Lab 1: Living in a Carbon World

The lab activity described here was created by Candace Dunlap of TERC for the EarthLabs project.

Summary and Learning Objectives

In Part A, students trace the pathway of carbon from the atmosphere into trees where carbon can be stored for hundreds to thousands of years. In Part B, students go outdoors and measure the amount of carbon in a local tree. In Part C, students use molecular model kits and Jmol images to explore how carbon compounds are built and how they are transformed into new carbon compounds as carbon moves through the carbon cycle. In Part D, students learn about combustion, a carbon cycle process that burns fossil fuels. Students analyze graphs and videos to determine if the human activity of burning fossil fuels is changing the chemical composition of the atmosphere.

After completing this investigation, students will be able to:

explain why carbon atoms can form the basis of millions of different types of carbon compound molecules;
describe how the carbon atoms in CO₂ absorbed via plant photosynthesis provide the carbon atoms for all of the new carbon compounds a plant produces;
explain how carbon compounds are transformed in four processes that are critical to the carbon cycle: photosynthesis, cell respiration, biosynthesis and combustion;
apply skills to measure the amount of carbon in a tree; and
explain how combustion moves the carbon atoms in fossil fuels into the atmosphere.

Open the Student Lab »

Activity Overview and Teaching Materials

Detailed overview of what students will do in each lab activity, how long it will take, and what materials are required to complete the lab.

Research by Michigan State indicates that students have a very limited understanding of how the global carbon cycle works. See What Carbon Cycle? College Students Lack Scientific Literacy, Study Finds Specifically, this research indicates that students do not understand the processes that transform carbon compounds nor do they understand that most of a tree's growth comes from atmospheric CO₂ and water. Lab 1 is designed to address these misconceptions and lack of understanding of basic carbon cycle processes that underpin the carbon cycle.

In Part A: Students view a TedEd video to consider the question, "Where does a tree get its biomass?" They analyze images to trace the pathways of carbon between trees, soil and the atmosphere. Time estimate: 1 class period.

In Part B: Students go into the field to measure the carbon stored in a local tree. They use allometry to calculate the mass of carbon stored in their local tree.

For each group:

A local, nearby tree - preferably having a circumference of 38cm (15 inches) or more.
A regular flexible tape measure that will fit around the circumference of the tree; or a diameter tape measure; and/or a long string, marker and push pin
Tree identification guide and/or tablet APP such as Leafsnap
Calculator/pencil/paper NOTE: Calculators with exponents capability are required.
A copy of the table "Allometric Coefficients for Common North American Trees." NOTE: See "Printed Materials" section below.
A Student Data Worksheet to fill in their data and calculations.

For the class:

Access to a spreadsheet program such as Microsoft Excel and Apple's Numbers
(Optional) Soil testing kits and meters for testing environmental variables such as NPK(fertilizer), soil moisture, soil pH, soil temperature etc.
A regular flexible tape measure that will fit around the circumference of the tree; or a diameter tape measure; and/or a long string, marker and push pin. NOTE: For larger trees, the string, marker and push pin may work best.

Time estimate: 2 class periods.

In Part C: Students carry out 4 investigations to learn how carbon compounds can be transformed into new, different carbon compounds.

In Investigation 1, students look for evidence of a chemical change when they bubble CO₂from their own breath into limewater (calcium hydroxide) producing two new compounds: calcium carbonate and water. For the class: NOTE: This first part is done as a class demo. However, the entire investigation can easily be done as a DEMO.

piece of chalk
white vinegar
eyedropper

For each group:

clear plastic cup partially filled with limewater
clear plastic cup partially filled with water
empty clear plastic cup
two drinking straws
small (#2) coffee filter
water
white vinegar
eyedropper

In Investigations 2 and 3, students use molecular model kits to model photosynthesis, respiration and biosynthesis of large, complex biomolecules built from multiple glucose molecules. For each group of 2-4 students:

A plastic baggie that contains 6 CO₂ molecules and 6 H₂O molecules. If you have nitrogen atoms available to use, you may want to consider using these in Investigation 3.

