Skip Navigation

Button that takes you back to the home page. Button that takes you to the teacher pages. Button that takes you to the modules and activities page. Button that takes you to the glossary page. Button that takes you to the related links page. Button that takes you to the references page. Button that takes you to the Problem Based Learning model page. Image map of some Yellowstone Fires puzzle pieces.  Please have someone assist you with this.

Button that takes you to the Combustion page.
Button that takes you to the Ignition page.
Image that says Fuel.

Image of Earth System Science Education Alliance logo that links to the Earth System Science page.

Image of Earth's Spheres logo that links to the Earth's Spheres page.

 

Fire Science: Fuel
The substance that is ignited and burned during the process of combustion is called a fuel. Fuels contain carbon (C) and hydrogen (H). Trees and other vegetation are fuels for wildland fires. These plants absorb carbon dioxide (CO2) from the atmosphere and produce sugars (C6H12O6) that contain C and H, as well as oxygen (O). This process is called photosynthesis. There are two main steps to photosynthesis. First, plants trap the sun's light energy in a compound called chlorophyll. Then, plants use the energy to produce sugar (C6H12O6). The process of photosynthesis requires water (H2O). Photosynthesis also produces water, as well as oxygen (O2). The net chemical reaction for the process of photosynthesis is:

Image showing the net chemical reaction for the process of photosynthesis.  Please have someone assist you with this.

When fuels react with oxygen (O2) in the air during burning, carbon dioxide (CO2) and water (H2O) are produced. Combustible (burnable) gases such as carbon monoxide (CO), hydrogen (H), and methane (CH4) are also produced. Energy is released in the form of heat and light. This process is called combustion.

A similar process occurs inside plants and animals. It is called respiration. Inside plant and animal tissue, sugars (fuel) are broken down to release the stored energy. The energy is needed by the organism to perform life functions (cell growth, heart beat, etc.). During this process, carbon dioxide is released to the atmosphere. The net chemical reaction for respiration is nearly the exact opposite of photosynthesis:

Image showing the net chemical reaction for the process of respiration.  Please have someone assist you with this.

Flammability is the term used to describe how easily a fuel burns. In other words, flammability is how easily a fuel ignites and how quickly the flames spread to nearby fuel. Many factors determine the flammability of fuel. For example, the flammability of fuel in a forest--trees and grasses--can vary from season to season. During some seasons, forests experience low temperatures and large amounts of precipitation. These conditions keep the vegetation cool and moist and decrease their flammability. That is to say, the vegetation become less likely to ignite and burn. However, seasons of high temperatures and little precipitation can reduce the amount of moisture in the forest fuels and increase their flammability. This allows them to burn more quickly and intensely once ignited.

Combustion ..|.. Ignition ..|.. Fuel
Glossary  |  Related Links  |  References |  PBL Model 

 Home  |  Teacher Pages  |  Modules & Activities

Button that takes you back to the Yellowstone Fires main page.

HTML code by Chris Kreger
Maintained by ETE Team
Last updated April 28, 2005

Some images © 2004 www.clipart.com

Privacy Statement and Copyright © 1997-2004 by Wheeling Jesuit University/NASA-supported Classroom of the Future. All rights reserved.

Center for Educational Technologies, Circuit Board/Apple graphic logo, and COTF Classroom of the Future logo are registered trademarks of Wheeling Jesuit University.