussion questions and
exercises are included. The background, material for various topics is
presented at a beginners level. Further reading would allow a more
sophisticated approach to the topics. A user who does not have access to
STELLA would have to rework the exercises in their own choice of
software.