Directions 1. Use the instructional model to show students where they are in the course of the unit. Show slide 2 of the 4.1 Tiny Pool and Flux Game PPT. Slide 3 and discuss Stability and Change as the main focus for this lesson. Students have been introduced to carbon pools in previous lessons. In this lesson, they will study carbon fluxes. 2. Students review the two-pools model of carbon in an ecosystem. Use Slide 4 to remind students how the carbon in the meadow simulation can be divided into five pools. Use Slide 5 to show how scientists categorize organisms into particular two pools of carbon, organic and inorganic. 3. Use Slides 6-9 to define fluxes as rates (mass/time). Show Slide 6. Explain the terms, movements and fluxes. Show Slide 7 to show students the two main pools. Show Slide 8 to show students the two main fluxes. Tell students that photosynthesis moves carbon from the inorganic to the organic pool. Cellular respiration moves carbon from the organic to the inorganic pool. Remind students that they found this during the Carbon Dice Game. Show Slide 9 to show the other fluxes within the organic carbon pool. Remind students that they traced their movement on this diagram in Lesson 3. 4. As a class, run through scenario 1 of the Tiny Pool Flux Game Handout one 4.1 Tiny Pool and Flux Worksheet to each student along with a 4.1 Tiny Pool and Flux Game Placemat and 10 markers. The game can be done by individual students or in pairs. Each student keeps their own data and graphs. Show Slides 10-12 to explain the game and setup. Show Slide 13. In this scenario, they will have 6 carbon atoms in the organic pool and 4 in the organic pool. Have students put the appropriate number of markers on placemat and starting points on the graph. Both the photosynthesis and cellular respiration rates are at 2 carbon atoms/year. Have class work through years by moving markers according to the fluxes and recording each year’s result in the chart and on the graph. Students should connect the dots for the organic (green) pool with a dashed line and use a solid line for the inorganic atmospheric pool Have students play through year 5, recording and graphing their data as they go. Have students compare their results to Slide 14. 5. Have students determine other starting conditions that yield the same graph. Show Slide 15. Have students find another set of fluxes that produce the same graph. Have students share their results. Discuss the pattern in the results. Students should find that any starting conditions with the same original pool sizes and equal flux rates will produce the same results. 6. Have students try Scenario 2. Show Slide 16. Have students try Scenario 2 and graph the results. Show Slide 17. Discuss the pattern. Show Slide 18. Have students try to find another set of fluxes that produce the same results. Students should find that any set of fluxes that differ by the same amount should produce the same results. 7. Challenge students to find a set of starting conditions that produces a graph with crossing lines. Use Slide 19 to challenge students to find a set of starting conditions that will make the graph lines cross. After the students find one set of conditions, challenge them to find another set of conditions that produce the same graph. Have students discuss their results and find patterns. 8. Allow students to try their own starting pools and fluxes. Show Slide 20 to have students try their own starting pools and fluxes. After, have them find different fluxes that produce the same graph. Have students share and discuss their results. 9. Have students summarize what they found about the relationship between pool size fluxes. Have students answer question B on the worksheet. Allow students to share their answers with a partner. 10. Introduce the idea of net flux. Use Slide 21 to have students summarize what they found about the relationship between pool size and fluxes as a whole class. Don’t show the bullet points until they are finished summarizing. Use the bullet points to introduce the idea of net flux. 11. Have students complete an exit ticket. Show slide 22 of the 4.1 Tiny Pool and Flux Game PPT. Conclusions: How do carbon fluxes change the size of carbon pools? Predictions: How are real ecosystems and the tiny ecosystem alike and different? On a sheet of paper or a sticky note, have students individually answer the exit ticket questions. Depending on time, you may have students answer both questions, assign students to answer a particular question, or let students choose one question to answer. Collect and review the answers. The conclusions question will provide you with information about what your students are taking away from the activity. Student answers to the conclusions question can be used on the Driving Questions Board (if you are using one). The predictions question allows students to begin thinking about the next activity and allows you to assess their current ideas as you prepare for the next activity. Student answers to the predictions question can be used as a lead into the next activity.
