4-6, Unit Seven, Activity 4: "Carbon Cycle Capers"

Students will be able to identify the cyclical relationship between carbon dioxide in the atmosphere and plants on earth which trap and store carbon. This is a fast-moving game of tag which pits the “trees” against the “CO2 molecules”.

Grades: 4 – 6
Time: 1 hour
Subjects: Physical science, physical education, life science


  • Enough rags to make armbands for half the group.

1. Review the basic greenhouse gas cycle.
2. Divide the group. One student will be the "Fuel Burner." The remaining students will be evenly divided--half will be "trees" and half will be "CO2 molecules." Choose either group to start wearing the armbands.
3. To start the game, set the boundaries of the playing area and have the "tree" and "CO2" teams go to the opposite ends of the playing area. The "Fuel Burner "waits on the sidelines at the start of the game.


  • The "trees’" objective is to absorb (capture) the "CO2 molecules." They do this by linking arms with the CO2.
  • Each Tree is allowed to absorb two CO2 molecules but can only “take” a molecule that has an open arm.
  • When a Tree has captured two molecules, it is “full” and must freeze in place.
  • When the "Fuel Burner" touches a "tree," the "tree" “dies” and releases its "CO2 molecules."
  • “Dead” Trees fall to the ground and stay there until the "Fuel Burner" plants them.
  • The "CO2 molecules’" objective is to “hang out” in the atmosphere with each other, basking in the radiated warmth of the Earth. They do this by linking arms with each other.
  • If a CO2 molecule has both arms linked to other molecules then a "tree" cannot absorb it. The "CO2 molecule" that has been absorbed by a "tree" must stay with that "tree" until it is freed by the "Fuel Burner," at which time the molecule goes back to “hanging out” in the atmosphere.
    The "Fuel Burner’s" objective is to tag 'trees," thereby cutting them down to burn for energy.
  • The "Fuel Burner" doesn’t enter the game until the "trees" and "CO2 molecules" have been playing for a few minutes.
  • There is no limit to the number of "trees" that the "Fuel Burner" may tag.
  • The "Fuel Burner" may also “plant” "Trees" by returning to a “dead” "tree" and helping it to catch and absorb a "CO2 molecule."
  • The game is over when you run out of time or "trees" or "CO2 molecules."

Discuss the results of the game. How does the game compare to the real carbon cycle in which the oceans play a role in balancing the amounts of carbon dioxide in the atmosphere? Are there any differences in the cycle before and after the "Fuel Burner" shows up? Does the Peace Park help the carbon cycle’s health by preserving large trees? What does this say about reforesting areas which were logged or burned?

Last updated: November 8, 2017

Contact the Park

Mailing Address:

PO Box 128
West Glacier, MT 59936


(406) 888-7800

Contact Us