Biology: Carbon Cycle

The atoms and molecules on the Earth cycle among living and nonliving components of the biosphere. In this activity, we are going to look at the importance of Carbon and the Carbon Cycle. 

In the carbon cycle, matter and energy flow through the system and chemical elements are recombined in different ways.  This is important to sustain life on earth. 

For long term space travel, we need to think about life support.  To live, we need a couple of basic things, air to breathe, water to drink and energy to survive.  On Earth, this is provided in a cycle between photosynthesis in plants and respiration in animals or in this case, the human animal. This is still the carbon cycle.

Astronauts on the International Space Station (ISS) have grown and eaten plants from a small garden on board.  The astronauts do breathe out carbon dioxide and make water through sweat and urine that is filtered and provided to the plants and themselves. But there are not currently enough plants on the ISS to have a full natural exchange. This means additional food is provided to the astronauts on the ISS and filtration systems assist in air filtration and oxygen production.


  • Go to:
  • Read the story “Can You Follow the Carbon Atom?” and as a carbon atom, choose your path at the end of each page.
  • Document your journey on the Carbon Story Journal Table. You can use the one provided or draw your own table.  Make at least 5 entries.
  • On another sheet of paper, draw your journey.
  • Now think about living on the ISS or on a Lunar or Mars habitat. Think about the importance of the carbon cycle on living things.  What parts of the cycle are most important to you as an astronaut for survival? Draw this space habitat carbon cycle. 

To earn your badge:

Share a photo of your Carbon Story Journal Table and your 2 drawings.