MiddleSchoolPortal/What Goes Around Comes Around: Carbon Cycle

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What Goes Around Comes Around:The Carbon Cycle - Introduction

This is the first publication in our series called What Goes Around Comes Around. The second publication covers the topic of the water cycle and the third, nitrogen cycle.

What goes around, goes around, goes around; Comes all the way back around.
—Justin Timberlake

The lyrics, like typical representations of nature’s cycles, oversimplify rather complex relationships. Elementary students often successfully memorize and repeat back the stages in cycles, with no deep conceptual understanding of the complexities of the processes involved. Their ability to synthesize knowledge of the cycles with a wider breadth of information related to real-world, unresolved environmental issues such as global warming, greenhouse gas emissions or the burning of biomass for fuel is probably less well developed.



Here we assume students are familiar with the carbon cycle, but their knowledge of carbon and carbon compound properties is assumed to be limited. Thus, we start with what students already know of the the carbon cycle sequence, back up from there to study the carbon atom and carbon compound properties, and then jump forward to carbon-related environmental issues that render the cycle not so picture perfectly cyclical after all.

In order to be fully prepared to engage in meaningful discussions of carbon-related environmental issues, students also need an understanding of the changing nature of the earth’s atmosphere. The relative proportion of nitrogen, carbon dioxide, oxygen, ozone and other gases is neither consistent around the world nor constant over time. What factors contribute to the variability in atmospheric content? Which of those factors are naturally occurring and which are augmented by human activity? Which of the factors should be controlled? What are the possible approaches to controlling them? Which are most feasible? What are the possible and probable outcomes of such controlling measures?

Resources provided in this publication will allow you to facilitate your students’ application of carbon, carbon compounds, and carbon cycle knowledge to real environmental issues. In this way they apply knowledge, analyze issues, synthesize concepts, and evaluate proposed solutions.

(Perhaps clips from the DVD An Inconvenient Truth can be your hook to engage students and begin your exploration of the carbon cycle. A class debate might serve as a summative assessment. See Mrs. Sunda's Debate Lessons for comprehensive information on managing student debate on topics including global warming.)

Background Information for Teachers

Frequently, instruction on the carbon cycle begins with an illustration showing the paths of carbon movement on earth and implying a rather simple concept. This approach assumes students know what carbon is, why it is important, and how it behaves. As you probably know from experience, this is usually not a safe assumption.

Trillions of living organisms representing an incomprehensible quantity of biomass have come and gone on this planet over the past several millions of years. How is it that the carbon on this planet has not been completely consumed? How do living things use carbon? What are the physical and chemical properties of carbon and some of its compounds both within and outside of living things? The resources provided here are intended to complement your content knowledge and provide you with additional contexts in which the carbon cycle is conceptually important.

First, take a look at the grades 6-8 Conservation of Matter map shown below, from the NSDL Strand Map Service. These maps illustrate connections between concepts and across grade levels. Clicking on a concept within the maps will show NSDL resources relevant to the concept, as well as information about related AAAS Project 2061 Benchmarks and National Science Education Standards. Move the pink box in the lower right hand corner of the page to see the grades 6-8 learning goals. Additional related maps are Use of Earth's Resources, Flow of Matter in Ecosystems and Energy Resources.

WebElements Periodic Table Click on carbon to get extensive information about the element and its compounds. A Scholar Edition, aimed at students, is also included.

Cell Biology Animation A detailed cell biology tutorial, created by graphic artist/biologist John Kyrk, will refresh your knowledge of respiration and photosynthesis and the complementary nature of the two processes involving carbon compounds. From here you can decide the level of detailed understanding you want your students to acquire and modify your instruction appropriately.

Global Change Instructional Modules This site supplies a good breadth and depth of information regarding earth systems. Note that the carbon cycle does not happen in a vacuum, but that other cycles are occurring concurrently. This awareness will enable you to avoid developing misconceptions in your students while focusing your teaching on the carbon cycle. Modules include biogeochemical cycles, biological consequences of climate change, human energy use, population growth, international environmental law, and stratospheric ozone depletion.

LEARN: Atmospheric Science Explorers This module was created by teachers. The seven sections include introductions to the atmosphere, climate, ozone, stratospheric ozone and tropospheric ozone, the greenhouse effect, and global climate change. Each section provides background information, general learning concepts, and a list of classroom activities.

