July 2012
Beginner
176 pages
7h 48m
English

REMAKING HISTORY
Make an impressively effective low-tech vacuum pump.
In the spring of 1654, German scientist Otto von Guericke staged a dramatic demonstration of his new invention, the vacuum pump. Guericke was the mayor (Bürgermeister) of Magdeburg, and he arranged for a public demonstration in the town square. Two teams of 15 horses would try to pull apart two 20"-diameter metal hemispheres.
The hemispheres were not bolted, welded, glued, or otherwise mechanically connected to one another. Instead, the air inside the sphere had been evacuated by means of ...