Lab 3: Carbon in the Atmosphere

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

Summary and Learning Objectives

The atmosphere serves as the main relay station for carbon atoms moving through the global cycle. In Part A, students learn about the basics of infrared radiation, greenhouse gas chemistry and the greenhouse effect. In Part B, students learn that historical ice core CO₂ and temperature data in combination with more current CO₂ and temperature data reveals the relationship between trends in global temperatures and atmospheric CO₂ levels. In Part C, students how individuals and families affect the carbon cycle and identify ways to reduce their carbon footprint.

After completing this investigation, students will be able to:

Explain how carbon dioxide and other greenhouse gases absorb infrared radiation and warm the atmosphere;
Explain how scientists use historical ice core CO₂ and temperature data in combination with more current CO₂ and temperature data to reveal the relationship between trends in global temperatures and atmospheric CO₂ levels.

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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.

In Part A: Students use an animation, charts, short videos to learn the basics of greenhouse gas chemistry, including what carbon compounds exist in the atmosphere and their relationship to the greenhouse effect.

Time estimate: 1-2 50-minute class periods

In Part B: Students use a graph and videos on historical ice core CO₂data in order to investigate the relationship between ices ages, interglacial periods and changes in CO₂ levels. Students then examine more current CO₂ and temperature to reveal the relationship between current trends in global temperatures and atmospheric carbon dioxide levels. They use CarbonTracker, developed by NOAA, to investigate and compare atmospheric CO₂ time series sampled from different parts of the world.

Time estimate: 1-2 50-minute class periods

In Part C: Students examine more current CO₂ and temperature to reveal the relationship between current trends in global temperatures and atmospheric carbon dioxide levels. They use CarbonTracker, developed by NOAA, to investigate and compare atmospheric CO₂ time series sampled from different parts of the world.

Time estimate: 1 50-minute 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."

Stop and Think Questions
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Teaching Notes and Tips

General recommendations and tips for classroom implementation.

General Recommendations:

If unfamiliar with a hands-on activity in this Lab, consider a practice run before implementation. Consider spending time to familiarize yourself with NOAA's CarbonTracker site before beginning that activity.
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).
The CarbonTracker tool Lab 3B is best used on a computer as opposed to a tablet. This tool can be used in many different ways so its a good idea to take time to familiarize yourself with everything this tool can do.
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 to find abstracts of new research that supports, contradicts or enhances current understanding on how the carbon cycle works.

By the end of Part A, students should have constructed an understanding of the relationship between CO₂ and temperature of the atmosphere. They will then apply this understanding in Lab 3B when they analyze graphs of historical CO₂ data.

You may want to have a discussion about the size of the atmosphere in the first image comparing the atmospheres of Mars, Venus and the Earth. Note that the ratio of the thickness of the atmosphere size to the diameter of the three planets is exaggerated for visual effect and that it is important for students to understand that the Earth's atmosphere is not that thick in relation to the Earth's diameter. To get a sense of the thickness of the troposphere and stratosphere layers of the atmosphere, try this simple exercise. Use a compass to draw a circle with a radius of 127 mm. This circle represents the Earth and the inner-most atmosphere. The 1 mm line drawn by your pencil represents the average thickness of the first two layers of the atmosphere: the troposphere, the region of weather, and the stratosphere, which protects us from most of the Sun's harmful ultraviolet (UV) radiation.

In Part B:

As with all the graphs, you may want to spend time projecting the graphs on the board and going over the graph elements with them.

Graph: CO2, Temperature and ice ages.

Students need to spend some time analyzing the first graph on CO₂, ice ages and temperatures. Consider projecting the graph on a board and asking students to think about what "stories" this graph tells about CO₂ and temperature over time. You may want to spend some time "unpacking" Milankovitch cycles, ice ages and ice cores depending on your classes. Students should see that trends in carbon dioxide seem to correlate with trends in temperature and ice ages over the past 800,000 years. Increased rates in CO₂ lags behind temperature. As temperature rises, CO₂ also rises possibly from a combination of a variety of sources such as increased soil respiration rates, outgassing of CO₂ from a warmer ocean etc. Increased CO₂ then acts as an amplifier of temperature as part of a positive feedback effect until "dialed down" by changes in the Milankovitch Cycles that reduce the amount of insolation Earth receives.

"Trends and variations" is a key concept in weather and climate science, ecosystem science, carbon cycle science in addition to other disciplines such as statistics. After watching the video, students will be applying their understanding of trends and variations to the Keeling Curve and to CO₂ time series graphs students create using Carbon Tracker.

The Keeling Curve is an iconic historical graph so you may to talk a little bit about the history. You will need to talk about variability versus the trend of the line. The "squiggy" lines represent seasonal variations in CO₂ dioxide due primarily to seasonal changes in the photosynthetic rates of deciduous forests. As an extension, use this graph to have students extrapolate the ppm of CO₂ in the future if you have time.

Carbon Tracker Activity

Students use CarbonTracker, developed by NOAA, to investigate and compare atmospheric CO₂ time series sampled from different parts of the world - including the Keeling Curve data from Mauna Loa. When students compare their graphs from around the world, they will see both similarities (trends of rising CO₂) and differences (example - some show greater variability and some less). These similarities and differences will generate some rich discussions.

In Part C:

The Keeling Curve is an iconic historical graph so you may to talk a little bit about the history. You will need to talk about variability versus the trend of the line. The "squiggy" lines represent seasonal variations in CO₂ due primarily to seasonal changes in the photosynthetic rates of deciduous forests. As an extension, use this graph to have students extrapolate the ppm of CO₂ in the future if you have time.

Carbon Tracker Activity

Students use CarbonTracker, developed by NOAA, to investigate and compare atmospheric CO₂time series sampled from different parts of the world - including the Keeling Curve data from Mauna Loa. When students compare their graphs from around the world, they will see both similarities (trends of rising CO₂) and differences (example - some show greater variability and some less). These similarities and differences will generate some rich discussions.

Student Notebooks

If you have your students keep a lab notebook and/or a journal, here are some suggestions to consider for Lab 3:

Have students write down the learning objectives for Lab 3.
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. For example, students' Carbon Tracker graphs and conclusions would be appropriate to include in a lab notebook.
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, or create your own assessments.

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 3
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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. The CarbonTracker activity in Lab 3C is a performance assessment.
Anything that students create such as graphs, diagrams, and conclusions would serve as good assessments.

Science Standards

Lab 3 supports following Next Generation Science Standards (NGSS).

Science and Engineering Practices

4. Analyzing and Interpreting Data

7. Engaging in Argument From Evidence

Disciplinary Core Ideas

ESS2.D Weather and Climate

ESS3.D Global Climate Change

Cross-Cutting Concepts

2. Cause and Effect: Mechanism and Explanation

Examples of how students engage with the standards:

Go to Next Generation Science Standards.

Additional Resources

Explore background information and content extensions related to Lab 3.

Content Extension

Use EarthViewer to investigate changes in CO₂, atmospheric composition, temperature, biodiversity, day length, and solar luminosity over the billions of years of Earth's history. This interactive is available as a free APP on iPhone and Android and is online.
The CarbonTracker tool can be used to develop time series graphs for methane, carbon isotopes and other greenhouse gases.
ESRL Global Monitoring Division - Global Greenhouse Gas Reference Network
Excellent animation of History of atm CO₂ from 800,000 years ago until January 2016

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