Magdeburg Sphere
Principle Illustrated: Force of pressure differentials
Otto von Guericke, Mayor of Magdeburg, Inventor
of vacuum pump
In 1654, in a famous series of experiments that were performed before Emperor
Ferdinand III at Regensburg, Guericke placed two copper bowls (Magdeburg
hemispheres) together to form a hollow sphere about 35.5 cm (14 inches) in
diameter. After he had removed the air from the sphere, horses were unable
to pull the bowls apart, even though they were held together only by the
air around them. Thus the tremendous force that air pressure exerts was first
demononstrated.
Our 5 inch sphere is vacuumed out using a hand-pump
and then sealed with a stopcock.
This demo can be found in cabinet D on shelf 4 of the UCSD PUL Demo Room
(WLH 2015).