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 pre-

algebra through calculus

Money Model

Money(t) = Money(t - dt) + (monthly_earnings - monthly_expenditures) * dt

INIT Money = 100monthly_earnings = 2000monthly_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 isincreasing. Bears have caused accidents on I-70. They foragefor food in neighborhoods.

The Department of NaturalResources wants to know ifhunting 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 representmany real world situations - a reservoir formed by a dam, a bathtub, drugs entering and exitingyour body. Each system is affectedby inflow and outflow rates.

Use the buret to investigate thecharacteristics of those rates.

The Flow Model

Model Output

Contact Information

Susan Ragan - Center Director– sragan@mvhs1.mbhs.edu

Maryland Virtual High School– 51 East University Blvd. – Silver Spring, MD 20901– http://mvhs.mbhs.edu 301-649-2880