For the class:

Ball and stick molecular model kit(s) that contain carbon atoms, hydrogen atoms, oxygen atoms and bonds. You can purchase One Mega Molecule kit for Photosynthesis and Cellular Respiration from Amazon.com. Alternatively, a "Molecules of Life" kit may be purchased through any major science catalog such as Carolina Biological. You will need 6 carbon atoms, 12 hydrogen atoms, 18 oxygen atoms and 36 bonds to build 6 carbon dioxide molecules and 6 water molecules needed for each group.
NOTE:
- Based on the number of students in your class and the size of the groups, you may need to order a second kit.
- You may want to considering ordering and using nitrogen atoms for building more complex molecules. If you have a "Molecules of Life" kit in your science department. you can use the nitrogen atoms that come with that kit.

In Part C, Investigation 4, students investigate what types of elements (atoms) carbon compounds can be made of by analyzing JMOL images of several plant-produced carbon compounds. This introduces students to the role of soil nutrients (nitrogen, phosphorus, sulfur, magnesium and iron etc) in building carbon compounds.
Each student will need:

Paper or lab notebook to create their CHNOPS chart;
Jmol color coding chart. This chart is embedded in the Part C student pages;

For the class (Optional):

Use the MolView interactive Jmol biomolecule visualization web app to allow students to rotate, zoom-in and find background information on biomolecules. For a tutorial and more information about MolView, check out this Using MolView YouTube video ahead of time. NOTE: MolView uses ribbon diagramming for protein structures, so the molecular images of DNA and Cytochrome C on the student page for Lab 1C will not look the same in MolView.

Time estimate: 2 class periods

In Part D, students use videos, graphs and interactives to explore the combustion of fossil fuels and increased fossil fuel emissions to the atmosphere since the beginning of the Industrial Revolution. Students analyze graphs and videos to determine if the human activity of burning fossil fuels is changing the chemical composition of the atmosphere.

Time estimate: 1-2 class periods

Printable Materials

Download and print files needed for each lab activity, including images, data tables, and Stop and Think questions.

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."

Lab 1B: Student Data Worksheet (Microsoft Word 2007 (.docx) 20kB Nov8 21) and Lab 1B: Student Data Worksheet PDF (Acrobat (PDF) 101kB Nov8 21) for the field activity "How Much Carbon is Stored in a Local Tree."
Allometric Coefficients for Common North American Trees. PDF (Acrobat (PDF) 124kB Nov8 21)]
Lab 1 Stop and Think Questions (Microsoft Word 2007 (.docx) 153kB Nov8 21) and Lab 1 Stop and Think Questions PDF (Acrobat (PDF) 239kB Nov8 21)
Suggested Answers PDF -- educator-only file

Suggested Answers PDF

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to Stop and Think Questions

Teaching Notes and Tips

General recommendations for classroom implementation.

General Recommendations:

If unfamiliar with a hands-on activity in this Lab, consider a practice run before implementation.
Print out any paper-based materials before starting the lab.
Have students keep a lab notebook or journal to record important notes, questions, data and findings.
Consider FLIPPING parts of the lessons. This will save you class time and reduce the need to have computer access in your classroom.
Discussion questions, Checking In questions and Stop and Think questions can be adapted and used in a variety of ways based on teachers' needs. For example, some questions might make great "DO Now" activities as students enter the classroom or great "exit quizzes" as students leave.
You may want to spend time projecting graphs and important images on the board and going over the elements (e.g. units of measure, variables on axis, trends, color schemes etc) with them.
You may want to spend time projecting graphs and important images on the board and going over the elements (e.g. units of measure, variables on axis, trends, color schemes etc) with them.
In many of the Optional Extensions sections throughout the carbon cycle module, students are prompted to "research the latest research" on important carbon cycle topics pertinent to the lab section they are working in. Rich conversations can ensue when students go to ScienceDaily and/or Phys.org - News and Articles on Science and Technology to find abstracts of new research that supports, contradicts or enhances current understanding on how the carbon cycle works.

In Part A:

Consider assigning the first part of Part A as part of a FLIPPED lesson.

