3 ms·

Computing Partial Differential Equations with Water

110 points by Phithagoras 8y ago

fernly 8y ago
In Sir Terry Pratchett's novel _Making Money_ there is a hydraulic analog computer used to model the economy of Ankh-Morpork[1]. Sounds very much as if Pratchett might have heard of this Russian one. However according to that article, the Glooper was in fact modeled after another hydraulic analog computer, the MONIAC[2]. [1] http://wiki.lspace.org/mediawiki/Glooper http://wiki.lspace.org/mediawiki/Glooper [2] https://en.wikipedia.org/wiki/MONIAC https://en.wikipedia.org/wiki/MONIAC
- andreareina 8y ago
  Not only was the Glooper used to model the economy, in typical Discworld fashion it came to actually mirror the economy, such that manipulating the Glooper would cause the same changes in the economy!
jgamman 8y ago
you can see the moniac running if you happen to be in wellington on the first(?) friday of the month. there's a refurbished one in the foyer of the reserve bank (invented by a NZer - while employed in another country of course).
- regularfry 8y ago
  I might be misremembering, but I'm pretty sure the one in the Science Museum in London runs, too.
motohagiography 8y ago
A more in depth version of this article that covers more examples: http://hplusmagazine.com/2013/05/10/gardens-as-crypto-water-computers/ http://hplusmagazine.com/2013/05/10/gardens-as-crypto-water-...
fredley 8y ago
The University of Cambridge has a Phillips machine that works, if you're lucky it's even possible to get a demonstration. Here's a video of a demo given in 2010: https://sms.cam.ac.uk/media/1094078 https://sms.cam.ac.uk/media/1094078 One interesting thing is that by attaching markers to the floats, and turning spools of paper on motors, it's possible for the machine to draw graphs as it operates.
Aardwolf 8y ago
Only partially off topic: I like the picture "Etienne Dupérac's bird's-eye plan view of the gardens at Villa d'Este, Tivoli" in the article, and (other than the fact that it can be seen as a giant water computer) specifically those multiple maze gardens in there. The fact that there are multiple maze gardens in there makes me think that maybe this was not as a cool attraction, but with the actual purpose of someone being able to walk all the way to the center of it, sit there with a book or so and have some actual peace and quiet time without too much disturbance of others? That's quite different from todays always connected world :)
jws 8y ago
More model than computer, but from 1939 to 1972 there was a water driven model of the Mississippi River basin used to solve the flood models. It covered 200 acres (a little less than 1 square kilometer) and was useful until computers replaced it. https://en.m.wikipedia.org/wiki/Mississippi_River_Basin_Model https://en.m.wikipedia.org/wiki/Mississippi_River_Basin_Mode... It is unmaintained but is now a park and can be visited.

110 points by Phithagoras 8y ago

In Sir Terry Pratchett's novel _Making Money_ there is a hydraulic analog computer used to model the economy of Ankh-Morpork[1]. Sounds very much as if Pratchett might have heard of this Russian one. However according to that article, the Glooper was in fact modeled after another hydraulic analog computer, the MONIAC[2]. [1] http://wiki.lspace.org/mediawiki/Glooper http://wiki.lspace.org/mediawiki/Glooper [2] https://en.wikipedia.org/wiki/MONIAC https://en.wikipedia.org/wiki/MONIAC

andreareina 8y ago
Not only was the Glooper used to model the economy, in typical Discworld fashion it came to actually mirror the economy, such that manipulating the Glooper would cause the same changes in the economy!

jgamman 8y ago

you can see the moniac running if you happen to be in wellington on the first(?) friday of the month. there's a refurbished one in the foyer of the reserve bank (invented by a NZer - while employed in another country of course).

regularfry 8y ago
I might be misremembering, but I'm pretty sure the one in the Science Museum in London runs, too.

motohagiography 8y ago

A more in depth version of this article that covers more examples: http://hplusmagazine.com/2013/05/10/gardens-as-crypto-water-computers/ http://hplusmagazine.com/2013/05/10/gardens-as-crypto-water-...

fredley 8y ago

The University of Cambridge has a Phillips machine that works, if you're lucky it's even possible to get a demonstration. Here's a video of a demo given in 2010: https://sms.cam.ac.uk/media/1094078 https://sms.cam.ac.uk/media/1094078 One interesting thing is that by attaching markers to the floats, and turning spools of paper on motors, it's possible for the machine to draw graphs as it operates.

Aardwolf 8y ago

Only partially off topic: I like the picture "Etienne Dupérac's bird's-eye plan view of the gardens at Villa d'Este, Tivoli" in the article, and (other than the fact that it can be seen as a giant water computer) specifically those multiple maze gardens in there. The fact that there are multiple maze gardens in there makes me think that maybe this was not as a cool attraction, but with the actual purpose of someone being able to walk all the way to the center of it, sit there with a book or so and have some actual peace and quiet time without too much disturbance of others? That's quite different from todays always connected world :)

jws 8y ago

More model than computer, but from 1939 to 1972 there was a water driven model of the Mississippi River basin used to solve the flood models. It covered 200 acres (a little less than 1 square kilometer) and was useful until computers replaced it. https://en.m.wikipedia.org/wiki/Mississippi_River_Basin_Model https://en.m.wikipedia.org/wiki/Mississippi_River_Basin_Mode... It is unmaintained but is now a park and can be visited.