Watch how a single case multiplies exponentially, and how vaccinations safely flatten the curve before the system collapses.
Moving beyond a single tank, we can chain stocks together to watch how populations move from one state to another. The SIR (Susceptible, Infected, Recovered) model maps the flow of a virus through a connected society.
Because the infection rate relies on both infected and susceptible people colliding, we get a fascinating, delayed wave effect.
The source tank of uninfected individuals. As this drains, the virus runs out of fuel.
A reinforcing loop driven by the contact rate. More infections lead to faster spread.
The final tank. As people recover (or get vaccinated), they break the chain of transmission.
Try this: Drag the
Infectivityhigher. Watch the peak of the Infected tank spike aggressively, overwhelming the system before burning out.Try this: Increase the
Vaccination_Fraction. Notice how it bypasses the dangerous Infected tank entirely, safely draining the susceptible pool straight into recovery.
While the SIR model burns through its fuel and eventually stops, biological systems in the wild often stabilize into eternal, repeating cycles.
Let's look at what happens when the "infected" pool needs the "susceptible" pool to survive long-term.