Steven Strogatz has a
intriguing column in the NY Times about a 1950s era “hydraulic computer,” which modelled the operation of a national economy using fluids flowing through a machine. As the water circulates it fills or empties tanks, trips levers, and occasionally plots a graph of the level of a particular tank through time. For example, when a tank called “Minimum Working Balance” fills up, it begins overflowing into a stream called “Income.” (Click to enlarge.) The thing has a series of input points where you can change something (modelling an external input of some kind) and see what happens as a result.
The commenters seem to focus on how charmingly obsolete the thing is, but my first reaction was: What a great teaching tool! Someone should create working online model of it, complete with all the rushing and gurgling sounds, that we can all play with on our laptops.
In a democracy, the greatest threat to national security is public ignorance. The same is true of a democratically governed city. That’s why as a transit planner, I’ve come to view explaining what I do as one of the most important parts of my job.
Continue Reading →