text: Otto von Guericke performed the Magdeburg experiment. He created the Magdeburg hemispheres, which were a pair of large copper hemispheres precisely cast so that their rims fit tightly together. When the rims were sealed with grease and the air was pumped out, the resulting sphere contained the world's first artificial vacuum. \n\nGuericke's most famous performance (the Magdeburg Experiment) was carried out on 8 May 1654 before the Emperor Ferdinand III, and attracted crowds from all over Saxony. Before the emperor and a large crowd, Guericke greased the rims of the two hemispheres and carefully fitted them together. Then the local blacksmith began vigorously pumping the air from inside the sealed copper globe. After a while he was joined by his assistants, as the cranking of the pump gradually became more and more laborious.\n\nThe crowd then watched as a team of eight horses harnessed together was led into the square and attached to one hemisphere of the copper globe. Another team of eight horses was then attached to the other hemisphere. At a signal from Guericke, the two teams of horses strained forward in opposite directions, attempting to pull the two hemispheres apart, but no matter how hard they pulled, the horses could not separate the spheres. Guericke told the crowd that all that was holding the hemispheres together was the pressure of the air surrounding them. The vacuum inside the globe meant there was no opposing pressure to balance this great outer force. They were held firmly together by the air pressure of the surrounding atmosphere.\n\nClick on the link below, which shows an illustration of the fantastic experiment.\n\nhttp://www.tau.ac.il/~phchlab/experiments/vacuum/MAGDEB-S.gif\n\nHope this helps!