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How Stocks Change Over Time - Three Scenarios
Read about each scenario and then click the links to explore how a stock (accumulation) can change over time. In each scenario, you will be able to change to what degree the amount of the stock increases and/or decreases. When done, just close the simulation window to return to WebEd.

Scenario 1: Water in a Bathtub
In this simple simulation, you will be able to control the amount of water in a bathtub by regulating the rate in which the water flows into the tub from a faucet.

Picture of Water in Bathtub

 

Instructions:

When you open this simulation, you will see a bathtub being filled with water. The tub is simultaneously filled via the faucet and emptied through the drain. Watch the tub for about a minute, noticing what happens.

Then, try to control the amount of water going in so that the tub does not overflow. Can you keep the level of water in the tub steady?

Open the Bathtub Simulator.

Scenario 2: Trees in a Forest
In this simulation, you will be able to affect the number of trees in a forest by controlling cutting and planting.

Picture of forest from simulation

 

Instructions:

When you open this simulation, you will see a forest scene. The mature trees are marked with red ribbons. You determine the number of foresters who plant trees and the number of lumberjacks who cut trees.

Try to keep the number of trees stable while allowing for at least some cutting.

Open the Forest Simulator.

Scenario 3: Populations in an Ecosystem
In this simulation, you will see how the number of rabbits and the amount of grass change over time based on an interdependent relationship between the two.

Picture of ecosystem simulation

 

Instructions:

When you open this simulation, you will see buttons, a graph, and slidebars on the left and a black square on the right. Click "Setup" to place initial populations of rabbits and grass in the box. Click "Go" to see what happens to the number of rabbits and the amount of grass over time. Watch the graphs and notice what patterns emerge.

If desired, you may change the sliders after you've stopped the simulation by clicking "Go" again.

Open the Ecosysytem Simulation.

The bathtub and forest simulations were created by
Linda Booth-Sweeney in coordination with the Schlumberger Excellence in Educational Development (SEED), a global non-profit education program that serves students aged 10-18.
Used with Permission. Additional information about SEED

The ecosystem simulation was created by
Wilensky, U. (2001). NetLogo Rabbits Grass Weeds model. http://ccl.northwestern.edu/netlogo/models/RabbitsGrassWeeds. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL.Copyright information

 
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