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Ecosystems | Activity 4.2

Activity 4.2: Changes in Ecosystems Over Time (40 min)

Students predict how carbon pool size changes over time with different fluxes. In this Activity, they talk about only two pools of carbon: the organic and the inorganic pools.

Materials You Provide

  • Computer
  • Projector

Resources Provided


For Activity 2, print one copy of 4.2 Carbon Fluxes Worksheet for each student. Prepare a computer and projector to display the presentation.


1. Have students read the handout about carbon fluxes.

Pass out a href="" target="_blank" >4.2 Carbon Fluxes Handout to each student. Have students work in pairs, alternating who reads each paragraph of a href="" target="_blank" >4.2 Carbon Fluxes Handout out loud to each other. After each paragraph, ask each pair to discuss the following questions and then share out:

  • After paragraph 1: Describe a flux in your own words. Describe how pools and fluxes are different.
  • After paragraph 2: Why is water going into and out of a swimming pool a good way to describe pools and fluxes?
  • After paragraph 3: What are some different ways scientists count carbon atoms in this story?

Accommodation: Instead of discussing the reading at the end, have students read one section of the handout at a time and discuss their answers to the “Questions” as a class.


Use 4.2 Grading the Carbon Fluxes Worksheet to grade student responses. At this point, students can be held accountable for correct answers. If students are still struggling with these concepts, you may want to revisit parts of the Lesson they are finding difficult.


Go through scenario 1 of the game in this Activity slowly to make sure students understand the meaning of a flux. After they understand, continue with scenario 2.


Have students work as individuals instead of in pairs.

Extending the Learning

Each round in this Activity presents a scenario with an event that causes the size of carbon pools to change. Have students brainstorm other things that happen in the world that might cause the organic or inorganic carbon pools to change size.