Otto von Guericke
Otto von Guericke (originally spelled Gericke) (born November 20, 1602 in Magdeburg, Germany, died November 11, 1686 in Hamburg, Germany, both dates according to the Julian calendar, according to the Gregorian calendar they are November 30 and November 21) was a Germany scientist, inventor, and politician (mayor of Magdeburg from 1646 to 1676).
His major scientific achievement was the establishment of the physics of vacuums. He invented the pisten air pump to produce a vacuum and investigated the properties of the vacuum in many experiments.
He demonstrated the force of air pressure with dramatic experiments, e.g. in 1663 at the court of Friedrich Wilhelm I of Brandenburg. Guericke had joined two copper hemispheres of 51 cm diameter (Magdeburg hemispheres) and pumped the air out of the enclosure. Then he harnessed a team of eight horses to each hemisphere and showed that they were not able to separate the hemishperes. When air was again let into the enclosure, they were easily separated. He repeated this demonstration in Berlin in 1663 with 24 horses.
With his experiments Guericke disproved the hypothesis of "horror vacui", that nature abhors a vacuum, that for centuries was a problem for philosophers and scientists. Guericke proved that substances were not pulled by a vacuum, but were pushed by the pressure of the surrounding fluids.
Guericke applied the barometer to weather prediction and thus prepared the way for meteorology.
His later works focussed on electricity, but little is preserved of his results. He invented the first electrostatic generator, the Magdeburg is named after him (
