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Finding the Carbon in Sugar

Author(s): Nancy P. Moreno, PhD, Barbara Z. Tharp, MS, and Judith Dresden, MS.

Finding the Carbon in Sugar

All living things are made out of molecules containing carbon. Plants take in carbon as carbon dioxide from the air. During photosynthesis, plants make energy-rich molecules, such as sugars, that have carbon as a backbone. Plants and all other organisms use these simple molecules to provide energy and raw materials to manufacture other substances necessary for life. We can see the evidence of the carbon in sugar as a black residue that appears when the sugar begins to burn. 

The formula for table sugar (sucrose) is: C12H22O11

The objectives of this activity are aligned with the National Science Education Standards, specifically those related to Science as Inquiry and Physical Science. Finding the Carbon in Sugar uses guided inquiry to illustrate how fire combines fuel with oxygen in a reaction that releases energy in the form of light and heat. Students will learn about combustion and energy by observing a burning candle in a sealed jar and the burning of white sugar. They will observe, measure, predict, record observations, infer, and draw conclusions based on their investigation.


  • Burning, or combustion, takes place when a fuel combines rapidly with oxygen. This is a chemical change. 
  • When something burns, carbon dioxide (CO2), water, and other substances are released.  
  • Fuels made from living materials contain carbon.

Student Worksheets

Student pages in the teacher’s guide are provided in English and in Spanish.

Funded by the following grant(s)

National Institute of Environmental Health Sciences, NIH

National Institute of Environmental Health Sciences, NIH

My Health My World: National Dissemination
Grant Number: 5R25ES009259
The Environment as a Context for Opportunities in Schools
Grant Number: 5R25ES010698, R25ES06932

Houston Endowment Inc.

Foundations for the Future: Capitalizing on Technology to Promote Equity, Access and Quality in Elementary Science Education