Cartesian Diver featuring Makerbot's AQUABOT

Print and assemble this cartesian diver, named after famed French philosopher, mathematician and scientist Rene Descartes.
Demonstrating the mechanics of buoyancy and the ideal gas law, this toy has fascinated young and old for hundreds of years.
In addition to your printed parts the only materials you'll need is a balloon, an empty large soda bottle and some glue.
The only tools you'll need are a bowl, some sandpaper and some scissors.
It makes and entertaining and attractive demons