The Spread of a Cold -- Applet Only

The applet below is a simulation of one possible model for the spread of a cold.

The left side of the applet above shows 100 students. They are colored a pale salmon color to indicate they are all susceptible to the cold that is about to arrive at their school. You can start the cold by clicking anyplace in the applet above. When you do so, five students will be infected by the cold and will turn a sickly pale green. They don't have any symptoms when they are first infected but they are contagious. The students will come in contact with each other randomly and each time an infected person comes in contact with a susceptible one there is some possibility that the susceptible one will catch the cold and turn a sickly pale green. After one day each infected student develops symptoms and turns a dark green. After a few days each infected student recovers and becomes immune to a repeat infection. As the students on the left become infected, spread the cold, develop symptoms, and recover, the three graphs at the right keep track of how many are susceptible, how many are infected, and how many have recovered and are now immune. The simulation in this applet lasts 30 days.

If you haven't already done so, click on the applet above to see this simulation. Click on it several times to see several different simulations. They will be somewhat different because there is a large element of chance involved in which students come in contact with each other and whether contacts result in the transmission of the cold.