Lab 2:The Carbon Cycle-What Goes Around Comes AroundThe lab activity described here was developed by Candace Dunlap of TERC for the EarthLabs project.
Use the button at the right to navigate to the student activity pages for this lab. To open the student pages in a new tab or window, right-click (control-click on a Mac) the "Open the Student Activity" button and choose "Open Link in New Window" or "Open Link in New Tab."
Investigation Summary and Learning Objectives
Students focus initially on a sub-section of Earth's natural carbon cycle related to the biosphere involving the cycling of carbon through the processes of photosynthesis, respiration, and decay. Following that, they study an annotated representation of the full carbon cycle with reservoirs and the processes that drive carbon from one reservoir to others. Finally, students learn about the interconnectedness of the Earth system, feedback loops, and how changes in the carbon cycle lead to other changes in the system.
After completing this investigation, students will be able to:
- Describe how the biosphere processes drive the carbon cycle.
- Identify the four major carbon reservoirs and describe the major fluxes of carbon that move between reservoirs
- Describe the effects of negative and positive feedback on a system.
- Provide examples of the various time scales at which carbon cycles through the Earth System's spheres.
For more information about the TOPIC, read the section titled Background Information under Additional Resources below
In Part A: Students learn about the role the biosphere plays in the global carbon cycle and the processes (photosynthesis, respiration, and decay) that move carbon between components of the Earth system. Some of these processes take place in a fraction of a second while others can take millions of years.
In Part B: Students get a broader introduction to the carbon cycle by using an interactive visualization that highlights the major carbon reservoirs (referred to as stores in the visualization) and the processes that drive the movement of carbon (fluxes) on a global scale.
In Part C: Students are introduced to the positive and negative feedback loops that play a critical role in either amplifying or damping change in the Earth system.
Printable MaterialsTo download one of the PDF or Word files below, right-click (control-click on a Mac) the link and choose "Save File As" or "Save Link As."
- Doc _______
- Stop and Think Questions: Part A and Part C. Stop and Think Part A and Part C (Microsoft Word 2007 (.docx) 26kB Mar5 13)
- Suggested Answers to Stop and Think Questions Stop and Think Part A and Part C answers (Microsoft Word 2007 (.docx) 27kB Mar5 13)
Teaching Notes and TipsIn the Carbon Journey activity in Part B, you may want to consider assigning groups specific starting points so groups don't chose the easier ones. You may also consider assigning each group two carbon pathways - one from a shorter time scale and the other from a longer. Students will need access to the carbon cycle interactive to do this activity. Student's flow charts can be fairly simple or they might want to enhance them with drawings and images. You may want to consider having students describe "how much carbon" is in each reservoir not only in metric gigatonnes, but also in number of school buses as described below.
Students' misconceptions and naive understandings to be aware of for this activity are:
1. Carbon is destroyed when fossil fuels are burned.
2. The carbon cycle consists of only photosynthesis and respiration.
3. Fossil Fuels have been around since the origins of the Earth.
4. Fossil Fuels are made from dead dinosaurs.
In part C, students are asked to begin thinking about connections between the carbon cycle and climate change and global temperature. You may want to consider doing Scenario 1 together as a class - perhaps by drawing a diagram on the board. They will return to feedbacks throughout the module.
Gigatons and Earth's biogeochemical cycles—the cycling of matter and energy among the components of the Earth system—occur at various time and spatial scales. The first image that students explore in this Lab portrays a sub-set of the carbon cycle, but provides worldwide totals for that sub-set in terms of gigatons per year. So how much is a gigaton? It's a billion metric tons. A metric ton is 1000 kilograms, or 2204 pounds. A typical school bus weighs about 10 metric tons, so the weight of about 100 million school buses would equal a gigaton.
You can assess student understanding of topics addressed in this Investigation by grading their responses to the Stop and Think questions. In addition, you can assess the flow chart developed by students in the carbon cycle activity, "A Carbon Journey" in Part B.
Assessment Lab 2 Assessment Lab 2 (Microsoft Word 2007 (.docx) 273kB Mar5 13)
Assessment Lab 2 with answers Assessment Lab 2 answers march 13 (Microsoft Word 2007 (.docx) 270kB Mar5 13)
State and National Science Teaching Standards
TO BE PROVIDED LATER
Developer will correlate activity to standards listed at this site:National Science Education Standards (SRI)
Background InformationThe first two links provide excellent background information on the carbon cycle. The third link, 'What Carbon Cycle,' reports on students misconceptions. The fourth link brings you to Dr. David Archer's lectures on The Carbon Cycle on YouTube. Dr. Archer is an expert on the Carbon Cycle. The lecture for chapter 8 - The Lungs of the Carbon Cycle - is especially relevant and interesting.
Carbon Cycle Background
What Carbon Cycle?
David Archer's University of Chicago lectures on The Carbon Cycle