In this model, students are modeling the spread of HIV through the bloodstream. Each of the triangles are called 'turtles' and each colored turtle represents a different type of cell or virus in the bloodstream. In this model, students chose to label the red turtles as red blood cells, white turtles as white blood cells, blue turtles as the HIV virus, and green turtles as white blood cells that have been infected by the virus.
Students were able to determine through research that the virus attaches itself to the white blood cells and use this as a method to reproduce. From each white blood cell that is affected, multiple viruses are reproduced. The red blood cells are a way of modeling the bloodstream, and simply reproduce. The number of infected white blood cells decrease, which causes less immunity to other diseases.
Students also decided to take into account the life of each type of turtle in the model, including birth rates and death rates. They made sliderbars for these factors in order to let the user determine what would happen if these factors were changed.
As the model runs for a time, the students model each step of the process through the oxygen outflow from the red blood cells. This oxygen is what allows all cells to reproduce, including the infected white blood cells which produce more viruses. So when your model begins flashing red, don't fret! It is simply another step of the model.
The 'setup' button allows the user to begin the experiment over again. The 'go' button allows the user to start the model after setup. Now, it is your time to view and experiment with the model.
Because this model is an applet, you must have a java plugin for your computer. We're sorry for any inconviences this may cause.