This is a model of a forest fire made using JavaScript. There are a few different variables that can affect the movement of the fire. You can change how fast the model runs using the 'speed of model' slider bar. The burn rate slider bar will increase or decrease the chance of a tree catching on fire when next to a burning tree. Finally, the density slider bar will change the chance of a spot being a tree versus being a pile of dirt. As you may know, a pile of dirt cannot catch on fire as it is fire retardant dirt. So the lower the density, the less trees there will be and the fire will not be able to spread. The blue circle represents the wind's direction. Changing the direction of the wind, will cause the fire to move in that direction. The graph at the bottom monitors the amount of the different types of trees.
To use this program, you set the slider bars to the settings that you want, then press regrow forest, which will set your specifications. Then click any of the trees and the fire will start.