Biomass: Energy from Wood, Garbage, and Agricultural Waste This resource explores renewable energy from biomass and how human activities intersect with the carbon cycle. Biomass fuels include wood, wood waste, straw, manure, sugar cane, and many other byproducts from agricultural processes.

Ethanol-Blended Fuels This free 61-page booklet in pdf form provides five teaching modules dealing with ethanol. You may choose to extract specific sections and adapt them for your particular teaching goals.

Lessons and Activities on the Carbon Cycle

This section is rather brief, as we assume middle school students have already been introduced to the carbon cycle. The resources here allow for efficient reviews of the cycle's highlights before moving on to the more complex environmental issues affecting the carbon cycle balance.

What Is the Carbon Cycle? Students articulate and illustrate their conceptions of the movement of a carbon atom on earth. After some class discussion and exposure to more sophisticated representations of the carbon cycle, students modify their own.

Observe an Animation Showing Evidence of the Carbon Cycle In this visual resource, students are presented with an animation and accompanying text that focus on carbon and plants. The text addresses how plants fit into the larger carbon cycle, including how carbon enters and leaves the biosphere, and it explains what students are viewing in the animation. The animation shows false color images on a flat map of the world. When the viewer clicks on the image (or the play button), the animation plays, and color patterns reveal changes in plant growth on land and water over a three-year period. Movie controls allow students to pause the animation, to replay the animation, or to move backward or forward through the images one month at a time.

Lessons and Activities Related to the Greenhouse Effect

Lessons and activities in this section will allow your students to begin connecting knowledge of carbon and carbon compound properties to environmental issues. The resources enable student development of deeper conceptual understanding of the science involved in hot-button issues, which in turn positions students to participate in meaningful discussions regarding carbon-related environmental issues.

The Habitable Planet: Interactive Carbon labs These labs are actually simulations which allow the learner to explore 1) the effects of burning variable amounts of fossil fuel on the atmosphere, 2) impacts on the ozone layer, and 3) human activities such as deforestation.

The Greenhouse Effect In this hands-on activity, students model the greenhouse effect, gaining an understanding of the physical factors that contribute to it.

Arctic Meltdown This radio broadcast conveys the story of an entrepreneur/explorer who was able to sail the North West Passage, which historically has always been icebound, indicating climate change. He was prompted to fund scientific research into global climate change as a result of this experience. This may provide an example for your students of how nonscientists can react to and become involved in scientific issues.

Lessons and Activities Related to Biofuels

The two sites below lend themselves to a WebQuest of your making. Different versions of your WebQuest might be distributed to students so that each student may learn something no one else did, creating opportunities for peer teaching and collaboration.

Biomass Biomass is defined, and students are presented with examples of biomass sources that can supply energy. Information is also provided about the benefits, limitations, and geographical considerations of using biomass. A sidebar offers links to other articles and information on the site that relate to biomass as an energy source. Three of these articles discuss the use of oat hulls, recycled French fries grease, and burnt switch grass as fuel. The article also provides annotated links to external materials about topics such as ethanol, biomass statistics, and the storage of excess carbon dioxide at the bottom of the ocean.

Latest Science News from the New York Times

NYT > Carbon Dioxide

News about Carbon Dioxide, including commentary and archival articles published in The New York Times.

NYT > Hydrocarbons

News about Hydrocarbons, including commentary and archival articles published in The New York Times.

SMARTR: Virtual Learning Experiences for Students

Visit our student site SMARTR to find related science-focused virtual learning experiences for your students! The SMARTR learning experiences were designed both for and by middle school aged students. Students from around the country participated in every stage of SMARTR’s development and each of the learning experiences includes multimedia content including videos, simulations, games and virtual activities.


The FunWorks Visit the FunWorks STEM career website to learn more about a variety of science-related careers (click on the Science link at the bottom of the home page).

National Science Education Standards

The variety of resources presented in this publication connects to the breadth of content standards in the National Science Education Standards.

