1. Have students read the Windows to the Universe page entitled The Carbon Cycle.
2. Introduction: Ask students to (based of the reading) list the places where carbon is found on Earth. As a class, brainstorm why carbon is important and why carbon is sometimes hazardous.
3. Tell students that for this online interactive game, they are all playing the role of carbon atoms. They will travel through the carbon cycle. If you are going to have students do one or more of the assessment items listed below, tell students to take notes about where they traveled during the game.
4. Post-game discussion questions:
   • How many stops can you make on your trip?
   • Will your journey ever end?
   • Was everyone’s journey the same? Why not?
   • What would happen if we burned more fossil fuels?

SUGGESTED ASSESSMENTS:

• Students write a paragraph about their trip through the carbon cycle. Include information about (1) where they went, and (2) how they got to each destination.
• Students create a "map" documenting their journey through the carbon cycle.

SUGGESTED EXTENSION ACTIVITIES:

• Classroom Activity: Carbon Dioxide Sources and Sinks
• Classroom Activity: Traveling Nitrogen Game

BACKGROUND INFORMATION:

Carbon is the 12th element in the periodic table. It is able to combine with a large variety of other elements and as such it is found in some very different places within the Earth system. Living things, including plants and animals, are made of carbon and the depend of carbon for nutrition. Carbon is also an important component in bones, sea shells, and chemical sedimentary rocks like limestone. Carbon can dissolve in water. In the atmosphere, carbon forms a greenhouse gas called carbon dioxide. Carbon continually moves through these parts of the Earth system. This is called the carbon cycle.

The carbon cycle is one of the biogeochemical cycles. Other biogeochemical cycles include the water cycle and the nitrogen cycle. In biogeochemical cycles, elements are transported between the atmosphere, biosphere (living things), hydrosphere (water) and geosphere (rocks, minerals, and soils). Thus, these cycles are excellent examples for teaching about Earth as a system. The basic construction of these cycles allows middle school students to explore the connections between living and non-living parts of the Earth system. Please note that in-depth understanding of these cycles will require understanding of chemistry and is more appropriate at the high school level.

The six locations along the online game board "map" (atmosphere, plants, soils, shallow ocean, deep ocean, and marine life) are called carbon reservoirs or carbon pools. These are places where carbon is stored in the cycle. You may wish to review the characteristics of these six items before students begin playing the game. Links to Windows to the Universe content pages about these areas are provided within the game and are also provided in the list below.

In this interactive game, students assume the identify of carbon atoms that are released into the atmosphere when fossil fuels are burned. It is important to review with students that all carbon, even the carbon that is sequestered deep underground in limestone rocks, coal, and fossil fuels, is part of the carbon cycle. These reservoirs, often known as deep carbon sinks, remove carbon from circulation through other parts of the carbon cycle for such long amounts of time that they are sometimes considered an extension of the carbon cycle called the "slow carbon cycle". For simplicity, the deep carbon sinks have been omitted from this interactive, however they are a very important part of the long-term cycle. While it may only take your students 10-20 minutes to complete their journey as a carbon atom through this interactive game, it can take actual carbon atoms millions of years to make it to all the reservoirs in the carbon cycle.

RELATED CONTENT FROM WINDOWS TO THE UNIVERSE

• Carbon and the Carbon Cycle
  • The Carbon Cycle
  • The Carbon Cycle Changes
  • Carbon Dioxide
  • What Is "Carbon Neutral"?
• Climate and Climate Change
  • Effects of Climate Change
  • Earth's Greenhouse Gases
  • The Greenhouse Effect
  • Climate and Global Change
• Carbon Reservoirs
  • Plants and Photosynthesis and Respiration
  • Earth's Atmosphere
  • Oceans and Seas
  • Deep Waters of the Ocean
  • Marine Life

OTHER USEFUL WEB RESOURCES

• Carbon Calculator
• NCAR Kids' Crossing: Living in the Greenhouse
• Kids' Crossing in the Classroom: A Guide for Educators
• UCAR: Our Research
• Project LEARN
• Climate Discovery Teacher's Guide