• Fire

    Grade: 3rd to 5th, 6th to 8th, High School

    Choose a starting place for a wildfire and enter the probability that it will spread; then, watch the results as the fire weaves through the forest or burns itself out.



    • Select a probability from the drop-down menu, or enter a custom probability in the box. If you enter a probability, it must be a value between 0 and 1.
    • Choose Burn Uninterrupted to watch the fire spread rapidly. Choose Burn Step-by-Step to see the fire progress more slowly.
      • If the Step-by-Step option is selected, you can advance the fire by clicking the Step Through Fire button below the forest.
    • Click on any tree in the forest to begin the fire. (The Highlight Center Tree button will show the tree in the exact middle of the forest.)
      • After a fire has burned, you can choose an unburned tree to start another fire, or you can choose Re-Grow Forest to restore all of the trees.
    • The Results box will display the percent of the forest that burned. It will also say how many iterations were required for the fire to burn out.


    Use this tool to simulate a fire in a densely populated forest.

    The probability indicates the likelihood of a tree catching on fire, given that an adjacent tree is on fire. Investigate the results for various probabilities.

    • What portion of the forest is destroyed?
    • How does the probability relate to the number of trees that burn?

    Objectives and Standards

    NCTM Standards and Expectations
    • Algebra
    • Probability / Data Analysis and Statistics
    • 3-5
    • 6-8
    • High School (9-12)
    • Algebra
    • Data Analysis and Probability