Link to Model
How to Open
First, click the link above. Then, you have two options. You can either click on the button labeled "Play" if you only want to run the model and view the simulation in a bigger screen, or "Design" to mess around with the simulation properties and shapes. For our purposes 'Design' will be more useful.How to Run
To run the model, click the button with the play symbol on it (rotated triangle). You can adjust the speed of the model by moving the scroll bar closer to the turtle (slower) or rabbit (faster). To move the model forward by a single timestep, press the button that looks like a play button next to a bar.How to Change Parameters
You can change the parameters of the model by clicking on the button that looks like a gear. A popup menu should appear and then you click on "Show Simulation Properties." Another popup should appear and then you can change the values of the variables. Adjusting base chance and death chance will control the rate of how fast the spread or death happens. Adjusting the north-south or east-west wind variables will change the direction of the "wind" in the model.
Screenshots
Without Wind, Base Chance 50%, Death Chance 25%
With Wind, Base Chance 50%, Death Chance 25%
You can observe some trends with both the progression screenshots. First of all, the model with all default variables, no wind, will behave like a forest fire- healthy trees next to burning trees are affected by nearest-neighbour burning and therefore a general 'diamond' spread will form. Generally, the fires will expand from the center and eventually cover the entire world. Now, taking a look at the wind model, the fires will generally spread in the direction you set the wind variable to. In this model, healthy trees are more likely to be left behind in the world's sight because of the fire's uneven spread.
The difference in trends affects the shape of both model's graphs. The model without wind will follow an interesting pattern - the number of healthy trees and burnt trees seem to be related, as one increases, the other decreases, like an inverse relationship. They are both curved, slowly changing at the start and endpoints of the model, and rapidly changing in the middle part, as time increases. This follows the observed behaviors as described before, as well as the burning trees having a spike where the change is happening.