[sorry for a way-too-quick write up – I was really excited to share these ideas with the boys and wrote it all up super fast before heading off to work this morning ]

Last Friday I saw a great presentation by Bill Rand about agent based modeling. One of the examples he shared was the “simple economy” simulation in NetLogo. You can find that simulation here:

NetLogo’s “Simple Economy” simulation

The idea was “new to me” and I thought it would be fun to share with the boys when I got back from the conference. The set up of the problem is definitely something that kids can understand:

You start with 500 people who each have $100. At each step of the simulation each person gives $1 to another person selected at random. How does the distribution of the money evolve over time?

Here’s how I introduced the problem to the boys – the really fun thing is they both guessed that there would eventually be a few people with lots of money and people with little amounts of money. They way my younger son reasoned through how the distribution would evolve was really fun to hear.

Now we went to the NetLogo website and ran the simulation:

At the end of the last video the simulation had run about 4,000 steps. We let it keep running to get a better sense of what would happen, and while it was running in the background I explained a modification to the problem that we’d look at next.

The modification is at each step a player will give away 1% of their wealth rather than $1. Here’s what the boys thought would happen in this new game:

Before jumping in to the next simulation we went back and looked at the prior simulation which had now run roughly 10,000 steps. After we discussed what had happened with the prior simulation I showed the boys how to modify the code to produce the new simulation:

Finally, we wrapped up the project by looking at the modified simulation:

This project was really fun to share with the boys. After we finished they played with a few more built in examples – flocking birds and one with bacteria spreading. I hope to share more of these examples with the boys in the next few weeks!