Lightning
Here we have a population of particles bouncing around inside a circle. In addition there is a “lightning storm” with one strike every second at a random place inside the circle. Any particle that is within a fixed distance δ of the strike produces an “offspring” that immediately become a new particle and goes off in a random direction. That’s how the population grows.
We ask the students whether this growth is exponential and if so, to find the theoretical equation for the population size.
Workshop
For a more in depth activity click for Lightning Workshop.