What is Compartmental models (SIR)?

A compartmental model, like the SIR model, is a way to understand how germs spread through a group of people, just like when you and your friends get sick at camp.

Imagine you're playing with your best friends in a big room. At first, everyone is healthy, we'll call them the Susceptible group. But then one person gets a cold, that's the Infected group. They start sneezing all over the place, and soon others catch it too.

Now, after a few days, some people get better, they're no longer sick, so we move them to the Recovered group. That’s where the name SIR comes from: Susceptible, Infected, Recovered.

It's like watching how germs travel through a classroom, some kids are still healthy (Susceptible), some are coughing and sneezing (Infected), and others are finally resting after being sick (Recovered).

This model helps grown-ups predict how many people might get sick, so they can prepare for things like flu season or even a big outbreak.