Science as Inquiry: Content Standard A

As a result of activities in grades 5-8, all students should develop:

  • Understandings about scientific inquiry

Recognize and Analyze Alternative Explanations and Predictions. Students should develop the ability to listen to and respect the explanations proposed by other students. They should remain open to and acknowledge different ideas and explanations, be able to accept the skepticism of others, and consider alternative explanations.

  • Scientific explanations emphasize evidence, have logically consistent arguments, and use scientific principles, models, and theories. The scientific community accepts and uses such explanations until displaced by better scientific ones. When such displacement occurs, science advances.
  • Science advances through legitimate skepticism. Asking questions and querying other scientists' explanations is part of scientific inquiry. Scientists evaluate the explanations proposed by other scientists by examining evidence, comparing evidence, identifying faulty reasoning, pointing out statements that go beyond the evidence, and suggesting alternative explanations for the same observations.

Physical Science: Content Standard B

As a result of their activities in grades 5-8, all students should develop an understanding of:

  • Properties and changes of properties in matter
  • Substances react chemically in characteristic ways with other substances to form new substances (compounds) with different characteristic properties. In chemical reactions, the total mass is conserved. Substances often are placed in categories or groups if they react in similar ways; metals is an example of such a group.

Life Science: Content Standard C

As a result of their activities in grades 5-8, all students should develop understanding of:

  • Structure and function in living systems
  • Cells carry on the many functions needed to sustain life. They grow and divide, thereby producing more cells. This requires that they take in nutrients, which they use to provide energy for the work that cells do and to make the materials that a cell or an organism needs.

Science and Technology: Content Standard E

As a result of activities in grades 5-8, all students should develop:

  • Understandings about science and technology
  • Perfectly designed solutions do not exist. All technological solutions have trade-offs, such as safety, cost, efficiency, and appearance. Engineers often build in back-up systems to provide safety. Risk is part of living in a highly technological world. Reducing risk often results in new technology.
  • Technological designs have constraints. Some constraints are unavoidable, for example, properties of materials, or effects of weather and friction; other constraints limit choices in the design, for example, environmental protection, human safety, and aesthetics.
  • Technological solutions have intended benefits and unintended consequences. Some consequences can be predicted, others cannot.

Science in Personal and Social Perspectives: Content Standard F

As a result of activities in grades 5-8, all students should develop understanding of:

  • Populations, resources, and environments
  • Science and technology in society
  • Natural environments may contain substances (for example, radon and lead) that are harmful to human beings. Maintaining environmental health involves establishing or monitoring quality standards related to use of soil, water, and air.
  • When an area becomes overpopulated, the environment will become degraded due to the increased use of resources.
  • Causes of environmental degradation and resource depletion vary from region to region and from country to country.
  • Human activities also can induce hazards through resource acquisition, urban growth, land-use decisions, and waste disposal. Such activities can accelerate many natural changes.
  • Science influences society through its knowledge and world view. Scientific knowledge and the procedures used by scientists influence the way many individuals in society think about themselves, others, and the environment. The effect of science on society is neither entirely beneficial nor entirely detrimental. (See Content Standard E (grades 5-8))
  • Societal challenges often inspire questions for scientific research, and social priorities often influence research priorities through the availability of funding for research.
  • Technology influences society through its products and processes. Technology influences the quality of life and the ways people act and interact. Technological changes are often accompanied by social, political, and economic changes that can be beneficial or detrimental to individuals and to society. Social needs, attitudes, and values influence the direction of technological development.
  • Science cannot answer all questions and technology cannot solve all human problems or meet all human needs. Students should understand the difference between scientific and other questions. They should appreciate what science and technology can reasonably contribute to society and what they cannot do. For example, new technologies often will decrease some risks and increase others.

Read the entire National Science Education Standards online for free or register to download the free PDF. The content standards are found in Chapter 6.

Author and Copyright

Mary LeFever is a resource specialist for the Middle School Portal 2: Math & Science Pathways project, a doctoral candidate in science education at Ohio State University, and presently teaches high school biology. She has taught middle school science, biology and natural sciences at Columbus State Community College.

Please email any comments to Connect with colleagues at our social network for middle school math and science teachers at

Copyright July 2007 - The Ohio State University. Last updated September 19, 2010. This material is based upon work supported by the National Science Foundation under Grant No. 0424671 and since September 1, 2009 Grant No. 0840824. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.