In Part B:

Gather materials for the tree carbon activity. You may want to go out to the area where students will be selecting and identifying trees and identify those trees that are on the Allometric Coefficients for Common North American Trees. (Microsoft Word 2007 (.docx) 98kB Feb23 15) table and flag them. Discuss with students the value of future classes collecting carbon data on the same trees.

In Part C:

Time is always an issue, so you may want to do the CO₂ and lime water experiment as a demo. Dealing with all of the atoms and bonds creates management issues, especially if you are doing this activity with more than one class. You will need to develop a management system that works for you keeping in mind that incoming students should have a baggie ready for them with six pre-made CO₂ and H₂O molecules. To save class time, students can do the Jmol molecules at home for homework.

In Part D:

To save time, you may want to FLIP the first part of this lesson. Then, you can have students do the graph and analysis activity "Are Humans Changing the Chemistry of the Atmosphere" together in class.

Student Notebooks

If you have your students keep a lab notebook and/or a journal, here are some suggestions to consider:

Have students write down the learning objectives for Lab 2.
Have students record answers to all Stop and Think questions.
Have students record answers to Discussion questions.
Have students record diagrams they have drawn, with labels and a short description of what the diagram represents.
Have students record important hands-on or minds-on activity components. This could include research questions, data, tables, observations, drawings, graphs, and conclusions.
Have students write down any questions they still have about the content covered in this lab.

Assessment

There are several options for assessment of student understanding of material introduced in this lab. Choose from the following list and/ or create your own assessments.

There are several types of assessment of student understanding of material introduced in this lab. Choose from the following list, or create your own assessments.

Assessment Options:

Assess student understanding of topics addressed in this investigation by grading their written responses to the Stop and Think questions or by using Stop and Think questions as part of whole-class or small group discussions.
Written test for Lab 1
Word file -- educator-only file

Word file

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,
PDF -- educator-only file

PDF

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. (
Test key -- educator-only file

Test key

This file is only accessible to verified educators. If you would like access to this file, please enter your email address below. If you are new to the site, you will be asked to complete a short request form. If you have already been verified by the EarthLabs project, you will be taken directly to the file download page.
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)
Many lab sections are a "learning assessment." While carrying out the activity, students are learning important concepts and demonstrating their understanding in a performance assessment. Lab 1B and 1D are good examples.
Anything that students create such as graphs, diagrams, conclusions etc. would serve as good assessments.

Science Standards

Lab 1 supports the following Next Generation Science Standards (NGSS):

Science and Engineering Practices
4. Analyzing and interpreting data
5. Using mathematics and computational thinking
7. Engaging in argument from evidence

Disciplinary Core Ideas
HS.ESS2.D: Weather and Climate
HS.ESS3.A: Natural Resources
HS. ESS3.B: Natural Hazards
HS.ESS3.C: Human Impacts on Earth Systems

Cross-Cutting Concepts
2. Cause and effect
7. Stability and change

Examples of how students engage with the standards:

Go to Next Generation Science Standards (NGSS)

Additional Resources

Explore background information and content extensions related to Lab 1.

The Nature Education Scitable site has multiple articles that can provide excellent background information for yourself and/or your students. These articles are more appropriate for AP level students. Knowledge Project at Scitable Here are some examples that are pertinent to Lab 1:
https://www.e-education.psu.edu/earth103/node/525 'Global Carbon Cycle on-line Module at Penn State' new gives additional background information on the global carbon cycle.
SkepticalScience is one of the best sites to go to read about and understand science-based arguments about climate change, the carbon cycle, the greenhouse effect and other subjects. Here are two excellent pages:
- Climate Myths vs What the Science Says
- A Scientific Guide to the Skeptics Handbook
Allometry:
- Allometry: The Study of Biological Scaling;
- Allometry: Globe Carbon Cycle
In many of the Optional Extensions sections throughout the carbon cycle module, students are prompted to "research the latest research" on important carbon cycle topics pertinent to the lab section they are working in. Rich conversations can ensue when students go to ScienceDaily and/or phys.org and find new research that supports, contradicts or enhances current understanding on how the carbon cycle works.

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