1. Ecosystems Unit Activity 4.2 Carbon Pools and Constant Flux Simulation
Carbon: Transformations in Matter and Energy
Environmental Literacy Project Michigan State University
Ecosystems Unit Activity 4.2 Carbon Pools and Constant Flux Simulation
Image Credit: Craig Douglas, Michigan State University

2. Unit map
You are here
Use the instructional model to show students where they are in the course of the unit.
Show Slide 2 of the 4.2 Carbon Pools and Constant Flux Simulation PPT.

3. Review of Tiny Pool and Flux Game
What patterns did you find in the Tiny Pool and Flux Game?
What is net flux?
Review the patterns found in Activity 4.1
Show Slide 3 of the 4.2 Carbon Pools and Constant Flux Simulation PPT. Have students discuss the patterns they found in Activity 4.1 and review the idea of net flux.

4. Introduction to Simulation
Read the information about the simulation.
Students run the simulation.
Show Slide 4 of the 4.2 Carbon Pools and Constant Flux Simulation PPT. Pass out a 4.2 Computer Model for Constant Flux Worksheet to each student. Have students read until the #1 for an overview of the simulation.

5. The Simulation Students run the simulation.
Show Slide 5 and open the simulation. Show students how to move the sliders and run an example. Point out the graphs and how they can slide the line of the graph to get data for a particular point in time.

6. Run 1 Students run the simulation.
Have students follow the instructions to run the simulation. Students should record their data in the table.
(Optional) Use slide 6 and 7 to discuss Run 1 and Run 2 as a class.

7. Run 2 Students run the simulation.
Have students follow the instructions to run the simulation. Students should record their data in the table.
(Optional) Use slide 6 and 7 to discuss Run 1 and Run 2 as a class.

8. Initial Setting (0 years)#
Initial Setting (0 years)
1 year
5 years
20 years
CO2 Pool
Organic Pool
Phs. Flux
CR Flux
Org.
Pool 1
500 kg
50 kg/yr 2
70 kg/yr 3 4 5 6 7
Students consider patterns in their results.
When students have completed the table, have students work individually and then with a partner to answer questions 6 and 7 on 4.2 Computer Model for Constant Flux Worksheet.
(Optional) Use slide 8 to complete the table as a class.

9. Discussion
What happens if you change the initial settings for pool size, but leave the fluxes the same? Why?
What patterns did you notice as you ran the model?
Discuss the patterns.
Show Slide 9 of 4.2 Carbon Pools and Constant Flux Simulation PPT. Have students share and discuss their answers to questions 6 and 7.

10. Rules for pools and fluxes
When opposing fluxes are equal, pool sizes don’t change.
When opposing fluxes are not equal, pool sizes change.
How fast the pool sizes changes depends on the difference between the opposing fluxes. We call the difference the net flux.
When the incoming fluxes are bigger than the outgoing fluxes, the net flux is positive and the pool grows.
When the incoming fluxes are smaller than the outgoing fluxes, The net flux is negative and the pool shrinks.
Review the patterns.
Show slide 10. Discuss with students how the rules from Activity 4.1 in the tiny system also are true of the larger system in the simulation.