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 primary biosphere processes of photosynthesis, cell respiration, decomposition and combustion move carbon atoms between the geosphere (atmosphere, lithosphere, hydrosphere) and the biosphere.
- Identify the four major carbon reservoirs and explain how carbon moves from one reservoir to another.
- Provide examples of the various time scales at which carbon cycles through the Earth System's spheres.
- Describe the effects of negative and positive feedback on the carbon cycle in a western U.S. forest ecosystem that has been disrupted by a pine bark beetle infestation.
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.
To 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."
- Stop and Think questions Part A (Microsoft Word 2007 (.docx) 47kB Jul1 14)
- Suggested Answers to Stop and Think Questions Part A (Microsoft Word 2007 (.docx) 72kB Jul1 14)
Teaching Notes and Tips
Part A: Follow the instructions on how to set up the forest carbon cycle stations at this link. Forest Carbon Cycle Instructions. Note: If you have AP students, you may want to skip this lesson and proceed directly to Lab 2B.
Part B: Students will need access to the carbon cycle interactive to do this activity. In 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.
Each group must describe two carbon pathways - one from a shorter time scale and the other from a longer. One of these pathways must include the ocean reservoir.
Students' 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.
Part C: Students are asked to begin thinking about connections between the carbon cycle and climate change and global temperature. The element strips are provided as scaffolding for this activity. If you have advanced students, you may want to consider not giving students the element strips and instead, have students read the provided resources and identify the elements of the Pine Bark Beetle and climate story.
Student NotebooksStudent notebooks are optional. Here are just a few suggestions for what to include in student notebooks for Lab 2:
- Drawings - Carbon Journey drawings from Lab 2B
- Drawings of Connection Circles and feedback loops in Lab 2C
- Drawings of models and any revisions
- Notes from videos and discussions
Assessment:There are several options for assessments of students understanding of material produced in this Lab. Teachers can choose from the following list or create their own assessments.
- Assess student understanding of topics addressed in this investigation by grading their responses to the Stop and Think questions.
- Assess the activity " Carbon's Journey Through the Carbon Cycle" in Lab 2B
- Written Test for Lab 2 (Microsoft Word 2007 (.docx) 436kB Jan21 14) (Answer Key (Microsoft Word 2007 (.docx) 458kB Jan21 14))
National Science Teaching Standards
Lab 2 supports the following Next Generation Science Standards (NGSS):
Science and Engineering Practices
2. Developing and Using Models
Disciplinary Core Ideas
ESS2.A Earth's Materials and Systems
LS2.A Ecosystem Functioning Dynamics and Resilience
2. Cause and effect
3. Scale, Proportion and Quantity
4. Systems and System Models
5. Energy and Matter
7. Stability and Change
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
The Pine Bark Beetle Blues
Content Extension:Have students use animation software or animation apps to animate their feedback loop.