Modeling with STELLA
Maryland Virtual High School of
Science and Mathematics
This project was supported,
in part, by the
STELLA Characteristics
A dynamic concept map
 Focuses on change over time
 Makes visible the feedback in a system
 Allows the input of data and equations
 Expresses output as data tables and graphs
 Appropriate for math levels from prealgebra through calculus

Money Model
Money(t) = Money(t - dt) + (monthly_earnings monthly_expenditures) * dt
INIT Money = 100
monthly_earnings = 2000
monthly_expenditures = 1900
Model Output - Graph
Model Output - Table
Money Model with Feedback
Feedback Output
Benefits of Modeling
Solve Real World Problems
 Learn from Personal Experiences
 Connect Data and Processes
 Clarify Abstract Concepts
 Extend Classroom ‘Wet-Lab’ Experiences
 Reveal Misconceptions

Hunting the Black Bear
Garrett County, Maryland
The black bear population is
increasing. Bears have caused
accidents on I-70. They forage
for food in neighborhoods.
The Department of Natural
Resources wants to know if
hunting should be resumed.
What should the quota be?
The Black Bear Model
Model Results
The Dangers of Tailgating
Montgomery County, Maryland
You are driving on I-95 in rush hour traffic. You learned the
two-second rule in Driver’s Education, but drivers cut in
front of you if you leave that much space.
What is a safe separation distance?
The Tailgating Model
Tailgating Scenario
Scenario Results
Carbon Cycle Objectives
Model the components and processes which
form the carbon cycle.
 Identify the characteristics of a system in
equilibrium.
 Identify feedback loops in a system.
 Illustrate the effects of a disturbance to a
system in equilibrium.

Mauna Loa Data
Carbon Cycle Model
Carbon Cycle Output
Enzyme Model Objectives
Determine the parameter values which
result in optimum performance for an
enzyme.
 Use a simulation to extend understanding of
enzyme reaction rates.
 Apply the results of the model to real world
situations.

Enzyme Model
Enzyme Model Output
Enzyme Model Analysis
The Flow Investigation
The buret shown can represent
many real world situations - a
reservoir formed by a dam, a
bathtub, drugs entering and exiting
your body. Each system is affected
by inflow and outflow rates.
Use the buret to investigate the
characteristics of those rates.
The Flow Model
Model Output
Contact Information

Susan Ragan - Center Director
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
sragan@mvhs1.mbhs.edu
Maryland Virtual High School
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51 East University Blvd.
Silver Spring, MD 20901
http://mvhs.mbhs.edu
301-649-2880