Biology Portal

This model provides an introduction to the agent-based modeling of chemical reactions, rates and equilibrium by reproducing the Party Hat Chemistry Classroom Activity in the form of an AgentSheets applet.

In the classroom activity, each student is given a die, a party hat and a rule sheet. The hat represents a chemical transformation, so students can be in either the "hat off" or "hat on" state. The rules might say something like, "If you roll a 1 or a 2, put your hat on." On each time-step (turn) the class rolls their dice and uses the rules to determine what to do.

To get started using AgentSheets applets, view the introduction to AgentSheets applets. This link assumes that you already have some familiarity with with running the AgentSheets application.

In the applet below, if you open the Simulation Properties Editor you will see a number of parameters that are chances or counts. Counts are simply keeping track of how many agents are in each state. These values are plotted on a chart titled "Reaction Progress" (which will open when you take a time-step). Chance properties reflect the number of rolls of the die that will cause you to take an action. For example if the "hat_on_chance" property is 2, this is equivalent to the rule above that says, "If you roll a 1 or a 2, put your hat on." There are some other properties that keep track of how many times transformation events occur, which are plotted on the "Conversions" chart. Finally there is a property called "diffusion", if you set it to 1 (or any positive value) your simulation will start to act a little more like a chemical reaction.

When you run the model for the first time click the "Step-Forward" button once. It is the button to the right of the "Run" button. This will cause two plot windows to open. Move the plot windows off to the side so that you can see the whole worksheet and the plot windows at the same time.

More detailed instructions on using this model can be found in the Model Guide, which you can download at the bottom of this page.